Basic Medical Sciences-1 (Anatomy and Physiology) PDF

Reading Material for Basic Medical Sciences-1 (Anatomy and Physiology) Compiled By: Punjab Medical Faculty Specialized Healthcare & Medical Education Department PREFACE A two years post matric teaching program of Allied Health Sciences. The foundation of knowledge needs to comment from “THE CELL”. The Cell is structural & functional unit of life and has role in normal homeostasis for appropriate functions. The purpose of this reading material is to provide basic education to the paramedics about Anatomy and Physiology. This reading material attempts to cover almost all the basic theoretical knowledge required by students about Anatomy and Physiology so that they can perform their work better in laboratory, medicine and various departments. i Table of Contents Chapter 1.................................................................................................................................... 1 Introduction to Anatomy............................................................................................................ 1 1.1 The Cytoplasm............................................................................................................ 2 1.2 Cell Cycle.................................................................................................................... 5 1.3 Tissue: Introduction..................................................................................................... 7 Chapter 2.................................................................................................................................. 15 Organ Systems......................................................................................................................... 15 The Circulatory System........................................................................................................... 15 Chapter No. 3........................................................................................................................... 17 The Lymphatic System............................................................................................................ 17 Chapter 4.................................................................................................................................. 19 The Gastrointestinal System.................................................................................................... 19 Chapter 5.................................................................................................................................. 21 The Respiratory System........................................................................................................... 21 5.1 Upper Respiratory Tract:........................................................................................... 21 5.2 Lower Respiratory Tract:.......................................................................................... 22 Chapter 6.................................................................................................................................. 23 The Nervous System................................................................................................................ 23 6.1 Central Nervous System (CNS)................................................................................ 24 6.2 Peripheral Nervous System (PNS)............................................................................ 24 Chapter 7.................................................................................................................................. 29 The Endocrine System............................................................................................................. 29 Chapter 8.................................................................................................................................. 31 Human Skin............................................................................................................................. 31 Chapter 9.................................................................................................................................. 33 The Urinary System................................................................................................................. 33 Chapter 10................................................................................................................................ 35 The Reproductive System........................................................................................................ 35 10.1 The Male Reproductive System................................................................................ 35 10.2 Female Reproductive System:................................................................................... 37 ii Chapter 11................................................................................................................................ 40 Human Skeletal System........................................................................................................... 40 11.1 Overview................................................................................................................... 40 11.2 Structure and Function of Human Skeleton.............................................................. 41 11.3 Gross Anatomy of a Long Bone................................................................................ 42 11.4 Bones of Upper Limb................................................................................................ 43 11.5 Bones of Lower Limb............................................................................................... 45 Chapter 12................................................................................................................................ 50 Joints........................................................................................................................................ 50 Chapter 13................................................................................................................................ 53 The Special Senses................................................................................................................... 53 13.1 Brief Anatomy of Eye............................................................................................... 53 13.2 Brief Anatomy of the Ear.......................................................................................... 54 13.3 Brief Anatomy of Nose:............................................................................................ 55 13.4 Brief Anatomy of Tongue.......................................................................................... 56 Chapter 14................................................................................................................................ 57 Approaches to Studying Anatomy........................................................................................... 57 Chapter 1.................................................................................................................................. 65 Introduction to Physiology....................................................................................................... 65 Cell Membrane (Plasma Membrane)....................................................................................... 65 Endocytosis—Ingestion by the Cell......................................................................................... 74 Cell Division and Reproduction............................................................................................... 75 Chapter 2.................................................................................................................................. 77 Tissues and Fluids of the Body................................................................................................ 77 Tissues...................................................................................................................................... 77 Body Fluids:............................................................................................................................. 82 Chapter 3.................................................................................................................................. 90 Cardiovascular System............................................................................................................. 90 Chapter 4.................................................................................................................................. 95 The Lymphatic System............................................................................................................ 95 Chapter 5.................................................................................................................................. 97 Respiratory System.................................................................................................................. 97 iii The Basic Mechanism of Respiration...................................................................................... 97 Cellular Respiration................................................................................................................. 98 Inspiration and Expiration........................................................................................................ 98 Artificial Respiration and Mouth Breathing.......................................................................... 101 Chapter 6................................................................................................................................ 103 Gastrointestinal System......................................................................................................... 103 Chapter 7................................................................................................................................ 108 Metabolism............................................................................................................................ 108 Chapter 8................................................................................................................................ 114 Endocrine System.................................................................................................................. 114 Chapter 9................................................................................................................................ 120 Reproductive System............................................................................................................. 120 The male reproductive system............................................................................................... 120 Functions of the Female Reproductive System..................................................................... 121 Menstrual Cycle..................................................................................................................... 121 Testosterone and other Male Sex Hormones......................................................................... 122 Chapter 10.............................................................................................................................. 125 Special Senses........................................................................................................................ 125 Chapter 11.............................................................................................................................. 133 Nervous System..................................................................................................................... 133 References.............................................................................................................................. 139 iv Chapter 1 Introduction to Anatomy Anatomy Human anatomy is the study and organization of the structures which make up the human body. There are many ways to study Anatomy. Regional anatomy considers the body as organized into segments or parts. Systemic anatomy sees the body as organized into organ systems. Surface anatomy provides information about structures that may be observed or palpated beneath the skin. Radiographic, sectional, and endoscopic anatomy allows appreciation of structures in the living, as they are affected by muscle tone, body fluids and pressures, and gravity. Clinical anatomy emphasizes application of anatomical knowledge to the practice of medicine. 1 The levels of structural complexity Anatomy encompasses various levels of complexity, from the microscopic level of cells to the macroscopic level of organs and organ systems. 1.1 The Cytoplasm Cells and extracellular material together comprise all the tissues that make up the organs of multicellular animals. In all tissues, cells themselves are the basic structural and functional units, the smallest living parts of the body. Animal cells are eukaryotic (Gr. eu, good, + karyon, nucleus), with distinct membrane-limited nuclei surrounded by cytoplasm containing many different organelles. 2 The main cellular functions performed by specialized cells in the body are listed in Table below: Table 2–1. Cellular functions in some specialized cells Function Specialized Cell(s) Movement Muscle and other contractile cells Form adhesive and tight junctions between cells Epithelial cells Synthesize and secrete components of the Fibroblasts, cells of bone and extracellular matrix cartilage Convert physical and chemical stimuli into action Neurons and sensory cells potentials Synthesis and secretion of enzymes Cells of digestive glands Synthesis and secretion of mucous substances Mucous-gland cells Synthesis and secretion of steroids Some adrenal gland, testis, and ovary cells Ion transport Cells of the kidney and salivary gland ducts Intracellular digestion Macrophages and some white blood cells Lipid storage Fat cells Metabolite absorption Cells lining the intestine Junqueira Basic Histology Cytoplasmic Organelles The cell is composed of two basic parts: cytoplasm and nucleus. The outermost component of the cell, separating the cytoplasm from its extracellular environment, is the plasma membrane (plasmalemma). The plasma, or cell, membrane functions as a selective barrier that regulates the passage of certain materials into and out of the cell and facilitates the transport of specific molecules. The cytoplasm is the part of the cell located outside the nucleus. It contains organelles like mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, and ribosomes. Nucleus The nucleus is a membrane-bound organelle found in eukaryotic cells (cells with a defined nucleus). It contains genetic material, including DNA, and is often referred to as the control center of the cell. The nucleus regulates cellular activities and houses the nucleolus, involved in ribosome production. 3 DNA (Deoxyribonucleic Acid): DNA is a molecule that carries genetic instructions for the development, functioning, growth, and reproduction of all known living organisms. It consists of two long strands forming a double helix, composed of nucleotides with adenine (A), thymine (T), cytosine (C), and guanine (G) bases. DNA is organized into structures called genes, which encode specific proteins. RNA (Ribonucleic Acid): RNA is another type of nucleic acid involved in protein synthesis and various cellular functions. Unlike DNA, RNA is usually single-stranded and contains uracil (U) instead of thymine. There are different types of RNA, including messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). Chromosomes: Chromosomes are structures composed of DNA and proteins found in the cell nucleus. They contain genes and carry hereditary information. Humans typically have 23 pairs of chromosomes (46 in total), with one set inherited from each parent. Mitochondria: Mitochondria are double-membraned organelles found in the cells of most living organisms, including humans. They are often referred to as the "powerhouses of the cell" due to their primary role in energy production. Mitochondria generate adenosine triphosphate (ATP), a molecule that provides energy for various cellular activities. The Endoplasmic reticulum: The endoplasmic reticulum (ER) is a cellular organelle involved in the synthesis, folding, modification, and transport of proteins and lipids. It consists of a network of membranes within the cell and comes in two forms: rough ER, studded with ribosomes on its surface, and smooth ER, lacking ribosomes. The Golgi apparatus: The Golgi apparatus, or Golgi complex, is a cellular organelle responsible for processing, packaging, and distributing molecules within or outside the cell. It consists of flattened membrane-bound sacs called cisternae. Key functions of the Golgi apparatus include modifying and sorting proteins and lipids synthesized in the endoplasmic reticulum (ER). During protein processing, the Golgi apparatus adds molecular tags, such as carbohydrates (glycosylation), and further refines the structure of these molecules. After modification, the Golgi sorts and packages them into vesicles for transport to their final destinations, which could be other cellular organelles or the cell membrane for secretion. 4 Lysosomes: Lysosomes are membrane-bound organelles within cells that contain enzymes responsible for breaking down and digesting cellular waste, damaged organelles, and foreign substances. These enzymes are acidic and work optimally in the acidic environment within lysosomes. Additionally, lysosomes are involved in the degradation of cellular organelles through a process known as autophagy, where damaged or obsolete organelles are engulfed and digested. 1.2 Cell Cycle The cell cycle represents a self-regulated sequence of events that controls cell growth and cell division The development of a single, fertilized egg cell to form a complex, multicellular organism involves cellular replication, growth and progressive specialization (differentiation) for a variety of functions. The fertilized egg (zygote) divides by a process known as mitosis to produce two genetically identical daughter cells, each of which divides to produce two more daughter cells and so on. Some of these daughter cells progressively specialize and eventually produce the terminally differentiated cells of mature tissues, such as muscle or skin cells. Most tissues however retain a population of relatively undifferentiated cells (stem cells) that are able to divide and replace the differentiated cell population as required. The interval between mitotic divisions is known as the cell cycle. All body cells divide by mitosis except for male and female germ cells, which divide by meiosis to produce gametes. Mitosis Mitosis is the process whereby one cell divides, giving rise to two daughter cells that are genetically identical to the parent cell. Each daughter cell receives the complete complement of 46 chromosomes. Before a cell enters mitosis, each chromosome replicates its deoxyribonucleic acid (DNA). During this replication phase chromosomes are extremely long, they are spread diffusely through the nucleus, and they cannot be recognized with the light microscope. With the onset of mitosis, the chromosomes begin to coil, contract, and condense; these events mark the beginning of prophase. Each chromosome now consists of two parallel subunits, chromatids, that are joined at a narrow region common to both called the centromere. Throughout prophase, the chromosomes continue to condense, shorten, and thicken but only at prometaphase do the chromatids become distinguishable. During metaphase, the chromosomes line up in the equatorial plane, and their doubled structure is clearly visible. Each is attached by microtubules extending from the centromere to the centriole, forming the mitotic spindle. 5 Soon, the centromere of each chromosome divides, marking the beginning of anaphase, followed by migration of chromatids to opposite poles of the spindle. Finally, during telophase, chromosomes uncoil and lengthen, the nuclear envelope reforms, and the cytoplasm divides. Each daughter cell receives half of all doubled chromosome material and thus maintains the same number of chromosomes as the mother cell. (fig, 2.3). Meiosis Meiosis is the cell division that takes place in the germ cells to generate male and female gametes, sperm and egg cells, respectively. Meiosis requires two cell divisions, meiosis I and meiosis II, to reduce the number of chromosomes to the haploid number of 23 (Fig. 2.4). As in mitosis, male and female germ cells (spermatocytes and primary oocytes) at the beginning of meiosis I replicate their DNA so that each of the 46 chromosomes is duplicated into sister chromatids. In contrast to mitosis, however, homologous chromosomes then align themselves in pairs, a process called synapsis. The pairing is exact and point for point except for the XY combination. Homologous pairs then separate into two daughter cells, thereby reducing the chromosome number from diploid to haploid. 6 Shortly thereafter, meiosis II separates sister chromatids. Each gamete then contains 23 chromosomes. Difference between Mitosis and Meiosis: Mitosis is a cell division process that results in two identical daughter cells with the same number of chromosomes as the parent cell. It is involved in growth, repair, and maintenance of body tissues. Meiosis, on the other hand, is a specialized cell division process that produces gametes (sperm and egg cells) with half the number of chromosomes. Meiosis involves two rounds of division, resulting in four non-identical daughter cells, each with a unique combination of genetic material 1.3 Tissue: Introduction A human tissue is a group of cells with similar structure and specialized function. Tissues combine to form organs, and organs work together in organ systems. For instance, muscle tissue is composed of muscle cells, and the heart is an organ made up of various tissues, including muscle tissue, connective tissue, and nerve tissue. The human body is composed of only four basic types of tissue: epithelial, connective, muscular, and nervous. These tissues, which are formed by cells and molecules of the extracellular matrix, exist not as isolated units but rather in association with one another and 7 in variable proportions, forming different organs and systems of the body. The main characteristics of these basic types of tissue are shown in Table 4–1. Junqueira Basic Histology Epithelial Tissue: Covers body surfaces and lines organs, serving as a protective barrier. Examples include skin epithelium and the lining of the digestive tract. Here are different epithelial tissue types. Simple Squamous Epithelium: Thin and flat cells that form a single layer, found in areas where diffusion or filtration occurs, such as the lining of blood vessels and air sacs of the lungs. Simple Cuboidal Epithelium: Single layer of cube-shaped cells, often involved in secretion and absorption. Found in kidney tubules and various glands. Simple Columnar Epithelium: Single layer of elongated cells, often with microvilli on the surface, found in the lining of the digestive tract, where absorption and secretion occur. Stratified Squamous Epithelium: Multiple layers of flat cells, providing protection. Found in the skin (epidermis) and lining of the mouth, esophagus, and vagina. Stratified Cuboidal Epithelium: Two or more layers of cube-shaped cells, relatively rare in the human body but found in certain ducts, like in the mammary glands. Stratified Columnar Epithelium: Multiple layers of elongated cells, found in the male urethra and parts of the pharynx. Pseudostratified Columnar Epithelium: Appears stratified as all cells touch the basement membrane but level of nuclei are different. Found in the respiratory tract, where it helps move mucus with cilia. 8 Transitional Epithelium: Specialized for stretching, found in the lining of the urinary bladder, ureters, and urethra. 9 10 Connective Tissue: provides a matrix that supports and physically connects other tissues and cells together to form the organs of the body. Unlike the other tissue types (epithelium, muscle, and nerve), which consist mainly of cells, the major component of connective tissue is the extracellular matrix (ECM). Extracellular matrices consist of different combinations of protein fibers (collagen and elastic fibers) and ground substance Specialized Connective Tissue Adipose Tissue, Cartilage, Bone & Blood 1. Adipose tissue Connective tissue in which fat-storing cells or adipocytes predominates is called adipose tissue. Adipose tissue normally represents 15%-20% of the body weight in men, somewhat more in women, serving as storage depots for neutral fats 2. Cartilage 11 A firm, flexible tissue found in areas like the nose and joints. Types include hyaline, elastic, and fibrocartilage. 3. Bone (Osseous Tissue) The main component of the adult skeleton, bone tissue provides solid support for the body, protects vital organs such as those in the cranial and thoracic cavities, and encloses internal (medullary) cavities containing bone marrow where blood cells are formed. Bone (or osseous) tissue also serves as a reservoir of calcium, phosphate, and other ions that can be released or stored in a controlled fashion to maintain constant concentrations in body fluid Hematopoietic Tissue: Found in the bone marrow and responsible for blood cell formation 4. Blood: Consists of red and white blood cells in a liquid matrix (plasma). It plays a crucial role in transportation and defense. Muscle Tissue: One of the basic tissues, responsible for movement by contracting and relaxing. Three types of muscle tissue can be distinguished on the basis of morphologic and functional characteristics, with the structure of each adapted to its physiologic role. Skeletal muscle contains bundles of very long, multinucleated cells with cross-striations. Their contraction is quick, forceful, and usually under voluntary control. Location: Attached to bones by tendons. Control: Voluntary control. Appearance: Striated (striped) appearance under a microscope. Function: Responsible for body movement, posture, and voluntary actions. 12 Cardiac muscle also has cross-striations and is composed of elongated, often branched cells bound to one another at structures called intercalated discs that are unique to cardiac muscle. Contraction is involuntary, vigorous, and rhythmic. Location: Exclusive to the heart. Control: Involuntary control. Appearance: Striated like skeletal muscle but with branching cells. Function: Contracts to pump blood, exhibits a rhythmic and synchronized contraction Smooth muscle consists of collections of fusiform cells that lack striations and have slow, involuntary contractions. In all types of muscle, contraction is caused by the sliding interaction of thick myosin filaments along thin actin filaments. Location: Found in the walls of internal organs (e.g., stomach, intestines). Control: Involuntary control. Appearance: Non-striated, with spindle-shaped cells. Function: Contracts slowly and rhythmically, regulating the movement of substances within organs. Nervous Tissue: The human nervous system, by far the most complex system in the body, is formed by a network of many billion nerve cells (neurons), all assisted by many more supporting cells called glial cells. Each neuron has hundreds of interconnections with other neurons, forming a very complex system for processing information and generating responses. Nerve tissue is distributed throughout the body as an integrated communications network. Anatomically, the general organization of the nervous system has two major divisions: Central nervous system (CNS), consisting of the brain and spinal cord Peripheral nervous system (PNS), composed of the cranial, spinal, and peripheral nerves conducting impulses to and from the CNS (sensory and motor nerves, respectively) and ganglia that are small aggregates of nerve cells outside the CNS. 13 Cells in both central and peripheral nerve tissue are of two kinds: neurons, which typically have numerous long processes, and various glial cells (Gr. glia, glue), which have short processes, support and protect neurons, and participate in many neural activities, neural nutrition, and defense of cells in the CNS 14 Chapter 2 Organ Systems Organs are structures composed of two or more tissue types, working together to perform specific functions. Organ systems are groups of organs that collaborate to carry out particular physiological functions. Examples include the cardiovascular, respiratory, and digestive systems, excretory system, nervous system etc. Major Organ Systems: Cardiovascular System: Heart, blood vessels, and blood for circulation. Respiratory System: Lungs and airways for breathing. Digestive System: Organs like stomach, intestines, and liver for processing and absorbing nutrients. Nervous System: Brain, spinal cord, and nerves for communication and control. Muscular System: Muscles for movement and support. Skeletal System: Bones and joints for support and protection. Endocrine System: Glands like the thyroid and pancreas for hormone regulation. The Circulatory System The circulatory system, also known as the cardiovascular system, is a complex network of organs and vessels that transport blood, nutrients, oxygen, and waste products throughout the body. Comprising the heart, blood vessels, and blood, this system plays a crucial role in maintaining homeostasis. 1. Heart: The heart, a muscular organ, serves as the central pump of the circulatory system. It is divided into four chambers: two atria (upper chambers) and two ventricles (lower chambers). Deoxygenated blood from the body returns to the right atrium and is pumped to the lungs for oxygenation by the right ventricle. Oxygenated blood from the lungs enters the left atrium and is pumped to the rest of the body by the left ventricle. 2. Blood Vessels: There are three types of blood vessels Arteries: Carry oxygenated blood away from the heart to the body's tissues, except the pulmonary arteries which carry deoxygenated blood from heart to lungs. The largest artery is the aorta. 15 Veins: Transport deoxygenated blood back to the heart, except the pulmonary veins which carry oxygenated blood from lungs to heart. The superior and inferior vena cava are major veins. Capillaries: Microscopic vessels connecting arteries and veins, facilitating the exchange of nutrients and waste products at the tissue level. 3. Blood: Composed of red blood cells (carry oxygen), white blood cells (immune defense), platelets (blood clotting), and plasma (fluid medium). The blood's main function is to transport oxygen, nutrients, hormones, and waste products throughout the body. Circulation: Systemic Circulation: The left side of the heart pumps oxygenated blood to the body through the aorta, and the deoxygenated blood returns via veins. Pulmonary Circulation: The right side of the heart pumps deoxygenated blood to the lungs through the pulmonary artery, and oxygenated blood returns via pulmonary veins. Regulation: The circulatory system is regulated by the autonomic nervous system and hormones. Hormones such as adrenaline can increase heart rate and blood pressure during stress or exercise. Homeostasis: The circulatory system contributes to maintaining a stable internal environment by regulating temperature, pH, and fluid balance. Diseases and Disorders: Conditions like atherosclerosis, hypertension, and heart failure can adversely affect the circulatory system. 16 Chapter No. 3 The Lymphatic System The lymphatic system is a vital part of the circulatory system and immune system, responsible for maintaining fluid balance, filtering harmful substances, and supporting immune function. Comprising lymph nodes, vessels, tonsils, spleen, and thymus, this network transports lymph, a clear fluid, throughout the body. Lymphatic vessels parallel blood vessels, collecting excess interstitial fluid from tissues. This fluid, now called lymph, contains white blood cells, proteins, and other waste products. Lymph nodes, strategically located along the vessels, filter and purify the lymph, trapping pathogens and foreign particles. This process helps prevent the spread of infections. Lymphocytes, a type of white blood cell, play a central role in the immune system and are produced in the lymphatic organs. The thymus, located behind the breastbone, is crucial for T- cell maturation, while the bone marrow is responsible for B-cell development. These lymphocytes circulate in the lymphatic system, combating infections and maintaining immune surveillance. The spleen, situated beneath the ribcage, acts as a blood filter, removing damaged blood cells and pathogens. Tonsils, found in the throat, function as the first line of defense against inhaled or ingested pathogens. When the lymphatic system malfunctions, conditions like lymphedema can occur, leading to fluid retention and swelling. Additionally, lymphomas, cancers affecting lymphocytes, may develop. In summary, the lymphatic system is integral to maintaining fluid balance, filtering harmful substances, and supporting immune responses, making it a crucial component of overall health. 17 18 Chapter 4 The Gastrointestinal System The gastrointestinal (GI) system, also known as the digestive system, is a long, twisting tube that starts at the mouth and goes through the esophagus, stomach, small intestine, large intestine and ends at the anus. The digestive system breaks down food into simple nutrients such as carbohydrates, fats and proteins. It is a complex network of organs responsible for processing food and extracting nutrients essential for the body's functioning. Mouth: Function: Mechanical and chemical breakdown of food begins with chewing and the action of saliva containing enzymes like amylase. The food is converted to semisolid Bolus. Salivary Glands: Produce saliva to aid in digestion. Esophagus: Function: Transports chewed food from the mouth to the stomach through coordinated muscle contractions called peristalsis. Stomach: Function: Further digestion and mixing of food with gastric juices containing hydrochloric acid and enzymes. This forms Chyme. Gastric Mucosa: Contains specialized cells secreting digestive enzymes and mucus. Small Intestine: Function: Primary site for nutrient absorption. Divided into three parts: duodenum, jejunum, and ileum. Villi and Microvilli: Increase surface area for absorption of nutrients into the bloodstream. Liver: Function: Produces bile, which emulsifies fats for easier digestion. Detoxifies harmful substances and stores nutrients. Gallbladder: Stores and releases bile into the small intestine. Pancreas: Function: Produces digestive enzymes (lipases, amylases, proteases) and releases them into the small intestine. Large Intestine (Colon): consists of Ascending colon, transverse colon, descending colon, sigmoid colon Function: Absorbs water and electrolytes, forming feces. Houses beneficial bacteria that aid in fermentation of undigested food. Rectum and Anus: Store and expel feces during the process of defecation. 19 Peritoneum: Function: Thin membrane lining the abdominal cavity, providing support and protection to the digestive organs. Hormones: Gastrin, Insulin, Glucagon: Regulate digestive processes and nutrient absorption. Secretin, Cholecystokinin (CCK): Control the release of digestive juices. Nervous Control: Enteric Nervous System: Intrinsic nerve network regulating gut function. Autonomic Nervous System: Sympathetic and parasympathetic branches influence digestive activity. Maintaining a healthy GI system is crucial for overall well-being, as it ensures proper nutrient absorption and waste elimination. Disorders like gastroenteritis, ulcers, and inflammatory bowel diseases can impact the functioning of the gastrointestinal system. 20 Chapter 5 The Respiratory System The respiratory system plays a vital role in gas exchange, providing oxygen to the body's cells and removing carbon dioxide. The respiratory system maintains homeostasis by adjusting the rate and depth of breathing to meet the body's oxygen demands. Disorders like asthma, chronic obstructive pulmonary disease (COPD), and pneumonia can affect respiratory function. 5.1 Upper Respiratory Tract: The upper respiratory tract (URT) comprises the structures involved in the initial stages of breathing and the filtration of air before it reaches the lower respiratory tract. Key components of the URT include: Nose: Structure: External nostrils lead to nasal cavities. Function: Filters, humidifies, and warms incoming air; contains sensory receptors for the sense of smell. Nasal Cavities: Structure: Divided by the nasal septum; lined with mucous membranes and cilia. Function: Filters, moistens, and warms inspired air; traps dust and pathogens. Paranasal Sinuses: Structure: Air-filled cavities in the bones surrounding the nasal cavities. Function: Lighten the skull, produce mucus, and contribute to voice resonance. Pharynx (Throat): Structure: Connects nasal cavities and mouth to the larynx and esophagus. Function: Common pathway for air and food; serves as a resonating chamber for speech. Larynx (Voice Box): Structure: Located below the pharynx; contains vocal cords. Function: Houses vocal cords, allowing for the production of sound during speech. The upper respiratory tract serves as the first line of defense against pathogens and particulate matter. The mucous membranes and cilia in the nasal cavities trap and move foreign particles, preventing them from entering the lower respiratory tract. Additionally, the nasal secretions contain enzymes and antibodies that contribute to immune defense. Common ailments affecting the upper respiratory tract include the common cold, sinusitis, and allergic rhinitis. These conditions often involve inflammation of the nasal passages, sinuses, or throat, leading to symptoms such as congestion, sneezing, and sore throat. Proper care and 21 hygiene, including handwashing and avoiding exposure to respiratory viruses, help maintain the health of the upper respiratory tract. 5.2 Lower Respiratory Tract: The lower respiratory tract consists of several key components: Trachea (Windpipe): A tubular structure that connects the larynx to the bronchi, allowing the passage of air to and from the lungs. Bronchi: The trachea branches into two bronchi (singular: bronchus), one leading to each lung. These bronchi further divide into smaller branches called bronchioles. Bronchioles: Smaller air passages that arise from the bronchi and extend into the lungs. They continue to divide into even smaller tubes, eventually leading to the alveoli. Alveoli: Tiny air sacs located at the end of the bronchioles. This is where the exchange of oxygen and carbon dioxide takes place between the air and the bloodstream. Lungs: The primary organs of the lower respiratory tract, consisting of lobes filled with bronchi, bronchioles, and alveoli. The right lung has three lobes, while the left lung has two. Pleura: A double-layered membrane surrounding the lungs and lining the chest cavity. The space between these layers contains a small amount of fluid, which helps reduce friction during breathing. The lower respiratory tract is crucial for the exchange of gases, allowing oxygen to be absorbed into the bloodstream and carbon dioxide to be expelled from the body. This process is essential for cellular respiration and maintaining proper oxygen levels in the body. 22 Chapter 6 The Nervous System The Nervous System is composed of neurons and supporting cells, transmitting electrical impulses and enabling communication within the nervous system. Found in the brain, spinal cord, and peripheral nerves. Neurons: Function: Transmit electrical signals. Structure: Cell body, dendrites (receive signals), and axon (sends signals). Types: Sensory neurons (carry sensory information), motor neurons (control muscles), interneurons (connect neurons in the central nervous system). Neuroglia (Glial Cells): Function: Support and protect neurons. Types: Astrocytes (support and nourish neurons), oligodendrocytes (produce myelin in the central nervous system), Schwann cells (produce myelin in the peripheral nervous system), microglia (immune defense), and ependymal cells (produce cerebrospinal fluid). Synapse: Function: Junction between neurons, allowing signal transmission. Components: Presynaptic terminal (sends signal), synaptic cleft (gap between neurons), postsynaptic membrane (receives signal). 23 6.1 Central Nervous System (CNS) Components: Brain and spinal cord. Function: Integration and processing of information. 6.2 Peripheral Nervous System (PNS) Components: Nerves outside the CNS. Function: Connects the CNS to the rest of the body, facilitating communication. Here are some key details about the central nervous system: Brain: Divisions: Forebrain, Midbrain, Hindbrain: Subdivisions of the brain, each with specific functions. Gray and White Matter: Gray matter contains neuron cell bodies, while white matter consists of myelinated nerve fibers. Understanding the central nervous system is vital for comprehending how the body perceives, processes information, and generates responses to the environment. Functions: Responsible for cognitive functions, sensory processing, motor control, and regulation of involuntary bodily functions. Here are some key parts of the brain: 24 Cerebrum: Functions: Responsible for conscious thought, voluntary actions, sensory perception, and language. Divisions: Consists of two hemispheres (left and right), each further divided into four lobes (frontal, parietal, temporal, and occipital). Cerebellum: Function: Coordinates voluntary muscle movements, balance, and posture. Brainstem: Components: Medulla Oblongata: Regulates vital functions like breathing, heart rate, and blood pressure. Pons: Involved in sleep, respiration, and facial movements. Midbrain: Involves in visual and auditory reflexes. Diencephalon: Components: Thalamus: Acts as a relay station for sensory information. Hypothalamus: Regulates body temperature, hunger, thirst, and controls the endocrine system via the pituitary gland. Limbic System: Components: Includes the hippocampus, amygdala, and hypothalamus. Function: Involved in emotions, memory, and basic survival instincts. Basal Ganglia: Function: Coordinates voluntary movements and plays a role in procedural learning. Reticular Formation: Function: Regulates arousal, sleep-wake cycles, and attention. Ventricals: Structure: Fluid-filled cavities within the brain. Function: Produce cerebrospinal fluid, which cushions the brain and spinal cord. 25 Medial view of brain Spinal Cord: Location: Extends from the brainstem down the vertebral column. Function: Acts as a communication pathway between the brain and the peripheral nervous system, transmitting signals to and from the body. 26 Meninges: Three layers of protective membranes (dura mater, arachnoid, and pia mater) surround the brain and spinal cord. Cerebrospinal Fluid (CSF): Acts as a cushion, providing buoyancy and protecting the CNS from mechanical injury. Blood-Brain Barrier: Function: Protects the brain from harmful substances by regulating the passage of molecules between the bloodstream and brain tissue. 6.2. The Peripheral Nervous System (PNS) is an extensive network of nerves and ganglia outside the central nervous system (CNS), comprising the brain and spinal cord. It is divided into two main components: the somatic nervous system and the autonomic nervous system. Somatic Nervous System (SNS): Voluntary Control: The SNS controls voluntary movements and sensory information from the external environment. It consists of sensory (afferent) neurons that transmit information from sensory receptors to the CNS and motor (efferent) neurons that convey signals from the CNS to skeletal muscles. Reflex Arc: Quick, automatic responses to stimuli are mediated by reflex arcs within the SNS. These reflexes often bypass the brain, involving a direct communication between sensory and motor neurons in the spinal cord. Autonomic Nervous System (ANS): Involuntary Functions: The ANS regulates involuntary bodily functions, maintaining internal balance and responding to stress. It is further divided into the sympathetic and parasympathetic branches. Sympathetic Nervous System (SNS): Activated during the "fight or flight" response, the SNS prepares the body for quick, intense action. It increases heart rate, dilates airways, and redirects blood flow to muscles, enhancing overall alertness and physical performance. Parasympathetic Nervous System (PNS): Responsible for the "rest and digest" response, the PNS promotes relaxation and recovery. It slows heart rate, stimulates digestion, and conserves energy. Neurons and Ganglia: Sensory Neurons: Transmit signals from sensory organs to the CNS, providing information about the external and internal environment. Motor Neurons: Transmit signals from the CNS to muscles or glands, executing responses. Interneurons: Facilitate communication between sensory and motor neurons within the CNS. Ganglia: Clusters of nerve cell bodies outside the CNS. In the PNS, ganglia serve as relay points for transmitting signals between neurons. Peripheral Nerves: 27 Peripheral nerves consist of bundles of axons, connective tissue, and blood vessels. They can be sensory, motor, or mixed, containing both sensory and motor fibers. Cranial Nerves: Arise from the brain and primarily serve the head and neck region. Spinal Nerves: Emerge from the spinal cord and are named based on their spinal cord segment. They innervate the rest of the body. (As shown in table 1.1) 28 Chapter 7 The Endocrine System The endocrine system is a complex network of glands that produce and release hormones, chemical messengers that regulate various physiological processes in the body. Major glands include the hypothalamus, pituitary, thyroid, parathyroid, adrenal glands, pancreas, ovaries (in females), and testes (in males). Hypothalamus: Located in the brain, it regulates the pituitary gland and connects the nervous and endocrine systems. Pituitary Gland: Often called the "master gland," it controls other glands and produces hormones like growth hormone and thyroid-stimulating hormone. Pituitary gland is located at the base of the brain below the hypothalamus. Thyroid Gland: Produces hormones that regulate metabolism, growth, and development. It is located in the lower and front area of the neck. It's has left and right lobes and an isthmus in between the two lobes. Thyroid cells are arranged in different size of thyroid follicles. Colloid is the proteinaceous material present in the thyroid follicles and contain the thyroid hormones. Parathyroid Glands: Regulate calcium levels in the blood, influencing bone health and nerve function. Parathyroid glands are small glands located behind the thyroid gland. Adrenal Glands: Situated on top of each kidney, they produce hormones such as cortisol and adrenaline, involved in stress response and metabolism. The adrenal cortex produce aldosterone (a mineralocorticoid), cortisol (a glucocorticoid), and androgens and estrogen (sex hormones). Following organs have endocrine functions. Pancreas: Secretes insulin and glucagon, regulating blood sugar levels. It is located near the gall bladder and liver. Ovaries (Females): Produce estrogen and progesterone, influencing menstrual cycles and pregnancy. Two ovaries are present in a female. Ovaries produce eggs which form a new born after meeting with the sperm. Testes (Males): Generate testosterone, controlling male reproductive functions and secondary sexual characteristics. Testes are present behind the penis in skin covered sacs called scrotum. Scrotal sacs lie outside of the abdomen and pelvis. 29 30 Chapter 8 Human Skin The skin is the largest single organ of the body, typically accounting for 15%-20% of total body weight and, in adults, presenting 1.5-2 m2 of surface to the external environment. Human skin consists of three main layers: the epidermis, dermis, and subcutaneous tissue. Epidermis: This is the outermost layer of the skin. It is primarily composed of keratinocytes, which produce the protein keratin, providing strength and waterproofing to the skin. The epidermis also contains melanocytes, responsible for pigmentation, and Langerhans cells, involved in immune response. Dermis: Beneath the epidermis lies the dermis, which is thicker and contains connective tissues, blood vessels, nerves, and various appendages. Collagen and elastin fibers in the dermis provide structural support and elasticity to the skin. Hair follicles, sebaceous glands, and sweat glands are also found in the dermis. Subcutaneous Tissue (Hypodermis): This is the deepest layer, primarily composed of adipose (fat) tissue. It serves as insulation, energy storage, and a cushioning layer. Blood vessels and nerves that supply the skin are located in the subcutaneous tissue. The skin functions as a protective barrier against pathogens, UV radiation, and physical trauma. It regulates body temperature through sweat production and blood flow. Sensory receptors in the skin enable the perception of touch, temperature, and pain. Skin Appendages: Skin appendages are structures that arise from the skin and have specific functions. The main types include: Hair: Composed of keratin, hair originates from hair follicles in the skin and serves various functions, such as insulation and protection. Nails: Formed from keratinized cells, nails protect the fingertips and enhance tactile sensation. Sebaceous Glands: These glands produce sebum, an oily substance that helps moisturize the skin and hair. Sweat Glands: Eccrine glands produce sweat for thermoregulation, while apocrine glands are associated with hair follicles and play a role in body odor. Arrector Pili Muscles: Small muscles connected to hair follicles that contract in response to cold or emotional stimuli, causing hair to stand on end. These skin appendages contribute to the overall function and protection of the skin. 31 32 Chapter 9 The Urinary System The human kidney has a distinct anatomy that includes various structures responsible for its vital functions as following Regulation of the balance between water and electrolytes (inorganic ions) and the acid- base balance. Excretion of metabolic wastes along with excess water and electrolytes in urine, the kidneys’ excretory product which passes through the ureters for temporary storage in the bladder before its release to the exterior by the urethra. The brief view of anatomy of urinary system is as follow Renal Cortex: The outer region of the kidney, containing the renal corpuscles and convoluted tubules. Renal Medulla: The inner region, composed of renal pyramids. The medulla houses structures like the loops of Henle and collecting ducts. Renal Pelvis: A funnel-shaped structure at the center of the kidney that collects urine from the nephrons. Nephron: The functional unit of the kidney, consisting of a renal corpuscle (Bowman's capsule and glomerulus) and renal tubule (proximal and distal convoluted tubules, loop of Henle). Renal Artery and Vein: The renal artery brings blood to the kidney for filtration, while the renal vein carries purified blood away. Ureter: A tube that connects the renal pelvis to the bladder, allowing the flow of urine from the kidneys to the bladder. Urinary Bladder: A muscular organ that stores urine until it is released through the urethra. Urethra: A tube through which urine is expelled from the bladder out of the body. Location of Kidneys The Kidneys lie behind the peritoneum in the abdomen, either side of vertebral column. They extend from T12 to L3, right kidney is slightly lower than the left due to the liver's position. Both kidneys function similarly, filtering blood and producing urine. 33 34 Chapter 10 The Reproductive System 10.1 The Male Reproductive System Consists of several organs that work together for the production and delivery of sperm. Here's a brief overview: Testes: Anatomy: Paired organs located in the scrotum, responsible for sperm and testosterone production. Physiology: Sperm production (spermatogenesis) occurs in the seminiferous tubules, while Leydig cells produce testosterone. Epididymis: Anatomy: Coiled tube attached to each testis. Physiology: Sperm mature and gain motility while stored in the epididymis. Vas Deferens: Anatomy: Duct that transports mature sperm from the epididymis to the urethra. Physiology: Sperm travel through the vas deferens during ejaculation. Seminal Vesicles: Anatomy: Glandular structures near the base of the bladder. Physiology: Produce seminal fluid, contributing to semen volume and providing nutrients for sperm. Prostate Gland: The prostate gland is a part of the male reproductive system, situated just below the bladder and surrounding the urethra. It plays a crucial role in the production of seminal fluid. Here's a detailed overview: Location: The prostate is located in the pelvis, beneath the bladder and in front of the rectum. Structure: The prostate is a walnut-sized gland with several lobes. It is composed of glandular and fibromuscular tissue. Function: The primary function of the prostate is to produce a fluid that, along with sperm from the testes and seminal vesicle fluids, makes up semen. This fluid helps nourish and transport sperm during ejaculation. Structure of Prostate: Peripheral Zone: The outer part of the prostate, where most prostate cancers originate. Central Zone: Surrounds the ejaculatory ducts and makes up a smaller portion of the gland. Transitional Zone: Located near the urethra, this zone is where benign prostatic hyperplasia (BPH) typically occurs. 35 Ducts and Glands: The prostate contains numerous ducts and glands that produce the prostatic fluid. This fluid is released into the urethra during ejaculation. Muscles: The fibromuscular tissue of the prostate helps propel semen during ejaculation. Nerve Supply: The prostate receives its nerve supply from the autonomic nervous system, which plays a role in controlling its functions. Prostate-Specific Antigen (PSA): A blood test measuring PSA levels is often used as a screening tool for prostate conditions, including prostate cancer. Problems: The prostate can be affected by various conditions, such as benign prostatic hyperplasia (BPH), prostatitis (inflammation), and prostate cancer. Bulbourethral Glands (Cowper's Glands): Anatomy: Small glands near the base of the penis. Physiology: Release a clear, lubricating fluid before ejaculation, preparing the urethra for sperm passage. Penis: Anatomy: External organ with erectile tissues. Physiology: During sexual arousal, blood flow increases to erectile tissues, causing an erection. The urethra passes through the penis, allowing the passage of semen during ejaculation. Hormonal Regulation: The hypothalamus releases gonadotropin-releasing hormone (GnRH), stimulating the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH stimulates testosterone production in the testes, and FSH stimulates spermatogenesis. The coordinated function of these structures allows for the production, maturation, and delivery of sperm, contributing to the male reproductive system's overall anatomy and physiology. 36 10.2 Female Reproductive System: The female reproductive system is complex and involves several organs and structures. The main components include: Ovaries: Ovaries are almond shaped paired organs, produce eggs (ova) and hormones such as estrogen and progesterone. Fallopian Tubes or Oviducts: Transport eggs from the ovaries to the uterus; the site of fertilization. Uterus: Uterus is a pear-shaped organ with thick, muscular wall , supports fetal development during pregnancy. Layers: Endometrium (inner lining), myometrium (muscular middle layer), and perimetrium (outer layer). Cervix: The cervix is the lower, cylindrical part of the uterus, connect the uterus to the vagina; allows sperm to enter the uterus during fertilization. Vagina: Connects the uterus to the external genitalia; serves as the birth canal during childbirth. External Genitalia: Labia: Outer folds protecting the vaginal and urethral openings. Clitoris: Sensitive organ associated with sexual arousal. 37 The menstrual cycle is a crucial aspect of female reproductive physiology. It involves a series of hormonal changes orchestrated by the hypothalamus, pituitary gland, and ovaries, leading to the release of an egg from the ovary (ovulation) and preparation of the uterus for a potential pregnancy. If fertilization doesn't occur, the uterine lining is shed during menstruation Mammary Glands (Breasts): Multicellular gland that produce milk for breastfeeding or during lactation. Structure and Function of Female Breast: Composition: Composed of lobules (milk-producing glands) and ducts (tubes that carry milk to the nipple). Adipose Tissue: Function: Provides shape and support to the breasts. Distribution: Surrounds and interweaves with the mammary glands. Connective Tissue: Function: Provides structural support to the breast. Nipple and Areola: Function: The nipple is the outlet for milk; the areola is the pigmented area surrounding the nipple. Breast Functions: Milk Production (Lactation): Triggered by hormonal changes during pregnancy and after childbirth. Mammary glands produce and release milk in response to infant suckling. Hormonal Regulation: Hormones like estrogen, progesterone, and prolactin play key roles in breast development, milk production, and lactation. Breastfeeding: Provides essential nutrients and antibodies to the infant. Promotes mother-infant bonding. Secondary Sexual Characteristics: Breasts undergo changes during puberty, influenced by hormonal fluctuations. Serve as secondary sexual characteristics and contribute to female body image. Understanding breast structure and function is crucial for reproductive health, breastfeeding, and overall well-being. Regular breast self-exams and mammograms are recommended for early detection of potential issues such as breast cancer. 38 39 Chapter 11 Human Skeletal System 11.1 Overview Bone is mineralized dense connective tissue Made up of few cells in mineralized matrix Consists of 30-40 % of our body weight. Functions of Bones: Support, Protection & Movement: Gives shape to the body. Supports body weight. Protects sensitive parts of the body. Blood Cell Formation: The red bone marrow found in the connective tissue of certain bones is the site of blood cell production. There are total 206 bones which make up the human skeleton. The skeletal is divided into two main parts, the axial skeleton (80) includes the skull, vertebral column, and rib cage, while the appendicular skeleton (126) comprises limbs, shoulders, and hips. Bones serve as attachment points for muscles, aiding movement, and store minerals like calcium. The skull safeguards the brain, ribs protect vital organs, and the spine offers spinal cord protection. Understanding this framework is crucial for comprehending human anatomy and physiology. 40 11.2 Structure and Function of Human Skeleton Skull: Composed of cranium and mandible. Protects the brain and houses sensory organs. Vertebral Column (Spine): Series of vertebrae (cervical, thoracic, lumbar, sacral, coccygeal). Supports the body, protects spinal cord, allows movement. Rib Cage: Protects thoracic organs. Consists of true ribs, false ribs, and floating ribs. Shoulder Girdle: Includes scapula and clavicle. Connects the upper limbs to the axial skeleton. Upper Limbs: 41 Arm bones (humerus, radius, ulna). Hand bones (carpals, metacarpals, phalanges). Pelvic Girdle: Consists of two hip bones (coxal bones). Supports the trunk and protects pelvic organs. Lower Limbs: Thigh bone (femur), leg bones (tibia, fibula). Foot bones (tarsals, metatarsals, phalanges). 11.3 Gross Anatomy of a Long Bone Diaphysis / Shaft / Body Composed of compact bone Epiphysis / Ends of the bone Composed mostly of spongy bone Structure of Long bone 1. Compact = Solid mass; dense & hard = Forms the outer layer of bone structure 2. cancellous or spongy = Contain spaces filled with bone marrow 42 11.4 Bones of Upper Limb The Scapula: The scapula, commonly known as the shoulder blade, is a flat, triangular bone located on the upper back. It has three borders (superior, medial, and lateral), three angles (superior, inferior, and lateral), and two surfaces (costal and dorsal). The acromion process extends from the superior angle, forming the highest point of the shoulder. The glenoid cavity is a shallow depression on the lateral aspect that articulates with the head of the humerus, forming the shoulder joint. The scapula plays a crucial role in shoulder movement and provides attachment points for various muscles. The Humerus: The humerus is the long bone of the upper arm, extending from the shoulder to the elbow. It consists of a proximal end, distal end, and a shaft. The proximal end consists of the head, which articulates with the glenoid cavity of the scapula, forming the shoulder joint. The anatomical neck is a slight constriction just below the head. The greater and lesser tubercles are prominent bony projections serving as muscle attachment sites. The surgical neck is a narrower region just below the tubercles and is a common site for fractures. The shaft of the humerus has a deltoid tuberosity for deltoid muscle attachment and various muscle attachment points throughout. Distally, the humerus articulates with the radius and ulna at the elbow joint. The lateral and medial epicondyles provide attachment sites for muscles and ligaments. Overall, the humerus facilitates arm movement and supports musculature essential for daily activities. The Radius: The radius is one of the two long bones in the forearm, along with the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist. The proximal end of the radius has a disc-shaped head that articulates with the humerus and the ulna, forming the radioulnar joint. The radial tuberosity, a bony prominence just below the head, serves as the attachment site for the biceps brachii muscle. The shaft of the radius runs along the forearm and has a slight curvature. Towards the distal end, the radius widens to form the styloid process, which provides attachment for ligaments and stabilizes the wrist joint. The radius plays an important role in forearm rotation, working in coordination with the ulna to allow for supination and pronation movements. It also contributes to the formation of the wrist joint, allowing for various hand and wrist movements. The Ulna: The ulna is the other long bone in the forearm, running parallel to the radius. It extends from the medial side of the elbow to the wrist. The shaft of the ulna runs alongside the radius and is generally longer than the radius. Distally, the ulna forms the head, which is part of the wrist joint and articulates with the ulnar notch of the radius. The ulna also has a styloid process at the distal end, providing attachment for ligaments and stabilizing the wrist. 43 The ulna is essential for forearm stability and contributes to the formation of the elbow and wrist joints. Together with the radius, it allows for various movements, including flexion and extension at the elbow, as well as pronation and supination of the forearm. The Bones of Hands: The bones of the hand consist of the carpals, metacarpals, and phalanges: Carpals: These are the eight small bones that form the wrist. They are arranged in two rows: Proximal row (from lateral to medial): Scaphoid, Lunate, Triquetrum, Pisiform Distal row (from lateral to medial): Trapezium, Trapezoid, Capitate, Hamate Metacarpals: There are five metacarpal bones, one for each digit (thumb to little finger). Numbered from the thumb side (lateral) to the little finger side (medial), they are often referred to as the first through fifth metacarpals. Phalanges: The phalanges are the finger bones. Each finger (except the thumb) has three phalanges: proximal, middle, and distal. The thumb has two phalanges: proximal and distal. So, in summary, the hand consists of a total of 27 bones: 8 carpals, 5 metacarpals, and 14 phalanges. 44 11.5 Bones of Lower Limb The lower limbs (extremities) are extensions from the trunk specialized to support body weight, for locomotion (the ability to move from one place to another), and to maintain balance. The Hip Bone: The hip bone is a large, irregularly shaped bone that forms a major part of the pelvis. It is composed of three fused bones: the ilium, ischium, and pubis. These three components meet at the acetabulum, a cup-shaped socket that articulates with the head of the femur, forming the hip joint. Ilium: The ilium is the largest and uppermost portion of the hip bone. It has a wing-like structure with a prominent crest called the iliac crest. The anterior superior iliac spine and the anterior inferior iliac spine are bony prominences on the ilium. The posterior superior iliac spine is present posteriorly. Ischium: The ischium is the posterior and lower part of the hip bone. It includes the ischial tuberosity, a bony prominence that bears body weight when sitting. The ischial spine is another notable feature. Pubis: The pubis is the anterior and inferior part of the hip bone. It includes the pubic symphysis, a cartilaginous joint where the left and right hip bones are connected in the front. The hip bone forms a crucial part of the pelvic girdle, providing support for the spine and connecting the axial skeleton with the lower limbs. The Femur: The femur is the longest and strongest bone in the human body, extending from the hip to the knee. It consists of a proximal end, a shaft, and a distal end. The head of the femur articulates with the acetabulum of the hip bone, forming the hip joint. The neck is a constricted region just below the head. Two prominent bony processes, the greater and lesser trochanters, serve as muscle attachment sites on the proximal femur. The shaft of the femur is relatively straight and bears the linea aspera, a ridge that provides attachment for thigh muscles. Distally, the femur forms the medial and lateral condyles, which articulate with the tibia, forming the knee joint. The patellar surface is a smooth, anterior part that articulates with the patella. The femur plays a critical role in weight-bearing and locomotion, supporting the body's weight and allowing for various leg movements. Its robust structure reflects its function as a major weight-bearing bone in the lower limb. The Tibia: The tibia, also known as the shinbone, is one of the two long bones in the lower leg, along with the fibula. It is larger and more weight-bearing than the fibula. The proximal end of the tibia features the medial and lateral condyles, which articulate with the femur, forming the knee joint. The intercondylar eminence is a bony prominence between the condyles. 45 The tibial tuberosity, located on the anterior surface, serves as the attachment site for the patellar ligament. The shaft of the tibia is relatively strong and bears the solely line, which marks the origin of the soleus muscle. Distally, the tibia forms the medial malleolus, a bony prominence on the inner side of the ankle. The tibia plays an important role in weight-bearing, transmitting forces from the femur to the foot. It is a major contributor to the knee and ankle joints, providing stability and support for various movements. Together with the fibula, it forms an essential part of the lower limb's skeletal framework. The Bones of Feet: The bones of the feet include the tarsals, metatarsals, and phalanges: Tarsals: There are seven tarsal bones that form the posterior half of the foot and ankle: Calcaneus (heel bone) Talus Navicular Medial cuneiform Intermediate cuneiform Lateral cuneiform Cuboid Metatarsals: Similar to the metacarpals in the hand, there are five metatarsal bones in the foot. They are numbered from the big toe side (medial) to the little toe side (lateral) and are often referred to as the first through fifth metatarsals. Phalanges: The toes contain phalanges, similar to the fingers. Each toe (except the big toe) has three phalanges: proximal, middle, and distal. The big toe has two phalanges: proximal and distal. In total, the foot consists of 26 bones: 7 tarsals, 5 metatarsals, and 14 phalanges. 46 47 Sternum, Clavicle and Ribs: The clavicle, sternum, and ribs are components of the human thoracic cage, providing structural support and protection for vital organs in the chest. Clavicle (Collarbone): The clavicle is a long, S-shaped bone located horizontally at the base of the neck. It connects the sternum to the scapula, forming part of the shoulder girdle. The lateral end of the clavicle articulates with the acromion process of the scapula, while the medial end connects to the sternum at the sternoclavicular joint. Sternum (Breastbone): The sternum is a flat, elongated bone located in the center of the anterior chest. It consists of three parts: Manubrium: The broad, upper part that articulates with the clavicles. Body: The midsection, forming the bulk of the sternum. Xiphoid process: The smallest and most inferior part, often cartilaginous in structure. Ribs: There are 12 pairs of ribs in the human body, and they are categorized into three types: True ribs (1-7): Directly attach to the sternum via costal cartilage. False ribs (8-12): Attach to the sternum indirectly or not at all. Floating ribs (11-12): Have no anterior attachment to the sternum. Together, the clavicle, sternum, and ribs create a protective cage around the thoracic organs such as the heart and lungs. They also play a role in respiration and support the upper limbs. 48 Vertebral bones and Sacrum: The vertebral column, or spine, is composed of individual vertebrae, and the sacrum is a triangular bone at the base of the spine. Here are the details: Vertebrae: There are 33 vertebrae in the human spine, grouped into different regions: Cervical Vertebrae (C1-C7): Located in the neck region. The first cervical vertebra is called the atlas, and the second is the axis. Thoracic Vertebrae (T1-T12): These are in the upper and mid-back, attached to the ribs. Lumbar Vertebrae (L1-L5): Found in the lower back, supporting more body weight. Sacral Vertebrae (S1-S5): Initially separate, these fuse into the sacrum, forming the back of the pelvis. Coccygeal Vertebrae (Co1-Co4): The coccyx or tailbone, consisting of fused vertebrae. Sacrum: The sacrum is a triangular bone formed by the fusion of five sacral vertebrae (S1- S5). It articulates with the last lumbar vertebra above and the coccyx below. The sacrum is part of the pelvic girdle, contributing to the formation of the pelvic cavity and supporting the weight of the upper body. Together, the vertebral column and sacrum provide structural support, protect the spinal cord, and facilitate various body movements. 49 Chapter 12 Joints Joint is a junction between two or more bones or cartilages. Hold the skeletal bones together. Allow the skeleton some flexibility so gross movement can occur. Make bone growth possible. Bone Marrow: Found in cavities of long bones. Produces red and white blood cells. Bone Tissue: Compact bone for strength, spongy bone for flexibility. Contains blood vessels and nerves. Types of Joints and their Movements: 50 Hinge Joint: Movement: Flexion and extension Example: Elbow joint Ball-and-Socket Joint: Movement: Flexion, extension, abduction, adduction, rotation Example: Shoulder joint, hip joint Pivot Joint: Movement: Rotation Example: Radioulnar joint in the forearm Ellipsoid Joint: Movement: Flexion, extension, abduction, adduction Example: Wrist joint Condylar Joint: Movement: permits movements in two directions Example: Temporomandibular joint (TMJ) Saddle Joint: Movement: Flexion, extension, abduction, adduction, circumduction Example: Carpometacarpal joint of the thumb Main Muscles of the Body: Quadriceps: Located in the front of the thigh, these muscles extend the knee. Hamstrings: Situated at the back of the thigh, these muscles flex the knee and extend the hip. Gluteus Maximus: The largest muscle in the buttocks, responsible for hip extension. Latissimus Dorsi: Broad muscles of the back that assist in arm movement and shoulder extension. Pectoralis Major: Chest muscles that contribute to shoulder and arm movements, such as pushing. Deltoids: Shoulder muscles involved in various arm movements. Biceps Brachii (Biceps): Located in the front of the upper arm, these muscles flex the elbow. Triceps Brachii (Triceps): Situated at the back of the upper arm, these muscles extend the elbow. Rectus Abdominis: Central abdominal muscles responsible for flexing the spine and supporting the core. Gastrocnemius: Calf muscles that enable plantarflexion of the foot. 51 These muscles work together to facilitate various movements and provide support for daily activities. Anatomical Terminology: Directional terms like anterior (front), posterior (back), superior (above), and inferior (below) are used for precise communication. Medical Imaging: Techniques like X-rays, CT scans, MRI, and ultrasound provide visual representations of internal structures. Understanding human anatomy is crucial for medical professionals, researchers, and anyone interested in comprehending how the body functions and maintaining good health. 52 Chapter 13 12 The Special Senses 13.1 Brief Anatomy of Eye The eyeball contains the optical apparatus of the visual system. It occupies most of the anterior portion of the orbit, suspended by six extrinsic muscles that control its movement. The eyeball proper has three layers; however, there is an additional connective tissue layer that surrounds the eyeball, supporting it within the orbit. The three layers of the eyeball are the: (Fig,7.49) Fibrous layer (outer coat), consisting of the sclera and cornea. Vascular layer (middle coat), consisting of the choroid, ciliary body, and iris. Inner layer (inner coat), consisting of the retina, which has both optic and non-visual parts Cornea: The transparent front part that refracts light. Iris: A colored, muscular structure controlling the size of the pupil. Pupil: The central opening in the iris regulating light entry. Lens: Behind the pupil, it focuses light onto the retina. Retina: At the back of the eye, contains photoreceptor cells (rods and cones) for light detection. Optic Nerve: Transmits visual information from the retina to the brain. Sclera: The tough, white outer layer providing structural support. Conjunctiva: Thin membrane covering the eye's surface. Extraocular Muscles: Control eye movement. They are six in number. Tear Glands: Produce tears for lubrication and protection. 53 13.2 Brief Anatomy of the Ear The ear consists of the external ear; the middle ear, or tympanic cavity; and the internal ear, or labyrinth, which contains the organs of hearing and balance. Outer Ear: Pinna (Auricle): The visible part of the ear that collects sound waves. External Auditory Canal: The tube that carries sound to the eardrum. Middle Ear: Eardrum (Tympanic Membrane): Separates the outer and middle ear, vibrates in response to sound waves. Ossicles (Malleus, Incus, Stapes): Three small bones that transmit vibrations from the eardrum to the inner ear. Inner Ear: Cochlea: Converts vibrations into electrical signals for the brain. Vestibular System: Maintains balance and spatial orientation. Auditory Nerve: Transmits signals from the cochlea to the brain for processing. These components work together to capture, transmit, and interpret sound and maintain balance. 54 13.3 Brief Anatomy of Nose: The nose is a crucial part of the respiratory system and includes several components: External Nose: Nostrils (Nares): Openings allowing air to enter. Internal Nose: Nasal Cavity: A hollow space behind the nose. Septum: Divides the nasal cavity into left and right sides. Nasal Conchae (Turbinate’s): Bony structures in the nasal cavity that increase surface area for air filtration and humidification. Sinuses: Air-filled cavities connected to the nasal cavity, serving various functions. Olfactory Epithelium: Specialized tissue in the upper nasal cavity responsible for the sense of smell. The nose plays a key role in breathing, filtering and humidifying air, and contributing to the sense of smell. 55 13.4 Brief Anatomy of Tongue The tongue is a muscular organ with various components: Papillae: Small projections on the tongue's surface, containing taste buds. Taste Buds: Clusters of sensory cells that detect taste stimuli (sweet, salty, sour, bitter, umami). Papillae Types: o Filiform Papillae: Provide a rough texture. Fungiform Papillae: Contain taste buds and are scattered across the tongue. Circumvallate Papillae: Larger papillae arranged in a V shape at the back of the tongue. Muscles: Intrinsic and extrinsic muscles enable movement for functions like swallowing and speech. Salivary Glands: Secrete saliva containing enzymes to aid in digestion. The tongue is crucial for taste perception, speech, and the initial stages of digestion. 56 Chapter 14 Approaches to Studying Anatomy The three main approaches to studying anatomy are regional, systemic, and clinical (or applied), reflecting the body's organization and purposes for studying it Regional Anatomy reflecting the body's organization and the priorities and purposes for studying it. response. 57 Dermis: Beneath the epidermis lies the dermis, which is thicker and contains connective tissues, blood vessels, nerves 58 Systemic Anatomy Systemic anatomy is the study of the body's organ systems that work together to carry out complex functions. 1. The integumentary system (dermatology) consists of the skin and its appendages—hair, nails, and sweat glands, for example—and the subcutaneous tissue just beneath it.. 2. The skeletal system (osteology) consists of bones and cartilage; it provides our basic shape and support for the body and is what the muscular system acts on to produce movement. It also protects vital organs such as the heart, lungs, and pelvic organs. 3. The articular system (arthrology) consists of joints and their associated ligaments, connecting the bony parts of the skeletal system and providing the sites at which movements occur. 4. The muscular system (myology) consists of skeletal muscles that act (contract) to move or position parts of the body (e.g., the bones that articulate at joints), or smooth and cardiac muscle that propels, expels, or controls the flow of fluids and contained substance. 5. The nervous system (neurology) consists of the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves and ganglia, together with their motor and sensory endings). The nervous system controls and coordinates the functions of the organ systems, enabling the body's responses to and activities within its environment. The sense organs, including the olfactory organ (sense of smell), eye or visual system (ophthalmology), ear (sense of hearing and balance—otology), and gustatory organ (sense of taste), are often considered with the nervous system in systemic anatomy. 6. The circulatory system (angiology) consists of the cardiovascular and lymphatic systems, which function in parallel to transport the body's fluids. 1. The cardiovascular system (cardiology) consists of the heart and blood vessels that propel and conduct blood through the body, delivering oxygen, nutrients, and hormones to cells and removing their waste products. 2. The lymphatic system is a network of lymphatic vessels that withdraws excess tissue fluid (lymph) from the body's interstitial (intercellular) fluid compartment, filters it through lymph nodes, and returns it to the bloodstream. 7. The alimentary or digestive system (gastroenterology) consists of the digestive tract from the mouth to the anus, with all its associated organs and glands that function in ingestion, mastication (chewing), deglutition (swallowing), digestion, and absorption of food and the elimination of the solid waste (feces) remaining after the nutrients have been absorbed. 8. The respiratory system (pulmonology) consists of the air passages and lungs that supply oxygen to the blood for cellular respiration and eliminate carbon dioxide from it. The diaphragm and larynx control the flow of air through the system, which may also 59 produce tone in the larynx that is further modified by the tongue, teeth, and lips into speech. 9. The urinary system (urology) consists of the kidneys, ureters, urinary bladder, and urethra, which filter blood and subsequently produce, transport, store, and intermittently excrete urine (liquid waste). 10. The genital (reproductive) system (gynecology for females; andrology for males) consists of the gonads (ovaries and testes) that produce oocytes (eggs) and sperms, the ducts that transport them, and the genitalia that enable their union. After conception, the female reproductive tract nourishes and delivers the fetus. 11. The endocrine system (endocrinology) consists of specialized structures that secrete hormones, including discrete ductless endocrine glands (such as the thyroid gland), isolated and clustered cells of the gut and blood vessel walls, and specialized nerve endings. ANATOMICAL TERMINOLOGY The anatomical position refers to the body position as if the person were standing upright with the: head, gaze (eyes), and toes directed anteriorly (forward), arms adjacent to the sides with the palms facing anteriorly, and lower limbs close together with the feet parallel. Anatomical Planes Anatomical descriptions are based on four imaginary planes (median, sagittal, frontal, and transverse) that intersect the body in the anatomical position (Fig. I.2): The median plane, the vertical plane passing longitudinally through the body, divides the body into right and left halves. Sagittal planes are vertical planes passing through the body parallel to the median plane. However, a plane parallel and near to the median plane may be referred to as a paramedian plane. Frontal (coronal) planes are vertical planes passing through the body at right angles to the median plane, dividing the body into anterior (front) and posterior (back) parts. Transverse planes are horizontal planes passing through the body at right angles to the median and frontal planes, dividing the body into superior (upper) and inferior (lower) parts. Radiologists refer to transverse planes as transaxial, which is commonly shortened to axial planes. 60 61 62 in the dermis Tissue (Hypodermis): This is the deepest layer, primarily composed of adipose (fat) tissue. It serves as insulation, energy storage, and a cushioning layer. Blood vessels 63 and nerves that supply the skin are located in the 64 Chapter 1 Introduction to Physiology It is the science that explain the physical and chemical mechanisms that are responsible for the origin, development, and progression of life. The basic unit of the body is cell. Following is the brief overview of the main components of a human cell and their functions: Cell Membrane (Plasma Membrane) The cell membrane, also known as the plasma membrane, plays a crucial role in maintaining the integrity cell. Here are detailed functions of the cell membrane: Selective Permeability: The membrane selectively allows substances to enter or exit the cell, regulating the passage of ions, molecules, and nutrients. This is essential for maintaining cellular homeostasis. Barrier Protection: Acts as a physical barrier, separating the internal cellular environment from the external surroundings. Receptor Recognition: Contains proteins, such as receptors, that recognize and bind to specific signaling molecules. 65 Cell Signaling: Participates in cell signaling by transmitting signals from the external environment to the inside of the cell. Cell Adhesion: Allows cells to adhere to each other, forming tissues and maintaining structural integrity. Cell adhesion is vital for tissue development, organization, and overall multicellular function. Transport of Molecules: Facilitates the transport of ions, nutrients, and other molecules across the membrane through various mechanisms such as diffusion, facilitated diffusion, and active transport. Cellular Recognition: The unique composition of lipids and proteins on the cell membrane's surface helps identify the cell as "self," enabling the immune system to recognize and distinguish between the body's own cells and foreign cells or pathogens. Cellular Respiration: Participates in cellular respiration by hosting proteins involved in the electron transport chain. This process occurs in the inner mitochondrial membrane, contributing to the production of ATP. 66 Endocytosis and Exocytosis: Facilitates processes like endocytosis (cellular uptake of materials by engulfing them) and exocytosis (release of substances from the cell). These processes are essential for nutrient uptake, waste removal, and cell communication. The cytoplasm is a complex cellular region with various functions: Cellular Support and Shape Maintenance: Provides structural support to the cell, maintaining its shape through the cytoskeleton, a network of protein filaments. Metabolic Processes: Houses metabolic reactions, including glycolysis, which generates energy in the form of ATP. Acts as the site for various enzymatic reactions involved in cellular metabolism. Transport and Storage: Serves as a medium for intracellular transport of organelles and molecules through the cytoplasmic streaming. Stores nutrients, ions, and other essential molecules. Protein Synthesis: Contains ribosomes, where protein synthesis occurs, either attached to the endoplasmic reticulum or freely floating in the cytoplasm. 67 Genetic Material Localization: Houses the nucleoid (in prokaryotes) or supports the movement of the nucleus (in eukaryotes), playing a role in genetic material organization. Signal Transduction: Participates in cellular communication by transmitting signals through the cytoplasm, allowing cells to respond to external stimuli. Waste Management: Acts as a medium for the breakdown of waste products through various cellular processes, including autophagy. Cell Division: Plays a crucial role in cell division by providing the environment for mitosis or meiosis to occur. Enzyme Activity: Hosts a variety of enzymes involved in diverse biochemical pathways, facilitating cellular functions. Maintenance of Cellular pH: Regulates the internal pH of the cell, ensuring an environment suitable for enzymatic activity and cellular processes. Nucleus: The cell nucleus is a critical organelle with several essential functions: Genetic Information Storage: Houses DNA, carrying the genetic instructions for the cell's structure and function. Transcription and RNA Synthesis: Acts as the site for transcription, where DNA is used as a template to synthesize messenger RNA (mRNA). 68 Nucleolus Function: Contains the nucleolus, involved in the assembly of ribosomal RNA (rRNA) and the formation of ribosomes. Genetic Regulation: Controls gene expression by regulating the transcription of specific genes, influencing protein synthesis. Chromatin Organization: Packages DNA into chromatin, helping to organize and protect genetic material during cell division. Cellular Reproduction: Directs cell division processes such as mitosis or meiosis, ensuring accurate distribution of genetic material to daughter cells. Ribosome Synthesis and Assembly: Coordinates the synthesis and assembly of ribosomal subunits, essential for protein production. Nuclear Pores and Transport: Contains nuclear pores that regulate the passage of molecules between the nucleus and the cytoplasm, controlling the flow of genetic information. DNA Repair Mechanisms: Engages in DNA repair processes to maintain genetic stability and integrity. Cellular Senescence and Apoptosis: Participates in cellular processes like senescence (aging) and apoptosis (programmed cell death), influencing the cell's lifecycle. Mitochondria: Mitochondria are vital organelles with diverse functions in human cells: 69 ATP Production: Generate adenosine triphosphate (ATP) through oxidative phosphorylation, a process that occurs in the inner mitochondrial membrane, providing energy for cellular activities. Cellular Respiration: Play a central role in aerobic respiration, involving the breakdown of glucose to produce ATP, carbon dioxide, and water. Metabolic Regulation: Participate in various metabolic pathways, including the metabolism of fatty acids and amino acids, influencing overall cellular metabolism. Calcium Homeostasis: Act as reservoirs for calcium ions, helping to regulate intracellular calcium levels, which are crucial for cell signaling and various cellular processes. Apoptosis Regulation: Play a role in apoptosis (programmed cell death) by releasing proteins that trigger the apoptotic process. Heat Production: Generate heat through uncoupling proteins, especially in brown adipose tissue, contributing to thermoregulation. Cell Signaling: Influence cell signaling pathways through the release of signaling molecules, modulating cellular responses to external stimuli. Inheritance and Replication: 70 Contain their own DNA (mitochondrial DNA) and replicate independently of the cell nucleus, contributing to mitochondrial inheritance. Endoplasmic Reticulum (ER): The endoplasmic reticulum (ER) is a multifunctional organelle with distinct roles in cellular processes: Protein Synthesis (Rough ER): Ribosomes on the rough endoplasmic reticulum (RER) synthesize proteins that are either secreted from the cell or inserted into cellular membranes. Lipid Synthesis (Smooth ER): The smooth endoplasmic reticulum (SER) is involved in lipid synthesis, including the production of phospholipids and steroids. Detoxification: The SER in certain cells, especially liver cells, is responsible for detoxifying drugs and harmful substances by modifying them to make them more water-soluble and easier to eliminate. Calcium Ion Storage: Acts as a reservoir for calcium ions, releasing them when needed to regulate various cellular processes, including muscle contraction and cell signaling. Intracellular Calcium Regulation: Regulates intracellular calcium levels, influencing cellular responses to signals and stress. Membrane Biogenesis: Contributes to the synthesis of membranes for the cell and other organelles. Transport of

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