Comprehensive Review Notes: Anatomy and Physiology (Prelim) PDF

Comprehensive Review Notes: Anatomy and Physiology (PRELIM) I. Anatomy vs. Physiology Anatomy refers to the study of the structure of the body, whereas physiology focuses on how these structures function. Examples of anatomical terms include medial (toward the...

Comprehensive Review Notes: Anatomy and Physiology (PRELIM) I. Anatomy vs. Physiology Anatomy refers to the study of the structure of the body, whereas physiology focuses on how these structures function. Examples of anatomical terms include medial (toward the body’s midline) and sagittal plane (dividing the body into right and left sides). II. Anatomical Terminology The anatomical position is the standard reference position used to describe the location of structures in the body. In this position: ✓ The person stands upright. ✓ The head faces forward. ✓ The arms are at the sides with palms facing forward. ✓ The feet are together and pointing forward. ✓ This position provides a consistent frame of reference for describing anatomical structures. Directional Terms Anterior (Ventral): Toward the front of the body. Example: The chest is anterior to the spine. Posterior (Dorsal): Toward the back of the body. Example: The spine is posterior to the heart. Superior (Cranial): Toward the head or upper part of a structure. Example: The head is superior to the chest. Inferior (Caudal): Away from the head, or lower part of a structure. Example: The stomach is inferior to the lungs. Medial: Toward the midline of the body. Example: The heart is medial to the lungs. Lateral: Away from the midline of the body. Example: The arms are lateral to the chest. Proximal: Closer to the origin or attachment of a limb to the body trunk. Example: The elbow is proximal to the wrist. Distal: Farther from the origin or attachment of a limb to the body trunk. Example: The fingers are distal to the elbow. Superficial: Toward or on the body surface. Example: The skin is superficial to the muscles. Deep: Away from the body surface or more internal. Example: The bones are deep to the skin. Body Planes and Sections Body planes are imaginary lines that divide the body into sections for descriptive purposes: ✓ Sagittal Plane: Divides the body into right and left portions. ✓ Midsagittal Plane: Divides the body into equal right and left halves. ✓ Parasagittal Plane: Divides the body into unequal right and left parts. ✓ Frontal (Coronal) Plane: Divides the body into anterior (front) and posterior (back) sections. 1  ✓ Transverse (Horizontal) Plane: Divides the body into superior (upper) and inferior (lower) sections, creating a cross-section. Regional Terms Regional terms help describe specific areas of the body: ✓ Antecubital: refers to the region of the arm that lies in front of the elbow. It is a common site for blood draws and the insertion of intravenous lines, making it clinically significant. ✓ Axillary: Relating to the armpit. ✓ Brachial: Relating to the upper arm. ✓ Carpal: Relating to the wrist. ✓ Cervical: Relating to the neck. ✓ Femoral: Relating to the thigh. ✓ Patellar: Relating to the knee. ✓ Thoracic: Relating to the chest. ✓ Umbilical: Relating to the navel (belly button). ✓ Lumbar: Relating to the lower back. ✓ Popliteal: Relating to the back of the knee. Abdominal Quadrants and Regions To describe the location of abdominal organs, the abdomen is divided into four quadrants and nine regions: Quadrants: Right Upper Quadrant (RUQ), Left Upper Quadrant (LUQ), Right Lower Quadrant (RLQ), Left Lower Quadrant (LLQ). Nine Regions: 1. Right Hypochondriac (under the ribs). 2. Epigastric (upper central region). 3. Left Hypochondriac (under the ribs on the left). 4. Right Lumbar (right lateral to the umbilical region). 5. Umbilical (center of the abdomen). 6. Left Lumbar (left lateral to the umbilical region). 7. Right Iliac (Inguinal) (near the hip bone on the right). 8. Hypogastric (Pubic) (lower central region). 9. Left Iliac (Inguinal) (near the hip bone on the left). Body Cavities The human body contains cavities that house organs and protect them from injury: Dorsal Body Cavity: Includes the cranial cavity (housing the brain) and the vertebral cavity (housing the spinal cord). Ventral Body Cavity Thoracic Cavity: Contains the lungs and heart. Abdominopelvic Cavity: Further divided into the abdominal cavity (contains digestive organs) and the pelvic cavity (contains the bladder, reproductive organs, and rectum). III. Cellular Structure and Function Cells are the basic units of life, with each cell containing various structures (organelles) that perform specific functions essential for the cell’s survival and function. Here is an overview of the major components and organelles found in cells: 1. Cell Membrane (Plasma Membrane) The cell membrane is the outer boundary of the cell. It is a flexible, selectively permeable barrier that controls the movement of substances in and out of the cell. Function: Regulates what enters and exits the cell, provides protection, and helps maintain the cell’s internal environment (homeostasis). Structure: Composed of a phospholipid bilayer with embedded proteins that assist in transport and communication. 2 2. Nucleus The nucleus is the control center of the cell, containing most of the cell’s genetic material (DNA). It directs the synthesis of proteins and manages cellular activities such as growth and reproduction. Function: Stores genetic information (DNA), controls gene expression, and regulates cell division. Structure: Surrounded by a double membrane called the nuclear envelope, which contains nuclear pores for material exchange. Inside, the nucleolus is responsible for producing ribosomes. 3. Cytoplasm The cytoplasm is the jelly-like substance that fills the cell, holding organelles in place. It is composed mainly of water, salts, and proteins. Function: Supports and protects organelles, and is the site of many chemical reactions. Cytosol: The fluid component of the cytoplasm, where dissolved molecules and ions are present. 4. Mitochondria The mitochondria are the powerhouses of the cell, where energy production takes place. They convert nutrients into adenosine triphosphate (ATP), the energy currency of the cell. Function: Produces energy (ATP) through cellular respiration. Structure: Has a double membrane with inner folds (cristae) that increase surface area for energy production. Mitochondria also contain their own DNA, allowing them to replicate independently of the cell. 5. Endoplasmic Reticulum (ER) The endoplasmic reticulum is a network of membranous tubules within the cell. There are two types: rough and smooth ER. Rough ER: Studded with ribosomes and involved in the synthesis and transport of proteins. Smooth ER: Lacks ribosomes and is involved in lipid synthesis, detoxification of chemicals, and storage of ions like calcium. 6. Ribosomes Ribosomes are small structures made of RNA and proteins, responsible for protein synthesis. Function: Assemble amino acids into proteins based on instructions from the genetic code (mRNA). Location: Found floating freely in the cytoplasm or attached to the rough ER. 7. Golgi Apparatus The Golgi apparatus is the cell’s packaging and distribution center. It modifies, sorts, and packages proteins and lipids that have been synthesized by the ER for transport to their final destinations. Function: Processes, packages, and distributes proteins and lipids. It also forms lysosomes and secretory vesicles. Structure: Composed of stacked, membrane-bound sacs called cisternae. 8. Lysosomes Lysosomes are membrane-bound organelles that contain digestive enzymes. They break down waste materials, cellular debris, and foreign invaders like bacteria. Function: Break down and recycle damaged organelles, macromolecules, and waste through a process called autophagy. Structure: Spherical organelles containing hydrolytic enzymes for digestion. 9. Peroxisomes Peroxisomes are small, membrane-bound organelles that contain enzymes used for breaking down fatty acids and detoxifying harmful substances, such as hydrogen peroxide. Function: Detoxification and lipid metabolism. Structure: Contain enzymes like catalase that break down reactive oxygen species. 10. Cytoskeleton 3  The cytoskeleton is a network of protein fibers that provide structural support, shape, and movement for the cell. It consists of microtubules, intermediate filaments, and microfilaments. Function: Maintains cell shape, aids in intracellular transport, and facilitates cell movement (e.g., in muscle contraction). Components: ✓ Microtubules: Hollow tubes that provide structure and are involved in cell division and transport. ✓ Microfilaments: Thin filaments that assist in movement and support. ✓ Intermediate Filaments: Provide mechanical strength to the cell. 11. Centrioles Centrioles are cylindrical structures involved in organizing microtubules during cell division. They are part of the centrosome, which regulates the formation of the mitotic spindle. Function: Play a role in cell division by forming the spindle fibers that separate chromosomes. Structure: Composed of microtubules arranged in a specific pattern. 12. Vacuoles Vacuoles are membrane-bound sacs used for storage, transport, and maintaining the internal environment of the cell. Function: Store nutrients, waste products, and other materials. In plant cells, the central vacuole also helps maintain turgor pressure, which is important for plant rigidity. 14. Cilia and Flagella Cilia and flagella are extensions of the cell membrane that are involved in movement. Cilia are short, hair-like structures that move substances along the surface of the cell, while flagella are long, whip-like structures that propel the cell itself. Function: Cilia: Move fluid, mucus, or cells over the cell surface. Flagella: Enable cell movement, such as the tail of a sperm cell. IV. Tissue Types and Components Tissues are groups of similar cells that work together to perform a specific function. The human body is made up of four primary types of tissues: epithelial, connective, muscle, and nervous tissues. Each type of tissue has a distinct structure that is adapted to its particular function. 1. Epithelial Tissue Epithelial tissue covers and lines surfaces throughout the body. It forms the outer layer of the skin, lines body cavities, and covers organs. This tissue type also forms glands. The cells in epithelial tissue are closely packed, with little space between them, and are arranged in continuous sheets. Functions: Protection, absorption, secretion, and filtration. Classifications: ✓ Simple Epithelium: Single layer of cells. Often found where absorption, secretion, and filtration occur (e.g., the lining of the intestines or alveoli in the lungs). ✓ Stratified Epithelium: Multiple layers of cells. Provides protection in areas exposed to wear and tear (e.g., skin). ✓ Shapes: Squamous (flat), Cuboidal (cube-like), and Columnar (tall and column-shaped). ✓ Example: Simple columnar epithelium lines the digestive tract and secretes mucus to protect the stomach lining and stratified squamous epithelium (found in the skin) Cartilage and Healing 2. Connective Tissue Connective tissue is the most abundant and widely distributed tissue type in the body. It connects, supports, binds, or separates other tissues or organs. Unlike epithelial tissue, the cells in connective tissue are usually spread out in an extracellular matrix that can vary from liquid (in blood) to solid (in bone). 4  Ground substance is the noncellular, gelatinous material found between cells in connective tissues. It is produced by connective tissue cells and consists of water, glycosaminoglycans, proteoglycans, and glycoproteins, providing a medium through which nutrients and waste products diffuse between blood and cells. Functions: Binding and supporting other tissues, protecting organs, insulating the body, storing energy, and transporting substances. ✓ Loose Connective Tissue: Includes areolar, adipose, and reticular tissue. It provides padding, insulation, and storage for fat. ✓ Dense Connective Tissue: Found in tendons and ligaments, providing strong, rope-like structures. ✓ Cartilage: Provides flexible support and is found in joints, the ear, and the nose. ✓ Bone (Osseous Tissue): Provides structural support and protection. ✓ Blood: A fluid connective tissue that transports oxygen, nutrients, and waste. ✓ Example: Adipose tissue (a type of loose connective tissue) stores fat and provides insulation and energy reserves. Fibrocartilage makes up intervertebral discs, providing cushioning and support. When tissues are damaged, regeneration occurs, where new functional tissue replaces the damaged one, restoring its original function. 3. Muscle Tissue Muscle tissue is specialized for contraction and movement. Muscle cells, also called fibers, can shorten in response to a stimulus and generate force. There are three types of muscle tissue, each with specific characteristics and locations in the body. Functions: Movement, maintaining posture, and generating heat. Types: ✓ Skeletal Muscle: Voluntary muscle attached to bones that enables movement. It has a striated appearance and is controlled consciously. ✓ Cardiac Muscle: Found only in the heart. It is involuntary, striated, and has intercalated discs that allow synchronized heart contractions. ✓ Smooth Muscle: Involuntary, non-striated muscle found in the walls of internal organs like the stomach, intestines, and blood vessels. It moves substances through the body by slow, rhythmic contractions. ✓ Example: Skeletal muscle is responsible for moving the skeleton and enabling voluntary movements like walking or lifting objects. 4. Nervous Tissue Nervous tissue is specialized for communication and control. It consists of neurons and supporting cells called neuroglia. Neurons are the basic structural and functional units of the nervous system, responsible for transmitting electrical signals throughout the body. The axon of the neuron carries impulses away from the cell body toward other cells, facilitating communication within the nervous system. Functions: Sensing stimuli, transmitting nerve impulses, and controlling responses. Components: ✓ Neurons: The cells that carry electrical impulses. They consist of a cell body, dendrites (which receive signals), and an axon (which transmits signals). ✓ Neuroglia: Support cells that nourish, protect, and assist neurons. ✓ Example: Motor neurons transmit impulses from the brain to muscles, resulting in movement. V. Cardiovascular System The cardiovascular system circulates blood throughout the body to provide oxygen, nutrients, and hormones while removing wastes like carbon dioxide. 5  Heart Pacemaker and Conduction System The heart’s primary pacemaker is the sinoatrial (SA) node, located in the right atrium. This node initiates electrical impulses that regulate the heart's rhythm. The impulse passes through the atrioventricular (AV) node, bundle of His, right and left bundle branches, and Purkinje fibers, triggering a coordinated contraction of the heart muscle. This pathway ensures proper timing of atrial and ventricular contractions. Coronary Circulation The heart muscle (myocardium) gets its blood supply through the right and left coronary arteries, which branch directly from the ascending aorta. This ensures the heart receives enough oxygen and nutrients to maintain its pumping function. Any obstruction of these arteries can lead to ischemia or infarction (heart attack). Heart Valves The heart has four valves that prevent the backflow of blood: Tricuspid valve: Located between the right atrium and right ventricle. Bicuspid (mitral) valve: Located between the left atrium and left ventricle, preventing backflow during ventricular contraction. The valves ensure one-way blood flow through the heart, maintaining efficiency during the cardiac cycle. Stroke Volume and Cardiac Output Stroke volume is the volume of blood pumped out by each ventricle with every beat, contributing to cardiac output—the total blood volume the heart pumps per minute. Reduced venous return leads to decreased stroke volume, ultimately lowering cardiac output. Pathway of Blood Flow through Pulmonary and Systemic Circulation The cardiovascular system circulates blood in two major loops: the pulmonary circulation and the systemic circulation. These two circuits work together to transport oxygen to tissues and remove carbon dioxide, maintaining homeostasis. 6  1. Pulmonary Circulation The pulmonary circulation is responsible for oxygenating blood by transporting it from the heart to the lungs and back. This process involves deoxygenated blood being sent to the lungs to exchange carbon dioxide for oxygen. Pathway: 1. Deoxygenated blood enters the right atrium from the body through the superior vena cava (from upper body) and inferior vena cava (from lower body). 2. The right atrium contracts, pushing blood through the tricuspid valve into the right ventricle. 3. The right ventricle contracts, and blood is pumped through the pulmonary valve into the pulmonary trunk, which branches into the right and left pulmonary arteries. 4. The pulmonary arteries carry deoxygenated blood to the lungs. 5. In the lungs, blood travels through smaller vessels until it reaches the capillaries surrounding the alveoli (air sacs). Here, carbon dioxide is exchanged for oxygen. 6. Oxygenated blood leaves the lungs through the pulmonary veins and returns to the left atrium of the heart. 2. Systemic Circulation The systemic circulation delivers oxygenated blood from the heart to all body tissues and returns deoxygenated blood back to the heart. This circuit provides cells with oxygen and nutrients while removing waste products like carbon dioxide. Pathway: 1. Oxygenated blood from the lungs enters the left atrium through the pulmonary veins. 2. The left atrium contracts, pushing blood through the bicuspid (mitral) valve into the left ventricle. 3. The left ventricle contracts forcefully, pumping blood through the aortic valve into the aorta (the body’s largest artery). 4. The aorta branches into smaller arteries, which further divide into arterioles and then capillaries. 5. In the capillaries, oxygen and nutrients are delivered to tissues, and carbon dioxide and waste products are picked up. 6. The now deoxygenated blood flows into venules, which converge into veins, and eventually return to the heart through the superior and inferior vena cavae, re-entering the right atrium, completing the cycle. Capillaries and Exchange Capillaries are the exchange vessels where gases, nutrients, and wastes are transferred between the blood and tissues. Diffusion is the primary mechanism for this exchange. Blood pressure is higher at the arterial end of the capillary, facilitating the movement of substances out of the bloodstream. Veins and Valves Veins have thinner walls compared to arteries and often contain valves to prevent the backflow of blood, particularly in the lower extremities. These valves are essential for returning blood to the heart, especially against gravity. Blood Vessels and Circulatory Dynamics ✓ The walls of blood vessels consist of three layers: ✓ Tunica intima (innermost): Composed of simple squamous epithelium. ✓ Tunica media (middle): Contains smooth muscle, regulating vessel diameter. ✓ Tunica externa (outermost): Provides structural support. ✓ Arteries are high-pressure vessels that carry oxygenated blood away from the heart (except for the pulmonary artery). ✓ Capillaries facilitate exchange between blood and tissues. ✓ Veins return deoxygenated blood to the heart, equipped with valves to prevent backflow. ✓ Blood pressure is highest in the arteries and lowest in the veins, as the force decreases as blood travels through the vascular system. VI. Respiratory System The respiratory system enables gas exchange, delivering oxygen to the blood and removing carbon dioxide. 7 Nasopharynx and Eustachian Tubes The nasopharynx contains openings for the eustachian tubes, which help equalize pressure between the middle ear and the atmosphere. Trachea and Bronchi The trachea is supported by cartilaginous rings, preventing it from collapsing during inhalation. It branches into the right and left bronchi, with the right bronchus being wider, making it more likely to trap inhaled foreign objects. Alveoli and Surfactant The lungs’ air sacs (alveoli) are where gas exchange occurs. Surfactant, a lipid-protein complex, reduces surface tension in the alveoli, preventing their collapse during exhalation. 8 VII. Lymphatic and Immune Systems The lymphatic system helps return excess tissue fluid to the bloodstream and plays a vital role in immune defense. Lymph Flow ✓ Lymph flows only toward the heart, moving through lymphatic vessels and passing through lymph nodes where immune responses are initiated. The thoracic duct and right lymphatic duct are the major vessels that return lymph to the venous circulation. Immune Function ✓ B cells, maturing in the bone marrow, produce antibodies in response to pathogens. MALT (Mucosa-Associated Lymphoid Tissue), including Peyer’s patches in the small intestine and tonsils, provides localized protection against pathogens at mucosal surfaces. VIII. Homeostasis and Body Systems Maintaining internal stability, or homeostasis, is essential for normal bodily function. The body uses negative feedback mechanisms to restore balance when variables deviate from their set points. Temperature Regulation If body temperature rises, vasodilation occurs in the blood vessels supplying the skin, allowing more heat to be released. Conversely, when body temperature is too low, the vessels constrict to conserve heat. 9