Human Physiology Set 2

🧊 Hydration

Q: What is the normal range of body water percentage?
A: 50–70% of body mass.

Q: How much water is typically lost during exercise?
A: 1–2 liters per hour.

Q: How does dehydration affect performance?
A: Dehydration exceeding 2.1% of body mass significantly impairs performance.

Q: What mechanisms regulate body water movement?
A: Osmosis, governed by differences in osmotic pressure.

Q: What are effective hydration strategies pre-exercise?
A: 500ml of water 1–2 hours before activity.

Q: What is recommended during exercise longer than 1 hour?
A: 600–1200ml/hour with sodium for fluid and electrolyte balance.

Q: How is hydration measured?
A: Urine osmolality, plasma osmolality, saliva testing, and bioelectrical impedance analysis (BIA).

Q: What are hypotonic, isotonic, and hypertonic beverages?
A: Hypotonic: <4% carbs, quick hydration; Isotonic: 6–8%, balance of energy/hydration; Hypertonic: >10%, for glycogen replenishment.

🌡 Thermoregulatory System

Q: What is the normal core body temperature range?
A: 36.5°C to 37.5°C.

Q: What are the primary modes of heat loss?
A: Radiation (60%), convection (12%), evaporation (25%), and conduction (2%).

Q: How does the body respond to heat stress?
A: Increased sweating and skin blood flow; core temperature rises.

Q: What are signs of heat exhaustion and stroke?
A: Fatigue, dizziness, nausea, core temperature >38°C (heat stroke).

Q: How does the body adapt to heat through acclimatization?
A: Earlier onset of sweating, more dilute sweat, reduced cardiovascular strain.

Q: What are physiological responses to cold?
A: Vasoconstriction, shivering, and hormonal regulation (e.g. thyroxine, adrenaline).

Q: What is the main thermoregulatory control center?
A: The hypothalamus.

🌬 Respiratory Function

Q: What is the primary function of the respiratory system?
A: Gas exchange, acid-base balance, and vocalization.

Q: How does Boyle’s Law apply to breathing?
A: An increase in thoracic volume reduces pressure, allowing air to flow in.

Q: Where does gas exchange occur?
A: In the alveoli of the lungs.

Q: What respiratory centers control breathing?
A: Medulla oblongata and pons.

Q: How is CO₂ primarily transported in blood?
A: As bicarbonate ions (70%).

Q: What is tidal volume (VT)?
A: The volume of air inhaled or exhaled during normal breathing (~500ml).

Q: What is COPD and how does it affect respiration?
A: Chronic Obstructive Pulmonary Disease; causes airway narrowing and reduced gas exchange.

❤ Cardiovascular System

Q: What are the four heart chambers?
A: Right atrium, right ventricle, left atrium, left ventricle.

Q: What is the cardiac cycle composed of?
A: Diastole (filling) and systole (contraction).

Q: What is cardiac output (CO)?
A: CO = Heart Rate (HR) × Stroke Volume (SV).

Q: What is the equation for mean arterial pressure (MAP)?
A: MAP = DBP + 1/3(SBP - DBP).

Q: What does the QRS complex represent in an ECG?
A: Ventricular depolarization.

Q: What autonomic inputs regulate heart rate?
A: Sympathetic increases HR; parasympathetic (vagus nerve) decreases HR.

Q: What is the significance of the rate pressure product (RPP)?
A: Indicates myocardial oxygen demand (RPP = SBP × HR).

🩸 Blood & Its Components

Q: What percentage of oxygen is transported by hemoglobin?
A: About 99%.

Q: How is carbon dioxide transported in the blood?
A: 70% as bicarbonate, 23% bound to hemoglobin, 7% dissolved in plasma.

Q: What is the Bohr effect?
A: Lower pH reduces hemoglobin’s affinity for oxygen.

Q: What is the Haldane effect?
A: Deoxygenated hemoglobin carries more CO₂.

Q: What is hematocrit?
A: The percentage of red blood cells in total blood volume.

Q: What hormones increase red blood cell production?
A: Erythropoietin (EPO), secreted by the kidneys.

🏔 High Altitude and Adaptations

Q: How does PO₂ change with altitude?
A: Decreases from 160 mmHg at sea level to ~50 mmHg at 4000m.

Q: What are acute responses to high altitude?
A: Increased ventilation and heart rate.

Q: What chronic adaptations occur at high altitude?
A: Increased RBC production, capillary density, and myoglobin concentration.

Q: What hormone mediates altitude adaptation?
A: Erythropoietin (EPO).

Q: What are common altitude sickness symptoms?
A: Headache, nausea, dizziness, shortness of breath.

Q: What is COPD?
A: Chronic lung disease causing airflow limitation and gas exchange impairment.

🧫 The Cell

Q: What are the major cell organelles?
A: Nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, ribosomes.

Q: What is the primary role of mitochondria?
A: ATP production through aerobic respiration.

Q: What is the function of the cell membrane?
A: Selectively allows substances in/out; phospholipid bilayer.

Q: What are the types of membrane transport?
A: Passive (diffusion, osmosis), active (requires ATP).

Q: What proteins form the cytoskeleton?
A: Actin (microfilaments), tubulin (microtubules), intermediate filaments.

🧠 The Neural System

Q: What are the two main divisions of the nervous system?
A: Central (CNS) and Peripheral (PNS).

Q: What is the function of myelin?
A: Speeds up action potential conduction.

Q: What is the resting membrane potential of a neuron?
A: Approximately -70 mV.

Q: What triggers an action potential?
A: Depolarization due to sodium influx.

Q: What is the function of the synapse?
A: Transfers signals via neurotransmitters between neurons.

Q: What is the role of the autonomic nervous system?
A: Controls involuntary functions (heart rate, digestion).

🧬 The Endocrine System

Q: What are the major endocrine glands?
A: Pituitary, thyroid, adrenal, pancreas, pineal, parathyroid.

Q: What are the types of hormones?
A: Steroid (lipid-soluble) and peptide (water-soluble).

Q: What is negative feedback in hormone regulation?
A: A process that inhibits hormone secretion when levels are sufficient.

Q: What is the stress response pathway?
A: Hypothalamus → pituitary → adrenal → cortisol/epinephrine.

Q: What is the difference between Type 1 and Type 2 diabetes?
A: Type 1: insulin deficiency (autoimmune); Type 2: insulin resistance.

💪 The Muscular System

Q: What is the functional unit of skeletal muscle?
A: The sarcomere.

Q: How does muscle contraction occur?
A: Via sliding filament theory: actin and myosin interaction powered by ATP.

Q: What triggers contraction at the molecular level?
A: Calcium binds troponin, revealing binding sites on actin.

Q: What are the types of muscle fibers?
A: Type I (slow-twitch), Type IIa/b (fast-twitch).

Q: What causes muscle fatigue?
A: Lactic acid buildup, hydrogen ions, and glycogen depletion.

Q: What are the types of muscle contractions?
A: Isometric (static), concentric (shortening), eccentric (lengthening).