2402 Final Exam Review Topics
Final Exam Review Topics
Miscellaneous
Regional Terms: Terms used to describe specific areas of the body relative to other areas.
Directional Terms: Terms that explain the position of one structure relative to another (e.g., anterior, posterior, dorsal, ventral).
Anatomic Planes and Sections: Concepts that refer to the methods of dividing the body into sections for study (e.g., sagittal, coronal, transverse).
Body Cavities: Spaces within the body that house organs and structures, including the cranial, thoracic, abdominal, and pelvic cavities.
Chapter 18: Blood
Functions of Blood:
Transport of oxygen and carbon dioxide through red blood cells (RBCs).
Distribution of nutrients, hormones, and waste products.
Regulation of body temperature, pH, and fluid balance.
Protection against infections through immune functions.
Functions of Blood Components:
Red Blood Cells (Erythrocytes): Carry oxygen.
White Blood Cells (Leukocytes): Part of the immune system, defend against pathogens.
Platelets (Thrombocytes): Involved in blood clotting.
Blood Types:
Antibodies: Proteins in the blood plasma that recognize foreign antigens.
Antigens: Molecules on the surface of red blood cells that determine blood type (A, B, AB, O).
Transfusions: The process of transferring blood into a patient’s circulation; must match blood types to prevent reactions.
Blood Cell Production:
Occurs in bone marrow.
Hormone: Erythropoietin stimulates the production of RBCs.
Stimulus: Low oxygen levels (hypoxia) trigger erythropoiesis.
Hematocrit:
Definition: The proportion of blood volume that is occupied by red blood cells.
Norms: Typically 38-45% in healthy adults.
Anemia: Condition characterized by low hematocrit or hemoglobin levels.
Polycythemia: Increased hematocrit, often due to dehydration or a bone marrow disorder.
Chapter 19: Heart
Blood Flow Through the Heart:
Pathway: Blood flows from the body into the right atrium → right ventricle → lungs → left atrium → left ventricle → body.
Composition: Blood is oxygen-poor in the right side of the heart and oxygen-rich in the left side of the heart.
What Causes Blood Movement:
Contraction of the heart muscle (myocardium) creates pressure that pushes blood through the chambers.
Cardiac Conduction Pathway:
Sequence of electrical impulses from the sinoatrial (SA) node through the atrioventricular (AV) node and into the ventricles.
Electrocardiogram (ECG):
Waves/Complexes: P wave (atrial depolarization), QRS complex (ventricular depolarization), T wave (ventricular repolarization).
Significance of each component in heart function assessment.
Calcium's Effect:
Calcium ions play a crucial role in cardiac muscle contraction; higher calcium levels can enhance heart contractility.
Chapter 20: Blood Vessels
Functions of Vessels:
Transport blood throughout the body.
Regulation of blood flow and pressure.
Exchange of gases, nutrients, and waste.
Pressure Along Blood Vessel Path:
Blood pressure decreases as blood moves away from the heart through arteries, arterioles, and ultimately to capillaries.
Consequences of Blood Pressure Levels:
Conditions associated with low blood pressure (hypotension) include dizziness or fainting.
High blood pressure (hypertension) can lead to heart disease and other complications.
Blood Flow Changes at Rest vs. Exercise:
Increased demand for oxygen during exercise increases blood flow to muscles.
Effects of Blood Doping:
Practice of increasing red blood cell count to enhance athletic performance, raising ethical concerns and risks of cardiovascular issues.
Adjustment to Low Venous Pressure:
Body uses muscle pumps and valves in veins to facilitate the return of blood to the heart.
Baroreceptor Reflex:
Mechanism by which blood pressure is regulated through reflex responses to changes in blood vessel stretch.
Chapter 21: Lymphatic System
Function of Lymphatic System:
Return excess interstitial fluid to the bloodstream.
Maintain fluid balance in the body.
Facilitate immune responses and filter pathogens.
Primary and Secondary Organs:
Primary: Bone marrow, thymus (where lymphocytes are produced and mature).
Secondary: Lymph nodes, spleen (where immune responses are triggered).
Chapter 22: Immune System
Innate vs. Adaptive Immune Response:
Innate: Non-specific defense mechanisms (e.g., barriers, phagocytes) that respond quickly to pathogens.
Adaptive: Specific response involving lymphocytes (B-cells and T-cells) that takes longer to activate but provides memory.
Cell-Mediated vs. Humoral Immunity:
Cell-Mediated: Involves T-cells that destroy infected cells.
Humoral Immunity: Involves B-cells and the production of antibodies that neutralize pathogens.
Antibody Classes:
Different types of antibodies (IgG, IgA, IgM, IgE, IgD) and their unique functions in immune response.
Immune Cell Functions:
Varied roles of different leukocytes in defending the body.
Importance of Helper T/CD4 Cells:
Critical in orchestrating the immune response and activating B-cells and cytotoxic T-cells.
Vaccines:
Prep of the immune system to recognize and combat pathogens by introducing a harmless form of the antigen.
Chapter 23: Respiratory System
Pathway of Air:
Sequence: Nasal cavity → pharynx → larynx → trachea → bronchi → bronchioles → alveoli.
Pulmonary Ventilation:
Definition: The process of air movement into and out of the lungs.
Process: Inhalation (diaphragm contracts, thoracic cavity expands) and exhalation (diaphragm relaxes).
Stimulus to Breathe:
Primarily regulated by CO2 levels in the blood detected by chemoreceptors.
Effects of Respiratory Diseases:
Asthma: Airway constriction, difficulty breathing.
Emphysema: Destruction of alveoli, reduced gas exchange efficiency.
Pneumonia: Alveoli fill with fluid or pus, impaired gas exchange.
Hyperventilation/Hypoventilation:
Hyperventilation: Excessive breathing, leads to low CO2 (hypocapnia), elevated pH (alkalosis).
Hypoventilation: Insufficient breathing, leading to high CO2 (hypercapnia), lowered pH (acidosis).
Gas Exchange:
Occurs in the alveoli where oxygen diffuses into the blood and CO2 diffuses out.
Surfactant Function:
Reduces surface tension in the alveoli, preventing collapse and aiding in lung expansion.
Chapter 24: Urinary System
Kidney Functions:
Regulate fluid and electrolyte balance, filter blood, remove waste products, produce hormones (e.g., erythropoietin).
Body's Response:
Dehydration: Release of aldosterone and ADH to conserve water.
High Blood Pressure: Release of natriuretic peptides to increase urine output.
Low Blood Pressure: Activation of the renin-angiotensin-aldosterone system (RAAS) to conserve volume and increase pressure.
Characteristics of Urine:
Normal urine is typically clear, light yellow; abnormalities may indicate disease (e.g., dark urine in dehydration).
Urinary Tract Infections (UTI):
Caused by bacteria, commonly affecting bladder or urethra.
Micturition Reflex:
The process of urination initiated by the stretching of the bladder, leading to neural signals for muscle contraction and relaxation of the sphincters.
Chapter 25: Fluid and Electrolytes
Compensations through Kidneys:
Regulation of electrolytes and acid-base balance through filtration and reabsorption.
Regulating Fluid Intake:
Controlled by thirst mechanisms activated by osmotic pressure or blood volume monitoring.
Arterial Blood Gases (ABG):
Measures to assess respiratory function; relates to conditions of acidosis vs. alkalosis:
Respiratory Acidosis: High CO2 from impaired respiration.
Respiratory Alkalosis: Low CO2 from hyperventilation.
Metabolic Acidosis/Alkalosis: Changes in bicarbonate levels.
Chemical Buffers:
Systems (e.g., bicarbonate, phosphate) that help maintain pH balance in the body.
Chapter 26: Digestive System
Organs:
Functions: Breakdown of food, absorption of nutrients, and elimination of waste.
Secretions: Enzymes and acids that aid digestion (e.g., saliva, gastric juice).
Functions of the Secretions: Facilitate chemical breakdown and prepare food for absorption.
Increasing Surface Area in Small Intestine:
Structures such as villi and microvilli significantly increase absorptive surface area, enhancing nutrient uptake.
Chapter 28/29: Reproductive System and G&D
Functions of Organs:
Male: Testes produce sperm and hormones (such as testosterone).
Female: Ovaries produce eggs and hormones (estrogen and progesterone).
Homologs of Males and Females:
Comparison of male and female reproductive structures that arise from common embryonic tissues.
Functions of Myometrium and Endometrium:
Myometrium: Muscle layer that contracts during labor.
Endometrium: Lining of the uterus, thickens and sheds during menstrual cycle.
Ovarian Cycle Phases Overlapping with Uterine Cycle Phases:
Phases where the uterine lining prepares for potential pregnancy; includes follicular and luteal phases.
Male Sexual Response:
Involves arousal, plateau, orgasm, and resolution phases governed by hormones and neural responses.
Differences between Spermatogenesis and Oogenesis:
Spermatogenesis: Continuous process producing millions of sperm daily.
Oogenesis: Discrete cyclical process producing one viable egg per menstrual cycle.
Hormone Functions:
Roles of hormones in regulation and function of reproductive system processes and cycles.
Hormones and Follicle/Corpus Luteum Development:
Hormonal changes such as estrogen and progesterone levels drive changes in these structures during the ovarian cycle phases.
Stages of Development from Fertilization to Blastocyst:
Early development stages leading to implantation in the uterine lining.
Importance of hCG:
Human chorionic gonadotropin (hCG) vital in maintaining early pregnancy by signaling the corpus luteum to continue hormone production.
Semen and Seminal Fluid:
Composition and role in nourishing and transporting sperm.
Puberty in Males vs. Females:
Different hormonal changes and physical developments during sexual maturation of each gender.
Chapter 17: Endocrine System
Study Your Hormone Chart:
Familiarize with key hormones, their sources, and actions.
Diseases and Disorders:
Key diseases associated with hormonal imbalances or organ dysfunctions.
Water-Soluble vs. Lipid-Soluble Hormones:
Water-soluble hormones (e.g., insulin) act via receptors on cell surfaces.
Lipid-soluble hormones (e.g., steroid hormones) can pass through cell membranes and bind to intracellular receptors.
Relationship Between Hormones and Receptors:
Specificity and signal transduction mechanisms of hormone-receptor interactions.
Nervous System vs. Endocrine System:
Comparison of signaling mechanisms, response times, and effects between these two systems.
Heredity
Terms: Define key terms related to genetics (e.g., allele, genotype, phenotype).
Types of Inheritance: Explain different inheritance patterns (e.g., autosomal dominant, recessive, co-dominance).
Reading Punnett Squares and Pedigrees:
Understand how to predict inheritance patterns and trace ancestry or traits through generations.
Final Exam Review Topics
Miscellaneous
Regional Terms: Terms used to describe specific areas of the body relative to other areas, providing a common language for anatomical locations.
Examples: Cephalic (head), cervical (neck), thoracic (chest), brachial (arm), femoral (thigh), pedal (foot).
Directional Terms: Terms that explain the position of one structure relative to another, aiding in clear communication about body structures.
Examples: Anterior (front)/Posterior (back), Superior (above)/Inferior (below), Medial (toward midline)/Lateral (away from midline), Proximal (closer to trunk)/Distal (farther from trunk), Superficial (closer to surface)/Deep (farther from surface), Dorsal (back side)/Ventral (belly side).
Anatomic Planes and Sections: Concepts that refer to the methods of dividing the body into sections for study, visualizing internal structures in 2D.
Sagittal Plane: Divides the body into left and right portions. A midsagittal plane divides it into equal left and right halves.
Coronal (Frontal) Plane: Divides the body into anterior (front) and posterior (back) portions.
Transverse (Horizontal) Plane: Divides the body into superior (upper) and inferior (lower) portions.
Body Cavities: Spaces within the body that house organs and structures, providing protection and allowing for organ movement.
Dorsal Cavity: Contains the cranial cavity (brain) and vertebral cavity (spinal cord).
Ventral Cavity:
Thoracic Cavity: Contains the lungs (pleural cavities) and heart (pericardial cavity), separated from the abdominal cavity by the diaphragm.
Abdominopelvic Cavity: Comprises the abdominal cavity (stomach, liver, intestines, etc.) and the pelvic cavity (bladder, reproductive organs, rectum).
Chapter 18: Blood
Functions of Blood: A vital connective tissue with multiple roles in maintaining homeostasis.
Transport: Carries oxygen from the lungs to tissues via hemoglobin in red blood cells (RBCs), and carbon dioxide from tissues back to the lungs. Also distributes nutrients from the digestive tract, hormones from endocrine glands, and metabolic waste products to kidneys and liver for excretion.
Regulation: Helps maintain body temperature by absorbing and distributing heat, regulates pH through buffer systems (e.g., bicarbonate buffer system), and maintains adequate fluid volume with salts and blood proteins.
Protection: Guards against infection through white blood cells (WBCs), antibodies, and complement proteins. Prevents blood loss by forming clots through platelets and plasma proteins.
Functions of Blood Components:
Red Blood Cells (Erythrocytes): Biconcave discs without nuclei, primarily responsible for oxygen transport due to their high content of hemoglobin. Also transport a small amount of carbon dioxide.
White Blood Cells (Leukocytes): Diverse group of immune cells that defend the body against pathogens (bacteria, viruses, parasites, tumor cells) and remove dead cells and debris. Includes neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
Platelets (Thrombocytes): Small, anucleated cell fragments derived from megakaryocytes, vital for hemostasis (blood clotting) by forming a plug and releasing factors that promote coagulation.
Blood Types: Classified based on the presence or absence of specific antigens on the surface of red blood cells.
Antigens: Genetically determined glycoproteins and glycolipids on the surface of RBCs (e.g., A, B, Rh factors). Determine a person's blood type (A, B, AB, O) and Rh status (+ or -).
Antibodies: Proteins (immunoglobulins) found in the blood plasma that are produced in response to foreign antigens. They will agglutinate (clump) red blood cells expressing the corresponding antigen (e.g., anti-A antibodies clump A antigens).
Transfusions: The process of transferring blood or blood components into a patient’s circulation. Requires careful cross-matching to ensure compatibility between donor and recipient blood types to prevent severe immunological reactions caused by agglutination of donor RBCs by recipient antibodies. O-negative is the universal donor (lacks A, B, and Rh antigens), while AB-positive is the universal recipient (lacks anti-A, anti-B, and anti-Rh antibodies).
Blood Cell Production (Hematopoiesis):
Occurs primarily in the red bone marrow of axial skeleton, girdles, and proximal epiphyses of the humerus and femur.
Hormone: Erythropoietin (EPO), a glycoprotein hormone produced mainly by the kidneys, stimulates the committed stem cells in bone marrow to differentiate into red blood cells (erythropoiesis).
Stimulus: Low oxygen levels (hypoxia) in the blood, often due to decreased RBC count, decreased availability of oxygen, or increased tissue demands, trigger the kidneys to release erythropoietin.
Other growth factors and cytokines stimulate the production of white blood cells (leukopoiesis) and platelets (thrombopoiesis).
Hematocrit:
Definition: The proportion of blood volume that is occupied by red blood cells, expressed as a percentage. It reflects the oxygen-carrying capacity of the blood.
Norms: Typically ranges from 38-45\% in healthy women and 42-50\% in healthy men.
Anemia: Condition characterized by abnormally low hematocrit or hemoglobin levels, indicating reduced oxygen-carrying capacity. Can be caused by blood loss, decreased RBC production, or increased RBC destruction.
Polycythemia: Increased hematocrit, meaning an abnormally high red blood cell count. This can be physiological (e.g., living at high altitudes) or pathological (e.g., bone marrow cancer, dehydration leading to concentrated blood), increasing blood viscosity and risk of clotting.
Chapter 19: Heart
Blood Flow Through the Heart: The circulatory path ensuring oxygenated blood reaches systemic tissues and deoxygenated blood returns to the lungs.
Pathway: Deoxygenated blood from the body enters the right atrium via the superior and inferior vena cava → passes through the tricuspid valve into the right ventricle → ejected through the pulmonary semilunar valve into the pulmonary artery to the lungs (for oxygenation) → oxygenated blood returns from the lungs via the pulmonary veins into the left atrium → passes through the mitral (bicuspid) valve into the left ventricle → ejected through the aortic semilunar valve into the aorta to the body.
Composition: Blood on the right side of the heart (right atrium and right ventricle) is oxygen-poor (deoxygenated), while blood on the left side of the heart (left atrium and left ventricle) is oxygen-rich (oxygenated).
What Causes Blood Movement:
The rhythmic contraction of the heart muscle (myocardium) creates pressure gradients that drive blood through the chambers and into the circulatory system. This is regulated by the cardiac cycle, involving cycles of systole (contraction) and diastole (relaxation).
Cardiac Conduction Pathway: The specialized electrical system that generates and transmits impulses, ensuring coordinated heart contractions.
Sequence: Electrical impulses originate spontaneously in the sinoatrial (SA) node (the heart's natural pacemaker) → spread across the atria, causing atrial depolarization and contraction → converge at the atrioventricular (AV) node (where impulse is delayed) → transmitted down the Bundle of His → into the right and left bundle branches → finally distributed throughout the ventricular walls by the Purkinje fibers, causing ventricular depolarization and contraction.
Electrocardiogram (ECG): A graphic recording of the electrical activity that accompanies each heartbeat, used to assess cardiac function.
Waves/Complexes:
P wave: Represents atrial depolarization, which leads to atrial contraction.
QRS complex: Represents ventricular depolarization, which triggers ventricular contraction. Atrial repolarization occurs simultaneously but is masked by the larger QRS complex.
T wave: Represents ventricular repolarization, indicating the recovery of the ventricular muscle for the next beat.
Significance: Abnormalities in these waves, intervals, or segments on an ECG can indicate various heart conditions, such as arrhythmias, myocardial ischemia, or hypertrophy.
Calcium's Effect:
Calcium ions (Ca^{2+}) play a crucial role in cardiac muscle excitation-contraction coupling. Following depolarization, Ca^{2+} enters the cardiac muscle cells from the extracellular fluid and sarcoplasmic reticulum, binding to troponin and initiating the sliding filament mechanism that causes contraction.
Higher extracellular calcium levels or increased influx of Ca^{2+} can enhance heart contractility (positive inotropic effect), leading to a stronger heartbeat.
Chapter 20: Blood Vessels
Functions of Vessels: The intricate network of arteries, capillaries, and veins that carry blood throughout the body.
Transport: Arteries carry oxygenated blood away from the heart, veins return deoxygenated blood to the heart, and capillaries are sites of exchange.
Regulation of Blood Flow and Pressure: Arterioles, through vasoconstriction and vasodilation, regulate blood flow to specific tissues and contribute significantly to overall blood pressure.
Exchange of Gases, Nutrients, and Waste: Capillaries, with their thin walls and large surface area, are the primary sites where oxygen, nutrients, hormones, and waste products are exchanged between blood and tissues.
Pressure Along Blood Vessel Path:
Blood pressure is highest in the aorta and large arteries (systolic around 120 mmHg, diastolic around 80 mmHg) and progressively decreases as blood moves away from the heart through the arterial system (arteries, arterioles), dropping significantly across the capillary beds due to increased resistance and total cross-sectional area. It continues to decrease in venules and veins, reaching nearly zero in the right atrium.
Consequences of Blood Pressure Levels:
Low Blood Pressure (Hypotension): Can lead to inadequate blood flow to tissues (ischemia), causing symptoms like dizziness, lightheadedness, or fainting (syncope), especially upon standing (orthostatic hypotension). Severe hypotension can result in shock.
High Blood Pressure (Hypertension): Persistently elevated blood pressure (typically 140/90 mmHg or higher) is a major risk factor for heart disease (coronary artery disease, heart failure), stroke, kidney disease, and peripheral artery disease, as it damages blood vessel walls and forces the heart to work harder.
Blood Flow Changes at Rest vs. Exercise:
At rest, blood flow is distributed to various organs, with a significant proportion going to digestive organs, kidneys, and brain.
During exercise, there is a dramatic redistribution of blood flow. Increased demand for oxygen and nutrients in active skeletal muscles leads to widespread vasodilation in those muscles, significantly increasing blood flow to them, while blood flow to less active areas (e.g., digestive organs, kidneys) is reduced via vasoconstriction.
Effects of Blood Doping:
Practice of artificially increasing red blood cell count, often through erythropoietin (EPO) injections or blood transfusions, to enhance athletic performance by improving oxygen-carrying capacity.
Risks: Raises ethical concerns and poses significant cardiovascular risks, including increased blood viscosity, which can lead to blood clots, stroke, heart attack, and heart failure.
Adjustment to Low Venous Pressure:
Because venous pressure is low, several mechanisms facilitate the return of blood to the heart:
Skeletal Muscle Pump: Contraction of skeletal muscles surrounding deep veins compresses them, milking blood toward the heart. One-way valves in veins prevent backflow.
Respiratory Pump: Changes in intra-abdominal and intra-thoracic pressures during breathing help to suck blood toward the heart.
Venous Tone: Sympathetic venoconstriction reduces venous volume and pushes blood toward the heart.
Baroreceptor Reflex:
A critical short-term mechanism for regulating blood pressure. Baroreceptors (pressure receptors) located in the carotid sinuses and aortic arch detect changes in arterial blood pressure.
When blood pressure increases, baroreceptors send signals to the cardiovascular center in the medulla oblongata, triggering parasympathetic activation (decreasing heart rate and contractility) and sympathetic inhibition (vasodilation), which lowers blood pressure. The opposite occurs when blood pressure decreases.
Chapter 21: Lymphatic System
Function of Lymphatic System: A vast network of vessels, tissues, and organs that plays a vital role in fluid balance and immunity.
Return Excess Interstitial Fluid: Collects lymph (tissue fluid and plasma proteins) that leaks from blood capillaries and returns it to the bloodstream, preventing edema and maintaining blood volume.
Maintain Fluid Balance: Essential for maintaining blood volume and pressure, as well as the protein content of blood.
Facilitate Immune Responses: Lymphatic vessels transport immune cells (lymphocytes) and foreign substances to lymph nodes, where immune responses are initiated and pathogens are filtered out.
Absorb Dietary Fats: Specialized lymphatic capillaries (lacteals) in the small intestine absorb digested fats and transport them to the bloodstream.
Primary and Secondary Organs:
Primary Lymphoid Organs: Sites where lymphocytes (T and B cells) are produced and mature, becoming immunocompetent.
Bone Marrow: Produces all blood cells, including B lymphocytes (which mature here) and pre-T lymphocytes.
Thymus: Site where T lymphocytes mature and gain the ability to recognize specific antigens.
Secondary Lymphoid Organs: Sites where mature, immunocompetent lymphocytes encounter antigens and are activated to mount an immune response.
Lymph Nodes: Small, bean-shaped organs clustered along lymphatic vessels, filtering lymph and housing lymphocytes that detect and destroy pathogens.
Spleen: The largest lymphoid organ, filters blood, removes old RBCs, and is a site for lymphocyte proliferation and immune surveillance against blood-borne pathogens.
Tonsils, Peyer's Patches, Appendix: Mucosa-Associated Lymphoid Tissues (MALT) that protect against pathogens entering the body through mucosal surfaces.
Chapter 22: Immune System
Innate vs. Adaptive Immune Response: Two main categories of the body's defense mechanisms.
Innate (Non-Specific) Immunity: The body's first line of defense, providing immediate, general protection against a wide range of pathogens. It does not require prior exposure and lacks memory.
Components: Physical barriers (skin, mucous membranes), chemical barriers (acid in stomach, enzymes in tears), phagocytic cells (neutrophils, macrophages), natural killer (NK) cells, inflammation, fever, and antimicrobial proteins (e.g., complement, interferons).
Adaptive (Specific) Immunity: A more specialized and potent defense system that targets specific pathogens and provides long-term protection. It takes longer to activate but exhibits specificity and immunological memory.
Components: Lymphocytes (B-cells and T-cells) and antigen-presenting cells (APCs).
Cell-Mediated vs. Humoral Immunity: The two arms of adaptive immunity.
Cell-Mediated Immunity: Primarily involves T-cells (T lymphocytes) that directly attack and destroy infected cells (e.g., virus-infected cells, cancer cells) or activate other immune cells. It is particularly effective against intracellular pathogens and abnormal body cells.
Key Players: Cytotoxic T-cells (CD8 cells), Helper T-cells (CD4 cells), Regulatory T-cells.
Humoral Immunity (Antibody-Mediated): Involves B-cells (B lymphocytes) and the production of antibodies (immunoglobulins) that circulate in body fluids (humors). Antibodies bind to extracellular pathogens (bacteria, viruses in body fluids) and their toxins, neutralizing them and marking them for destruction by other immune cells.
Key Players: B-cells, plasma cells (antibody-secreting B-cells), antibodies.
Antibody Classes: Five major classes of antibodies, each with unique structures and functions:
IgG: Most abundant (75-80%) in plasma, crosses the placenta to confer passive immunity to fetus, involved in secondary immune response.
IgA: Found in secretions (mucus, tears, saliva, breast milk), protects mucosal surfaces.
IgM: Pentamer, first antibody produced in primary immune response, potent agglutinating agent.
IgE: Involved in allergic reactions and combating parasitic infections, binds to mast cells and basophils.
IgD: Functions as a B-cell receptor (BCR), important for B-cell activation.
Immune Cell Functions: Varied roles of different leukocytes in defending the body.
Neutrophils: Phagocytes, first responders to bacterial infection, release antimicrobial chemicals.
Macrophages: Large phagocytes, engulf pathogens and cellular debris, act as antigen-presenting cells (APCs).
Lymphocytes (T and B cells): Key players in adaptive immunity, responsible for specific recognition and memory.
Eosinophils: Combat parasitic infections, modulate allergic reactions.
Basophils/Mast Cells: Release histamine and other inflammatory mediators in allergic reactions.
Dendritic Cells: Potent APCs, critical for initiating adaptive immune responses.
Importance of Helper T/CD4 Cells:
Critical Orchestrators: Helper T-cells (Th or CD4 cells) are central to the adaptive immune response. They do not directly kill infected cells but recognize antigens presented by APCs and then secrete cytokines.
Activation: These cytokines activate B-cells (for antibody production), cytotoxic T-cells (CD8 cells, for cell-mediated killing), and other immune cells like macrophages, thereby coordinating and amplifying the entire immune response.
Vaccines:
A biological preparation that provides active artificial immunity to a particular infectious disease. It works by introducing a harmless or attenuated form of a pathogen (or its antigens/toxoids) into the body.
This exposure stimulates the immune system to produce antibodies and memory cells against the pathogen without causing the disease. Upon subsequent exposure to the actual pathogen, the immune system can mount a rapid and robust secondary immune response, preventing illness.
Chapter 23: Respiratory System
Pathway of Air: The sequence of structures through which air travels during breathing.
Sequence: Air enters through the nasal cavity (or oral cavity) → passes through the pharynx (throat, common pathway for air and food) → enters the larynx (voice box, contains vocal cords) → moves into the trachea (windpipe, cartilaginous tube) → branches into two main bronchi → further divides into progressively smaller bronchioles → finally reaches the microscopic air sacs called alveoli (where gas exchange occurs).
Pulmonary Ventilation:
Definition: The process of air movement into (inhalation/inspiration) and out of (exhalation/expiration) the lungs. It is driven by pressure changes within the thoracic cavity.
Process:
Inhalation: The diaphragm contracts (moves downward) and the external intercostal muscles contract (pulling rib cage upward and outward), increasing the volume of the thoracic cavity. This decreases intrapulmonary pressure below atmospheric pressure, causing air to rush into the lungs.
Exhalation: Primarily a passive process at rest. The diaphragm relaxes and moves upward, and external intercostals relax, decreasing thoracic cavity volume. This increases intrapulmonary pressure above atmospheric pressure, forcing air out of the lungs (elastic recoil). Forced exhalation involves contraction of internal intercostals and abdominal muscles.
Stimulus to Breathe:
Primarily regulated by CO2 levels (and thus pH) in the blood and cerebrospinal fluid (CSF), detected by chemoreceptors.
Central Chemoreceptors: Located in the brainstem (medulla oblongata), they are highly sensitive to changes in P_{CO2} and pH in the CSF. A rise in CO2 (hypercapnia) leads to a drop in CSF pH, strongly stimulating increased breathing rate and depth.
Peripheral Chemoreceptors: Located in the carotid bodies and aortic arch, they are sensitive to changes in arterial P{CO2} and P{O2}. While less sensitive to P{CO2} than central chemoreceptors, they are critically important for sensing decreases in P{O2} (hypoxemia), which becomes a primary stimulus when P_{O2} drops significantly (below 60 mmHg).
Effects of Respiratory Diseases:
Asthma: Chronic inflammatory disease characterized by airway constriction (bronchospasm), mucus production, and airway hyperactivity, leading to recurrent episodes of wheezing, shortness of breath, chest tightness, and coughing.
Emphysema: A type of COPD (Chronic Obstructive Pulmonary Disease) characterized by the progressive destruction of the elastic walls of the alveoli, leading to enlarged air spaces and a significant reduction in surface area for gas exchange, impairing oxygen uptake and CO2 removal.
Pneumonia: An infection that inflames the air sacs (alveoli) in one or both lungs, causing them to fill with fluid or pus, severely impairing gas exchange and leading to symptoms like cough, fever, chills, and difficulty breathing.
Hyperventilation/Hypoventilation:
Hyperventilation: Excessive breathing (rate and/or depth) that removes CO2 from the blood faster than it is produced. This leads to low CO2 (hypocapnia), which causes a shift in the bicarbonate buffer system, resulting in elevated pH (respiratory alkalosis). Symptoms include dizziness, tingling, and muscle spasms.
Hypoventilation: Insufficient breathing to meet metabolic demands or remove CO2 effectively. This leads to high CO2 (hypercapnia) in the blood, which shifts the buffer system, resulting in lowered pH (respiratory acidosis). Can be caused by airway obstruction, drug overdose, or respiratory muscle weakness.
Gas Exchange:
Occurs in the alveoli (lungs) and in the tissue capillaries. It is driven by partial pressure gradients of oxygen (P{O2}) and carbon dioxide (P{CO2}) between the blood and the air (in lungs) or tissues (in systemic capillaries).
In the lungs, oxygen diffuses from the alveoli (high P{O2}) into the blood (low P{O2}), while CO2 diffuses from the blood (high P{CO2}) into the alveoli (low P{CO2}).
In the tissues, the gradients are reversed: oxygen diffuses from the blood into the tissues, and CO2 diffuses from the tissues into the blood.
Surfactant Function:
A complex mixture of phospholipids and lipoproteins secreted by Type II alveolar cells. It forms a film on the inner surface of the alveoli.
Reduces surface tension of the alveolar fluid, which otherwise would cause the thin-walled alveoli to collapse due to water's strong cohesive forces. By reducing surface tension, surfactant prevents alveolar collapse, reduces the work of breathing, and aids in lung expansion during inspiration.
Chapter 24: Urinary System
Kidney Functions: Paired organs that play central roles in maintaining body homeostasis.
Filter Blood: Remove metabolic waste products (urea, creatinine, uric acid) from the blood, forming urine.
Regulate Fluid and Electrolyte Balance: Control total body water and the concentration of various ions (Na+, K+, Ca2+, Cl-, PO4^3-) by selectively reabsorbing or secreting them.
Regulate Acid-Base Balance: Adjust plasma pH by conserving bicarbonate ions and excreting hydrogen ions.
Produce Hormones: Secrete renin (to regulate blood pressure), erythropoietin (to stimulate RBC production), and convert vitamin D to its active form (calcitriol, for calcium homeostasis).
Body's Response in Specific Situations: Hormonal mechanisms that enable the kidneys to maintain homeostasis.
Dehydration: Triggers the release of Antidiuretic Hormone (ADH) from the posterior pituitary and Aldosterone from the adrenal cortex.
ADH: Increases water reabsorption in the collecting ducts and distal convoluted tubule, conserving water and producing a concentrated urine.
Aldosterone: Increases Na+ reabsorption (and thus water follows) and K+ secretion in the distal convoluted tubule and collecting duct, leading to volume conservation.
High Blood Pressure (Hypervolemia): Triggers the release of Natriuretic Peptides (ANP and BNP) from the heart. These hormones inhibit ADH and renin release, decrease Na+ reabsorption, and promote vasodilation, all leading to increased urine output (diuresis and natriuresis) and a reduction in blood volume and pressure.
Low Blood Pressure (Hypotension/Hypovolemia): Activates the Renin-Angiotensin-Aldosterone System (RAAS).
Renin is released by the kidneys, leading to the formation of angiotensin II, a potent vasoconstrictor that also stimulates aldosterone and ADH release. This system collectively acts to conserve volume, increase thirst, and induce vasoconstriction to raise blood pressure.
Characteristics of Urine: Diagnostic indicators of kidney function and overall health.
Normal urine is typically clear to light yellow (due to urochrome pigment), with a slight aromatic odor, and a pH ranging from 4.5 to 8.0 (average 6.0). Its specific gravity (measure of solute concentration) ranges from 1.003 to 1.030.
Abnormalities (e.g., dark urine in dehydration, foamy urine indicating protein, presence of glucose, blood, or ketones) may indicate disease or metabolic imbalance.
Urinary Tract Infections (UTI):
Caused by proliferation of bacteria (most commonly E. coli) that ascend the urinary tract.
Commonly affect the bladder (cystitis) or urethra (urethritis), causing symptoms like painful urination (dysuria), frequent urge to urinate, urgency, and lower abdominal discomfort. If untreated, they can ascend to the kidneys (pyelonephritis), leading to more severe symptoms and potential kidney damage.
Micturition Reflex:
The process of urination, partially voluntary and partially involuntary.
Initiated by the stretching of the bladder wall as it fills with urine, which activates stretch receptors. These receptors send afferent signals to the sacral region of the spinal cord.
This leads to parasympathetic efferent signals that stimulate the detrusor muscle (bladder wall muscle) to contract and inhibit the internal urethral sphincter to relax. Conscious control allows for coordinated relaxation of the external urethral sphincter for voluntary voiding.
Chapter 25: Fluid and Electrolytes
Compensations through Kidneys: The kidneys are the primary organs for long-term regulation of fluid and electrolyte balance and acid-base homeostasis.
Electrolyte Regulation: By adjusting filtration, reabsorption, and secretion rates, kidneys precisely control the levels of key electrolytes like Na+, K+, Cl-, Ca2+, and phosphate, responding to hormonal cues (e.g., aldosterone, ADH, PTH).
Acid-Base Balance: Compensate for respiratory or metabolic acid-base imbalances by selectively reabsorbing or generating new bicarbonate ions (a major buffer) and excreting hydrogen ions (H^{+}) or ammonium ions in the urine.
Regulating Fluid Intake:
Primarily controlled by the thirst mechanism, which is a conscious desire to drink.
Thirst is activated by a rise in plasma osmolarity (detected by osmoreceptors in the hypothalamus), a significant decrease in blood volume or pressure (detected by baroreceptors and triggering RAAS), or dry mouth.
Arterial Blood Gases (ABG): A diagnostic test that measures the pH, partial pressure of oxygen (P{O2}), partial pressure of carbon dioxide (P{CO2}), and bicarbonate (HCO_{3}^{-})) levels in arterial blood. Used to assess respiratory function and acid-base balance. Relates to conditions of acidosis vs. alkalosis:
Respiratory Acidosis: Characterized by a low pH (pH < 7.35) and high P{CO2} (P{CO2} > 45 mmHg), usually from impaired or inadequate respiration (hypoventilation), leading to excessive accumulation of CO2 in the blood.
Respiratory Alkalosis: Characterized by a high pH (pH > 7.45) and low P{CO2} (P{CO2} < 35 mmHg), typically from excessive breathing (hyperventilation), leading to rapid expulsion of CO2 from the body.
Metabolic Acidosis: Characterized by a low pH (pH < 7.35) and low HCO{3}^{-} (HCO{3}^{-} < 22 mEq/L), resulting from an accumulation of metabolic acids (e.g., lactic acid, ketoacids) or excessive loss of bicarbonate (e.g., severe diarrhea).
Metabolic Alkalosis: Characterized by a high pH (pH > 7.45) and high HCO{3}^{-} (HCO{3}^{-} > 26 mEq/L), usually due to loss of stomach acid (e.g., prolonged vomiting) or excessive intake of antacids.
Compensation: The body attempts to correct acid-base imbalances through respiratory (changing CO2 exhalation) or renal (changing HCO_{3}^{-} and H^{+} excretion) mechanisms.
Chemical Buffers:
Systems composed of a weak acid and its conjugate base that resist drastic changes in pH by either binding to excess H^{+} or releasing H^{+} when needed. They act very rapidly.
Bicarbonate Buffer System: Most important extracellular buffer, involves carbonic acid (H{2}CO{3}) and bicarbonate ions (HCO_{3}^{-}); closely linked to respiratory and renal regulation.
Phosphate Buffer System: Important intracellular buffer and in urine.
Protein Buffer System: Most abundant buffer in the body, primarily intracellular (e.g., hemoglobin in RBCs, plasma proteins).
Chapter 26: Digestive System
Organs: The gastrointestinal (GI) tract and accessory organs work together to process food.
Functions:
Ingestion: Taking food into the digestive tract.
Propulsion: Movement of food through the alimentary canal (swallowing, peristalsis).
Mechanical Digestion: Physical breakdown of food (chewing, churning in stomach, segmentation).
Chemical Digestion: Enzymatic breakdown of complex food molecules into their chemical building blocks.
Absorption: Passage of digested end products from the lumen of the GI tract into blood or lymph.
Defecation: Elimination of indigestible substances as feces.
Secretions: Various glands produce enzymes, acids, and other substances crucial for digestion.
Saliva: From salivary glands; contains amylase (starch digestion) and lingual lipase (fat digestion in acidic environment).
Gastric Juice: From gastric glands in stomach; contains HCl (denatures proteins, activates pepsinogen), pepsin (protein digestion), intrinsic factor (B12 absorption).
Pancreatic Juice: From pancreas; contains digestive enzymes for all food types (amylase, lipase, proteases) and bicarbonate (neutralizes chyme).
Bile: From liver, stored in gallbladder; emulsifies fats, enhancing lipase activity.
Intestinal Juice: From intestinal glands; contains enzymes for final digestion of carbohydrates, proteins, and fats.
Functions of the Secretions: Facilitate chemical breakdown of macromolecules (carbohydrates into monosaccharides, proteins into amino acids, fats into fatty acids and glycerol) and prepare food for absorption across the intestinal lining.
Increasing Surface Area in Small Intestine: The small intestine is highly specialized for nutrient absorption, maximized by several structural adaptations.
The inner surface of the small intestine features circular folds (plicae circulares), finger-like projections called villi (containing capillaries and lacteals), and microscopic projections on the villi epithelial cells called microvilli (forming a 'brush border').
These structures immensely increase the absorptive surface area (to about 200 m^2), enhancing the efficiency and rate of nutrient uptake into the bloodstream and lymphatic system.
Chapter 28/29: Reproductive System and G&D
Functions of Organs: Primary reproductive organs (gonads) produce gametes and sex hormones.
Male Reproductive System: Testes produce sperm (male gametes) and secrete androgens, primarily testosterone, which is crucial for the development of male secondary sex characteristics and spermatogenesis.
Female Reproductive System: Ovaries produce oocytes (female gametes, or eggs) and secrete female sex hormones, estrogen and progesterone, vital for regulating the menstrual cycle, supporting pregnancy, and developing female secondary sex characteristics.
Homologs of Males and Females: Structures in males and females that develop from the same embryonic tissues, indicating shared developmental origins.
Clitoris (female) and Penis (male): Both develop from the genital tubercle and contain erectile tissue (corpora cavernosa), responsible for sexual arousal.
Labia Majora (female) and Scrotum (male): Both develop from the labioscrotal folds and primarily function in protecting the internal reproductive structures.
Ovaries (female) and Testes (male): Both develop from the gonadal ridges and are homologous as the primary sex organs (gonads) that produce gametes and sex hormones.
Functions of Myometrium and Endometrium: Layers of the uterine wall.
Myometrium: The thickest layer of the uterine wall, composed of interlacing bundles of smooth muscle. Its primary function is to contract powerfully during labor and delivery to expel the fetus. It also causes uterine contractions during menstruation.
Endometrium: The inner mucosal lining of the uterus. It undergoes cyclical changes in response to ovarian hormones. Its main function is to thicken and vascularize in preparation for implantation of a fertilized egg. If pregnancy does not occur, the stratum functionalis layer of the endometrium sheds during menstruation.
Ovarian Cycle Phases Overlapping with Uterine Cycle Phases: The two cycles are intricately linked and occur concurrently, regulated by fluctuating hormone levels.
Ovarian Cycle: Describes events in the ovaries:
Follicular Phase (Days 1-14): Follicles mature, dominant follicle selected. Driven by FSH, producing estrogen.
Ovulation (Day 14): Release of the oocyte from the dominant follicle, triggered by an LH surge.
Luteal Phase (Days 14-28): Ruptured follicle transforms into the corpus luteum, producing progesterone and some estrogen.
Uterine (Menstrual) Cycle: Describes changes in the uterine lining (endometrium):
Menstrual Phase (Days 1-5): Shedding of the stratum functionalis of the endometrium, resulting in menstrual bleeding.
Proliferative Phase (Days 6-14): Estrogen secreted by growing follicles stimulates regeneration and thickening of the endometrium.
Secretory Phase (Days 15-28): Progesterone from the corpus luteum enhances vascularization and glandular secretion of the endometrium, preparing it for implantation.
Male Sexual Response: A series of physiological events leading to procreation.
Involves four distinct phases:
Arousal (Excitement): Triggered by tactile or psychological stimuli, leading to parasympathetic reflexes that cause vasodilation in penile arteries, resulting in an erection due to engorgement of erectile tissues (corpora cavernosa and corpus spongiosum with blood).
Plateau: Increased heart rate, blood pressure, muscle tension, and further erection rigidity.
Orgasm (Climax/Emission & Expulsion):
Emission: Sympathetic stimulation causes prostatic smooth muscle and seminal vesicle walls to contract, propelling semen into the urethra.
Expulsion: Rhythmic contractions of muscles at the base of the penis lead to ejaculation of semen. Accompanied by intense pleasure.
Resolution: A period of muscular and physiological relaxation, and loss of erection. A refractory period follows orgasm, during which another erection cannot be achieved.
Differences between Spermatogenesis and Oogenesis: The processes of gamete formation in males and females, respectively.
Spermatogenesis (Male):
Timing: Begins at puberty and continues throughout a male's life, typically into old age.
Number of Gametes: Produces four viable sperm from each primary spermatocyte.
Gamete Production: Continuous, producing millions of sperm daily.
Meiotic Completion: Meiosis II is completed before sperm are released.
Oogenesis (Female):
Timing: Begins in the fetal period (primary oocytes arrested in prophase I until puberty), then occurs cyclically from puberty until menopause.
Number of Gametes: Produces one viable secondary oocyte (and two or three polar bodies) from each primary oocyte.
Gamete Production: Discrete and cyclical, releasing typically one oocyte per menstrual cycle.
Meiotic Completion: Meiosis I is completed before ovulation, but Meiosis II is only completed upon fertilization by a sperm.
Hormone Functions in Reproduction: Key hormones regulate the entire reproductive process.
GnRH (Gonadotropin-Releasing Hormone): From hypothalamus, stimulates FSH and LH release.
FSH (Follicle-Stimulating Hormone):
Males: Stimulates sperm production in testes.
Females: Stimulates follicle growth and estrogen production in ovaries.
LH (Luteinizing Hormone):
Males: Stimulates testosterone production by Leydig cells in testes.
Females: Triggers ovulation and stimulates the formation and maintenance of the corpus luteum, promoting progesterone secretion.
Estrogen:
Females: Primary female sex hormone, responsible for female secondary sex characteristics, endometrial proliferation, and surge leading to ovulation.
Progesterone:
Females: Main hormone of pregnancy, maintains uterine lining for implantation, inhibits uterine contractions.
Testosterone:
Males: Primary male sex hormone, responsible for male secondary sex characteristics, spermatogenesis, and libido.
Hormones and Follicle/Corpus Luteum Development:
FSH stimulates growth and development of ovarian follicles.
As follicles grow, they secrete estrogen, which promotes proliferation of the uterine endometrium and, at a certain threshold, triggers a surge in LH.
The LH surge induces ovulation and the transformation of the ruptured follicle into the corpus luteum.
The corpus luteum then secretes large amounts of progesterone and some estrogen, which maintain the secretory phase of the uterine cycle, preparing the uterus for potential pregnancy. If no pregnancy, the corpus luteum degenerates, causing hormone levels to drop.
Stages of Development from Fertilization to Blastocyst: Early embryonic development following fertilization.
Fertilization: Fusion of sperm and egg, forming a zygote.
Cleavage: Rapid mitotic divisions of the zygote without significant growth, forming smaller cells called blastomeres.
Morula: A solid ball of 16 or more blastomeres, typically formed around 3-4 days post-fertilization.
Blastocyst: A hollow ball of cells with an inner cell mass (embryoblast, which forms the embryo) and an outer layer (trophoblast, which forms part of the placenta). It forms around 5-7 days and is ready for implantation in the uterine lining.
Importance of hCG (Human Chorionic Gonadotropin):
A hormone produced by the trophoblast cells of the early embryo (and later the placenta) shortly after implantation.
It is vital in maintaining early pregnancy by signaling the maternal corpus luteum to continue hormone production (estrogen and progesterone), preventing its degeneration. This ensures the uterine lining remains intact and nourished, supporting the developing embryo until the placenta can take over hormone production (around week 8-12). It is the hormone detected in pregnancy tests.
Semen and Seminal Fluid:
Semen: The fluid ejaculated by the male, a mixture of sperm (about 5\% of volume) and seminal fluid.
Seminal Fluid: Produced by accessory glands (seminal vesicles, prostate gland, bulbourethral glands). Its composition and role include:
Nourishing Sperm: Contains fructose (energy source for sperm).
Transporting Sperm: Fluid medium for sperm motility.
Protecting Sperm: Contains prostaglandins (stimulate uterine contractions, reverse peristalsis) and buffers (to neutralize acidic vaginal environment).
Activating Sperm: Contains clotting factors (to keep sperm in vagina initially) and fibrinolysin (to liquefy semen after a few minutes).
Puberty in Males vs. Females: The process of sexual maturation driven by hormonal changes, leading to the development of secondary sexual characteristics and reproductive capability.
Males:
Typically begins between ages 11-14. Initiated by increased GnRH, leading to increased FSH and LH, which stimulate testosterone production.
Physical developments: Testicular enlargement, pubic hair growth, penile growth, deepening of voice, increased muscle mass, facial and body hair.
Females:
Typically begins between ages 8-13. Initiated by increased GnRH, leading to increased FSH and LH, which stimulate estrogen production.
Physical developments: Breast development (thelarche), pubic hair growth, growth spurt, onset of menstruation (menarche), widening of hips.
Chapter 17: Endocrine System
Study Your Hormone Chart: Essential for understanding the endocrine system. Familiarize yourself with major endocrine glands, the key hormones they secrete, their target organs/cells, and their specific physiological actions.
Diseases and Disorders: Hormonal imbalances or dysfunctions of endocrine glands can lead to various diseases.
Diabetes Mellitus:
Type 1: Autoimmune destruction of pancreatic beta cells, leading to absolute insulin deficiency.
Type 2: Insulin resistance and/or insufficient insulin production.
Thyroid Disorders:
Hypothyroidism: Underproduction of thyroid hormones (e.g., Hashimoto's disease, iodine deficiency), causes low metabolic rate, weight gain, fatigue.
Hyperthyroidism: Overproduction of thyroid hormones (e.g., Graves' disease), causes high metabolic rate, weight loss, nervousness.
Adrenal Disorders:
Cushing's Syndrome: Excess cortisol (e.g., adrenal tumor, long-term steroid use).
Addison's Disease: Deficient cortisol and aldosterone production.
Water-Soluble vs. Lipid-Soluble Hormones: Distinguished by their chemical nature and mechanism of action.
Water-Soluble Hormones (e.g., all amino acid-based hormones except thyroid hormone):
Cannot pass directly through the lipid bilayer of the cell membrane.
Bind to receptors on the cell surface (plasma membrane).
Trigger a cascade of intracellular events involving second messenger systems (e.g., cAMP, IP_3-Ca^{2+}), leading to a rapid and short-lived cellular response.
Lipid-Soluble Hormones (e.g., steroid hormones, thyroid hormones):
Can readily diffuse across the cell membrane.
Bind to intracellular receptors (in the cytoplasm or nucleus).
The hormone-receptor complex then moves to the nucleus, where it directly interacts with DNA, altering gene expression and leading to synthesis of new proteins, producing slower but more prolonged effects.
Relationship Between Hormones and Receptors: The cornerstone of endocrine signaling.
Specificity: Hormones act only on target cells that possess specific protein receptors to which they can bind. The receptor's shape and chemical properties are complementary to the hormone's.
Affinity and Saturation: Receptors exhibit affinity for their specific hormone and can become saturated if all available receptors are bound.
Signal Transduction: Binding of a hormone to its receptor initiates a series of intracellular events (signal transduction pathway) that ultimately lead to a cellular response, which can involve changes in enzyme activity, gene expression, or membrane permeability.
Up-regulation/Down-regulation: Target cells can adjust their sensitivity to a hormone by increasing (up-regulation) or decreasing (down-regulation) the number of receptors in response to chronic low or high hormone levels, respectively.
Nervous System vs. Endocrine System: Two major regulatory systems of the body with distinct characteristics.
Nervous System:
Signaling Mechanism: Electrical impulses (action potentials) transmitted along neurons and chemical neurotransmitters released at synapses.
Speed of Response: Rapid (milliseconds).
Duration of Response: Generally short-lived.
Target Cells: Specific cells (muscle cells, glands, other neurons) connected by neural pathways.
Control: Precise, localized control.
Endocrine System:
Signaling Mechanism: Chemical hormones released into the bloodstream.
Speed of Response: Slower (seconds to hours to days).
Duration of Response: Generally prolonged.
Target Cells: Any cell in the body with specific receptors for the hormone; widespread effects.
Control: Broad, general control.
Heredity
Terms: Define key terms related to genetics, the study of inheritance.
Allele: An alternative form of a gene at a specific locus on a chromosome (e.g., for eye color, there are alleles for blue, brown, green).
Genotype: The specific genetic makeup of an individual for a particular trait, represented by the combination of alleles (e.g., BB, Bb, bb).
Phenotype: The observable physical or biochemical characteristics of an individual, resulting from the interaction of its genotype with the environment (e.g., brown eyes, blue eyes).
Homozygous: Having two identical alleles for a particular gene (e.g., BB or bb).
Heterozygous: Having two different alleles for a particular gene (e.g., Bb).
Dominant Allele: An allele that expresses its phenotypic effect even when heterozygous with a recessive allele (e.g., in Bb, if B results in brown eyes, B is dominant).
Recessive Allele: An allele that expresses its phenotypic effect only when homozygous; its expression is masked in the presence of a dominant allele (e.g., in Bb, b for blue eyes is recessive).
Types of Inheritance: Explain different patterns by which genetic traits are passed from parents to offspring.
Autosomal Dominant: A single copy of the disease-associated allele on a non-sex chromosome is sufficient to cause the trait/disease (e.g., Huntington's disease).
Autosomal Recessive: Two copies of the disease-associated allele on a non-sex chromosome are required for the trait/disease to manifest (e.g., Cystic Fibrosis, Sickle Cell Anemia).
Co-dominance: Both alleles in a heterozygote are fully and simultaneously expressed without blending of the phenotype (e.g., AB blood type, where both A and B antigens are expressed).
Incomplete Dominance: The heterozygous phenotype is intermediate between the two homozygous phenotypes (e.g., red and white flowers creating pink flowers).
X-linked Inheritance: Genes located on the X chromosome; often affect males more frequently due to having only one X chromosome (e.g., red-green color blindness, hemophilia).
Reading Punnett Squares and Pedigrees: Tools used to predict and trace inheritance patterns.
Punnett Squares: A grid diagram used to predict the possible genotypes and phenotypes of offspring resulting from a genetic cross. It illustrates all possible combinations of alleles from two parents, allowing calculation of probabilities for specific traits.
Pedigrees: A chart that diagrams the inheritance of a trait through several generations of a family. It uses standardized symbols to represent individuals, their relationships, and whether they express the trait. Pedigrees help trace ancestry, identify carriers, understand modes of inheritance (dominant, recessive, X-linked), and predict recurrence risks for genetic disorders.