1. What are the respiratory organs in animals?
Answer: The respiratory organs in animals include gills in fish, lungs in mammals, birds, and reptiles, tracheae in insects, and skin in amphibians like frogs.
2. Describe the respiratory system in humans.
Answer: The human respiratory system includes the nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, and lungs. It functions to facilitate gas exchange, supplying oxygen to the body and removing carbon dioxide.
3. Explain the mechanism of breathing in humans.
Answer: Breathing involves inspiration (inhaling) and expiration (exhaling). During inspiration, the diaphragm contracts and moves downward, and the intercostal muscles contract, expanding the chest cavity and allowing air to enter the lungs. During expiration, these muscles relax, reducing the chest cavity’s volume and pushing air out of the lungs.
4. How is respiration regulated in humans?
Answer: Respiration is regulated by the respiratory center in the medulla oblongata and pons of the brain, which respond to changes in blood levels of carbon dioxide and oxygen, and pH levels. Chemoreceptors in the carotid bodies and aortic bodies also play a role.
5. What are respiratory volumes?
Answer: Respiratory volumes include tidal volume (TV), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), residual volume (RV), and vital capacity (VC). These volumes measure the amount of air involved in different phases of the respiratory cycle.
6. Describe the transport of gases in the human body.
Answer: Oxygen is transported from the lungs to the tissues by hemoglobin in red blood cells. Carbon dioxide is transported from the tissues to the lungs in three forms: dissolved in plasma, as bicarbonate ions (HCO₃⁻), and bound to hemoglobin as carbaminohemoglobin.
7. What is asthma and how does it affect the respiratory system?
Answer: Asthma is a chronic inflammatory disease of the airways that causes periodic episodes of bronchoconstriction, leading to wheezing, shortness of breath, chest tightness, and coughing.
8. What is emphysema?
Answer: Emphysema is a chronic respiratory disorder where the alveolar walls are damaged, leading to decreased surface area for gas exchange, difficulty in breathing, and reduced oxygen supply to the body.
9. What are occupational respiratory disorders?
Answer: Occupational respiratory disorders are diseases caused by inhaling harmful substances at the workplace, such as pneumoconiosis (from dust), asbestosis (from asbestos fibers), and silicosis (from silica dust).
10. What is the composition of blood?
Answer: Blood is composed of plasma (55%), which contains water, proteins, electrolytes, nutrients, and waste products, and formed elements (45%), which include red blood cells (RBCs), white blood cells (WBCs), and platelets.
11. Describe the process of blood coagulation.
Answer: Blood coagulation involves a cascade of reactions that result in the formation of a blood clot. Key steps include the conversion of prothrombin to thrombin, which then converts fibrinogen to fibrin, forming a mesh that stabilizes the clot.
12. What is the function of the lymphatic system?
Answer: The lymphatic system helps maintain fluid balance, absorbs fats from the digestive tract, and provides immune defense by transporting lymph, which contains lymphocytes and other immune cells.
13. Describe the structure of the human heart.
Answer: The human heart has four chambers: two atria (upper chambers) and two ventricles (lower chambers). It includes structures such as the septum, valves (tricuspid, mitral, pulmonary, and aortic), and is surrounded by the pericardium.
14. What is the cardiac cycle?
Answer: The cardiac cycle consists of systole (contraction phase) and diastole (relaxation phase). During systole, the ventricles contract, pumping blood into the arteries. During diastole, the heart relaxes, and the atria fill with blood.
15. Explain the double circulation in humans.
Answer: Double circulation refers to the separate circulation of blood through the lungs (pulmonary circulation) and the rest of the body (systemic circulation), ensuring oxygenated and deoxygenated blood are kept separate.
16. What is hypertension?
Answer: Hypertension, or high blood pressure, is a condition where the force of blood against the artery walls is too high, which can lead to heart disease, stroke, and other health problems.
17. Describe the human excretory system.
Answer: The human excretory system includes the kidneys, ureters, bladder, and urethra. It functions to remove waste products and excess substances from the blood, maintain fluid and electrolyte balance, and regulate blood pressure.
18. What is the role of the kidneys in osmoregulation?
Answer: The kidneys regulate the body’s osmotic balance by adjusting the amount of water and salts reabsorbed from the filtrate during urine formation, influenced by hormones like ADH and aldosterone.
19. What is the function of the hypothalamus in the endocrine system?
Answer: The hypothalamus regulates the endocrine system by releasing hormones that control the pituitary gland, which in turn regulates other endocrine glands and processes like growth, metabolism, and stress response.
20. What is diabetes insipidus?
Answer: Diabetes insipidus is a disorder characterized by excessive thirst and excretion of large amounts of dilute urine. It results from a deficiency of antidiuretic hormone (ADH) or a failure of the kidneys to respond to ADH.