Endocrine System

Hormones: Sources and Major Effects

The endocrine system regulates body functions through hormones, which are chemical messengers secreted by glands. Each hormone has a specific source and physiological effect.

• Source (Endocrine Gland): Examples include the pituitary, thyroid, adrenal glands, pancreas, and gonads.

• Major Effects: Hormones regulate growth, metabolism, stress response, reproduction, and homeostasis.

• Example: Insulin (from the pancreas) lowers blood glucose; Thyroxine (from the thyroid) increases metabolic rate.

Blood

Formed Elements of Blood

Blood consists of plasma and formed elements, each with distinct functions.

• Erythrocytes (Red Blood Cells): Transport oxygen and carbon dioxide.

• Leukocytes (White Blood Cells): Defend against pathogens; types include neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

• Platelets (Thrombocytes): Involved in blood clotting.

Cardiovascular System

Internal Structures of the Heart

The heart is a muscular organ with four chambers and associated valves and vessels.

• Major Structures: Right and left atria, right and left ventricles, tricuspid and bicuspid (mitral) valves, pulmonary and aortic valves, septa, chordae tendineae, papillary muscles.

EKG Deflection Waves

An electrocardiogram (EKG/ECG) records the electrical activity of the heart.

• P wave: Atrial depolarization (contraction).

• QRS complex: Ventricular depolarization (contraction).

• T wave: Ventricular repolarization (relaxation).

Blood Flow and Blood Pressure

Blood flow and pressure are influenced by several factors.

• Factors: Cardiac output, blood volume, vessel diameter, blood viscosity, and peripheral resistance.

• Relationship: Increased resistance or cardiac output raises blood pressure; vasodilation lowers resistance and pressure.

• Equation: (where P is pressure, CO is cardiac output, R is resistance)

Major Arteries of the Body

Arteries transport oxygenated blood from the heart to tissues.

• Examples: Aorta, carotid arteries, subclavian arteries, renal arteries, femoral arteries.

Lymphatic and Immune Systems

Functions of the Lymphatic System

• Returns interstitial fluid to the bloodstream.

• Absorbs dietary fats from the intestine.

• Provides immune defense via lymphocytes and lymphoid organs.

Body’s Three Lines of Defense

• First Line: Physical and chemical barriers (skin, mucous membranes).

• Second Line: Innate immunity (phagocytes, inflammation, fever).

• Third Line: Adaptive immunity (B and T lymphocytes, antibodies).

• Example: Skin (first), macrophages (second), antibodies (third).

Respiratory System

Major Anatomical Features of the Lungs

• Lobes: Right lung (3), left lung (2).

• Coverings: Pleura (visceral and parietal layers).

• Other Features: Bronchi, alveoli, hilum.

Transport of Respiratory Gases by Blood

• Oxygen: Mostly bound to hemoglobin in red blood cells.

• Carbon Dioxide: Dissolved in plasma, as bicarbonate ions, or bound to hemoglobin.

• Equation:

Digestive System

Alimentary Canal vs. Accessory Digestive Organs

• Alimentary Canal: Mouth, pharynx, esophagus, stomach, small and large intestines, anus.

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

Major Digestive Processes and Locations

• Ingestion: Mouth

• Propulsion: Esophagus, stomach, intestines

• Mechanical Digestion: Mouth, stomach

• Chemical Digestion: Stomach, small intestine

• Absorption: Small and large intestines

• Defecation: Anus

Nutrition and Metabolism

Primary Functions of Major Nutrients

• Carbohydrates: Main energy source

• Proteins: Build and repair tissues, enzymes, hormones

• Lipids: Energy storage, cell membranes, hormones

• Vitamins and Minerals: Cofactors, structural components

Biochemical Pathways of Glucose Oxidation

• Glycolysis: Occurs in cytoplasm; splits glucose into pyruvate, yields 2 ATP.

• Krebs Cycle (Citric Acid Cycle): In mitochondria; processes acetyl-CoA, yields 2 ATP and electron carriers.

• Electron Transport Chain: In mitochondria; uses electrons to produce up to 34 ATP.

• Total ATP: Up to 38 ATP per glucose molecule.

Urinary System

Structural and Functional Units of the Kidney

• Nephron: The functional unit; filters blood and forms urine.

• Parts: Renal corpuscle (glomerulus + Bowman's capsule), renal tubule (proximal tubule, loop of Henle, distal tubule).

Processes Involved in Urine Formation

• Filtration: In glomerulus; blood plasma filtered into nephron.

• Reabsorption: Useful substances returned to blood.

• Secretion: Additional wastes added to filtrate.

Major Routes of Water and Electrolyte Entry and Exit

• Entry: Ingestion (food, drink), metabolic water production.

• Exit: Urine, sweat, feces, respiration.

Reproductive System

Pathway of Sperm Cells

• Testes → Epididymis → Vas deferens → Ejaculatory duct → Urethra → Exterior

Products of Meiosis in Males

• Four haploid sperm cells from each primary spermatocyte.

Sexual Response Events and Nervous System Control

• Excitement: Parasympathetic control

• Orgasm: Sympathetic control

• Resolution: Parasympathetic control

Pathway of Egg Cells

• Ovary → Uterine (fallopian) tube → Uterus → Cervix → Vagina → Exterior

Development and Heredity

Conceptus Terms and Ages

• Zygote: Fertilized egg (0–1 week)

• Embryo: 2–8 weeks

• Fetus: 9 weeks to birth

Fates of Embryonic Germ Layers

• Ectoderm: Forms nervous system, skin

• Mesoderm: Forms muscles, bones, circulatory system

• Endoderm: Forms lining of digestive and respiratory tracts

Patterns of Inheritance

• Dominant-Recessive: One allele masks another (e.g., brown eyes over blue)

• Codominance: Both alleles expressed (e.g., AB blood type)

• Sex-linked: Genes on X or Y chromosome (e.g., hemophilia)

Additional info: This guide expands on the exam objectives by providing definitions, examples, and key processes for each topic, ensuring a comprehensive review for the cumulative final exam in Anatomy & Physiology II.