Comprehensive Review Notes for ANP College Course: Endocrine, Digestive, Respiratory, Cardiovascular, Urinary, Lymphatic, and Immune Systems

Homeostasis and Feedback Mechanisms

Homeostasis

Homeostasis is the process by which the body maintains a stable internal environment despite external changes. It is essential for normal physiological function.

• Definition: The maintenance of a constant internal environment.

• Homeostatic Imbalance: Occurs when the body cannot maintain homeostasis, leading to disease or dysfunction.

Feedback Mechanisms

Feedback mechanisms regulate homeostasis through positive or negative feedback loops.

• Negative Feedback: Reduces the effect of the original stimulus (e.g., regulation of blood glucose by insulin).

• Positive Feedback: Enhances the original stimulus (e.g., blood clotting, childbirth).

• Systems Involved:

  • Nervous System: Fast, brief, targets muscle fibers or glands.

  • Endocrine System: Slow, long-lasting, targets cells throughout the body.

Endocrine System

Hormonal Regulation

• Parathyroid Hormone (PTH): Raises blood calcium by releasing calcium from bones and increasing GI absorption.

• Insulin: Secreted in response to high blood glucose; lowers blood glucose by promoting uptake into cells.

• Growth Hormone: Stimulates protein synthesis in bones and muscles (anabolic effect).

• Adrenocorticotropic Hormone (ACTH): Stimulates adrenal cortex to release hormones.

Feedback Mechanisms in Endocrine Regulation

• Neural Messages: Fast, direct regulation.

• Chemical Messages: Hormones, slower, widespread effects.

Hormones and Receptors

• Protein Hormones: Act via second messengers (e.g., cAMP).

• Hormone Receptors: Cells respond only if they have specific receptors for the hormone.

• Types of Hormonal Receptors:

  • Membrane-bound: Bind amino acid-based hormones.

  • Intracellular: Bind steroid hormones.

Endocrine vs. Exocrine Glands

• Endocrine Glands: Secrete hormones directly into the bloodstream.

• Exocrine Glands: Secrete substances into ducts (e.g., sweat, saliva).

Insulin & Glucagon

• Secreted by: Pancreas (Islets of Langerhans).

• Insulin: Released after meals; lowers blood glucose.

• Glucagon: Released during fasting; raises blood glucose.

Digestive System and Metabolism

Anatomy and Function

• Small Intestine: Villi increase surface area for absorption.

• GI Tract Layers:

  • Serosa: Attaches organs to body wall.

  • Mucosa: Responsible for absorption.

• Deglutition: Swallowing; involves mouth, pharynx, esophagus (not pylorus).

• Mastication: Physical breakdown of food by chewing.

Chemical Digestion and Metabolism

• Catabolism: Breakdown of large molecules into smaller ones.

• Glycolysis: Converts glucose to pyruvic acid and ATP.

  • ATP Produced: 2 ATP per glucose molecule.

• Gluconeogenesis: Formation of glucose from non-carbohydrate sources.

• Glycogenolysis: Breakdown of glycogen to glucose.

Enzymes

• Definition: Biological catalysts that speed up reactions without being consumed.

Nutrient Absorption and Metabolism

• Small Intestine: Main site of nutrient absorption.

• Bile Production: Hepatocytes in liver produce bile.

• Krebs Cycle & Electron Transport Chain: Require oxygen for glucose catabolism.

Endocrine Functions in Digestion

• Pineal Gland: Produces melatonin, regulates sleep.

• Thymosin: Promotes T-cell development.

• Epinephrine: Triggers fight-or-flight response.

Additional Digestive Concepts

• Peristalsis: Propels food through esophagus.

• Pancreatic Enzymes: Bicarbonate secreted into duodenum.

• Anabolic vs. Catabolic Reactions: Anabolic builds molecules; catabolic breaks them down.

Six Essential Activities of Digestion

• Ingestion

• Propulsion

• Mechanical digestion

• Chemical digestion

• Absorption

• Defecation

GI Tract Layers and Functions

• Mucosa: Absorption and secretion.

• Submucosa: Supports mucosa, contains blood vessels.

• Muscularis externa: Muscle for movement.

• Serosa: Protective outer layer.

Metabolism

• Anabolism: Building up molecules.

• Catabolism: Breaking down molecules.

• ATP: Main energy currency of the cell.

• ATP from Glycolysis: 2 ATP per glucose.

• ATP from Glycolysis, Krebs, ETC: 36-38 ATP per glucose.

• Oxygen: Required for aerobic metabolism; CO2 is a waste product from Krebs cycle.

Respiratory System

Mechanics of Breathing

• Diaphragm & Intercostal Muscles: Contract to increase thoracic volume, decrease pressure, causing inspiration.

• Intrapulmonary vs. Atmospheric Pressure: Air flows from high to low pressure.

Gas Exchange

• Alveoli: Site of gas exchange.

• External Respiration: Exchange of gases between alveoli and blood.

• Internal Respiration: Exchange of gases between blood and tissues.

• Factors: Partial pressures, solubility.

Respiratory Regulation

• CO2 and O2: CO2 levels are primary regulators of breathing.

• Respiratory Centers: Located in the brainstem.

Respiratory Physiology

• Inspiration: Diaphragm contracts, thoracic volume increases.

• Expiration: Diaphragm relaxes, thoracic volume decreases.

• Gas Transport: Oxygen mainly bound to hemoglobin; CO2 transported as bicarbonate.

• Exercise: Increases respiratory rate and gas exchange.

Oxygen and Carbon Dioxide Transport

• Oxygen: High partial pressure in lungs; low in tissues.

• CO2: High partial pressure in tissues; low in lungs.

Cardiovascular System

Heart Anatomy and Function

• Chambers: Right/left atria and ventricles; receive and pump blood.

• Valves: Tricuspid, bicuspid (mitral), semilunar; prevent backflow.

• Cardiac Cycle: Systole (contraction), diastole (relaxation).

Blood Vessels

• Arteries: Carry blood away from heart; thick walls.

• Veins: Carry blood to heart; thinner walls, valves.

• Capillaries: Site of exchange.

• Pulmonary vs. Systemic Circuits: Pulmonary (lungs), systemic (body).

Blood Pathway and Cardiac Cycle

• Pathway: Body → right atrium → right ventricle → lungs → left atrium → left ventricle → body.

• Systole: Contraction phase.

• Diastole: Relaxation phase.

Blood Composition

• Plasma: 55% of blood; contains water, proteins, nutrients.

• Formed Elements:

  • Erythrocytes: Red blood cells; carry oxygen.

  • Leukocytes: White blood cells; immune function.

  • Thrombocytes: Platelets; clotting.

Blood Types and Compatibility

• ABO System: Based on presence of A/B antigens.

• Rh Factor: Positive or negative.

• Agglutinogens: Antigens on RBCs.

• Agglutinins: Antibodies in plasma.

Urinary System

Components and Functions

• Kidneys: Filter blood, produce urine.

• Nephrons: Functional units; consist of renal corpuscle (glomerulus, capsule) and renal tubule (proximal, loop, distal).

Filtrate vs. Urine

• Filtrate: Fluid filtered from blood; becomes urine after processing.

Urine Formation Steps

• Glomerular filtration

• Tubular reabsorption

• Tubular secretion

Bodily pH Control

• Buffer Systems: Immediate response.

• Respiratory Rate: Rapid adjustment.

• Renal Excretion: Slow, long-lasting.

Erythropoietin

• Function: Stimulates red blood cell production.

Filtration Pressures

• Blood Osmotic Pressure: High solute concentration in glomerulus.

• Capsular Hydrostatic Pressure: Resistance in capsule.

• Glomerular Hydrostatic Pressure: Maintained by arteriole structure.

Filtration Processes

• Glomerular Filtration: Plasma forced into capsule.

• Tubular Secretion: Substances moved from capillaries to filtrate.

• Reabsorption: Water and solutes reabsorbed in tubules.

Net Filtration Pressure (NFP)

• Definition: Filtration pressure after opposing pressures cancel out.

Glomerular Filtration Rate (GFR)

• Definition: Rate of filtrate formation; decreases after blood loss.

Juxtaglomerular Complex

• Function: Regulates GFR.

Urine Pathway

• Renal pelvis → ureter → bladder → urethra

• Peristalsis: Moves urine through ureters.

Lymphatic System

Lymph Flow

• Afferent Lymphatics: Bring lymph into nodes.

• Efferent Lymphatics: Carry lymph out of nodes.

Organs and Functions

• Spleen: Removes old RBCs.

• Thymus: Matures T cells.

Immune System

General Functions

• Protects against pathogens.

Three Main Parts

• Lymphatics

• Lymph

• Lymph nodes

Innate Defenses

• First Line: Skin, mucous membranes.

• Second Line: Phagocytes, NK cells, inflammation, antimicrobial proteins, fever.

Adaptive Defenses

• Humoral: B-cells produce antibodies for extracellular targets.

• Cellular: T-cells target cells directly or indirectly.

Antigen

• Definition: Substance that triggers an immune response.

Complement System Functions

• Promotes phagocytosis

• Causes agglutination, precipitation, neutralization, complement activation

Macrophage Presentation

• Presents antigens to naive CD4/CD8 T cells.

Inflammation

• Histamine: Released to stimulate inflammation.

Chemotaxis

• Neutrophils/macrophages follow chemical signals to infection site.

Antibody Production

• Plasma Cells: Produce antibodies.

Antigen Presentation

• Macrophages bring antigens to lymph nodes, activate T-cells.

Cell-Mediated Immunity

• Cytotoxic T Cells: Directly kill infected cells.

Thymus Gland

• Programs cytotoxic T cell precursors.

Interferon Release

• Released in response to viral infection.

HIV Target

• Targets and kills Helper T Cells.

Memory Cells

• Enable faster, stronger response to repeat invaders.

Key Equations and Tables

ATP Production from Glucose

$\text{Glycolysis:}~2~\text{ATP}~\text{per glucose}$ $\text{Krebs Cycle:}~2~\text{ATP}$ $\text{Electron Transport Chain:}~32-34~\text{ATP}$ $\text{Total:}~36-38~\text{ATP}$

Blood Pressure Equation

$\text{Blood Pressure} = \text{Cardiac Output} \times \text{Peripheral Resistance}$

Comparison Table: Endocrine vs. Exocrine Glands

Feature	Endocrine Glands	Exocrine Glands
Secretion	Hormones	Enzymes, sweat, saliva
Delivery	Bloodstream	Ducts
Examples	Thyroid, adrenal	Salivary, sweat

GI Tract Layers Table

Layer	Function
Mucosa	Absorption, secretion
Submucosa	Support, blood vessels
Muscularis externa	Movement
Serosa	Protection, attachment

Blood Cell Types Table

Cell Type	Function
Erythrocytes	Oxygen transport
Leukocytes	Immune defense
Thrombocytes	Clotting

Innate vs. Adaptive Immunity Table

Feature	Innate Immunity	Adaptive Immunity
Speed	Immediate	Delayed
Specificity	Non-specific	Specific
Components	Skin, phagocytes	B-cells, T-cells