SSC CGL Human Body Questions and Answers – Page 3

Therefore option C, Melanin, is factually consistent with the stem, the marked correct index, and the explanation.✅ Correct Answer: C — Melanin Melanin is the pigment produced by specialized cells called Melanocytes in the epidermis (outermost skin layer). More melanin = darker skin (protection from UV). Less melanin = lighter skin. Melanin also determines hair and eye color. Haemoglobin — Haemoglobin is the red-colored protein in RBCs that carries oxygen; it gives blood its red color, not skin color. Keratin — Keratin is a structural protein in skin, hair, and nails providing strength and waterproofing; it doesn't give color. Carotene — Carotene (beta-carotene) can give a slight yellowish tint to skin when consumed in large amounts (carrots); it is not the primary skin pigment. 📝 Important Note: Melanin = Skin color pigment (produced by Melanocytes). Albinism = absence of melanin (white skin, pink eyes). More melanin = more UV protection. People near the equator have more melanin. SSC CGL skin biology key topic.

Therefore option C, Spleen, is factually consistent with the stem, the marked correct index, and the explanation.✅ Correct Answer: C — Spleen The Spleen is the largest lymphoid organ in the human body, located in the upper left abdomen. Thymus — Thymus is a lymphoid organ where T-lymphocytes mature; it is smaller than spleen and located in the chest. It is largest in childhood. Lymph nodes — Lymph nodes are small bean-shaped structures scattered throughout the body; they filter lymph fluid but are much smaller than the spleen. Tonsils — Tonsils are small lymphoid tissues at the back of the throat; much smaller than the spleen. 📝 Important Note: Spleen = largest lymphoid organ (blood filter + blood reservoir + immune functions). Liver = largest internal organ overall. Skin = largest organ in body. Spleen is called the 'graveyard of RBCs'. Spleen can be removed (splenectomy) but immunity is slightly reduced.

Therefore option C, Red bone marrow, is factually consistent with the stem, the marked correct index, and the explanation.✅ Correct Answer: C — Red bone marrow In adults, Red Blood Cells (RBCs) are produced in the Red Bone Marrow through a process called Erythropoiesis. Red bone marrow is found in flat bones (sternum, ribs, pelvis, skull, vertebrae) and the ends of long bones. The hormone Erythropoietin (EPO) from the kidneys stimulates RBC production when oxygen levels are low. ❌ Why other options are wrong: Spleen — In embryo/fetus, spleen produces RBCs but NOT in adults. Liver — Liver produces RBCs during fetal development (from 2nd to 7th month) but NOT in adults. Thymus — Thymus is where T-lymphocytes mature; it does NOT produce RBCs at any age. 📝 Important Note: Adult RBC production = Red Bone Marrow (Erythropoiesis). Fetal RBC production = Liver and Spleen. Destroyed in Spleen (adults).

cle in the human body is In the human body, this option has the required identity, location, function, secretion, deficiency relationship, or disease association. Orbicularis is incorrect because it refers to a different organ, substance, process, or medical association. Platysma is also incorrect; it may be biologically important, but its principal role or defining feature is not the one being tested here. Corrugator is incorrect because its function, source, target, or disease relationship does not match the question. Therefore option A, Stapedius, is factually consistent with the stem, the marked correct index, and the explanation. Stapedius muscle in the middle ear is the smallest muscle in the human body.

Therefore option C, Gluteus maximus, is factually consistent with the stem, the marked correct index, and the explanation.✅ Correct Answer: C — Gluteus maximus Gluteus maximus is the largest and heaviest muscle in the human body. It is a thick, powerful muscle essential for upright posture. Biceps — Biceps brachii is a muscle in the upper arm that flexes the elbow; it is a relatively small muscle compared to gluteus maximus. Deltoid — Deltoid is the shoulder muscle responsible for arm abduction; it is not the largest muscle in the body. Quadriceps — Quadriceps (group of 4 muscles in the front thigh) is the largest muscle group but gluteus maximus is the largest single muscle. 📝 Important Note: Largest muscle = Gluteus maximus (buttock). Smallest muscle = Stapedius (middle ear). Longest muscle = Sartorius (thigh). Strongest muscle = Masseter (jaw). Hardest-working muscle = Heart (cardiac). SSC CGL body facts - very commonly asked!

ation.✅ Correct Answer: C — Ball and socket joint The ball and socket joint allows the greatest range of movement among all joint types. In this joint, the rounded head (ball) of one bone fits into the cup-like socket of another bone. This structure permits movement in all planes: flexion, extension, abduction, adduction, rotation, and circumduction. Examples include the shoulder joint (humerus fits into glenoid cavity of scapula) and the hip joint (head of femur fits into acetabulum of pelvis). Hinge joint — Allows movement in only one plane (like a door hinge), e.g., elbow and knee joints. It permits only flexion and extension, not rotation or lateral movement. Gliding joint — Also called plane joint; allows only limited sliding or gliding movement between flat bone surfaces, e.g., between carpals in the wrist. Pivot joint — Allows only rotational movement around a single axis, e.g., the joint between atlas and axis vertebrae (allows head rotation left/right). 📝 Important Note: There are 6 types of synovial joints: hinge, ball and socket, pivot, gliding/plane, condyloid, and saddle. Ball and socket joint has the widest range of motion. Shoulder joint is the most mobile but also the most easily dislocated joint in the human body.

The bones of the skull are joined by fibrous joints called sutures. Sutures are immovable (synarthrosis) joints where bones are held tightly together by dense fibrous connective tissue. In adults, these joints are completely fused and allow no movement at all, which is essential to protect the brain. The word "suture" comes from Latin meaning "seam." In infants, these joints are not yet fused — the soft spots called fontanelles allow the skull to compress during birth and expand as the brain grows. ❌ Why other options are wrong: Ball and socket joint — A freely movable (diarthrosis) synovial joint found in the shoulder and hip. It allows the greatest range of motion and is not found in the skull. Hinge joint — A synovial joint that allows movement in one plane only (flexion/extension), like the elbow or knee. Skull bones do not use this type. Pivot joint — Allows only rotational movement, found between atlas and axis vertebrae (C1-C2). It is not involved in skull bone connections. 📝 Important Note: Joints classification: Fibrous (suture, syndesmosis), Cartilaginous (synchondrosis, symphysis), Synovial (hinge, ball-socket, pivot, gliding). Skull sutures are examples of synarthrosis — completely immovable joints.

The kidneys and lungs work together to regulate blood pH: the lungs control CO₂ levels (respiratory regulation) and kidneys control bicarbonate (metabolic regulation). Blood with this pH would indicate severe acidosis and would be incompatible with life. While blood pH of 7.0-7.2 is above pure acid, it is still below the normal blood pH and would represent dangerous acidosis. 7.8 to 8.0 — This range is more alkaline than normal blood. Normal blood pH is maintained by bicarbonate buffer system (HCO₃⁻/H₂CO₃). The kidneys regulate blood pH by excreting or reabsorbing bicarbonate.

Therefore option C, Thyroid gland, is factually consistent with the stem, the marked correct index, and the explanation.✅ Correct Answer: C — Thyroid gland Thyroxine (T4) and Triiodothyronine (T3) are produced by the Thyroid Gland, a butterfly-shaped gland located at the front of the neck. Pituitary gland — Pituitary releases TSH (Thyroid Stimulating Hormone) which stimulates the thyroid to produce thyroxine, but it doesn't produce thyroxine itself. Adrenal gland — Adrenal gland produces Adrenaline (epinephrine), Cortisol, Aldosterone; not thyroxine. Parathyroid gland — Parathyroid glands (4 small glands behind thyroid) produce PTH (Parathyroid Hormone) which regulates calcium levels; not thyroxine. 📝 Important Note: Thyroid gland = Thyroxine (T3, T4). Hyperthyroidism = excess thyroxine (fast metabolism, weight loss). Hypothyroidism = low thyroxine (slow metabolism, weight gain). Goitre = enlarged thyroid from iodine deficiency. TSH from pituitary controls thyroid.

Haemoglobin contains a heme group with an iron (Fe²⁺) ion at its center that binds to oxygen. When dietary iron is insufficient, the body cannot produce enough haemoglobin, resulting in fewer and smaller red blood cells. This leads to anaemia, characterized by fatigue, pale skin, weakness, and breathlessness. Iron-rich foods include spinach, lentils, red meat, liver, and fortified cereals. Calcium — Deficiency of calcium causes rickets in children and osteoporosis in adults (weak, brittle bones). It is NOT responsible for anaemia. Iodine — Deficiency of iodine causes goitre (enlarged thyroid gland) and hypothyroidism. It has no direct role in causing anaemia. Zinc — Deficiency of zinc causes growth retardation, delayed sexual maturation, impaired immune function, and taste/smell disturbances. It does not cause anaemia. 📝 Important Note: Mineral deficiency diseases — Iron = Anaemia; Calcium = Rickets/Osteoporosis; Iodine = Goitre; Zinc = Growth retardation. Vitamin B12 and Folate deficiency cause megaloblastic (pernicious) anaemia — not iron deficiency anaemia. Women and children are most at risk of iron deficiency.