SSC CGL Human Body and Biology Questions and Answers – Page 5

The liver can store about 100–120 grams of glycogen. Muscles also store glycogen but only for their own use (not released into blood). Kidney — The kidneys filter blood and regulate blood pressure, electrolytes, and water balance. They do not store glycogen as an energy reserve. Spleen — The spleen is the largest lymphoid organ. It does not store glycogen. Heart — The heart is a muscular organ that pumps blood. It uses glucose and fatty acids for energy but does NOT store glycogen reserves for the rest of the body. 📝 Important Note: Glycogen storage — Liver: 100-120g (for whole body glucose supply); Muscles: 300-400g (only for muscle use). Insulin = promotes glycogenesis (glucose → glycogen). Glucagon = promotes glycogenolysis (glycogen → glucose). Liver also performs detoxification, bile production, and protein synthesis.

x) for near vision; when they relax, the lens flattens for far vision. Light first passes through the cornea (which provides most of the refraction), then through the lens which fine-tunes the focus onto the retina. Cornea — The cornea is the transparent outer layer of the eye that provides the major part of the eye's refracting power. Iris — The iris is the colored, circular part of the eye that regulates the size of the pupil (amount of light entering the eye). It controls light entry, not focusing. Pupil — The pupil is simply an opening (hole) in the center of the iris that allows light to enter the eye. It is not a physical structure that can focus light — it only regulates the amount of light entering. 📝 Important Note: Parts of the eye and their functions — Cornea: refracts light; Lens: focuses light (accommodation); Iris: controls pupil size; Retina: contains photoreceptors (rods=dim light, cones=color); Optic nerve: transmits signals to brain. Defects: Myopia (short-sightedness) = concave lens; Hypermetropia (far-sightedness) = convex lens. SSC CGL commonly asks about eye parts and their functions.

During the "fight or flight" response triggered by stress, cortisol (along with adrenaline) prepares the body to handle danger. Insulin — Insulin is secreted by the beta cells of the Islets of Langerhans in the pancreas. It is NOT the stress hormone. Thyroxine — Thyroxine (T4) is secreted by the thyroid gland. It is NOT specifically the stress hormone. Melatonin — Melatonin is secreted by the pineal gland. It regulates the sleep-wake cycle (circadian rhythm) and is often called the "sleep hormone." It is NOT the stress hormone. 📝 Important Note: Hormone source chart — Cortisol: Adrenal cortex (stress hormone); Adrenaline (epinephrine): Adrenal medulla (fight or flight); Insulin: Pancreas (lowers blood sugar); Melatonin: Pineal gland (sleep); Thyroxine: Thyroid (metabolism). Cushing's syndrome = excess cortisol; Addison's disease = cortisol deficiency.

el is damaged, platelets rush to the site, become "sticky," and clump together to form a temporary platelet plug. They also release chemical signals that trigger the coagulation cascade, leading to the formation of a fibrin clot. Platelets do NOT have a nucleus. ❌ Why other options are wrong: Erythrocytes — Erythrocytes is the scientific name for Red Blood Cells (RBCs), not platelets. They are the most numerous blood cells (4.5–5.5 million per microliter). Leucocytes — Leucocytes is the scientific name for White Blood Cells (WBCs), not platelets. WBCs are the immune cells that fight infections and pathogens. Monocytes — Monocytes are a specific type of white blood cell (leucocyte) that differentiate into macrophages to engulf pathogens and foreign particles. They are NOT platelets. 📝 Important Note: Blood cell names — RBC = Erythrocytes; WBC = Leucocytes; Platelets = Thrombocytes. Platelets have a lifespan of only 8–10 days.

Kupffer cells in the liver are specialized immune cells that destroy bacteria and foreign particles from the blood. The liver also produces bile for fat digestion, synthesizes clotting factors, and stores vitamins A, D, B12, and iron. Kidney — The kidneys filter blood and remove metabolic waste (urea, creatinine) through urine. While kidneys do filter blood, they are NOT the primary organ for detoxification of toxins and drugs — that function belongs to the liver. Spleen — The spleen filters old, damaged red blood cells from the blood and plays an immune role. Lymph node — Lymph nodes filter lymph fluid and help fight infections by trapping pathogens. They are part of the lymphatic system and do NOT detoxify blood. 📝 Important Note: The liver is the largest gland in the human body (weighing about 1.5 kg). Key liver functions: Detoxification, Bile production (fat digestion), Glycogen storage, Protein synthesis (albumin, fibrinogen), Urea formation (from ammonia), Storage of vitamins (A, D, B12), and Fat metabolism. Hepatitis = liver inflammation. Cirrhosis = liver scarring (usually due to excess alcohol). Very important for SSC CGL Biology.

Growth hormone stimulates growth of bones (especially long bones like femur), muscles, and other organs. Thyroid — The thyroid gland secretes Thyroxine (T3/T4) which regulates basal metabolic rate (BMR), and Calcitonin which lowers blood calcium. It does NOT secrete growth hormone. Adrenal — The adrenal glands (located on top of kidneys) secrete Cortisol (stress hormone), Aldosterone (regulates sodium), and Adrenaline (epinephrine - fight or flight response). Pineal — The pineal gland secretes Melatonin, which regulates the sleep-wake cycle (circadian rhythm). It does NOT produce growth hormone. 📝 Important Note: Pituitary gland (Master gland) hormones — Anterior pituitary: GH (growth), TSH (thyroid), ACTH (adrenal), FSH and LH (sex organs), Prolactin (milk), MSH (melanin). Posterior pituitary: ADH/Vasopressin (water reabsorption), Oxytocin (uterine contractions, milk ejection). Pituitary is controlled by hypothalamus.

There are two main types: Type 1 (autoimmune destruction of beta cells — insulin-dependent) and Type 2 (insulin resistance — lifestyle-related, most common). It has absolutely NO relation to insulin deficiency. Dwarfism — Dwarfism is caused by deficiency of Growth Hormone (GH) from the pituitary gland during childhood. It is NOT related to insulin. Anaemia — Anaemia is caused by iron deficiency (most common), or Vitamin B12/folate deficiency. It is NOT caused by insulin deficiency. 📝 Important Note: Hormone deficiency diseases — Insulin: Diabetes mellitus; Growth Hormone (GH): Dwarfism (children); Thyroxine: Cretinism (children), Myxoedema (adults); ADH: Diabetes insipidus. Glucose tolerance test is used to diagnose diabetes.

This information helps the brain maintain balance, coordination, and spatial orientation. The utricle and saccule (also in the inner ear) detect linear acceleration and gravity. Hearing — Hearing is the function of the cochlea (snail-shaped structure in the inner ear). The cochlea converts sound vibrations into nerve impulses. The semicircular canals do NOT process sound. Amplifying sound — Sound amplification in the middle ear is done by the three ossicles (malleus, incus, stapes — the smallest bones in the body). Semicircular canals have no role in amplifying sound. Filtering sound — No part of the ear specifically "filters" sound. Sound processing happens in the auditory cortex of the brain. Semicircular canals have nothing to do with filtering sound. 📝 Important Note: Inner ear structure — Cochlea: converts sound to nerve impulse (hearing); Semicircular canals: balance and rotational movement detection; Utricle and Saccule: linear acceleration and gravity. Motion sickness occurs when semicircular canal signals conflict with visual signals. Vestibulocochlear nerve (8th cranial nerve) carries both hearing and balance signals.

s sound waves to nerve impulses? Eardrum is incorrect because it refers to a different organ, substance, process, or medical association. Semicircular canals is also incorrect; it may be biologically important, but its principal role or defining feature is not the one being tested here. Ossicles is incorrect because its function, source, target, or disease relationship does not match the question. Therefore option B, Cochlea, is factually consistent with the stem, the marked correct index, and the explanation. Cochlea in the inner ear converts sound vibrations into electrical nerve impulses that are sent to the brain via the auditory nerve.

Then, the coagulation cascade activates, converting fibrinogen (soluble) to fibrin (insoluble threads) that form a mesh to reinforce the platelet plug, creating a stable clot. Vitamin K is essential for the synthesis of clotting factors II, VII, IX, and X. Haemolysis — This is the rupture or destruction of red blood cells, releasing haemoglobin into the surrounding fluid. It is the OPPOSITE of clotting and is associated with certain diseases like sickle cell anaemia. Agglutination — This refers to the clumping together of cells (especially red blood cells or bacteria) in the presence of antibodies. It is important in blood typing but is NOT blood clotting. Phagocytosis — This is the process by which certain white blood cells (neutrophils and macrophages) engulf and destroy pathogens, debris, or damaged cells. It is an immune response, not blood clotting. 📝 Important Note: Key clotting facts — Vitamin K deficiency = impaired clotting; Haemophilia = genetic disorder with defective clotting factor VIII or IX; Thrombin converts fibrinogen to fibrin. Platelets (thrombocytes) are essential for clotting.