Anatomy and Physiology Level 3 // Revision questions and answers// Complete test bank.

Describe the structural differences between compact bone and spongy bone and explain how each contributes to overall bone function ️ Compact bone is dense and organized into osteons, providing strength and resistance to stress, while spongy bone has a porous trabecular structure that reduces weight and allows space for bone marrow, aiding in blood cell production and shock absorption Explain how the sliding filament theory accounts for muscle contraction at the molecular level ️ The sliding filament theory states that actin and myosin filaments slide past each other through cross-bridge cycling powered by ATP, shortening the sarcomere and causing muscle contraction Discuss how the structure of the alveoli maximizes gas exchange efficiency in the lungs ️ Alveoli have thin walls, a large surface area, and are surrounded by capillaries, allowing rapid diffusion of oxygen into the blood and carbon dioxide out Explain how negative feedback regulates body temperature in humans ️ When body temperature rises, mechanisms like sweating and vasodilation are triggered to cool the body, while a drop in temperature triggers shivering and vasoconstriction to generate and conserve heat Describe the pathway of blood through the heart and explain the significance of valves ️ Blood flows from the vena cava to the right atrium, right ventricle, lungs, left atrium, left ventricle, and out through the aorta, with valves ensuring one-way flow and preventing backflow Explain how the nephron filters blood to form urine ️ The nephron filters blood in the glomerulus, reabsorbs useful substances in the tubules, and secretes wastes, resulting in urine formation Discuss how the nervous system and endocrine system differ in communication methods ️ The nervous system uses rapid electrical impulses and neurotransmitters for immediate responses, while the endocrine system uses hormones in the bloodstream for slower, longer-lasting effects Explain how enzymes function in digestion and why they are specific ️ Enzymes speed up chemical reactions by lowering activation energy and are specific because their active sites match only particular substrates Describe how oxygen is transported in the blood and what factors influence its release ️ Oxygen binds to hemoglobin in red blood cells and is released based on factors like pH, temperature, and carbon dioxide levels 2 Explain the role of the hypothalamus in maintaining homeostasis ️ The hypothalamus monitors internal conditions and regulates temperature, hunger, thirst, and hormone release via the pituitary gland Discuss the structure and function of the spinal cord in reflex actions ️ The spinal cord transmits nerve impulses and coordinates reflexes by processing stimuli and generating immediate responses without brain involvement Explain how synaptic transmission occurs between neurons ️ An electrical impulse triggers neurotransmitter release into the synaptic cleft, which binds to receptors on the next neuron, generating a new impulse Describe how the immune system distinguishes between self and non-self cells ️ The immune system recognizes antigens on foreign cells and ignores the body’s own cells due to self-markers like MHC proteins Explain how hormones regulate blood glucose levels ️ Insulin lowers blood glucose by promoting uptake and storage, while glucagon raises it by stimulating glycogen breakdown Discuss how lung ventilation is achieved through pressure changes ️ The diaphragm and intercostal muscles change thoracic volume, altering pressure to draw air in and push it out Explain the role of platelets in blood clotting ️ Platelets aggregate at injury sites and release chemicals that initiate clot formation to prevent blood loss Describe the function of the liver in metabolism and detoxification ️ The liver processes nutrients, stores glycogen, produces bile, and detoxifies harmful substances Explain how ATP is produced during cellular respiration ️ ATP is generated through glycolysis, the Krebs cycle, and the electron transport chain using oxygen to produce energy Discuss the structure of DNA and its role in protein synthesis ️ DNA is a double helix that stores genetic information, which is transcribed into RNA and translated into proteins Explain how joints allow movement and provide stability ️ Joints connect bones and vary in mobility, with structures like ligaments and cartilage ensuring stability and reducing friction Describe the role of calcium in muscle contraction ️ Calcium ions bind to troponin, exposing binding sites on actin for myosin, enabling contraction Explain how the respiratory and circulatory systems work together ️ The respiratory system supplies oxygen to the blood, while the circulatory system transports it to tissues and removes carbon dioxide 3 Discuss the function of the skin as an organ ️ The skin protects against pathogens, regulates temperature, prevents water loss, and contains sensory receptors Explain how the eye converts light into nerve signals ️ Photoreceptors in the retina detect light and convert it into electrical signals sent to the brain via the optic nerve Describe how the ear maintains balance ️ The vestibular system detects head movements and position, sending signals to maintain balance and posture Explain how the digestive system breaks down carbohydrates ️ Enzymes like amylase and maltase break carbohydrates into glucose for absorption Discuss how the lymphatic system supports immunity ️ It transports lymph, filters pathogens in lymph nodes, and produces immune cells Explain how red blood cells are adapted for oxygen transport ️ They lack a nucleus, contain hemoglobin, and have a biconcave shape to maximize surface area Describe how the pancreas functions in both digestion and hormone regulation ️ It releases digestive enzymes into the small intestine and hormones like insulin and glucagon into the blood Explain how dehydration affects body systems ️ It reduces blood volume, affects temperature regulation, and impairs cellular function Discuss how aging affects the musculoskeletal system ️ Bone density decreases, joints become less flexible, and muscle mass declines Explain how the brain processes sensory information ️ Sensory receptors send signals to specific brain areas where they are interpreted Describe how antibiotics target bacterial cells without harming human cells ️ They target structures unique to bacteria, like cell walls or ribosomes Explain how the body responds to stress physiologically ️ The fight-or-flight response releases adrenaline, increasing heart rate and energy availability Discuss the importance of homeostasis in survival ️ Maintaining stable internal conditions ensures optimal functioning of enzymes and cells Explain how the cardiovascular system adapts during exercise ️ Heart rate and stroke volume increase to deliver more oxygen to muscles Describe how bile aids in fat digestion ️ Bile emulsifies fats into smaller droplets, increasing surface area for enzyme action 4 Explain how genetic mutations can affect protein function ️ Mutations alter DNA sequences, potentially changing amino acids and protein structure Discuss how the endocrine system maintains long-term regulation ️ Hormones act over