100+ Free BGCSE Physical Education Practice Questions

Explanation: Hematopoiesis is the process by which blood cells (red blood cells, white blood cells, and platelets) are produced within the red bone marrow found in flat bones and the ends of long bones. While bones also store minerals, provide leverage for movement, and protect organs, blood cell production specifically occurs in red bone marrow. Understanding this metabolic function highlights the skeleton as a living, dynamic system beyond structural support.

Explanation: Ball-and-socket joints (such as the shoulder and hip joints) feature a rounded head of one bone fitting into a cuplike cavity of another. This structural arrangement permits multiaxial movement across all three anatomical planes. In contrast, hinge joints permit movement in only one plane, and pivot joints permit rotation around a single axis.

Explanation: An isotonic concentric contraction occurs when a muscle generates force while shortening, overcoming resistance to cause joint movement. During the upward pushing phase of a push-up, the triceps brachii shortens as it contracts to extend the elbow joint. Eccentric contractions involve muscle lengthening under tension, whereas isometric contractions involve force generation without a change in muscle length.

Explanation: Skeletal muscles work in antagonistic pairs because muscles can only pull, not push. During elbow flexion in a biceps curl, the biceps brachii contracts as the agonist (prime mover) to pull the forearm upward, while the triceps brachii relaxes and lengthens as the antagonist to control or allow smooth movement.

Explanation: Cardiac muscle is specialized involuntary striated muscle tissue found only in the walls of the heart. It contains intercalated discs, which are specialized cell junctions that facilitate rapid electrical impulse transmission between cardiac muscle cells, allowing synchronized heart contractions. Skeletal muscle is under voluntary control and lacks intercalated discs.

Explanation: Cardiac output (Q) is calculated using the formula: Q = Heart Rate (HR) x Stroke Volume (SV). Here, Q = 60 beats/min x 70 mL/beat = 4,200 mL/min, which converts to 4.2 liters per minute. This equation demonstrates the total volume of blood pumped by the heart's left ventricle per minute.

Explanation: The vascular shunt mechanism redistributes cardiac output during exercise. Arterioles supplying active skeletal muscles undergo vasodilation (widening) to increase local blood flow, while arterioles supplying non-essential organs (like the stomach and kidneys) undergo vasoconstriction (narrowing). Precapillary sphincters assist in controlling capillary bed blood flow.

Explanation: Gaseous exchange in the lungs relies on simple diffusion down a partial pressure gradient. Oxygen moves from the alveoli (where partial pressure of O2 is high, ~104 mmHg) into deoxygenated capillary blood (where pO2 is low, ~40 mmHg). Concurrently, carbon dioxide diffuses down its partial pressure gradient from blood into alveoli to be exhaled.

Explanation: Tidal volume is the amount of air inhaled or exhaled with each quiet, resting breath (typically about 500 mL in an average adult). Vital capacity represents the maximum volume of air that can be forcibly expired following maximum inhalation, and residual volume is the air remaining in the lungs after maximal expiration.

Explanation: The ATP-PC (alactic anaerobic) system relies on stored adenosine triphosphate (ATP) and phosphocreatine (PC) within muscle cells. It produces energy rapidly without oxygen or lactic acid formation, making it the dominant energy provider for explosive, maximal-effort activities lasting up to 10 seconds.