JAMB Biology: Human Physiology — Body Systems Guide

JAMB Biology: Human Physiology Questions — Circulatory, Respiratory & Nervous Systems

Human physiology is one of the most heavily tested areas in JAMB UTME Biology — and for good reason. The circulatory, respiratory, and nervous systems appear in multiple questions every year, often in ways designed to catch unprepared candidates off guard. This guide maps directly to the official JAMB Biology syllabus and covers every examinable topic across all three body systems, complete with past-question-style MCQs, comparison tables, and clear explanations of the "trick" questions JAMB examiners love to set.

Why Human Physiology Matters in JAMB Biology

JAMB UTME Biology consists of 40 multiple-choice questions, and you must attempt all of them. Each question has four options (A–D). Expert study guides consistently identify physiology, genetics, and ecology as the three most frequently examined clusters — meaning you can expect between 8 and 12 physiology-related questions in any given sitting.

The JAMB Biology syllabus explicitly lists the following under human physiology:

• Transport and the mammalian circulatory system
• Respiratory organs, gaseous exchange, aerobic and anaerobic respiration
• Nervous coordination, the reflex arc, sense organs, and hormonal control

Let's go system by system.

🫀 The Circulatory System

Double Circulation and the Four-Chambered Heart

Mammals (including humans) have a closed, double circulatory system. "Closed" means blood always stays inside blood vessels. "Double" means blood passes through the heart twice per complete circuit — once through the pulmonary circuit (heart → lungs → heart) and once through the systemic circuit (heart → body → heart).

This separation of oxygenated and deoxygenated blood makes circulation more efficient — a key adaptation for warm-blooded mammals. By contrast, many invertebrates like arthropods (e.g., cockroaches) have an open circulatory system, where hemolymph is pumped into open body cavities rather than contained blood vessels.

Blood Vessels — Know the Difference

• Arteries carry blood away from the heart. They have thick, elastic walls to withstand high pressure.
• Veins carry blood back to the heart. They have thinner walls and contain valves to prevent backflow.
• Capillaries are the site of exchange between blood and tissues — walls are just one cell thick.

⚠️ Classic JAMB Trick Question: Pulmonary Artery vs. Pulmonary Vein

This question appears repeatedly in JAMB past papers and catches many candidates:

• The pulmonary artery carries deoxygenated blood from the heart to the lungs.
• The pulmonary vein carries oxygenated blood from the lungs back to the heart.

This is the opposite of what most students expect, because arteries are generally associated with oxygenated blood. JAMB examiners know this — memorise it.

Quick JAMB Facts: Circulatory System

• The left side of the heart contains oxygenated blood
• Blood functions include transporting nutrients, hormones, and oxygen; regulating pH and body temperature; and fighting disease
• In Amoeba, diffusion alone is sufficient for transport — no circulatory system is needed because the organism is small enough
• Blood is composed of plasma, red blood cells (erythrocytes), white blood cells (leukocytes), and platelets

Practice MCQ:

The pulmonary vein carries which type of blood? A. Deoxygenated blood from the lungs B. Oxygenated blood to the lungs C. Oxygenated blood from the lungs ✅ D. Deoxygenated blood to the body

🫁 The Respiratory System

Respiratory Organs Across Organisms (Comparative Table)

JAMB tests your ability to match respiratory organs to the correct organism. Study this table carefully:

Note on the adult toad: Gaseous exchange occurs through three surfaces — the skin, the buccal cavity (mouth lining), and the lungs. Questions about toads frequently require all three to score the correct answer.

Aerobic vs. Anaerobic Respiration

Aerobic respiration requires oxygen and takes place in two stages:

1. Glycolysis — occurs in the cytoplasm; glucose is broken down into pyruvate, yielding a net gain of 2 ATP
2. Krebs Cycle (Citric Acid Cycle) — occurs in the mitochondrial matrix; acetyl-CoA is further oxidised, producing NADH, FADH₂, and a small amount of ATP

The mitochondria are known as the "powerhouse of the cell" because of their central role in ATP production. For JAMB purposes, aerobic respiration produces 36 ATP — this is the accepted answer in Nigerian syllabi and past question marking schemes, even though newer biochemistry literature suggests 30–32 ATP.

Anaerobic respiration proceeds without oxygen and produces far less ATP. The end products differ by organism:

• In yeast and plants: glucose → ethanol + carbon dioxide (this process is called fermentation)
• In animals (including humans): glucose → lactic acid (causes muscle fatigue)

Quick JAMB Facts: Respiratory System

• Glycolysis is anaerobic and takes place in the cytoplasm
• The Krebs Cycle takes place in the mitochondrial matrix
• Fermentation = anaerobic respiration in yeast
• The trachea is the respiratory organ of cockroaches

Practice MCQ:

Anaerobic respiration of yeast in a solution of sugar is known as: A. Oxidation B. Fermentation ✅ C. Transpiration D. Glycolysis

🧠 The Nervous System

Brain Divisions and Their Functions

The brain is divided into several key regions, all of which are examinable in JAMB:

⚠️ Classic JAMB Trick Question: Cerebellum vs. Medulla Oblongata

A well-known JAMB past question (2014) asked which part of the brain controls muscular activity and balance. The answer is the cerebellum. Do not confuse it with the medulla oblongata, which controls involuntary functions like breathing and heartbeat.

Also note: Some older practice question banks incorrectly associate the cerebellum with reflex actions. This is biologically wrong — reflex arcs bypass the brain entirely and are coordinated at the spinal cord level. Be cautious with low-quality third-party question sources.

The Reflex Arc — Sequence JAMB Tests Directly

A reflex action is an automatic, rapid response to a stimulus that does not involve conscious thought. The pathway of a reflex arc is:

Stimulus → Receptor → Sensory Neuron → Spinal Cord (Inter-neuron) → Motor Neuron → Effector → Response

Reflex arcs are processed at the spinal cord, not the brain — this is what makes them fast. JAMB may ask you to identify the correct order of this sequence or identify the role of each component.

Nervous System vs. Endocrine (Hormonal) System

Both systems coordinate body activities, but they work differently:

Key endocrine glands tested in JAMB include: pituitary (master gland), thyroid, parathyroid, adrenal glands, pancreas, and gonads.

Quick JAMB Facts: Nervous System

• Coordination in mammals is achieved by nerves and hormones
• The neuron is the basic structural and functional unit of the nervous system
• The cerebrum is the largest part of the brain
• Reflex actions are coordinated at the spinal cord, not the brain
• Sense organs tested in JAMB: skin (touch), nose (smell), tongue (taste), eye (sight), ear (hearing)

Practice MCQ:

Which part of the brain is responsible for balance and coordination of movement? A. Cerebrum B. Medulla oblongata C. Thalamus D. Cerebellum ✅

Recommended JAMB-Approved Textbooks

The JAMB Biology syllabus recommends the following textbooks for deeper study:

• New School Biology by H. Stone and S. Cozen
• Senior Secondary Biology by D. Ramalingam
• Biology: A Functional Approach by M.B.V. Roberts
• Biological Science by D.J. Mackean

Always confirm the current recommended textbook list directly with the JAMB official website (jamb.gov.ng), as updates may occur.

FAQ: JAMB Biology Human Physiology

Q1: Which human physiology topics come up most often in JAMB Biology?

The circulatory system (especially blood vessels and double circulation), the nervous system (brain functions and reflex arc), and respiratory system (aerobic vs. anaerobic respiration and respiratory organs in different organisms) are consistently the most tested. Past questions show that the pulmonary artery/vein distinction, cerebellum function, and fermentation all appear regularly.

Q2: What is the difference between the pulmonary artery and pulmonary vein in JAMB?

The pulmonary artery carries deoxygenated blood from the heart to the lungs, while the pulmonary vein carries oxygenated blood from the lungs back to the heart. This is a classic trick question — JAMB tests it frequently because most students assume arteries always carry oxygenated blood.

Q3: How many ATP molecules does aerobic respiration produce according to JAMB?

For JAMB UTME purposes, aerobic respiration produces 36 ATP molecules. While newer biochemistry research suggests the actual yield is closer to 30–32 ATP, Nigerian syllabi and JAMB marking schemes use 36 ATP as the standard answer. Confirm this with your approved textbook if in doubt.

Q4: What is the correct reflex arc sequence for JAMB?

The correct order is: Stimulus → Receptor → Sensory Neuron → Inter-neuron (Spinal Cord) → Motor Neuron → Effector → Response. JAMB may present this as a sequence-ordering question or ask you to identify the role of a specific component. Remember that reflex actions are coordinated at the spinal cord, not the brain.

Q5: How does the nervous system differ from the endocrine system in JAMB Biology?

The nervous system uses electrical impulses transmitted through neurons and acts quickly but briefly. The endocrine system uses chemical hormones transported through the blood — it acts more slowly but produces longer-lasting effects. Both systems work together to achieve coordination and regulation of body functions in mammals.

Start Practising with PassMate

Knowing the theory is only half the battle — JAMB rewards candidates who can apply concepts under exam conditions with a timer running. PassMate gives you access to JAMB-style Biology questions mapped directly to the official syllabus, including full coverage of human physiology topics like the ones in this guide. With instant explanations, performance tracking, and adaptive practice sessions, PassMate helps you identify your weak spots in the circulatory, respiratory, and nervous systems — and fix them before exam day.

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