Blood (Chapter 17)

Functions of Blood

Blood is a vital fluid that performs multiple essential functions in the human body:

• Transport: Carries oxygen, nutrients, hormones, and waste products.

• Regulation: Maintains body temperature, pH, and fluid balance.

• Protection: Defends against infection and blood loss.

• Clotting: Prevents excessive bleeding through hemostasis.

• Immune Response: Contains cells and proteins for immune defense.

• Homeostasis: Helps maintain internal stability.

Composition and Function of Plasma

Plasma is the liquid component of blood, making up about 55% of its volume.

• Composition: Water (90%), proteins (albumin, globulins, fibrinogen), electrolytes, nutrients, gases, hormones, and waste products.

• Function: Transports substances, maintains osmotic pressure, and provides a medium for cellular elements.

Erythrocytes (Red Blood Cells)

• Function: Transport oxygen and carbon dioxide.

• Production: Formed in bone marrow via erythropoiesis, regulated by erythropoietin.

Chemical Makeup of Hemoglobin

• Structure: Four polypeptide chains (globin) and four heme groups, each containing iron.

• Function: Binds oxygen for transport.

Leukocytes (White Blood Cells)

• Classes: Granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (lymphocytes, monocytes).

• Functions: Immune defense, phagocytosis, antibody production.

Leukocyte Genesis

• Origin: Produced in bone marrow from hematopoietic stem cells.

Platelets

• Structure: Small, disc-shaped cell fragments.

• Function: Essential for blood clotting.

Hemostasis

• Process: Vascular spasm, platelet plug formation, coagulation.

• Limiting Factors: Anticoagulants, fibrinolysis.

Transfusion Reactions

• Basis: Occur when incompatible blood types are mixed, leading to immune response.

Blood Expanders

• Function: Used to restore blood volume in emergencies.

• Examples: Saline, albumin, dextran.

The Heart (Chapter 18)

Cardiac Muscle Structure and Function

Cardiac muscle is specialized for continuous rhythmic contraction.

• Structure: Striated, branched cells with intercalated discs.

• Function: Pumps blood throughout the body.

• Difference from Skeletal Muscle: Involuntary, autorhythmic, and resistant to fatigue.

Conduction System of the Heart

• Components: SA node, AV node, AV bundle, bundle branches, Purkinje fibers.

• Pathway: Electrical impulses travel from SA node to Purkinje fibers, coordinating contraction.

Electrocardiogram (ECG)

• Waves: P wave (atrial depolarization), QRS complex (ventricular depolarization), T wave (ventricular repolarization).

• Intervals: PR, QT, ST intervals.

Cardiac Cycle

• Phases: Atrial systole, ventricular systole, diastole.

• Events: Blood flows through chambers, valves open/close, heart sounds produced.

Regulation of Stroke Volume and Heart Rate

• Factors: Preload, contractility, afterload, autonomic nervous system.

Autonomic Nervous System and Cardiac Output

• Sympathetic: Increases heart rate and force.

• Parasympathetic: Decreases heart rate.

Cardiovascular: Blood Vessels (Chapter 19)

Structure of Blood Vessels

• Three Layers: Tunica intima (inner), tunica media (middle), tunica externa (outer).

• Function: Provide strength, elasticity, and regulation of blood flow.

Vasoconstriction and Vasodilation

• Vasoconstriction: Narrowing of blood vessels, increases blood pressure.

• Vasodilation: Widening of blood vessels, decreases blood pressure.

Types of Arteries

• Elastic Arteries: Large, conduct blood from heart.

• Muscular Arteries: Medium-sized, distribute blood.

• Arterioles: Smallest, regulate flow into capillaries.

Veins vs. Arteries

• Veins: Thinner walls, larger lumen, valves to prevent backflow.

• Arteries: Thicker walls, higher pressure.

Capillary Beds

• Structure: Network of capillaries connecting arterioles and venules.

• Function: Exchange of gases, nutrients, and waste.

Blood Flow, Pressure, and Resistance

• Blood Flow: Volume of blood moving through vessels.

• Blood Pressure: Force exerted by blood on vessel walls.

• Resistance: Opposition to flow, mainly due to vessel diameter.

Relationship:

• Blood flow () is related to pressure difference () and resistance ():

Blood Pressure Regulation

• Factors: Cardiac output, blood volume, vessel diameter.

• Regulation: Neural, hormonal, and renal mechanisms.

Hypertension

• Definition: Chronic high blood pressure.

• Symptoms: Often asymptomatic; headaches, dizziness.

• Consequences: Heart disease, stroke, kidney damage.

Capillary Dynamics

• Factors: Hydrostatic and osmotic pressures.

• Significance: Determines fluid movement and exchange.

Circulatory Shock

• Definition: Inadequate blood flow to tissues.

• Causes: Blood loss, heart failure, vessel dilation.

Pulmonary and Systemic Circuits

• Pulmonary Circuit: Blood flow from heart to lungs and back.

• Systemic Circuit: Blood flow from heart to body tissues.

Hepatic Portal System

• Structure: Veins from digestive organs to liver.

• Function: Processes nutrients and detoxifies substances.

The Lymphatic System (Chapter 20)

Lymphatic Vessels

• Structure: Thin-walled, valved vessels.

• Distribution: Throughout body, except CNS and avascular tissues.

• Function: Return interstitial fluid to bloodstream, transport fats.

Lymph and Lymph Transport

• Source: Interstitial fluid collected by lymphatic capillaries.

• Mechanism: Skeletal muscle contraction, respiratory movements, valves.

Lymphoid Tissue and Organs

• Structure: Reticular connective tissue with lymphocytes.

• Major Organs: Lymph nodes, spleen, thymus, tonsils.

Lymph Nodes

• Location: Along lymphatic vessels.

• Structure: Cortex and medulla with lymphatic follicles.

• Function: Filter lymph, immune surveillance.

Other Lymphoid Organs

• Spleen: Filters blood, stores platelets.

• Thymus: T cell maturation.

• Tonsils: Protect against pathogens in oral cavity.

The Immune System: Innate and Adaptive Defenses (Chapter 21)

Surface Membrane Barriers

• Skin and Mucous Membranes: Physical and chemical barriers.

• Function: Prevent entry of pathogens.

Phagocytosis and Natural Killer Cells

• Phagocytosis: Engulfment and destruction of pathogens by macrophages and neutrophils.

• Natural Killer Cells: Destroy infected or abnormal cells.

Inflammatory Process

• Steps: Vasodilation, increased permeability, leukocyte migration.

• Chemicals: Histamine, prostaglandins, cytokines.

Antimicrobial Substances

• Examples: Interferons, complement proteins.

• Function: Inhibit microbial growth, enhance immune response.

Fever

• Function: Increases body temperature to inhibit pathogens.

Antigens

• Definition: Substances that provoke an immune response.

• Complete Antigen: Fully stimulates immune response.

• Hapten: Small molecule, not immunogenic alone.

• Antigenic Determinant: Specific region recognized by immune cells.

B and T Lymphocytes

• Origin: Bone marrow.

• Maturation: B cells mature in bone marrow; T cells in thymus.

• Function: B cells produce antibodies; T cells mediate cellular immunity.

Humoral Immunity

• Definition: Immunity mediated by antibodies.

• Clonal Selection: Activation and proliferation of B cells.

• Plasma Cells: Produce antibodies.

• Memory Cells: Provide long-term immunity.

Active vs. Passive Humoral Immunity

• Active: Exposure to antigen, long-lasting.

• Passive: Transfer of antibodies, temporary.

Antibody Structure and Classes

• Monomer: Y-shaped, two heavy and two light chains.

• Classes: IgG, IgA, IgM, IgD, IgE.

Cell-Mediated Immunity

• Activation: T cells recognize antigen, proliferate.

• Function: Destroy infected cells, regulate immune response.

Autoimmune Disease

• Factors: Genetic, environmental, immune dysregulation.

The Respiratory System (Chapter 22)

Respiratory Passageways

• Order: Nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli.

• Conducting Zone: Air transport.

• Respiratory Zone: Gas exchange.

Protective Mechanisms

• Cilia, mucus, coughing, sneezing: Remove particles and pathogens.

Respiratory Membrane

• Structure: Alveolar and capillary walls.

• Function: Facilitates gas exchange.

Lungs and Pleural Coverings

• Lungs: Spongy organs for gas exchange.

• Pleura: Double-layered membrane.

Boyle's Law and Breathing

• Boyle's Law: Pressure and volume are inversely related.

Respiratory Muscles and Lung Elasticity

• Muscles: Diaphragm, intercostals.

• Elasticity: Allows lungs to expand and recoil.

Partial Vacuum in Intrapleural Space

• Importance: Prevents lung collapse.

Pulmonary Ventilation Factors

• Factors: Airway resistance, lung compliance, alveolar surface tension.

Lung Volumes and Capacities

• Examples: Tidal volume, vital capacity, residual volume.

Dead Space

• Definition: Air not involved in gas exchange.

Dalton's and Henry's Laws

• Dalton's Law: Total pressure is sum of partial pressures.

• Henry's Law: Gas solubility in liquid is proportional to partial pressure.

Oxygen and Carbon Dioxide Transport

• Oxygen: Bound to hemoglobin, dissolved in plasma.

• CO2: Dissolved, bound to hemoglobin, as bicarbonate.

Neural Control of Respiration

• Centers: Medulla, pons.

• Regulation: Chemoreceptors, stretch receptors.

Respiratory Disorders

• Examples: Chronic bronchitis, emphysema, asthma, lung cancer.

The Digestive System (Chapter 23)

Function and Organs

• Function: Breakdown and absorption of nutrients.

• Alimentary Canal: Mouth, pharynx, esophagus, stomach, intestines.

• Accessory Organs: Teeth, tongue, salivary glands, liver, pancreas, gallbladder.

Digestive Processes

• Processes: Ingestion, propulsion, mechanical digestion, chemical digestion, absorption, defecation.

Peritoneum and Retroperitoneal Organs

• Peritoneum: Serous membrane lining abdominal cavity.

• Retroperitoneal: Organs located behind peritoneum (e.g., kidneys).

Layers of Alimentary Canal

• Mucosa: Secretion and absorption.

• Submucosa: Blood vessels, nerves.

• Muscularis: Muscle for movement.

• Serosa: Protective outer layer.

Teeth and Dental Formula

• Deciduous: Primary teeth.

• Permanent: Adult teeth.

Saliva and Salivation

• Composition: Water, enzymes, mucins.

• Function: Lubricates, begins digestion.

Chewing and Swallowing

• Mechanisms: Mastication, deglutition.

Stomach and Small Intestine Modifications

• Stomach: Rugae, gastric glands.

• Small Intestine: Villi, microvilli.

Gastric Juice

• Components: HCl, pepsinogen, mucus.

• Cell Types: Parietal, chief, mucous cells.

Bile and Pancreatic Juice

• Bile: Emulsifies fats.

• Pancreatic Juice: Contains digestive enzymes.

Large Intestine Functions

• Functions: Water absorption, feces formation.

Enzymes of Digestion

• Proteases: Proteins → amino acids.

• Lipases: Fats → fatty acids.

• Amylases: Carbohydrates → sugars.

• Nucleases: Nucleic acids → nucleotides.

Absorption in Small Intestine

• Process: Nutrients pass into blood and lymph.

The Urinary System (Chapter 25)

Anatomy of the Kidney

• Structure: Cortex, medulla, renal pelvis.

• Coverings: Fibrous capsule, adipose tissue.

Blood Supply

• Pathway: Renal artery → afferent arteriole → glomerulus → efferent arteriole → peritubular capillaries → renal vein.

Nephron Anatomy

• Parts: Glomerulus, Bowman's capsule, proximal tubule, loop of Henle, distal tubule, collecting duct.

Kidney Functions

• Homeostasis: Regulates water, electrolytes, acid-base balance, removes waste.

Filtration, Reabsorption, Secretion

• Filtration: Occurs in glomerulus.

• Reabsorption: Returns useful substances to blood.

• Secretion: Removes additional wastes.

Aldosterone and ANP

• Aldosterone: Increases sodium reabsorption.

• ANP: Decreases sodium reabsorption.

Medullary Osmotic Gradient

• Mechanism: Countercurrent multiplication.

Dilute vs. Concentrated Urine

• Dilute: Low solute concentration.

• Concentrated: High solute concentration.

Urine Properties

• Normal: Clear, yellow, pH 4.5–8.0.

• Abnormal: Protein, glucose, blood, ketones.

Ureters, Bladder, Urethra

• Ureters: Transport urine to bladder.

• Bladder: Stores urine.

• Urethra: Conducts urine out of body.

Micturition Reflex

• Definition: Reflex contraction of bladder for urination.

Fluid, Electrolyte, and Acid-Base Balance (Chapter 26)

Body Water Content

• Factors: Age, gender, body fat.

Fluid Compartments

• Intracellular: Inside cells.

• Extracellular: Plasma, interstitial fluid.

Electrolytes vs. Non-Electrolytes

• Electrolytes: Dissociate into ions, affect osmotic balance.

• Non-Electrolytes: Do not dissociate, less osmotic effect.

Fluid Shifts

• Factors: Osmosis, hydrostatic pressure.

Water Intake and Output

• Intake: Drinking, food, metabolism.

• Output: Urine, sweat, feces, respiration.

Regulation of Water Balance

• Feedback: Thirst mechanism, ADH.

Obligatory Water Loss

• Importance: Minimum urine output to remove wastes.

Dehydration and Edema

• Dehydration: Water loss exceeds intake.

• Edema: Excess fluid in tissues.

Electrolyte Balance

• Sodium: Major extracellular ion, affects blood pressure.

• Potassium, Calcium, Anions: Regulated by hormones.

Acid-Base Balance

• Sources of Acids: Metabolism, respiration.

• Regulation: Kidneys and lungs adjust hydrogen and bicarbonate ions.

Acidosis vs. Alkalosis

• Acidosis: Low blood pH.

• Alkalosis: High blood pH.

• Compensation: Respiratory and renal mechanisms.

The Reproductive System (Chapter 27)

Meiosis vs. Mitosis

• Meiosis: Cell division producing gametes with half the chromosome number.

• Mitosis: Cell division producing identical cells.

Spermatogenesis

• Events: Formation of sperm in testes.

Hormonal Regulation of Testicular Function

• Testosterone: Stimulates spermatogenesis, male characteristics.

Oogenesis

• Process: Formation of ova in ovaries.

• Comparison: Fewer ova produced, arrested at prophase I until puberty.

Ovarian Cycle

• Phases: Follicular, ovulation, luteal.

Regulation of Ovarian and Uterine Cycles

• Hormones: FSH, LH, estrogen, progesterone.

Estrogen and Progesterone Effects

• Estrogen: Promotes female secondary sex characteristics.

• Progesterone: Prepares uterus for pregnancy.

Male and Female Sexual Response

• Male: Erection, emission, ejaculation.

• Female: Arousal, plateau, orgasm, resolution.