RAWR PDF - Human Anatomy Chapter 1

A4 CHAPTER 1 REMEMBERING AND UNDERSTANDING 1. Define anatomy, surface anatomy, anatomical imaging, and physiology. - Anatomy is a scientific discipline that deals with the structure of the body, how it functions, and how it works or relates to one another. One of the ways to examine...

A4 CHAPTER 1 REMEMBERING AND UNDERSTANDING 1. Define anatomy, surface anatomy, anatomical imaging, and physiology. - Anatomy is a scientific discipline that deals with the structure of the body, how it functions, and how it works or relates to one another. One of the ways to examine internal structures of a living person is the surface anatomy. Surface anatomy focuses on the surface or external part of the body which are used by the health professionals as landmarks for locating structures in the body. The other way is anatomical imaging. The process involves capturing the body with a technology, such as x-rays, which makes it easier to examine body structures that cannot be seen by our naked eye. On the other hand, Physiology is a scientific discipline that focuses on the functions of living things and it recognizes body structures as dynamic, meaning constantly changing. 2. List six structural levels at which the body can be studied. - Chemical Level - Cell level - Tissue level - Organ level - Organ system level - Organism level 3. Define tissue. What are the four primary tissue types? - Tissue is a collection of similar cells and the materials around them. The way these cells and surrounding materials are made up, decides how the tissue works and what it does. These tissues are classified into four primary types, namely: epithelial, connective, muscle, and nervous tissue. 4. Define organ and organ system. What are the eleven organ systems of the body and their functions? - An organ is made up of two or more types of tissues that work together to do specific functions. A group of organs that work together to carry a common function is called the organ system. The eleven organs systems of the body are: 1. Integumentary - protects and covers the body which helps regulate body temperature 2. Skeletal - this is the body’s structure and support, which allows movement, production of body cells, and storing of minerals. 3. Muscular - facilitates movement, maintains posture and produces body heat. 4. Nervous - this controls and coordinates body activities and intellectual functions. 5. Endocrine - emit hormones that influence metabolism, growth, and many other functions. 6. Cardiovascular - circulates blood and transports nutrients, waste products, gases and hormones throughout the body. 7. Lymphatic - supports immune function by removing foreign substances from the blood and lymph and maintains fluid balance. 8. Respiratory - facilitates breathing and gas exchange. 9. Digestive - processes and absorbs nutrients.  10. Urinary - removes waste products from the blood and regulates pH level, ion and water balance. 11. Reproductive - enables the creation of offspring. 5. Name six characteristics of life. - The six characteristics of life are organization, metabolism, responsiveness, growth, development, reproduction. 6. What does the term homeostasis mean? If a deviation from homeostasis occurs, what kind of mechanism restores homeostasis? - Homeostasis, “homeo” - the same, “stasis” - to stop, is the maintenance or balancing of a variable or an environment within the body around an ideal normal value, it does not keep variables of the body exactly at a precise value but within range. If a deviation from homeostasis occurs, the body uses mechanisms such as negative and positive feedback to restore homeostasis. 7. Describe a negative-feedback mechanism in terms of receptor, control center, and effector. Give an example of a negative-feedback mechanism in the body. - A negative-feedback mechanism operates by reducing the deviation from a set point to maintain homeostasis. It involves three main components: a receptor, a control center, and an effector. The receptor monitors the value of a variable by detecting changes in the environment. For instance, receptors in the skin monitor body temperature. The control center determines the set point for the variable and receives input from the receptor. It compares the current value to the set point to decide if a response is necessary. If a response is needed, the control center stimulates the effectors, such as sweat glands, to produce a response that adjusts the variable back toward the set point. In the case of rising body temperature, the sweat glands are activated to secrete sweat, which helps cool the body. Once the body temperature returns to the normal range, the effectors stop their activity, which is the sign of negative feedback—it does not prevent variation but maintains it within a normal range. 8. Define positive feedback. Why are positive-feedback mechanisms generally harmful? Give one example each of a harmful and a beneficial positive-feedback mechanism in the body. - Positive feedback occurs when a response to an original stimulus causes a deviation from the set point to increase further. In other words, the response amplifies the change instead of the other way around. Positive-feedback mechanisms are generally harmful because they can lead to a dangerous cycle where the deviation from homeostasis becomes increasingly severe, potentially resulting in a life-threatening situation. During severe blood loss, the heart receives insufficient blood, leading to decreased blood pressure. This further reduces the heart's ability to pump blood, causing a continuous cycle of worsening blood flow and pressure, ultimately leading to heart failure and death. On the other hand, during childbirth, the stretching of the uterus triggers uterine contractions, which further increase the  stretching. This cycle continues until the baby is born, at which point the stimulus (stretching) is removed, ending the positive-feedback loop. This process is essential for the delivery of the baby and is a normal and necessary positive-feedback mechanism. 9. Wh y is knowledge of the etymology of anatomical and physiological terms useful? - Knowledge of the etymology of anatomical and physiological terms is useful because it makes the communication easier with the people who are in the same place or position as you - such as people in the medical field. It is just like learning a language of a different country in order to communicate with them or for them to understand you as well. Having this knowledge is like having a whole dictionary in your brain, which you can use when you encounter words associated with these. 10. Describe the anatomical position. Why is it important to remember the anatomical position when using directional terms? - The anatomical position is described as a person standing upright with the face directed forward, upper limbs hanging at the sides, and the palms of the hands facing forward. It is important to remember this when using directional terms because these terms describe parts of the body relative to each other based on this standard position. Regardless of the body's actual orientation, directional terms are defined with reference to the anatomical position. This consistency ensures clear communication when describing the locations and relationships of body structures. 11. Define and give an example of the following directional terms: inferior, superior, anterior, posterior, dorsal, ventral, proximal, distal, lateral, medial, superficial, and deep. - Inferior: Means "below." Example: The feet are inferior to the head. - Superior: Means "above." Example: The head is superior to the feet. - Anterior: Means "in front of." Example: The chest is anterior to the spine. - Posterior: Means "behind." Example: The spine is posterior to the chest. - Dorsal: Another term for "posterior" or "back." Example: The spine is on the dorsal side of the body. - Ventral: Another term for "anterior" or "belly." Example: The belly button is on the ventral side of the body. - Proximal: Means "close to" the point of attachment or origin. Example: The elbow is proximal to the hand. - Distal: Means "far from" the point of attachment or origin. Example: The hand is distal to the elbow. - Lateral: Means "away from the midline." Example: The ears are lateral to the nose.  - Medial: Means "toward the midline." Example: The nose is medial to the ears. - Superficial: Refers to a structure close to the surface of the body. Example: The skin is superficial to the muscles. - Deep: Refers to a structure toward the interior of the body. Example: The bones are deep to the skin. 12. List the subdivisions of the trunk, the upper limbs, and the lower limbs. - Trunk: 1. Thorax (chest cavity containing the heart and lungs) 2. Abdomen (contains organs like the liver, stomach, and intestines) 3. Pelvis (contains the bladder and reproductive organs) - Upper Limbs: 1. Arm (shoulder to elbow) 2. Forearm (elbow to wrist) 3. Wrist 4. Hand - Lower Limbs: 1. Thigh (hip to knee) 2. Leg (knee to ankle) 3. Ankle 4. Foot 13. Describe the four-quadrant and nine-region methods of subdividing the abdomen. What is the purpose of these methods? The abdomen is subdivided into four quadrants by two imaginary lines—one horizontal and one vertical—that intersect at the navel. The quadrants are: 1. Right-upper quadrant 2. Left-upper quadrant 3. Right-lower quadrant 4. Left-lower quadrant The abdomen is subdivided into nine regions using four imaginary lines—two horizontal and two vertical—that create a tic-tac-toe grid. The nine regions are: 1. Epigastric 2. Right hypochondriac 3. Left hypochondriac 4. Umbilical 5. Right lumbar 6. Left lumbar 7. Hypogastric 8. Right iliac 9. Left iliac  - These methods are used by health professionals as reference points to locate and describe the position of underlying organs. For example, they help in identifying the source of pain or pathology, such as determining that pain in the right-lower quadrant might be related to the appendix. 14. Define the sagittal, median, transverse, and frontal planes of the body. - Sagittal Plane - plane that separates the body or a structure into right and left halves. - Median Plane - specific sagittal plane that passes through the midline of the body, dividing it into equal right and left halves. - Transverse (Horizontal) Plane - plane that runs parallel to the ground, dividing the body into superior (upper) and inferior (lower) portions. - Frontal (Coronal) Plane - plane that divides the body into front (anterior) and back (posterior) halves. 15. Define the longitudinal, transverse, and oblique sections of an organ. - Longitudinal Section - cut along the length of an organ, similar to slicing a hot dog bun. - Transverse (Cross) Section - cut that goes completely through an organ, similar to slicing a hot dog or banana into round pieces. - Oblique Section - cut made diagonally across the long axis of an organ. 16. Define the following cavities: thoracic, abdominal, pelvic, and abdominopelvic. What is the mediastinum? - Thoracic Cavityb is located superior to the abdominopelvic cavity and primarily houses the heart and lungs. It is further subdivided into two lateral pleural cavities, each enclosing a lung, and a medial mediastinum, which contains the heart and its major blood vessels, as well as the thymus, trachea, and esophagus. - Abdominal Cavity: This cavity is the superior part of the abdominopelvic cavity and is enclosed by abdominal muscles. It contains the majority of the digestive organs, including the stomach, intestines, and liver, as well as the spleen. - Pelvic Cavity: The pelvic cavity is the inferior part of the abdominopelvic cavity. It lies below the pelvis and contains the urinary bladder, urethra, rectum, and reproductive organs. - Abdominopelvic Cavity: This cavity is a combination of the abdominal and pelvic cavities. It is enclosed by the abdominal muscles and contains organs from both the digestive and reproductive systems. - The mediastinum is a central compartment within the thoracic cavity. It houses the heart and its major blood vessels, the thymus, the trachea, and the esophagus. It separates the two pleural cavities, which each contain a lung. 17. What is the difference between the visceral and parietal layers of a serous membrane? What function do serous membranes perform? - The visceral serous membrane covers the surface of internal organs, while the parietal serous membrane lines the walls of the body cavities. - These membranes reduce friction between moving organs by producing a thin film of serous fluid, allowing the organs to move smoothly within the cavities. 18. Name the serous membranes associated with the heart, lungs, and abdominopelvic Organs. - Heart: The serous membrane is called the pericardium. The parietal layer is the parietal pericardium, and the visceral layer is the visceral pericardium. The space between them is the pericardial cavity filled with pericardial fluid. - Lungs: The serous membrane is called the pleura. The parietal layer is the parietal pleura, and the visceral layer is the visceral pleura. The space between them is the pleural cavity filled with pleural fluid. - Abdominopelvic Organs: The serous membrane is called the peritoneum. The parietal layer is the parietal peritoneum, and the visceral layer is the visceral peritoneum. The space between them is the peritoneal cavity filled with peritoneal fluid. 19. Define mesentery. What does the term retroperitoneal mean? Give an example of a retroperitoneal organ. - Mesentery: A double-folded sheet of visceral peritoneum that attaches the digestive organs to the posterior wall of the abdominopelvic cavity, providing a pathway for nerves and blood vessels. - Retroperitoneal: Refers to organs that are located behind the peritoneum, with peritoneum covering only the side facing the peritoneal cavity. An example of a retroperitoneal organ is the kidney. CRITICAL THINKING 1. A male has lost blood as a result of a gunshot wound. Even though the bleeding has been stopped, his blood pressure is low and dropping, and his heart rate is elevated. Following a blood transfusion, his blood pressure increases and his heart rate decreases. Propose a physiological explanation for these changes. - Before the blood transfusion, the blood loss reduced his blood volume. To make up for this, his body tried to raise his blood pressure by speeding up his heart rate. The idea was that a faster heart rate could help push the remaining blood through the system more efficiently. However, because there wasn’t enough blood to begin with, this effort was not successful. Instead, the heart had to pump harder and faster, but with insufficient blood to fill it, this actually caused the blood pressure to drop further. Essentially, his body’s attempt to increase heart rate and blood pressure ended up creating a harmful cycle, showing a breakdown of normal negative feedback. After receiving a blood transfusion, his blood volume was restored. This allowed his heart to pump more effectively and his blood pressure to rise back to normal levels. With the increased blood volume, the heart didn’t need to work as hard or beat as fast, so his heart rate decreased to a more normal level. The transfusion corrected the initial imbalance and restored the body’s ability to maintain homeostasis. 2. During physical exercise, the respiration rate increases. Two students are discussing the mechanisms involved. Student A claims they are positive-feedback mechanisms, and student B claims they are negative-feedback mechanisms. Do you agree with student A or student B, and why? - I agree with Student B that the mechanisms involved in increasing the respiration rate during physical exercise are negative-feedback mechanisms. Because during physical exercise, your body needs more oxygen and must expel more carbon dioxide. This need is detected by your body’s sensors that monitor level of carbon dioxide and oxygen. When these levels deviate from their set points, your body responds by increasing the respiration rate. This adjustment helps bring the blood levels of these gases back to normal, stabilizing your internal environment. 3. Of the six characteristics of life, why is organismal reproduction a characteristic of life? - Organismal reproduction is a characteristic of life because it ensures the survival of species and enables growth and development. By producing new cells or individuals, reproduction prevents extinction and allows organisms to grow from a single cell into complex forms. This continuous cycle of creating new life supports both the persistence of species and the development of individuals. 4. Describe, using as many directional terms as you can, the relationship between your kneecap and your heel. - The kneecap is superior to the heel. Additionally, the kneecap is anterior to the heel, meaning it is situated toward the front of the body compared to the heel, which is posterior. The heel is inferior to the kneecap, being below it in relation to the body. In terms of proximity, the kneecap is proximal to the heel, as it is closer to the point of attachment of the leg to the body compared to the heel, which is distal. 5. In some traditions, a wedding band is worn closest to the heart, and an engagement ring is worn as a “guard” on the outside. Should a person’s wedding band be worn proximal or distal to the engagement ring? - The wedding band should be worn proximal to the engagement ring. Since the wedding band is worn closer to the heart, it would be positioned proximal to the engagement ring on the finger as it will be the one “guarding” the band, it will defeat the purpose of the engagement ring as a guard if it would be distal. 6. In which quadrant and region would a person experience discomfort in the event of a urinary bladder infection? - In the event of a urinary bladder infection, discomfort would likely be experienced in the hypogastric region, which is the lower central area of the abdomen. This region falls within both the right-lower and left-lower quadrants of the abdomen, as it is located just above the pelvis, where the bladder is situated. 7. During pregnancy, which would increase more in size, the mother’s abdominal cavity or her pelvic cavity? Explain. - During pregnancy, the mother's abdominal cavity would increase more in size than her pelvic cavity. This is because the abdominal cavity is the more superior part of the abdominopelvic cavity and houses the majority of the growing fetus, as well as  the expanding uterus. The pelvic cavity, which is more inferior, contains organs such as the bladder and reproductive organs, but does not expand as significantly. As the pregnancy progresses, the growing uterus pushes upward into the abdominal cavity, leading to its increased size. 8. A bullet enters the left side of a male, passes through the left lung, and lodges in the heart. Name in order the serous membranes and the cavities through which the bullet passes. the order of the serous membranes and the cavities through which the bullet passes is: 1. Parietal pleura 2. Pleural cavity 3. Visceral pleura 4. Pleural cavity 5. Parietal pleura 6. Parietal pericardium 7. Pericardial cavity 8. Visceral pericardium 9. Can a kidney be removed without cutting through the parietal peritoneum? Explain. - Yes, a kidney can be removed without cutting through the parietal peritoneum. The kidneys are located in a retroperitoneal position, meaning they are situated behind the peritoneum, which is the serous membrane lining the abdominal cavity. Because of this positioning, the kidneys are covered by the peritoneum only on their anterior side, and the posterior side is in direct contact with the posterior abdominal wall. Therefore, surgical access to the kidneys can be achieved from the back without the need to cut through the parietal peritoneum. CHAPTER III REMEMBERING AND UNDERSTANDING 1. Define cytoplasm and organelle. - Cytoplasm, enclosed by a cell membrane, is a living material surrounding the nucleus. It contains many types of organelles, which are specialized structures within cells that perform specific functions. 2. List the functions of a cell. - Cell metabolism and energy use - Cells break down nutrients to release energy, which they use to perform tasks like building molecules and moving muscles, and maintain temperature. - Synthesis of molecules - Cells make different important molecules like proteins and fats, which help them function and give them their unique roles. - Communication - Cells send and receive signals to communicate to each other, which helps them work together, like nerves telling muscles to move. - Reproduction and inheritance - Cells carry genetic information that they pass on when they reproduce, ensuring traits are inherited. 3. Describe the structure of the cell membrane. What functions does it perform? - The cell membrane, or plasma membrane, is the outer boundary or layer of the cell, separating the cytoplasmic substances, substances inside the cell, from the extracellular substances, substances outside cell. It supports the cell's contents, acts as a selective barrier that controls what enters and exits the cell, and facilitates communication between cells. The membrane is mainly composed of phospholipids and proteins, with cholesterol and carbohydrates also included. 4. Define solution, solute, solvent, diffusion, and concentration gradient. - Solution: A mixture of solutes, dissolved substances, in a solvent. - Solute: A substance that is dissolved in a solvent within a solution. - Solvent: The liquid or gas in which solutes are dissolved to form a solution. - Diffusion: The movement of solutes from an area of higher concentration to an area of lower concentration in a solution. - Concentration Gradient: The difference in concentration of a solute between two points, with substances naturally moving from high to low concentration areas. 5. How do lipid-soluble molecules, small molecules that are not lipid-soluble, and large molecules that are not lipid-soluble cross the cell membrane? - Lipid-soluble molecules, such as O2, CO2, and steroids, can easily pass through the cell membrane by diffusing directly through the phospholipid bilayer. Small molecules that are not lipid-soluble, like ions, cross the membrane by passing through specific cell membrane channels, which are large protein molecules that allow only certain substances to pass based on their size, shape, and charge. Large molecules that are not lipid-soluble cannot pass through the membrane by diffusion; instead, they require facilitated diffusion, a process involving carrier proteins or channels to move  them across the membrane from areas of higher concentration to lower concentration. 6. Define osmosis and osmotic pressure. - Osmosis is the diffusion of water across a selectively permeable membrane, like the cell membrane, from an area of higher water concentration to an area of lower water concentration. This movement occurs to balance the concentration of solutes on both sides of the membrane, with water moving toward the side with a higher solute concentration. The force required to prevent water from moving across the selectively permeable membrane by osmosis is the osmotic pressure. It reflects the tendency of water to move into a solution with a higher solute concentration. The greater the solute concentration in a solution, the higher its osmotic pressure, therefore, the stronger the force needed to stop the water movement. 7. What happens to cells that are placed in isotonic solutions? In hypertonic or hypotonic solutions? What are crenation and lysis? - When cells are placed in an isotonic solution, the concentration of solutes and water is the same inside and outside the cell. As a result, there is no net movement of water, and the cell remains unchanged in size and shape. In a hypertonic solution, the solution has a higher concentration of solutes and a lower concentration of water compared to the inside of the cell. Water moves out of the cell by osmosis, causing the cell to shrink. This shrinkage of the cell is known as crenation. In a hypotonic solution, the solution has a lower concentration of solutes and a higher concentration of water compared to the inside of the cell. Water moves into the cell by osmosis, causing the cell to swell. If the swelling continues, the cell may burst, a process known as lysis. 8. What is carrier-mediated transport? How are facilitated diffusion and active transport similar, and how are they different? Carrier-Mediated Transport involves the movement of substances across the cell membrane via specific proteins. These proteins, known as carriers or transporters, help substances that cannot easily pass through the phospholipid bilayer to cross the membrane. Facilitated Diffusion and Active Transport are both types of carrier-mediated transport but differ in their processes. They both involve the use of membrane proteins (channels or carriers) to move substances across the cell membrane, and are necessary due to the selective permeability of the cell membrane, helping substances that cannot diffuse directly through the lipid bilayer. Their differences are that facilitated diffusion moves substances from an area of higher concentration to an area of lower concentration, following the concentration gradient, therefore does not require energy. On the other hand, active transport moves substances from an area of lower concentration to an area of higher concentration, against the concentration gradient. This process requires energy in the form of ATP to occur. 9. How does secondary active transport work? Define cotransport and counter transport. - Secondary Active Transport works by first using active transport to create a concentration gradient of one substance, which then drives the movement of another substance across the cell membrane. - Cotransport is when the substance moving down its concentration gradient helps transport another substance in the same direction across the membrane, while the countertransport is when the substance moving down its concentration gradient helps transport another substance in the opposite direction across the membrane. 10. Describe receptor-mediated endocytosis, phagocytosis, pinocytosis, and exocytosis. What do they accomplish? Receptor-mediated endocytosis, phagocytosis, pinocytosis, and exocytosis are processes cells use to transport materials in and out. Receptor-mediated endocytosis is when the cell membrane has specific receptors tha t bind to certain molecules. When these molecules bind to the receptors, the membrane folds inward to form a vesicle, bringing the bound molecules into the cell. Phagocytosis, known as "cell-eating," is the process involving the cell membrane engulfing solid particles, like bacteria or debris, to form a vesicle inside the cell. It’s a way for cells, such as white blood cells, to ingest and destroy harmful substances. Pinocytosis, also called "cell-drinking," involves the cell membrane forming smaller vesicles to take in liquids and dissolved substances. Lastly, exocytosis is the reverse process of endocytosis. It is when a vesicle inside the cell fuses with the cell membrane, releasing its contents outside the cell. This is used for processes like secreting enzymes or mucus. These processes help cells take in necessary materials, remove waste, and release substances needed elsewhere in the body. —--------------------------- 11. Describe the structure of the nucleus and the nuclear envelope. Name the structures in the nucleus, and give their functions. - The nucleus is a large organelle that acts as the control center of the cell. It is enclosed by the nuclear envelope, which consists of an outer and inner membrane separated by a narrow space. The nuclear envelope has nuclear pores that allow materials to move in and out of the nucleus. Inside the nucleus, chromosomes made of DNA and proteins contain the cell's genetic material. These chromosomes are usually in a loosely coiled form known as chromatin when the cell is not dividing. During cell division, the chromosomes become tightly coiled and visible under a microscope. The genes on the chromosomes control the structure and function of the cell by determining the production of proteins. The nucleus also contains one or more nucleoli, which are regions without a surrounding membrane. Nucleoli are involved in producing the subunits of ribosomes, which are essential for protein synthesis. Proteins from the cytoplasm enter the nucleus and combine with ribosomal RNA (rRNA) in the nucleolus to form ribosomal subunits. These subunits then exit the nucleus through the nuclear pores and assemble into functional ribosomes in the cytoplasm, where they play a critical role in protein synthesis. 12. Where are ribosomes assembled, and what kinds of molecules are found in them? - Ribosomes are assembled in the nucleolus within the nucleus. The ribosomes consist of proteins and ribosomal RNA (rRNA) molecules. 13. What is endoplasmic reticulum? Compare the functions of rough and smooth endoplasmic reticulum. - The endoplasmic reticulum (ER) is a network of membranes forming sacs and tubules that extends from the outer nuclear membrane into the cytoplasm. The rough endoplasmic reticulum (rough ER) has ribosomes attached to it and is involved in synthesizing large amounts of protein for export from the cell. The smooth endoplasmic reticulum (smooth ER), which has no ribosomes, is involved in lipid synthesis, detoxification of chemicals within cells, and, in skeletal muscle cells, the storage of calcium ions (Ca2+). 14. Describe the Golgi apparatus, and state its function. - The Golgi apparatus, also known as the Golgi complex, is composed of closely packed stacks of curved, membrane-bound sacs. Its primary function is to collect, modify, package, and distribute proteins and lipids produced by the endoplasmic reticulum (ER). - - For example, proteins made at the ribosomes enter the Golgi apparatus from the ER, where they may undergo chemical modification, such as the attachment of carbohydrate or lipid molecules. The Golgi apparatus then packages these proteins into vesicles, which pinch off from its margins. These vesicles may remain in the cytoplasm as lysosomes, be incorporated into the cell membrane, or function as secretory vesicles. The Golgi apparatus is particularly prominent in cells that secrete proteins, such as those in the salivary glands or the pancreas. 15. Where are secretory vesicles produced? What are their contents, and how are they released? - Secretory vesicles are produced by pinching off from the Golgi apparatus. These vesicles contain materials that need to be transported or stored within cells. The vesicles move to the cell membrane, where they fuse with it and release their contents to the exterior of the cell through a process called exocytosis. Secretory vesicles often accumulate in the cytoplasm and are released when the cell receives a signal, such as the release of neurotransmitters by nerve cells or insulin by pancreatic cells. 16. What are the functions of lysosomes and peroxisomes? - Lysosomes are membrane-bound vesicles formed from the Golgi apparatus and contain enzymes that function as intracellular digestive systems. - They break down extracellular material brought into the cell, such as bacteria phagocytized by white blood cells. Malfunction of lysosomal enzymes can lead to diseases, such as Pompe disease, where glycogen accumulates in cells. - Peroxisomes are small, membrane-bound vesicles containing enzymes that break down fatty acids, amino acids, and hydrogen peroxide (H2O2). The enzymes in peroxisomes convert hydrogen peroxide, a toxic by-product, into water and oxygen, aiding in detoxification processes within cells like liver and kidney cells. 17. Describe the structure and function of mitochondria. - Mitochondria are small organelles with inner and outer membranes separated by a space. The outer membrane is smooth, while the inner membrane is folded into structures called cristae, which project into the mitochondrial matrix. The matrix contains enzymes and mitochondrial DNA (mtDNA). Mitochondria are the main sites of adenosine triphosphate (ATP) production in cells through aerobic respiration, which requires oxygen to break down food molecules. Cells with high energy demands, such as muscle cells, have more mitochondria to meet their energy needs. 18. Name the components of the cytoskeleton, and give their functions. The cytoskeleton is the internal framework of the cell, consisting of three types of protein structures which are; Microtubules - the Hollow structures that support the cytoplasm, assist in cell division, and form components of organelles like cilia and flagella, microfilaments - Small fibrils that support the cytoplasm and determine cell shape. They are also involved in cell movement, such as in muscle cell contraction, lastly, Intermediate filaments - the Fibrils that provide mechanical support to the cell. An example is keratin, which is associated with skin cells. 19. Describe the structure and function of centrioles. - Centrioles are small, cylindrical organelles composed of microtubules arranged in nine triplets. These organelles are located in the centrosome, a specialized area of the cytoplasm near the nucleus. Centrioles are usually oriented perpendicular to each other and play a crucial role in cell division (mitosis) by facilitating the formation of microtubules that organize the mitotic spindle. 20. Describe the structure and function of cilia, flagella, and microvilli. - Cilia are cylindrical projections from the cell surface composed of microtubules organized similarly to centrioles and enclosed by the cell membrane. They can move and are often numerous on the surfaces of cells, such as those lining the respiratory tract. Cilia's coordinated movement helps transport mucus and trapped particles away from the lungs. Flagella are similar in structure to cilia but are much longer and usually present as a single structure per cell. The most common example is the sperm cell, which uses its flagellum to propel itself. Microvilli are small, non-motile projections supported by microfilaments that increase the surface area of cells. They are abundant on cells involved in absorption, such as those lining the intestines and kidneys. 21. Describe how proteins are synthesized and how the structure of DNA determines the structure of proteins. - Proteins are synthesized through a process that involves two main stages, transcription and translation, both of which are directly influenced by the structure of DNA. Transcription is the first step and takes place in the nucleus of the cell. During transcription, a specific segment of DNA unwinds, and the two strands separate. The sequence of nucleotides in one strand of the DNA serves as a template for the  formation of a complementary strand of messenger RNA (mRNA). DNA has four types of nucleotides: thymine (T), adenine (A), cytosine (C), and guanine (G). In mRNA, thymine is replaced by uracil (U). The sequence of DNA nucleotides pairs with the corresponding RNA nucleotides (A with U, T with A, C with G, and G with C) to create the mRNA strand. After the mRNA is synthesized, it leaves the nucleus and carries the genetic information to the ribosomes in the cytoplasm. Translation is the second step and occurs at the ribosomes. The mRNA sequence is read in groups of three nucleotides called codons, with each codon specifying a particular amino acid. The ribosome facilitates the binding of transfer RNA (tRNA) to the mRNA. Each tRNA molecule has an anticodon that pairs with the corresponding codon on the mRNA and carries a specific amino acid. As the ribosome moves along the mRNA, it helps to align the tRNAs so that the amino acids they carry can be linked together, forming a polypeptide chain. This chain folds into a specific three-dimensional structure, which becomes a functional protein. - - Transcription occurs in the nucleus, where a segment of DNA unwinds and separates into two strands. One strand serves as a template to create a complementary mRNA strand, replacing thymine (T) in DNA with uracil (U) in mRNA. After synthesis, the mRNA leaves the nucleus and travels to the ribosomes in the cytoplasm. During translation, the ribosome reads the mRNA in codons (groups of three nucleotides), with each codon specifying an amino acid. Transfer RNA (tRNA) pairs with these codons, bringing the corresponding amino acids. The ribosome links these amino acids together, forming a polypeptide chain that folds into a functional protein. - The structure of DNA determines the structure of proteins because the sequence of nucleotides in DNA dictates the sequence of amino acids in the protein. Any change in the DNA sequence can lead to a change in the mRNA sequence, which can result in the incorporation of a different amino acid, potentially altering the protein's structure and function. Thus, the precise order of nucleotides in DNA is crucial for the accurate synthesis of proteins. 22. Define autosome, sex chromosome, and diploid number. - An autosome is any chromosome that is not a sex chromosome. Humans have 22 pairs of autosomes. - Sex Chromosome: These are the chromosomes that determine the sex of an individual. Humans have two sex chromosomes: X and Y. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). - Diploid Number: The diploid number refers to the total number of chromosomes in a cell. For humans, the diploid number is 46, which includes 23 pairs of chromosomes (22 pairs of autosomes and 1 pair of sex chromosomes). 23. How do the sex chromosomes of males and females differ? - Males have one X and one Y chromosome (XY), while females have two X chromosomes (XX). The Y chromosome carries genes that are crucial for male sex determination and development. 24. Describe what happens during interphase and each stage of mitosis. What kinds of tissues undergo mitosis?  - During Interphase, the cell prepares for division by growing (G1 phase), replicating its DNA (S phase), and preparing the necessary components for mitosis (G2 phase). After that, it will undergo Prophase where chromatin condenses into visible chromosomes, and the nucleolus and nuclear envelope disappear. Spindle fibers begin to form and attach to chromosomes. Then, Metaphase, where Chromosomes align in the center of the cell, regulated by spindle fibers. Then, Anaphase, where Chromatids separate and are pulled to opposite poles of the cell by the spindle fibers. Lastly, Telophase, where Chromosomes begin to untangle, the nuclear envelope reforms, and the cell starts to divide its cytoplasm where two separate daughter cells are produced. Tissues that undergo mitosis include most somatic (body) cells, especially those in areas of growth and repair, such as skin, intestinal lining, and bone marrow. 25. Define cell differentiation. In general terms, how does differentiation occur? - Cell differentiation is the process by which a cell develops specialized structures and functions. Although all cells in an individual have the same DNA, different genes are activated or inactivated in each cell type during differentiation. This selective gene expression leads to the development of various cell types, such as muscle cells, nerve cells, and bone cells, each with specific roles in the body. CRITICAL THINKING 1. The body of a man was found floating in the water of Grand Pacific Bay, which has a salt concentration slightly greater than that of body fluids. When examined during an autopsy, the cells in his lung tissue were clearly swollen. Choose the most logical conclusion and explain your choice. a. He probably drowned in the bay. b. He may have been murdered elsewhere. c. He did not drown. - The presence of swollen cells in the lung tissue suggests he was exposed to a hypotonic solution which causes cells to take in water and swell. Since the Grand Pacific Bay has a salt concentration slightly greater than that of body fluids, making it hypertonic, cells in the lungs would have shrunk if he had drowned there. Therefore, we can eliminate the possibility that he drowned in the bay. Given this information, the most logical conclusion is that he may have drowned in other form of water which is a hypotonic one and was later placed in the bay. The option B is the conclusion that closely aligns with the evidence, though there could be other explanations, such as the man accidentally drowning in a different form of water with hypotonic solution and just being washed into the bay (because as far as I know some bodies of water are connected), so who knows, he would have not been murdered. 2. Patients with kidney failure can be kept alive by dialysis, which removes toxic waste products from the blood. In a dialysis machine, blood flows past one side of a selectively permeable dialysis membrane, and dialysis fluid flows on the other side of the membrane. Small substances, such as ions, glucose, and urea, can pass through the dialysis membrane, but larger substances, such as proteins, cannot. If you wanted to use a dialysis machine to remove only the toxic waste product urea from blood, what could you use for the dialysis fluid? Explain your choice. a. a solution that is isotonic and contains only protein b. a solution that is isotonic and contains the same concentration of substances as blood, except for having no urea in it c. distilled water d. Blood - To remove the toxic waste product urea from the blood using a dialysis machine, the best choice is to use a solution that is isotonic which contains the same concentration of substances as the blood, but with no urea in it. This setup allows urea, which is present in higher concentrations in the blood, to naturally move across the dialysis membrane into the fluid, effectively removing it from the blood. At the same time, the isotonic nature of the fluid ensures that other important substances remain balanced, preventing any unwanted movement of water that could cause blood cells to swell or shrink. 3. Secretory vesicles fuse with the cell membrane to release their contents to the outside of the cell. In this process, the membrane of the secretory vesicle becomes part of the cell membrane. Because small pieces of membrane are continually added to the cell membrane, we would expect the cell membrane to become larger and larger as secretion continues. However, the cell membrane stays the same size. Explain how this happens. - The cell membrane remains the same size despite the continuous addition of membrane pieces from secretory vesicles because there is a balancing process that removes small portions of the membrane at the same rate they are added. This balance between adding new components and removing old ones ensures that the cell membrane maintains a consistent size. - The process that removes small portions of the cell membrane to balance its size is primarily endocytosis. During endocytosis, the cell membrane folds inward to form vesicles that bring materials into the cell, effectively removing sections of the membrane. This process counteracts the addition of membrane material from secretory vesicles, keeping the overall size of the cell membrane constant. 4. Suppose that a cell has the following characteristics: many mitochondria, well- developed rough ER, well-developed Golgi apparatuses, and numerous vesicles. Predict the major function of the cell. Explain how each characteristic supports your prediction. - The cell's major function is likely to produce and export large amounts of proteins. This is supported by the presence of many mitochondria, which provide the energy needed for protein synthesis and transport. The well-developed rough ER is crucial for making proteins, especially those destined for export, while the well-developed Golgi apparatus modifies, packages, and prepares these proteins for release. Numerous vesicles then transport the proteins from the Golgi apparatus to the cell membrane, where they are released outside the cell. These characteristics all work together to efficiently produce, process, and export proteins. 5. The proteins (hemoglobin) in red blood cells normally organize relative to one another, forming “stacks” of proteins that are, in part, responsible for the normal shape of red blood cells. In sickle-cell anemia, proteins inside red blood cells do not stack normally. Consequently, the red blood cells become sickle-shaped and plug up small blood vessels. Sickle-cell anemia is hereditary and results from changing one nucleotide for a different nucleotide within the gene that is responsible for producing the protein. Explain how this change results in an abnormally functioning protein. - A protein is made up of amino acids, and the specific sequence of these amino acids is determined by a gene sequence. In sickle-cell anemia, a single nucleotide change in the gene responsible for producing hemoglobin causes a change in the amino acid sequence. This change happens during the process of transcription, where the gene's nucleotide sequence is transcribed into an mRNA molecule. When the nucleotide is altered, the mRNA sequence changes as well, leading to a different codon. During translation, these codons dictate the amino acid sequence of the protein. A change in the amino acid sequence alters the protein's shape. In the case of sickle-cell anemia, this altered shape prevents hemoglobin from stacking properly, leading to the sickle shape of the red blood cells, which can block small blood vessels which can lead to various health problems. This happens during the process where DNA is copied into a messenger RNA (mRNA) template, which is then used to build the protein. If the DNA has an error, the mRNA carries that error, leading to a different amino acid being added. This changes the shape of the hemoglobin protein. Normally, hemoglobin proteins stack together neatly, helping red blood cells keep their round shape. But with sickle-cell anemia, the misfolded hemoglobin causes the cells to become sickle-shaped, which can block small blood vessels and cause health problems. CHAPTER IV REMEMBERING AND UNDERSTANDING 1. Define tissue and histology. - Tissue is a collection of similar cells and the materials around them. The way these cells and surrounding materials are made up, decides how the tissue works and what it does. These tissues are classified into four primary types, namely: epithelial, connective, muscle, and nervous tissue. The microscopic study of the tissue structure is called histology. 2. In what areas of the body is epithelium located? What are four characteristics of epithelial tissue? - Epithelium is found covering our body surfaces, lining cavities, and forming glands in the body, basically like everywhere. The four characteristics of the epithelial tissue are that it is mostly composed of cells, covers body surfaces, has specialized cell connections and matrix attachments, and is capable of regeneration. 3. Explain how epithelial tissue is classified according to the number of cell layers and the shape of the cells. What are pseudostratified columnar and transitional epithelium? - Epithelial tissue is classified based on two primary characteristics: the number of cell layers and the shape of the cells. The number of cell layers are classified into three, which are; simple epithelium which consists of a single layer of cells, where each cell extends from the basement membrane to the free surface; stratified epithelium which contains more than one layer of cells, with only the deepest layer attaching to the basement membrane; and lastly, pseudostratified columnar epithelium which appears to be stratified but is actually a single layer of cells where all cells are attached to the basement membrane. The illusion of multiple layers occurs because some cells are taller and extend to the free surface, while others are shorter and do not. The shape of the cells are also classified into three, which are; squamous cells which are flat and scalelike; cuboidal cells which are cube-shaped, and about as wide as they are tall; and lastly, columnar cells which are tall and thin, and also resemble columns. Transitional epithelium is a type of stratified epithelium that appears cuboidal when the organ or tube it lines is not stretched and squamous when the organ or tube is stretched. It is found in organs that need to expand, such as the urinary bladder. 4. What kinds of functions does a single layer of epithelium perform? A stratified layer? Give an example of each. - Single layer of epithelium is primarily involved in diffusion, secretion, or absorption. For example, simple squamous epithelium in the alveoli of the lungs allows for the diffusion of gases, oxygen and carbon dioxide, between the air and blood. On the other hand, stratified layer of epithelium provides protection against abrasion and forms barriers. For example, stratified squamous epithelium in the skin protects underlying tissues from physical damage and infection. 5. Contrast the functions performed by squamous cells with those of cuboidal or columnar cells. Give an example of each.  - Squamous cells are flat and thin, making them ideal for diffusion and filtration. For example, simple squamous epithelium in the blood vessels allows for the efficient exchange of gases and nutrients between the blood and surrounding tissues. On the other hand, cuboidal and columnar cells are larger and more robust, making them suited for secretion and absorption. For example, simple cuboidal epithelium in the kidney tubules is involved in the secretion and absorption of substances during the formation of urine and simple columnar epithelium in the intestines absorbs nutrients and secretes digestive enzymes. 6. What is the function of an epithelial free surface that is smooth? of one that has microvilli? of one that has cilia? - Smooth free surface reduces friction between tissues. For example, the smooth surface of the endothelium lining blood vessels minimizes friction as blood flows through the vessel. While microvilli increases surface area to enhance absorption or secretion. For example, microvilli on the epithelial cells of the small intestine increase the surface area for nutrient absorption. And lastly, cilia move substances across the surface of the epithelium. For example, cilia on the epithelial cells of the trachea help move mucus, containing trapped particles, toward the throat to be swallowed and eliminated. 7. Name the ways in which epithelial cells may be connected to one another, and give the function for each way. - The ways in which epithelial cells may be connected to one another are namely; desmosomes which mechanically bind cells together, providing strength in tissues subjected to stress, such as the skin; hemidesmosomes which bind epithelial cells to the basement membrane, ensuring the stability of the epithelium; tight junctions which create a barrier that prevents the passage of materials between cells, found in places like the stomach and bladder where such regulation is crucial, below tight junctions adhesion belts are found which helps it to anchor epithelial cells to each other; and lastly gap junctions which allow intercellular communication by letting ions and small molecules pass between adjacent cells, facilitating coordinated functions, such as in cardiac muscle. 8. Define gland. Distinguish between an exocrine and an endocrine gland. - Gland is a specialized structure composed of epithelial tissue that secretes substances. The two major glands in the body are; exocrine glands which secrete their products through ducts onto an epithelial surface; and endocrine glands which on the other hand, secrete hormones directly into the bloodstream, without the use of ducts. 9. Explain the differences among connective tissue cells that are termed blast, cyte, and clast cells. - Blast cells are immature cells that create the extracellular matrix, while cyte cells are mature cells that maintain the extracellular matrix, and lastly, blast cells are cells that break down the extracellular matrix for remodeling. 10. What are the functions of connective tissues?  - The functions of connective tissues are enclosing and separating tissues, connecting tissues to one another, supporting and moving body parts, storing compounds, cushioning and insulating, transporting substances, and lastly, protecting against toxins and injury. 11. What are the major connective tissue types? How are they used to classify connective tissue? - The major connective tissue types are embryonic and adult connective tissue. And these are classified into; connective tissue proper which includes loose and dense connective tissues, supporting connective tissue which includes cartilage and bone, and fluid connective tissue which includes blood. 12. Describe areolar connective tissue, and give an example. - Areolar connective tissue is a loose connective tissue made of network of collagen and few elastic fibers. It is widely distributed throughout the body, providing support. An example of this is its attachment to the skin and it is also found around organs, blood vessels, and nerves. 13. How is adipose tissue different from other connective tissues? List the functions of adipose tissue. - Adipose tissue differs from other connective tissues by having large cells that store lipids, with very little extracellular matrix. Its functions are storing energy, cushioning and protecting organs, and providing insulation to conserve body heat. - 14. Describe dense collagenous connective tissue and dense elastic connective tissue, and give two examples of each. - Dense collagenous connective tissue are tissues which contain mostly collagen fibers, providing great tensile strength, examples for this are the connective tissues on tendons and ligaments. Dense elastic connective tissue are tissues which contain both collagen and elastic fibers, allowing tissues to stretch and recoil, examples for this are the connective tissues on vocal cords and elastic ligaments between vertebrae. 15. Describe the components of cartilage. Give an example of hyaline cartilage, fibrocartilage, and elastic cartilage. - Components of cartilage are chondrocytes within lacunae, surrounded by an extracellular matrix composed of collagen fibers and proteoglycans. An example for hyaline cartilage, which provides smooth surfaces for joints and flexibility, is articular surface of bones. An example for fibrocartilage, which withstands compression and resists pulling forces, are intervertebral discs. An example for elastic cartilage, which provides flexibility and the ability to recoil is the external part of ear. 16. Describe the components of bone. - Bone is composed of osteocytes, bone cells, located within lacunae, surrounded by a mineralized matrix that provides rigidity. The bone matrix consists of collagen fibers, providing strength, and mineral salts like calcium phosphate, providing hardness. Bone tissue is classified as either spongy, with spaces between trabeculae, or compact, with dense layers of mineralized matrix. 17. Describe the cell types and matrix of blood, and list the functions of blood. - Blood consists of formed elements (cells and cell fragments) suspended in a fluid matrix. The main cell types in blood include red blood cells, erythrocytes, white blood cells, leukocytes, and platelets, thrombocytes. Blood transports oxygen, carbon dioxide, nutrients, hormones, and waste products throughout the body. It also provides protection against infections through white blood cells and plays a role in temperature regulation. 18. Functionally, what is unique about muscle? Which of the muscle types is under voluntary control? What tasks does each type perform? - Muscle tissue is specialized for contraction, allowing movement. This contraction results from the interaction of proteins within muscle fibers. There are three types of muscles which are; skeletal muscle which facilitates body movement and posture, and is also the one under voluntary control; cardiac muscle which pumps blood throughout the body, working involuntarily; and lastly, smooth muscle which controls the size of organs, moves fluids through tubes, and is involved in involuntary processes like digestion and regulating blood vessel diameter. 19. Functionally, what is unique about nervous tissue? What do neurons and glia accomplish? What is the difference between an axon and a dendrite? - Nervous tissue is specialized for communication and control, transmitting electrical signals to coordinate body functions. Neurons conduct electrical signals, process information, and store memories. Glia support and protect neurons, and assist in signal transmission. The difference between axon and a dendrite is that axon transmits signals away from the neuron's cell body while dendrite receives signals and transmits them toward the cell body. 20. Compare mucous and serous membranes according to the type of cavity they line and their secretions. Name the serous membranes associated with the lungs, heart, and abdominopelvic organs. - Mucous membranes line cavities that open to the outside of the body such as digestive, and respiratory tracts. They secrete mucus, which traps particles and protects underlying tissues. While serous membranes line cavities that do not open to the exterior such as pericardial, and pleural cavities. They secrete serous fluid, which reduces friction between organs. The serous membranes associated with lungs are called pleura, with heart are called pericardium and with abdominopelvic organs are called peritoneum. 21. What is the function of the inflammatory response? Name the five symptoms of inflammation, and explain how each is produced. - The inflammatory response is the body's way of protecting itself by isolating and removing harmful agents, promoting healing. The five symptoms of inflammation are; redness which is caused by increased blood flow to the area due to dilated blood vessels; heat which is a result of increased blood flow and metabolic activity at the site; swelling which is due to the accumulation of fluid in the tissues from increased permeability of blood vessels; pain which is caused by the release of chemicals that stimulate nerve endings, and by the pressure from swelling; and lastly, disturbance of  function which are results from pain and swelling that can limit the use of the affected area. 22. Define tissue repair. What is the difference between regeneration and fibrosis? - Tissue Repair is the process of replacing dead or damaged cells with new ones. Regeneration involves the replacement of damaged cells with the same type of cells, restoring normal function, while fibrosis involves the replacement of damaged tissue with scar tissue, which does not restore full function. 23. Describe the process of tissue repair when the edges of a wound are close together versus when they are far apart. - In close edges the wound quickly fills with blood, and a clot forms. The clot forms a scab, and the surrounding epithelium regenerates beneath it. Granulation tissue forms and is eventually replaced by normal connective tissue, with minimal scarring. While in far apart edges, the wound takes longer to heal due to the larger gap. Granulation tissue forms extensively, and wound contraction occurs as fibroblasts pull the edges together. This can lead to more significant scarring and tissue distortion. 24. Describe the effect of aging on cell division and the formation of extracellular matrix. - Cell division slows down with age, leading to delayed healing and reduced production of new cells. While aging in extracellular matrix causes connective tissues to become less flexible and more fragile due to changes in collagen and elastic fibers. This contributes to wrinkles, decreased bone strength, and less elastic blood vessels, making tissues more prone to injury and less capable of repair. CRITICAL THINKING 1. What types of epithelium are likely to be found lining the trachea of a heavy smoker? Predict the changes that are likely to occur after he or she has stopped smoking for 1 or 2 years. - In heavy smokers, the normal pseudostratified ciliated columnar epithelium in the trachea is replaced by stratified squamous epithelium. This change occurs because the stratified squamous epithelium provides better protection against the irritants in smoke, but it lacks cilia and the ability to efficiently remove debris from the airways. After 1 or 2 years of not smoking, the original pseudostratified ciliated columnar epithelium can regenerate, restoring the ability to produce mucus and clear debris from the trachea. 2. The blood-brain barrier is a specialized epithelium, called endothelium, in capillaries that prevents many materials from passing from the blood into the brain. What kind of cell connections would you expect to find in the blood-brain barrier? - In the blood-brain barrier, you would expect to find tight junctions between the endothelial cells. These tight junctions form a highly selective barrier that prevents most substances from passing between the cells, ensuring that only certain essential molecules can enter the brain from the bloodstream. 3. One of the functions of the pancreas is to secrete digestive enzymes that are carried by ducts to the small intestine. How many cell layers and what cell shape, cell surface, and type of cell-to-cell connections would you expect to be present in the epithelium that produces the digestive enzymes? - The epithelium that produces digestive enzymes in the pancreas is typically a simple epithelium, consisting of a single layer of columnar cells. These cells have microvilli on their free surface, which increases the surface area for enzyme secretion. The cells are connected by tight junctions, which help prevent the digestive enzymes from damaging the underlying tissues. 4. Explain the consequences a. if simple columnar epithelium replaced the nonkeratinized stratified squamous epithelium that lines the mouth - If the nonkeratinized stratified squamous epithelium in the mouth were replaced by simple columnar epithelium, the mouth would lose its protection against abrasion. The simple columnar epithelium is not designed to withstand the mechanical stress of chewing and could be easily damaged, leading to increased susceptibility to injury and infection. b. if tendons were composed of dense elastic connective tissue instead of dense collagenous connective tissue - Tendons composed of dense elastic connective tissue would be more flexible but less strong than those made of dense collagenous connective tissue. Tendons need to be strong and resistant to stretching to effectively transmit the force of muscle contractions to bones. If tendons were elastic, they would stretch too much, reducing the efficiency of muscle movements and potentially leading to injury. c. if bones were made entirely of elastic cartilage - If bones were made entirely of elastic cartilage, they would lack the rigidity and strength necessary to support the body and protect vital organs. Elastic cartilage is flexible and resilient, but it cannot provide the structural support that bones do. As a result, the skeleton would not be able to withstand the forces exerted on it, leading to significant functional impairments. (in short they would all lead to injury, so no) 5. Some dense connective tissue has elastic fibers in addition to collagen fibers. This enables a structure to stretch and then recoil to its original shape. Examples are certain ligaments that hold together the vertebrae (bones of the back). When the back is bent (flexed), the ligaments are stretched. How does the elastic nature of these ligaments help the back function? How are the fibers in the ligaments organized? - The elastic fibers in the ligaments of the vertebral column allow the back to bend and then return to its original position, which is essential for maintaining an upright posture. The elastic fibers are organized parallel to the length of the ligaments, providing strength and elasticity in the direction needed to support and move the vertebrae. 6. The aorta is a large blood vessel attached to the heart. When the heart beats, blood is ejected into the aorta, which expands to accept the blood. The wall of the aorta is constructed with dense connective tissue that has elastic fibers. How do you think the fibers are arranged? - The elastic fibers in the wall of the aorta are likely arranged in concentric layers around the vessel. This arrangement allows the aorta to expand as blood is ejected from the heart and then recoil to help maintain blood pressure and ensure smooth blood flow through the circulatory system. 7. Antihistamines block the effect of a chemical mediator, histamine, which is released during the inflammatory response. When could taking an antihistamine be harmful, and when could it be beneficial? - Taking an antihistamine could be harmful if it prevents the body from mounting an effective inflammatory response to fight off an infection or heal an injury, as histamine induced inflammation increases blood flow and white blood cell migration to the affected area. However, antihistamines can be beneficial in reducing the unpleasant symptoms of inflammation, such as in allergic reactions, where the inflammatory response may be excessive or unnecessary. CHAPTER V REMEMBERING AND UNDERSTANDING pgs 284-317 1. Name the components of the integumentary system. - The components of the integumentary system are the skin and accessory structures such as hair, glands, and nails. 2. What kind of tissue is the epidermis? In which stratum of the epidermis are new cells formed? From which stratum are they sloughed? - The epidermis is made of stratified squamous epithelium. New cells are formed in the stratum basale, and they are sloughed off from the stratum corneum. 3. Define keratinization. What structural changes does keratinization produce to make the skin resistant to abrasion and water loss? - Keratinization is the process where cells become filled with keratin, making them rigid and durable. It produces an outer layer of dead cells that resist abrasion and act as a waterproof barrier. 4. What type of tissue is the dermis? What is responsible for its structural strength? How does the dermis supply the epidermis with blood? - The dermis is composed of dense collagenous connective tissue, which provides structural strength through collagen and elastic fibers. The upper part of the dermis which has dermal papillae contain blood vessels that supply nutrients and remove waste from the epidermis. 5. Name the cells that produce melanin. What happens to the melanin after it is produced? What is the function of melanin? - Melanin is produced by cells called melanocytes. After being produced, melanin is packaged into melanosomes and transferred to epithelial cells. Melanin protects the skin from UV radiation. 6. Describe the factors that determine the amount of melanin produced in the skin. - The amount of melanin produced in the skin is determined by genetic factors, exposure to light, and hormonal influences. 7. How do melanin, blood, carotene, and collagen affect skin color? - Melanin contributes to brown to black color, blood circulation gives a reddish hue, carotene provides a yellowish tint, and collagen can scatter light, influencing skin tone. 8. What type of tissue is the subcutaneous tissue, and what are its functions? - The subcutaneous tissue is loose connective tissue that contains adipose tissue. Its functions include attaching the skin to underlying bone and muscle, providing padding and insulation, and supplying the skin with blood vessels and nerves. 9. What is a hair follicle? Define the root, shaft, and hair bulb of a hair. What kinds of cells are found in a hair?  - A hair follicle is an invagination of the epidermis that extends into the dermis, from which hair arises. The root is below the skin's surface, the shaft is the part above the skin, and the hair bulb is the expanded base of the root. The hair consists of epithelial cells. 10. Why is a hair follicle important in the repair of skin? - Hair follicles contain epithelial cells that can divide and serve as a source of new cells to repair the epidermis when damaged. 11. What part of a hair is the site of hair growth? What are the stages of hair growth? - Hair growth occurs in the hair bulb, which is nourished by blood vessels in the hair papilla. Hair grows in cycles with growth and resting stages. During the growth stage, the hair lengthens, and during the resting stage, growth stops and the hair is held in the follicle until the next growth cycle begins. 12. What happens when the arrector pili of the skin contract? - When the arrector pili contract, the hair stands on end, producing a raised area of skin called a "goose bump". 13. What secretion do the sebaceous glands produce? What is the function of the secretion? - Sebaceous glands produce sebum, which are released by holocrine secretion. It functions as an oily substance that lubricates the hair and skin, preventing drying and protecting against bacteria. 14. Which glands of the skin are responsible for cooling the body? Which glands are involved in producing body odor? - Eccrine sweat glands are responsible for cooling the body, while apocrine sweat glands produce the organic substances that result in body odor. 15. Name the parts of a nail. Where are the cells that make up the nail produced, and what kind of cells make up a nail? What is the lunula? Describe nail growth. - The parts of a nail include the nail body, nail root, cuticle, nail bed, and nail matrix, it consists of layers of dead stratum corneum cells that contain a very hard type of keratin. The nail matrix and bed are epithelial tissue with a stratum basale that gives rise to the cells that form the nail. The lunula is the crescent-shaped whitish area at the base of the nail. Nails grow continuously as cells in the nail matrix divide. 16. How do the components of the integumentary system provide protection? - The integumentary system provides protection, the intact skin reduces water loss through lipids, acting as a barrier against microorganisms, and shielding underlying tissues from abrasion. Melanin absorbs harmful ultraviolet light, while hair offers protection by insulating the head and preventing foreign objects from entering sensitive areas like the eyes and nose. Nails protect the tips of fingers and toes from injury. 17. List the types of sensations detected by receptors in the skin. - Sensations detected by receptors in the skin are pain, heat, cold, and pressure. 18. Describe the production of vitamin D by the body. What is the function of vitamin D? - When exposed to ultraviolet light, the skin produces a precursor to vitamin D, which is then modified by the liver and kidneys to become active vitamin D. Its function is to stimulate the small intestine to absorb calcium and phosphate, essential for bone growth and muscle function. 19. How does the integumentary system help regulate body temperature? - The integumentary system helps regulate body temperature by altering blood flow through the skin, transferring heat from deeper tissues to the skin, and sweat production. Increased blood flow releases heat, while sweat cools the body through evaporation. Blood vessel constriction conserves heat in cold environments. 20. Name the substances excreted by skin glands. Is the skin an important site of excretion? - Sweat contains water, salts, urea, uric acid, and ammonia. The skin does not play a significant role in excretion. 21. Why is the skin a useful diagnostic aid? Give three examples of how the skin functions as a diagnostic aid. - The skin can indicate underlying health issues, three examples are; Cyanosis (bluish skin) signals impaired circulatory or respiratory function; Jaundice (yellowish skin) can indicate liver problems; lastly, Rashes/lesions can be symptoms of infections or allergic reactions. 22. Define the different categories of burns. How is repair accomplished after each type? - The different categories of burns are partial-thickness burns, full-thickness burns, and fourth-degree burns. Partial-thickness burns affect either the epidermis alone—also called first-degree burns—which heal within a week with no scarring, or both the epidermis and dermis—also called second-degree burns—which can heal with or without scarring depending on severity. Full-thickness burns, or third-degree burns, extend through the epidermis and dermis, often damaging underlying tissues, which require healing from the edges and may need skin grafts due to significant tissue damage. Fourth-degree burns are even more severe, reaching beyond the subcutaneous tissue to damage muscles and bones; here, amputation or complete removal of the damaged tissue is required. CRITICAL THINKING 1. A woman has stretch marks on her abdomen, yet she states that she has never been pregnant. Is this possible? Explain your conclusion. - Yes, it is possible for a woman who has never been pregnant to have stretch marks on her abdomen. Stretch marks occur when the skin is overstretched due to various factors like rapid growth, obesity, or hormonal changes. These marks are not exclusive to pregnancy and can result from any condition that causes the skin to stretch significantly. 2. It has been several weeks since Tom has competed in a tennis match. After the match, he discovers that a blister has formed beneath an old callus on his foot and the callus has fallen off. When he examines the callus, it appears yellow. Can you explain why? - The yellow appearance of the callus is due to the accumulation of thickened layers of dead skin cells (keratinized cells), which typically become yellowish as they harden. A blister formed beneath the callus because of friction during the tennis match, and the fluid pressure from the blister loosened the callus, causing it to fall off. The yellow color is a sign of the old, toughened skin. 3. The lips are muscular folds forming the anterior boundary of the oral cavity. A mucous membrane covers the lips internally, and the skin of the face covers them externally. The red part of the lips (called the vermillion border) is covered by keratinized epithelium that is a transition between the epithelium of the mucous membrane and the facial skin. The vermillion border can become chapped (dry and cracked), whereas the mucous membrane and the facial skin do not. Propose as many reasons as you can to explain why the vermillion border is more prone to drying than the mucous membrane or the facial skin. - The vermillion border of the lips is more prone to drying than the mucous membrane or facial skin due to; first, the vermillion border lacks sebaceous glands, meaning it does not produce sebum, which normally keeps the skin moisturized. Second, the vermillion border is less keratinized than facial skin, so it has fewer layers of protective cells and lipids. Third, the vermillion border is exposed to the external environment, making it more susceptible to moisture loss compared to the inner mucous membrane, which is kept moist by saliva and mucus. 4. Pulling on hair can be quite painful, but cutting hair is not painful. Explain. - Pulling hair is painful because it stimulates the nerve endings in the hair follicle, which is embedded in the skin and rich in nerve supply. Cutting hair is not painful because hair itself is composed of dead keratinized cells, and there are no nerve endings in the hair shaft. Thus, no pain is felt when cutting hair. 5. Given what you know about the cause of acne, propose some ways to prevent or treat it. - Several methods can help prevent or treat acne such as; using products with antibiotics to kill Propionibacterium acnes, the bacteria responsible for acne, taking medications like isotretinoin to reduce sebum production, using of exfoliating agents, like sulfur compounds, which helps unplug clogged follicles by speeding up skin peeling. 6. Consider the following statement: Dark-skinned children are more susceptible to rickets (insufficient calcium in the bones) than light-skinned children. Defend or refute this statement. - Dark-skinned children are more susceptible to rickets because darker skin contains more melanin, which reduces the skin's ability to produce vitamin D when exposed to sunlight. Since vitamin D is essential for calcium absorption and bone health, dark-skinned individuals living in areas with limited sunlight or without sufficient dietary vitamin D may be at a higher risk of developing rickets. 7. Harry, a light-skinned man, jogs on a cool day. What color would you expect his skin to be (a) after going outside and just before starting to run, (b) during the run, and (c) 5 minutes after the run? - (a) After going outside and before running, his skin would appear pale due to constriction of blood vessels, which conserves body heat in response to the cold. - (b) During the run his skin would turn red as dilation of blood vessels occurs to help release heat generated by the physical activity. - (c) 5 Minutes after the run, his skin would remain red as the body continues to remove excess heat, but the redness would gradually fade as his body temperature normalizes. CHAPTER VI - SKELETAL SYSTEM REMEMBERING AND UNDERSTANDING pgs 320-416 1. What are the primary functions of the skeletal system? - The functions of the skeletal system are: Body support, which provides the rigid structure for supporting soft tissues and maintaining body shape. Organ protection, which encloses and shields organs, e.g., skull for brain, rib cage for heart and lungs. Body movement, as bones act as levers, with joints allowing movement; tendons and ligaments facilitate this by connecting muscles and bones. Mineral storage which stores minerals like calcium and phosphorus, releasing them into the bloodstream as needed. Blood cell production, red bone marrow in certain bones produces blood cells and platelets. 2. Name the major types of fibers and molecules in the extracellular matrix of the skeletal system. How do they contribute to the functions of tendons, ligaments, cartilage, and bones? Major types of fibers and molecules in the extracellular matrix of the skeletal system: - Collagen Fibers: Provide flexibility and tensile strength, essential for tendons, ligaments, and the shock absorption in cartilage. - Proteoglycans: These molecules trap water, making cartilage smooth and resilient. - Hydroxyapatite: A mineral component providing compressive strength to bones. Contribution to the functions of tendons, ligaments, cartilage, and bones: - Tendons and Ligaments: Composed primarily of collagen, providing strength and the ability to resist pulling forces. - Cartilage: Contains collagen and proteoglycans, giving it flexibility and shock-absorbing properties. - Bones: Collagen provides flexible strength, while hydroxyapatite offers compressive strength. 3. Define diaphysis, epiphysis, epiphyseal plate, medullary cavity, articular cartilage, periosteum, and endosteum. - Diaphysis: The central shaft of a long bone, primarily composed of compact bone with a hollow medullary cavity. - Epiphysis: The rounded ends of a long bone, primarily made of spongy bone covered by a thin layer of compact bone. - Epiphyseal Plate: A growth plate of hyaline cartilage between the diaphysis and epiphysis, responsible for bone lengthening during development. - Medullary Cavity: The hollow central cavity in the diaphysis, containing bone marrow (red in children, yellow in adults).  - Articular Cartilage: Hyaline cartilage covering the epiphyses, reducing friction and absorbing shock in joints. - Periosteum: A dense, fibrous membrane covering the outer surface of bones, containing nerves, blood vessels, and osteoblasts. - Endosteum: A thin layer of connective tissue lining the internal surfaces of bones, including the medullary cavity and trabeculae. 4. Describe the structure of compact bone. How do nutrients reach the osteocytes in compact bone? - Osteon/Haversian System: The basic structural unit, consisting of concentric lamellae (rings) surrounding a central canal with blood vessels and nerves. - Lamellae: Layers of bone matrix in the osteon. - Lacunae: Small cavities between lamellae housing osteocytes. - Canaliculi: Tiny channels connecting lacunae, allowing nutrients and waste exchange between osteocytes. - Nutrient Pathway: Nutrients enter through blood vessels in the central canal, pass through the canaliculi to reach osteocytes. 5. Describe the structure of spongy bone. What are trabeculae? How do nutrients reach osteocytes in trabeculae? - Trabeculae: Thin, interconnecting rods or plates of bone, providing structural support with minimal weight. It reduces bone weight while maintaining strength and provides space for marrow. - Nutrient Pathway: Nutrients reach osteocytes through diffusion from the marrow-filled spaces around trabeculae into the canaliculi. 6. Define and describe intramembranous and endochondral ossification. Intramembranous Ossification: - Begins in embryonic connective tissue. - Osteoblasts form bone matrix directly within a fibrous membrane, creating trabeculae. - Occurs in flat bones like the skull and clavicle. Endochondral Ossification: - Begins with a hyaline cartilage model. - Cartilage is progressively replaced by bone tissue. - Forms most of the bones in the body, including long bones like the femur. - Primary ossification starts in the diaphysis; secondary ossification occurs in the epiphyses. 7. How do bones grow in diameter? How do long bones grow in length? - Bone Growth in Diameter: The provided text does not directly address how bones grow in diameter. Generally, bones increase in diameter through a process called appositional growth, where new bone tissue is added to the outer surface by osteoblasts. - Long Bone Growth in Length: Long bones grow in length at the epiphyseal (growth) plates. These plates are regions of cartilage located at the ends of long bones. The cartilage cells multiply and push the epiphysis away from the  diaphysis, lengthening the bone until the cartilage is fully replaced by bone tissue. 8. What is accomplished by bone remodeling? How does bone repair occur? - Bone Remodeling: While the provided text does not specify bone remodeling, this process generally maintains bone strength and mineral balance, replacing old bone tissue with new tissue and allowing the bone to adapt to stress. - Bone Repair: The text doesn't directly describe bone repair. Typically, bone repair involves four stages: hematoma formation, fibrocartilaginous callus formation, bony callus formation, and bone remodeling. It restores bone integrity following a fracture. 9. Define the axial skeleton and the appendicular skeleton. - Axial Skeleton: The provided information primarily covers the axial skeleton, which includes the skull bones (such as the frontal, parietal, occipital, temporal, ethmoid, and sphenoid bones), the vertebral column, and the rib cage. - Appendicular Skeleton: The text does not cover this, but the appendicular skeleton generally includes the bones of the limbs and girdles (shoulder and pelvic bones). 10. Name the bones of the braincase and the face. - Braincase (Cranial Bones): Frontal, the 2 parietal, occipital, the 2 temporal, sphenoid, and ethmoid bones. - Facial Bones: pair of zygomatic bones, pair of maxilla bones, pair of palatine bones, pair of lacrimal bones, pair of nasal bones, mandible, vomer, and pair of inferior nasal conchae. 11. Give the locations of the paranasal sinuses. What are their functions? - Locations of Paranasal Sinuses: Found in the frontal bone, ethmoid bone, sphenoid bone, and maxilla. - Functions: They decrease the weight of the skull and act as resonating chambers when speaking. 12. What is the function of the hard palate? - The hard palate separates the nasal cavity from the mouth, enabling humans to chew and breathe at the same time. 13. Through what foramen does the brain connect to the spinal cord? - The brain connects to the spinal cord through the foramen magnum in the occipital bone. 14. How do the vertebrae protect the spinal cord? Where do spinal nerves exit the vertebral column? - Protection of the Spinal Cord: The vertebrae form a vertebral column that encases and protects the spinal cord. Each vertebra has a central opening, called the vertebral foramen, through which the spinal cord passes. The  series of vertebral foramina create the vertebral canal, providing a bony protective passageway for the spinal cord. - Exit of Spinal Nerves: Spinal nerves exit the vertebral column through openings called intervertebral foramina, which are formed between adjacent vertebrae. These foramina are created by the notches on the pedicles of neighboring vertebrae. 15. Name and give the number of each type of vertebra. Describe the characteristics that distinguish the different types of vertebrae from one another. - Cervical Vertebrae: 7 vertebrae (C1–C7). - Thoracic Vertebrae: 12 vertebrae (T1–T12). - Lumbar Vertebrae: 5 vertebrae (L1–L5). - Sacral Vertebrae: 1 sacrum, formed by the fusion of 5 sacral vertebrae (S1–S5). - Coccygeal Vertebrae: 1 coccyx, formed by the fusion of 4-5 coccygeal vertebrae. Characteristics: Cervical Vertebrae: Small bodies, bifid spinous processes (except C7), transverse foramina in the transverse processes. Thoracic Vertebrae: Medium-sized bodies, long spinous processes that project inferiorly, facets on the bodies and transverse processes for rib attachment. Lumbar Vertebrae: Large bodies, thick and short spinous processes, articular processes oriented for increased stability and weight-bearing. Sacral Vertebrae: Fused to form a triangular-shaped bone, articulates with the hip bones at the sacroiliac joints. Coccygeal Vertebrae:Small, fused vertebrae forming the tailbone, providing minimal function. 16. What is the function of the thoracic cage? Name the parts of the sternum. Distinguish among true, false, and floating ribs. - Function of the Thoracic Cage: Protects vital organs, such as the heart and lungs, and supports the upper limbs. It also plays a role in respiration by aiding in the expansion and contraction of the thoracic cavity. - Parts of the Sternum: - Manubrium: The superior part, articulates with the clavicles and the first two pairs of ribs. - Body: The elongated central part, articulates with ribs 2 through 7. - Xiphoid Process: The small, inferior portion, provides attachment for abdominal muscles. - Types of Ribs: - True Ribs (1-7): Attach directly to the sternum via costal cartilages. - False Ribs (8-10): Attach indirectly to the sternum via the cartilage of the seventh rib. - Floating Ribs (11-12): Do not attach to the sternum at all, end in the posterior abdominal wall. 17. Name the bones that make up the pectoral girdle, arm, forearm, wrist, and hand. How many phalanges are in each finger and in the thumb? - Pectoral Girdle: Bones: Scapula and Clavicle. - Arm: Bone: Humerus. - Forearm: Bones: Radius (lateral) and Ulna (medial). - Wrist: Bones: 8 Carpal bones. - Hand: Bones: a. Metacarpals: 5 bones forming the palm. b. Phalanges: i. Fingers: Each finger (except the thumb) has 3 phalanges: Proximal, Middle, and Distal. ii. Thumb (Pollex): Has 2 phalanges: Proximal and Distal. 18. Define the pelvic girdle. What bones fuse to form each hip bone? Where and with what bones do the hip bones articulate? - Pelvic Girdle: The pelvic girdle is formed by the two hip bones (coxal bones) and the sacrum. It supports the weight of the body, attaches the lower limbs, and protects internal organs. - Bones Fused to Form Each Hip Bone: Ilium: The largest, superior part. Ischium: The posterior, inferior part. Pubis: The anterior part. - Articulations of the Hip Bones: Anteriorly: The two hip bones articulate at the pubic symphysis. Posteriorly: Each hip bone articulates with the sacrum at the sacroiliac joints. Laterally: The acetabulum of each hip bone articulates with the head of the femur to form the hip joint. 19. Name the bones of the thigh, leg, ankle, and foot. - Thigh: Bone: Femur. - Leg: Bones: Tibia (medial) and Fibula (lateral). - Ankle: Bones: The primary bone is the Talus, which articulates with the tibia and fibula. - Foot: Bones: Tarsals: 7 bones (Talus, Calcaneus, Navicular, Medial Cuneiform, Intermediate Cuneiform, Lateral Cuneiform, and Cuboid). Metatarsals: 5 bones.  Phalanges: 14 bones (each toe has 3 phalanges, except the big toe, which has 2). 20. Define joint, or articulation. Name and describe the differences among the three major classes of joints. - A joint, or articulation, is the connection between two bones. Joints are classified structurally as fibrous, cartilaginous, or synovial, depending on the connective tissue that binds the bones and whether there is a fluid-filled joint capsule. Fibrous joints: These joints are connected by fibrous connective tissue, have no joint cavity, and allow little or no movement. Examples include sutures in the skull. Cartilaginous joints: Bones are connected by cartilage, and these joints also allow little or no movement. Examples include synchondroses (hyaline cartilage) and symphyses (fibrocartilage), like the intervertebral discs. Synovial joints: These joints are more complex, containing synovial fluid, and allow significant movement. Most joints in the appendicular skeleton are synovial joints, such as the knee or shoulder. 21. Describe the structure of a synovial joint. How do the different parts of the joint permit joint movement? - A synovial joint consists of: Articular cartilage: Covers the ends of the bones, providing a smooth surface for movement. Joint cavity: A space between the bones filled with synovial fluid, which lubricates the joint and allows smooth movement. Joint capsule: Surrounds the joint, consisting of an outer fibrous layer for strength and an inner synovial membrane that produces synovial fluid. Ligaments and tendons: These support the joint, holding bones together while allowing movement in certain directions. Bursae: Fluid-filled sacs that cushion between tendons and bones. These structures allow free movement in various directions while maintaining joint stability. 22. On what basis are synovial joints classified? Describe the different types of synovial joints, and give examples of each. What movements does each type of joint allow? - Synovial joints are classified based on the shape of the adjoining surfaces and the movement they allow: 1. Plane (gliding) joints: Flat surfaces that allow sliding movement (e.g., joints between vertebrae). 2. Saddle joints: Biaxial, allowing movement in two planes (e.g., thumb joint). 3. Hinge joints: Uniaxial, allowing flexion and extension (e.g., elbow, knee). 4. Pivot joints: Uniaxial, allowing rotational movement (e.g., the joint between the radius and ulna). 5. Ball-and-socket joints: Multiaxial, allowing a wide range of movements (e.g., shoulder, hip).  6. Ellipsoid (condyloid) joints: Biaxial, allowing movement in two axes with limited rotation (e.g., joint between the skull and the first vertebra). 23. Describe and give examples of flexion/extension, abduction/adduction, and supination/pronation. - Flexion: A movement that decreases the angle between two bones (e.g., bending the elbow). - Extension: Increases the angle between two bones (e.g., straightening the knee). - Abduction: Movement away from the midline of the body (e.g., raising arms sideways). - Adduction: Movement toward the midline (e.g., lowering arms back down). - Supination: Rotation of the forearm so the palm faces upward (e.g., turning the hand to hold soup). - Pronation: Rotation of the forearm so the palm faces downward. CRITICAL THINKING 1. A 12-year-old boy fell while playing basketball. The physician explained that the head (epiphysis) of the femur was separated from the shaft (diaphysis). Although the bone was set properly, by the time the boy was 16, it was apparent that the injured lower limb was shorter than the normal one. Explain why this difference occurred. - The epiphysis is the site of new bone growth, as it contains the epiphyseal plate. In this 12-year-old boy’s case, the injury caused a separation between the epiphysis and diaphysis at the epiphyseal plate, which is respons