List five functions of the human skeletal system and distinguish between cartilage and bone in a table.

Here are the answers to the questions:

4.

a) State FIVE main functions of the human skeletal system.

1. Support: Provides a framework for the body, holding it upright.
2. Protection: Safeguards vital internal organs (e.g., skull protects the brain, rib cage protects heart and lungs).
3. Movement: Serves as attachment points for muscles, allowing movement at joints.
4. Mineral Storage: Stores essential minerals like calcium and phosphate.
5. Blood Cell Production: Red bone marrow produces blood cells (hematopoiesis).

b) In tabular form distinguish between:

(i) Cartilage and bone.

Feature	Cartilage	Bone
Structure	Flexible, elastic, smooth	Rigid, hard, strong
Composition	Chondrocytes in a matrix of collagen and elastin fibers	Osteocytes in a matrix of collagen and calcium salts
Blood Supply	Avascular (no direct blood supply)	Vascular (rich blood supply)
Function	Provides flexibility, reduces friction in joints, forms structural components (nose, ear)	Provides support, protection, mineral storage, blood cell production

(ii) Axial skeleton and appendicular skeleton.

Feature	Axial Skeleton	Appendicular Skeleton
Components	Skull, vertebral column, rib cage, sternum	Limbs (arms and legs), pectoral girdle (shoulder), pelvic girdle (hips)
Function	Provides central support, protects internal organs	Enables movement and manipulation of the environment

(iii) Tendons and ligaments.

Feature	Tendons	Ligaments
Connection	Connect muscle to bone	Connect bone to bone
Composition	Dense regular connective tissue, less elastic	Dense regular connective tissue, more elastic
Function	Transmit force from muscle to bone, facilitating movement	Stabilize joints, prevent excessive movement

c) Name SIX types of synovial joints and state a location for each in the human body.

1. Ball-and-socket joint: Shoulder joint, hip joint.
2. Hinge joint: Elbow joint, knee joint, interphalangeal joints (fingers/toes).
3. Pivot joint: Atlantoaxial joint (between C1 and C2 vertebrae in the neck), radioulnar joint (forearm).
4. Condyloid (Ellipsoidal) joint: Wrist joint (radiocarpal), metacarpophalangeal joints (knuckles).
5. Saddle joint: Carpometacarpal joint of the thumb.
6. Plane (Gliding) joint: Intercarpal joints (between wrist bones), intertarsal joints (between ankle bones).

5.

a) Define each of the following terms.

(i) Excretion.
Excretion is the process by which metabolic waste products and excess substances are removed from the body of an organism.

(ii) Osmoregulation.
Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids to maintain the homeostasis of the body's water content and electrolyte balance.

(iii) Homeostasis.
Homeostasis is the ability of an organism to maintain a stable internal environment despite changes in external conditions, ensuring optimal functioning of physiological processes.

b) Draw a large and neatly labelled diagram of the longitudinal section of the kidney.
(As an AI, I cannot draw. However, a well-labelled diagram of a longitudinal section of the kidney should include the following structures):

• Renal capsule
• Renal cortex
• Renal medulla
• Renal pyramids
• Renal columns
• Renal papilla
• Minor calyx
• Major calyx
• Renal pelvis
• Ureter
• Renal artery
• Renal vein

c) Why is it not advisable to delay the urge to urinate?
Delaying the urge to urinate can lead to several issues. It can cause the bladder to overstretch, potentially weakening its muscles over time. More importantly, holding urine for too long allows bacteria to multiply in the bladder, significantly increasing the risk of developing a urinary tract infection (UTI).

d) Explain how the liver and the pancreas regulate blood glucose.
The pancreas plays a central role in blood glucose regulation through its endocrine cells (islets of Langerhans). When blood glucose levels are high, the beta cells of the pancreas release insulin. Insulin promotes the uptake of glucose by body cells (especially muscle and adipose tissue) and stimulates the liver to convert glucose into glycogen for storage (glycogenesis), thereby lowering blood glucose. When blood glucose levels are low, the alpha cells of the pancreas release glucagon. Glucagon primarily acts on the liver, stimulating it to break down stored glycogen into glucose (glycogenolysis) and to synthesize new glucose from non-carbohydrate sources (gluconeogenesis), which then raises blood glucose levels. The liver acts as a major storage site for glucose in the form of glycogen and is crucial for releasing glucose into the bloodstream when needed, under the influence of pancreatic hormones.

6.

a) Define the following terms:

(i) A food chain.
A food chain is a linear sequence illustrating how energy is transferred from one living organism to another through feeding, starting with producers and moving through various consumers.

(ii) An ecosystem.
An ecosystem is a community of living organisms (biotic components) interacting with each other and with their non-living physical environment (abiotic components) in a specific area.

(iii) Pollution.
Pollution is the introduction of harmful substances or products into the environment, causing adverse changes or damage to the environment and living organisms.

(iv) Parasitism.
Parasitism is a symbiotic relationship between two organisms where one organism, the parasite, lives on or in another organism, the host, and benefits by deriving nutrients at the host's expense, often causing harm to the host.

b) Describe the ... ecosystem. (The question is cut off, but assuming it asks to describe a general ecosystem.)
An ecosystem comprises both biotic (living) and abiotic (non-living) components that interact to form a functional unit. Biotic components include producers (e.g., plants that photosynthesize), consumers (e.g., herbivores, carnivores, omnivores that feed on other organisms), and decomposers (e.g., bacteria and fungi that break down dead organic matter). Abiotic components include physical and chemical factors such as sunlight, water, soil, temperature, pH, and atmospheric gases. Energy flows through the ecosystem, typically starting from the sun and captured by producers, then transferred to consumers. Nutrients are cycled within the ecosystem, moving between living organisms and the physical environment.

c) State FIVE ... taken to reduce water pollution. (The question is cut off, but assuming it asks for measures to reduce water pollution.)

1. Wastewater Treatment: Treating domestic sewage and industrial effluents before discharging them into water bodies to remove pollutants.
2. Reduce Agricultural Runoff: Minimizing the use of chemical fertilizers and pesticides in agriculture to prevent them from washing into rivers and lakes.
3. Proper Waste Disposal: Ensuring proper disposal of solid waste and hazardous materials to prevent leaching into groundwater and surface water.
4. Prevent Oil Spills: Implementing strict regulations and safety measures to prevent oil spills from ships and industrial facilities.
5. Public Awareness and Education: Educating the public about the importance of water conservation and the impact of pollution, encouraging responsible practices.