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BIO 181 Unit I-III Comprehensive Notes: Blood, Heart, Vessels, Lymphatics, and Immunology (Chapters 17–21)

Blood

  • Functions of the cardiovascular system (blood, heart, vessels)

    • Transport of respiratory gases (O₂ from lungs to tissues; CO₂ from tissues to lungs)

    • Transport of nutrients, wastes, hormones, and other molecules

    • Regulation of pH and electrolyte/water balance

    • Temperature regulation and distribution of heat

    • Protection via immune cells and signaling molecules

    • Hemostasis (clotting) to prevent blood loss after injury

  • General and physical characteristics of blood

    • Blood is a specialized connective tissue with formed elements suspended in plasma

    • Components: plasma ( clear extracellular fluid) and formed elements (RBCs, WBCs, platelets)

    • Normal pH ~7.35–7.45; viscosity, temperature, and volume display individual variation

    • Blood volume ~5 L in an average adult (varies with body size and sex)

  • Chemical composition and purpose/role of hemoglobin; oxyhemoglobin vs deoxyhemoglobin; cooperativity

    • Hemoglobin (Hb) is a tetrameric protein with four globin chains and four heme groups; each heme contains an iron ion that binds one O₂ molecule

    • Oxyhemoglobin: Hb bound to O₂; deoxyhemoglobin: Hb after releasing O₂

    • Hemoglobin exhibits cooperativity: binding of O₂ to one heme increases affinity at remaining sites; loading in lungs and unloading in tissues follows a sigmoidal (S-shaped) curve

    • Bohr effect and allosteric factors (CO₂, pH, temperature, 2,3-BPG) shift the dissociation curve to the right (unloading) or left (loading)

  • Functions, characteristics, and relative amounts of blood components

    • Red blood cells (erythrocytes): carry O₂/CO₂

    • White blood cells (leukocytes): immune defense; granular (neutrophils, eosinophils, basophils) and agranular (monocytes, lymphocytes)

    • Hemoglobin (heme, globin): carries O₂ via heme iron; globin chains provide structural support and oxygen affinity regulation

    • Platelets (thrombocytes): essential for hemostasis and clot formation

    • Plasma: water, electrolytes, nutrients, wastes, hormones, plasma proteins (albumin, globulins, fibrinogen)

    • Water makes up most plasma; plasma proteins contribute to osmotic pressure and coagulation

  • Structural characteristics of an erythrocyte and how each relates to function

    • Biconcave disc shape increases surface area for gas diffusion and allows deformation as they traverse capillaries

    • Anucleate in most mammals; flexible cytoskeleton (spectrin, actin) supports shape and durability

    • Lack of organelles minimizes oxygen consumption within the RBC

    • Diameter ~7–8 μm; optimized for gas exchange in capillaries

  • Red blood cell senescence and RBC recycling; roles of macrophages/Kupffer cells; ferritin; transferrin; hemosiderin; bilirubin; stercobilin; urobilin

    • RBCs have a ~120-day lifespan in humans

    • Senescent RBCs are removed by macrophages in the spleen and liver (Kupffer cells in liver)

    • Heme iron is salvaged and stored in ferritin; iron is transported in plasma by transferrin

    • Excess iron stored as hemosiderin when ferritin is saturated

    • Heme ring is degraded to bilirubin (unconjugated) and transported to liver for conjugation

    • In the liver, bilirubin is conjugated and excreted into bile; bacterial metabolism yields urobilinogen; stercobilin gives fecal color; urobilin gives urine color

  • Hematopoiesis: function, location, requirements, and regulation; major events & stages of erythropoiesis

    • Hematopoiesis: formation of blood cells from hematopoietic stem cells in the red bone marrow

    • Erythropoiesis is the production of erythrocytes; stimulated by erythropoietin (EPO)

    • EPO is produced primarily by kidneys (adult) in response to hypoxia; stimulates progenitors in bone marrow to produce more RBCs

    • Stages of erythropoiesis include proerythroblast, basophilic erythroblast, polychromatophilic erythroblast, orthochromatic erythroblast, reticulocyte, mature erythrocyte

  • Role of erythropoietin: site of production, trigger for release, function

    • Primary site: kidneys (peripheral sensors detect hypoxia)

    • Trigger: reduced oxygen delivery to tissues (hypoxia) stimulates EPO release

    • Function: promotes erythroid progenitor survival, proliferation, and differentiation to mature RBCs; increases RBC count and oxygen-carrying capacity

  • Define, list the types, and briefly describe causes and treatment of anemia and polycythemia

    • Anemia: reduced RBC count or Hb concentration; causes include blood loss, decreased production, or increased destruction; symptoms include fatigue, pallor, dyspnea

    • Polycythemia: increased RBC mass; relative polycythemia due to plasma volume loss or absolute polycythemia due to increased RBC production (e.g., polycythemia vera) or chronic hypoxia

    • Treatments depend on cause: iron supplementation for iron-deficiency anemia; transfusions or erythropoietin modulation for other anemias; phlebotomy or drugs to reduce hematocrit in polycythemia

  • ABO and Rh blood typing systems; role of antibodies; compatible donor/recipient relationships

    • ABO system: A, B, AB, O; blood type determined by surface antigens (A and B) on erythrocytes; antibodies against the absent antigen exist in plasma (e.g., type A has anti-B IgG/IgM)

    • Rh system: presence or absence of D antigen (Rh+ vs Rh−)

    • Donor/recipient compatibility: O can donate to all types (universal donor for ABO; but Rh compatibility matters); AB can receive from all ABO types (universal recipient for ABO) but Rh compatibility still matters

    • Rh incompatibility can cause sensitization and anti-D antibodies upon exposure; management during pregnancy and transfusion is important

  • Hemostasis: sequence of events; vascular spasm, platelet plug formation, and coagulation

    • Vascular spasm (vasoconstriction) reduces blood loss at injury site

    • Platelet plug formation: adhesion (via von Willebrand factor to exposed collagen); activation with release of ADP, thromboxane A₂; platelet aggregation via fibrinogen bridging through glycoprotein IIb/IIIa

    • Coagulation (blood clotting) cascade: involves intrinsic and extrinsic pathways converging on the common pathway to convert fibrinogen to fibrin; stabilization of the clot

  • Intrinsic, extrinsic, and common pathways; coagulation factors, coenzymes, and fibrin production

    • Intrinsic pathway: activation begins within blood; involves factors XII, XI, IX, VIII

    • Extrinsic pathway: activation by tissue factor (thromboplastin) released from damaged tissue; involves factor VII

    • Common pathway: activation of factor X, leading to prothrombin (II) activation to thrombin, which converts fibrinogen (I) to fibrin; fibrin clot stabilized with factor XIII

    • Final outcome: stable fibrin mesh that traps cells and reinforces the platelet plug; subsequently, clot dissolution via fibrinolysis

Heart

  • Size, location, and orientation of the heart

    • Size roughly closed fist; located in the thoracic cavity between the lungs, in the mediastinum

    • Base oriented superiorly, posteriorly; apex points inferiorly and to the left

  • Pericardium and heart wall architecture (parietal and visceral pericardium/epicardium, myocardium, endocardium)

    • Fibrous pericardium: tough outer layer; anchors heart, prevents overdistension

    • Serous pericardium: parietal layer lines the fibrous pericardium; visceral layer (epicardium) covers the heart

    • Pericardial cavity with serous fluid reduces friction during beating

    • Myocardium: thick muscular layer; cardiac muscle with intercalated discs containing gap junctions and desmosomes

    • Endocardium: smooth inner lining of chambers and valves

  • Diagram of blood flow through systemic, pulmonary, and coronary circulations

    • Systemic: left heart to systemic arteries, arterioles, capillaries, venules, veins, back to right heart

    • Pulmonary: right heart to pulmonary arteries to lungs, pulmonary veins back to left heart

    • Coronary circulation: coronary arteries arise from the aorta just above the aortic valve; coronary veins drain into the coronary sinus

  • Flow of blood through the heart; major vessels; distinguishing oxygenated vs. deoxygenated blood

    • Right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary trunk → lungs (gas exchange) → pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta → systemic circulation

    • Right-sided chambers carry deoxygenated blood; left-sided chambers carry oxygenated blood

  • Functional anatomy of the heart; external and internal structures

    • External: atria, ventricles, major coronary vessels, great vessels (aorta, pulmonary arteries/veins)

    • Internal: atrioventricular (AV) valves (tricuspid, mitral); semilunar valves (pulmonary, aortic); papillary muscles; chordae tendineae; interatrial and interventricular septa

  • Function of the heart valves; major heart sounds from valve closure

    • AV valves prevent backflow from ventricles to atria during systole

    • Semilunar valves prevent backflow from arteries to ventricles during diastole

    • S1 (lub): closure of AV valves at the start of ventricular systole

    • S2 (dub): closure of semilunar valves at the end of ventricular systole

  • Cardiac muscle physiology; role of intercalated discs

    • Cardiac muscle cells are connected via intercalated discs containing gap junctions and desmosomes

    • Gap junctions enable electrochemical coupling and synchronous contraction (functional syncytium)

    • Desmosomes provide mechanical strength to withstand contraction

  • Conduction system: SA node, AV node, AV bundle (bundle of His), L and R bundle branches, Purkinje fibers

    • SA node = natural pacemaker; initiates impulse ~60–100 bpm in adults

    • Impulse travels to AV node; slower conduction permits atrial contraction to fill ventricles

    • AV bundle (bundle of His) → bundle branches → Purkinje fibers distribute impulse to ventricles

  • Comparison of SA nodal and ventricular action potentials with neuronal action potential; role of ions and ion channels

    • SA nodal cells: unstable resting potential; pacemaker potential due to If channels (funny current) allowing spontaneous depolarization; influx of Ca²⁺ through T-type and then L-type Ca²⁺ channels drives action potential; no true resting potential

    • Ventricular myocytes: stable resting potential; rapid depolarization via Na⁺ influx; plateau phase due to Ca²⁺ influx through L-type Ca²⁺ channels; repolarization via K⁺ efflux

    • Key ions: Na⁺, Ca²⁺, K⁺

  • Autonomic nervous system effects on firing of cardiac action potentials and heart rate

    • Sympathetic stimulation (norepinephrine/epinephrine) via β1 receptors increases heart rate and contractility by increasing cAMP and Ca²⁺ availability

    • Parasympathetic stimulation (acetylcholine) via muscarinic receptors decreases heart rate by opening K⁺ channels and reducing Ca²⁺ influx

  • Basic parts of an EKG (ECG); events of the heart they represent; reading an EKG

    • P wave: atrial depolarization (contraction)

    • PR segment: conduction delay through AV node

    • QRS complex: ventricular depolarization (and atrial repolarization hidden)

    • ST segment: isoelectric period; ventricular plateau

    • T wave: ventricular repolarization

  • Events during the cardiac cycle; systole vs diastole; sequence and mechanical events

    • Atrial systole: atrial contraction completes ventricular filling

    • Isovolumetric contraction: ventricles contract with all valves closed; no change in volume

    • Ventricular ejection: semilunar valves open; blood expelled to aorta/pulmonary trunk

    • Isovolumetric relaxation: ventricles relax with all valves closed

    • Ventricular filling: AV valves open; ventricles fill passively; atrial contraction may contribute to late filling

  • Relationship between cardiac output, heart rate, and stroke volume; definitions

    • Cardiac output (CO): amount of blood pumped by each ventricle per minute

    • CO = Heart Rate (HR) × Stroke Volume (SV)

    • Typical resting values: HR ~ 60–100 bpm; SV ~ 70 mL; CO ~ 4.2–6.0 L/min

  • Factors affecting cardiac output, heart rate, and stroke volume; including hormones, autonomic innervation, end diastolic volume, end systolic volume, venous return, filling time, preload, contractility, afterload

    • HR is modulated by autonomic input (sympathetic vs parasympathetic) and circulating hormones

    • SV is influenced by preload (EDV), contractility (myocardial force), and afterload (aortic/pulmonary pressure opposing outflow)

    • Venous return and filling time affect preload; afterload affected by systemic vascular resistance

  • Define angina pectoralis and myocardial infarct (heart attack)

    • Angina pectoralis: chest pain due to transient myocardial ischemia; reversible adverse effects with rest or nitroglycerin

    • Myocardial infarct: necrosis of heart muscle due to prolonged ischemia from blocked coronary blood flow; can cause permanent damage

  • Fetal circulation: fetal vessels and the role of the fossa ovalis and ligamentum arteriosum

    • Fetal circulation includes shunts that bypass lungs: foramen ovale allows blood to pass from right to left atrium; ductus arteriosus connects pulmonary artery to aorta

    • After birth: foramen ovale becomes fossa ovalis; ductus arteriosus becomes ligamentum arteriosum; pulmonary and systemic circulations separate more completely

Blood Vessels

  • Anatomy and function of blood vessels (elastic arteries, muscular arteries, arterioles, capillaries, venules, veins); compare layers, size, thickness, pressure, velocity, compliance, cross-sectional area, and valves

    • Elastic arteries (conducting): large-diameter; high elastin content to accommodate pulsatile output; include aorta and major branches

    • Muscular arteries (distributing): more smooth muscle; regulate blood flow to specific tissues via vasoconstriction/vasodilation

    • Arterioles: small diameter; major site of vascular resistance to control tissue perfusion

    • Capillaries: smallest vessels; site of exchange between blood and tissues; three types below

    • Venules and veins: return low-pressure blood to the heart; valves in larger veins prevent backflow; capacitance vessels with high compliance

    • Vessel layers: tunica intima (endothelium), tunica media (smooth muscle), tunica externa/adventitia (connective tissue)

  • Define: Systolic pressure, Diastolic pressure, Pulse pressure

    • Systolic pressure: peak arterial pressure during ventricular systole

    • Diastolic pressure: arterial pressure during ventricular diastole

    • Pulse pressure: difference between systolic and diastolic pressures; PP = SBP − DBP

  • Process of measuring blood pressure and the mean arterial pressure (MAP) formula

    • Blood pressure is typically measured indirectly with a cuff and sphygmomanometer; auscultatory method detects Korotkoff sounds

    • MAP (mean arterial pressure) can be approximated as MAP \,=\frac{SBP + 2\cdot DBP}{3} or more generally as MAP = CO \times TPR where TPR is total peripheral resistance

  • Nine clinically important arterial pulse points

    • Common carotid (neck)

    • Brachial (arm, at the elbow)

    • Radial (wrist)

    • Femoral (groin)

    • Popliteal (knee area)

    • Posterior tibial (ankle/medial ankle region)

    • Dorsalis pedis (top of foot)

    • Temporal (temple) and facial arteries (as clinically relevant points)

  • Factors that affect blood pressures throughout the circulatory system; including stroke volume, heart rate, vascular resistance, and total peripheral resistance (TPR)

    • SBP/DBP influenced by CO, arterial compliance, and TPR

    • Stroke volume, heart rate, and vascular resistance collectively determine arterial pressure

  • Mechanisms to maintain blood pressure: baroreflexes, chemoreflexes, hormonal influences

    • Baroreflexes: stretch receptors in carotid sinus and aortic arch detect BP changes; reflexive adjustments alter HR, contractility, and vascular tone

    • Chemoreflexes: respond to CO₂, O₂, and pH levels to regulate respiration and vascular tone

    • Hormonal influences: sympathetic catecholamines (NE/EPI), angiotensin II, vasopressin, natriuretic peptides modulate pressure and volume homeostasis

  • Differences between continuous, fenestrated, and sinusoidal capillaries; materials each type permits

    • Continuous capillaries: uninterrupted endothelium; permits diffusion of water, small solutes; common in muscle, skin, and lungs

    • Fenestrated capillaries: have pores (fenestrations) that increase permeability to small molecules and some proteins; found in kidneys, small intestine, and endocrine glands

    • Sinusoidal (discontinuous) capillaries: have large gaps and poorly formed basement membranes; allow passage of larger molecules and cells (e.g., liver, bone marrow, spleen)

  • Capillary exchange via bulk flow (hydrostatic pressure and osmotic pressure); how altering parameters affects capillary dynamics

    • Bulk flow (filtration/reabsorption) depends on Starling forces: net filtration pressure = (hydrostatic pressure difference) − (colloid osmotic pressure difference)

    • Key pressures: capillary hydrostatic pressure (Pc), interstitial hydrostatic pressure (Pi), capillary colloid osmotic pressure (πc), interstitial colloid osmotic pressure (πi)

    • Net filtration = Kf[(Pc − Pi) − (πc − πi)], where Kf is filtration coefficient

    • Changes in these pressures affect fluid movement: increased capillary hydrostatic pressure promotes filtration into interstitium; increased plasma protein concentration (π_c) promotes reabsorption

  • Mechanisms to maintain blood pressure: autoregulation (metabolic, myogenic), neuronal (medullary cardiovascular centers, baroreflexes, chemoreflexes), and hormonal

    • Autoregulation adjusts local blood flow through metabolic byproducts, pH, O₂ levels, and myogenic response to stretch

    • Medullary cardiovascular centers integrate inputs and coordinate autonomic output to regulate heart rate, contractility, and vessel tone

    • Hormonal controls include renin-angiotensin-aldosterone system, vasopressin, natriuretic peptides, and catecholamines

  • Major blood vessels of the systemic circulatory system and areas they service

    • Aorta and major branches: supply systemic circulation to head, trunk, and limbs

    • Carotid arteries: head and brain

    • Subclavian and axillary arteries: upper limbs

    • Celiac trunk, mesenteric arteries: abdominal viscera

    • Renal arteries: kidneys

    • Iliac arteries: lower limbs

    • Venous drainage mirrors arterial distribution through the venous system, returning blood to the heart

The Lymphatic System

  • Functions of the lymphatic system; major lymphatic tissues and cells

    • Returns excess interstitial fluid to the bloodstream to maintain fluid balance

    • Transports dietary lipids (via lacteals in the small intestine)

    • Provides immune defense via lymph nodes, spleen, thymus, tonsils, and other lymphoid tissues

    • Houses immune cells (lymphocytes, macrophages, dendritic cells) and antigen-presenting cells (APCs)

  • Differentiate between blood, interstitial fluid, and lymph

    • Blood: circulatory fluid inside vessels; high protein content in plasma

    • Interstitial fluid: fluid surrounding tissue cells; low protein content

    • Lymph: returned interstitial fluid that has entered lymphatic capillaries; contains immune cells and occasionally pathogens; low protein initially

  • Flow of lymph through lymphatic capillaries and vessels, lymph nodes, thoracic and right lymphatic ducts

    • Lymphatic capillaries absorb interstitial fluid; lymph travels through vessels with valves; passes through lymph nodes for immune surveillance

    • Lymphatic trunks drain into ducts: right lymphatic duct (drains right upper body) and thoracic duct (drains rest of the body) into venous circulation near the subclavian veins

  • Lymphatic organs: structure, location, and function (lymph nodes, tonsils, lymphoid tissues, spleen, thymus)

    • Lymph nodes: filter lymph; sites of immune cell activation

    • Tonsils: guard against inhaled or ingested pathogens

    • Spleen: filters blood; site of immune responses to blood-borne antigens; also recycles old RBCs

    • Thymus: site of T cell maturation and education

    • Lymphoid tissues: mucosa-associated lymphoid tissue (MALT), including Peyer’s patches, etc.

  • Factors influencing lymph flow

    • Skeletal muscle contractions, breathing (thoracic pressure changes), smooth muscle tone in lymphatic vessels, and intrinsic lymphatic pumps

Immunology

  • Functions of the immune system

    • Defense against pathogens, cancer surveillance, wound healing, and removal of dead/damaged cells

  • Innate vs adaptive defense systems

    • Innate: immediate, non-specific defenses (physical barriers, phagocytes, NK cells, complement, inflammatory responses)

    • Adaptive: specific, slower-onset responses (humoral immunity via B cells and antibodies; cell-mediated immunity via T cells)

  • First, second, and third lines of defense

    • First line: physical and chemical barriers (skin, mucous membranes, acidity, mucociliary escalator, tears/lysozyme, defecation/vomiting, urine, coughing/sneezing)

    • Second line: nonspecific defenses (phagocytes, NK cells, interferons, complement, inflammation, fever)

    • Third line: specific adaptive responses (humoral and cellular immunity with memory)

  • Roles of components in the first line of defense

    • Skin and mucous membranes provide barrier protection

    • pH, urine, mucous membranes, tears/lysozyme, defecation/vomiting, coughing/sneezing, mucociliary escalator act to prevent pathogen entry and dissemination

  • Roles of components in the second line of defense

    • Phagocytes: neutrophils, macrophages remove pathogens

    • Natural killer (NK) cells: destroy infected or abnormal cells without prior sensitization

    • Interferons: antiviral signaling molecules that inhibit viral replication

    • Complement: cascade of proteins that enhance phagocytosis, promote inflammation, and form membrane attack complexes

    • Inflammation: redness, heat, swelling, pain; functional impairment; coordinated by chemical signals (cytokines, histamine)

    • Fever: systemic response to infection; can boost immune activity and inhibit pathogen growth

  • Inflammatory response and the 4 characteristic traits of inflammation

    • Redness (rubor), heat (calor), swelling (tumor), pain (dolor); sometimes loss of function

    • Movement of fluid and immune cells to the affected site; increased vascular permeability

  • Steps of humoral and cellular immune responses

    • Humoral (B-cell mediated): antigen presentation → B cell activation → clonal expansion → plasma cells produce antibodies; memory B cells form for faster future responses

    • Cellular (T-cell mediated): antigen presentation to T cells → activation of cytotoxic T cells, helper T cells; cytotoxic T cells kill infected cells; memory T cells provide faster response on re-exposure

  • Define and describe the role of pathogens, antigens, MHC, APCs

    • Pathogens: disease-causing organisms (bacteria, viruses, fungi, parasites)

    • Antigens: molecules or parts of molecules that the immune system recognizes as foreign

    • MHC (major histocompatibility complex): cell-surface proteins presenting antigen fragments to T cells; MHC class I (all nucleated cells) and MHC class II (antigen-presenting cells)

    • Antigen-presenting cells (APCs): dendritic cells, macrophages, B cells that process and present antigens via MHC to T cells

  • Lymphocytes: differentiate and describe functions of B, T, and NK cells

    • B cells: produce antibodies; mediate humoral immunity; can become plasma cells and memory B cells

    • T cells: include cytotoxic T cells (CD8+) that kill infected cells; helper T cells (CD4+) that activate other immune cells; regulatory T cells modulate immune responses; memory T cells provide rapid response upon re-exposure

    • NK cells: part of innate immunity; kill virally infected and tumor cells without prior sensitization; can interact with antibody-coated targets via antibody-dependent cellular cytotoxicity (ADCC)

  • Summary of Humoral Immunity steps and role of plasma cells, antibodies, antigens, and memory cells

    • Antigen recognition by B cell receptor or via presentation by APCs

    • Activation and clonal expansion of B cells; differentiation into plasma cells and memory B cells

    • Plasma cells secrete antibodies that neutralize pathogens, mark them for destruction, or activate complement

    • Memory B cells persist for rapid response upon future exposure

  • Five antibody classes and unique characteristics of each

    • IgG: most abundant in serum; crosses placenta; protects against bacteria and viruses

    • IgM: first antibody produced in an immune response; efficient agglutination; pentameric structure

    • IgA: present in secretions (tears, saliva, mucous, breast milk); provides mucosal immunity

    • IgD: B cell receptor on naive B cells; low circulating levels

    • IgE: allergic responses and defense against parasitic infections

  • Differences between primary and secondary immune responses and immunological memory

    • Primary response: slower, lower magnitude, needs clonal activation; antibodies predominantly IgM initially, later IgG

    • Secondary response: faster and stronger due to memory B and T cells; predominantly IgG and higher affinity antibodies

  • Effects of Cell-Mediated Immunity (CMC) including role of Cytotoxic T, Helper T cells, Memory cells

    • Cytotoxic T cells destroy infected or abnormal cells presenting antigen on MHC I

    • Helper T cells coordinate immune responses by activating B cells, cytotoxic T cells, and macrophages via cytokines

    • Memory T cells persist to provide rapid response on re-exposure

  • Vaccines mechanism and role in creating immunity

    • Vaccines present antigens in a safe form to elicit adaptive immune responses without causing disease

    • Induce memory B and memory T cells to provide rapid and robust protection upon subsequent exposure

  • Concepts of allergies and autoimmune diseases

    • Allergies: hypersensitivity reactions (often IgE-mediated) to benign substances; can involve mast cell degranulation and histamine release

    • Autoimmune diseases: immune system mistakenly targets self-antigens (e.g., type 1 diabetes, rheumatoid arthritis, multiple sclerosis); may involve loss of tolerance and autoreactive T or B cells

  • Notes on connections to foundational principles and real-world relevance

    • Blood and cardiovascular systems underpin oxygen transport, nutrient delivery, and waste removal essential for cellular metabolism

    • Lymphatic and immune systems maintain fluid balance and defend against pathogens; vaccination is a practical public health application

    • Understanding hemostasis clarifies responses to injury and risks of thrombosis or hemorrhage

    • Cardiac electrophysiology links cellular ion channels to whole-organ function, with clinical relevance in arrhythmias and ECG interpretation

  • Ethical, philosophical, and practical implications

    • Vaccination ethics and public health considerations (herd immunity; access and equity)

    • Balancing anticoagulant therapy with bleeding risk in clinical care

    • Implications of autoimmune disease management for patient quality of life

  • Formulas and key numerical references

    • Cardiac output: CO = HR \times SV

    • Mean arterial pressure: MAP = \frac{SBP + 2 \cdot DBP}{3}

    • Capillary bulk flow (Starling forces): Jv = Kf \bigl[(Pc - Pi) - (\pic - \pii)\bigr]

    • Cardiac cycle timing and events are described qualitatively; quantitative values vary with age and fitness (e.g., typical resting HR ~60–100 bpm, SV ~70 mL)

  • Connections to lab objectives and practical understanding

    • Students should be able to identify and describe each listed component, pathway, and physiological mechanism

    • Expect to interpret diagrams of heart flow, EKG tracings, capillary exchange concepts, and lymphatic flow in exams

    • Be prepared to differentiate pathways (intrinsic vs extrinsic coagulation), capillary types, and immune system lineages in short-answer or essay questions