Exercise 21: Arteries, Veins, Capillaries

Exercise 21: Arteries, Veins, and Capillaries

• Arteries carry blood away from the heart. They are more elastic, have no valves, and thicker walls. They carry oxygen-rich blood (except pulmonary arteries, which carry deoxygenated blood), have a smaller lumen, and blood pressure increases.
• Veins carry blood back to the heart. They are less elastic, have valves, and thinner walls. They carry oxygen-poor blood (except pulmonary veins, which carry oxygenated blood), have a larger lumen, and blood pressure decreases.
• Capillaries are one cell layer thick, forming networks called capillary beds. They facilitate gas exchange between tissues and blood.

Exercise 21: Blood Vessels - Layers

• Blood vessels have three layers: tunica intima, tunica media, and tunica externa.
• Tunica intima forms a friction-reducing lining and contains endothelium.
• Tunica media is smooth muscle and elastic tissue, controlled by the sympathetic nervous system.
• Tunica externa is the outermost covering, mostly fibrous connective tissue, providing support.

Exercise 21: Major Blood Vessels

• Aorta is the largest artery, leaving from the left ventricle (LV) of the heart.
• Superior vena cava drains the head and arms, entering the right atrium (RA) of the heart.
• Inferior vena cava drains the lower body, entering the RA of the heart.

Exercise 22: Cardiac Cycle and Blood Pressure

• Cardiac cycle involves atria and ventricle contractions/relaxations, leading to changes in blood volume and pressure.
• Pulse is the alternating surges of pressure in arteries with each left ventricle beat (70-76 BPM usually).
• Blood pressure is the force exerted by blood against inner blood vessel walls, measured in arteries.
• Systolic pressure is the highest pressure during ventricular contraction.
• Diastolic pressure is the lowest pressure during ventricular relaxation.
• A sphygmomanometer measures blood pressure, with Korotkoff sounds indicating resuming blood flow in the forearm after cuff pressure is released.
• Cardiac output is the amount of blood pumped out of the left ventricle per minute.
• Peripheral resistance is the friction blood encounters as it flows through vessels, influenced by blood vessel constriction, viscosity, and volume.

Exercise 23 & 24: The Respiratory System

• Pulmonary ventilation is the movement of air into and out of the lungs (breathing).
• External respiration involves gas exchange between pulmonary blood and alveoli (O2 loading and CO2 unloading).
• Internal respiration involves gas exchange between blood and tissue cells in systemic capillaries.
• Respiratory membrane is the "air-blood barrier" formed by alveolar and capillary walls, facilitating gas exchange.
• Respiratory zone structures (respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli) are the only sites of gas exchange, while conducting zones include passageways leading to these areas.
• Tidal volume (TV) is the normal amount of air moved in or out of the lungs during a quiet breath (typically 500 mL).
• Residual volume (RV) is the air remaining in the lungs after exhalation.
• Vital capacity (VC) is the total exchangeable air volume (TV + Inspir. Reserve Vol. + Expir. Reserve Vol.) and varies between individuals. The normal values are 4800 mL for men and 3100 mL for women.
• Pharynx (throat) is a common passageway for air and food.
• Larynx (voice box) is for air and food passage.
• Trachea (windpipe) is a 4-inch tube connected to the larynx, lined with ciliated mucosa.
• Main bronchi are formed by trachea division, each entering a lung at the hilum.
• Lungs are divided into lobes by fissures (2 lobes in the left lung, 3 lobes in the right lung).
• Serosa is the outer lung covering, consisting of visceral and parietal pleura, with pleural fluid preventing friction during breathing.

Exercise 25: The Digestive System

• The digestive system breaks down food, absorbs nutrients, and eliminates waste.
• Accessory organs include the liver, gallbladder, pancreas, and salivary glands.
• These organs aid digestion by secreting enzymes and bile.
• Specific components, like the pharynx, esophagus, stomach, duodenum, jejunum, ileum, and large intestine are involved in the digestion and absorption processes.
• Mucosal lining, villi and circular folds increase surface area for absorption.

Exercise 26: The Urinary System

• The urinary system maintains homeostasis by removing waste products, regulating blood pressure, and producing hormones.
• Kidneys filter blood, producing urine containing wastes and excess ions.
• Structures include kidneys, ureters, urinary bladder, and urethra. Kidneys have three regions: cortex, medulla, and pelvis.
• Nephrons are the functional units of kidneys with two main components, renal corpuscle, and renal tubules.
• Renal corpuscles consist of glomerulus (fed by afferent arterioles, drained by efferent arterioles) and glomerular capsule (Bowman's capsule).
• Urine formation involves glomerular filtration, tubular reabsorption, and tubular secretion.
• Filtration forces fluid into Bowman's capsule.
• Reabsorption reclaims valuable substances such as water, glucose, and ions from filtered fluid.
• Secretion removes additional metabolic wastes, such as hydrogen ions.