Big picture
Anatomy studies body structure, while physiology studies how body parts function. To understand a jump, anatomy identifies bones, joints and muscles; physiology explains muscle contraction, oxygen delivery and energy demand. Together they help teachers plan appropriate movement and explain performance.
During a game of kho-kho, muscles move the limbs, joints guide movement, the heart increases blood delivery and breathing supports gas exchange. No system works alone. This chapter follows those connections so that definitions, labelled diagrams and exercise questions form a coherent explanation.
Learning goals
Distinguish anatomy from physiology and explain their sporting importance.
Describe skeletal functions, bone types and joint classifications.
Explain muscle properties and coordinated movement.
Trace blood through the heart and both circulations.
Trace air through the respiratory system and explain gas exchange.
Calculate cardiac output and minute ventilation with correct units.
Core ideas
1. Anatomical position and directional language
The anatomical position is standing upright, facing forward, arms at the sides and palms facing forward. It provides a reference for describing the body even when the person changes posture. Anterior means towards the front, posterior towards the back, superior above, inferior below, medial towards the midline and lateral away from it.
Proximal means nearer the attachment or origin of a limb and distal farther away. The elbow is proximal to the wrist, while the wrist is distal to the elbow. Precise language prevents confusion when describing a joint or exercise. It does not replace the need to demonstrate a movement clearly.
2. Functions and divisions of the skeleton
The adult skeleton is conventionally described as having 206 bones, although individual variation exists. It provides support, protects organs, contributes to movement, stores minerals and contains marrow involved in blood-cell production. Bones are living tissues, not inert rods.
Function | Explanation | Example |
|---|---|---|
Support | Forms the body's framework | Vertebral column supports the trunk |
Protection | Shields delicate structures | Skull protects the brain |
Movement | Provides levers and muscle attachments | Femur participates in lower-limb movement |
Mineral storage | Stores minerals such as calcium | Bone participates in mineral regulation |
Blood-cell formation | Red marrow produces blood cells | Marrow in appropriate bones |
The axial skeleton includes the skull, vertebral column and rib cage. The appendicular skeleton includes the limbs and their shoulder and pelvic girdles. For a labelled diagram, show the skull, vertebral column, ribs, humerus, radius, ulna, pelvis, femur, tibia and fibula in their correct regions.
3. Classification of bones
Type | Main shape or feature | Examples |
|---|---|---|
Long | Longer than wide, with a shaft and ends | Femur, humerus |
Short | Roughly similar dimensions | Many wrist and ankle bones |
Flat | Thin protective or broad attachment surfaces | Sternum, ribs, many skull bones |
Irregular | Complex shape | Vertebrae |
Sesamoid | Develops within a tendon | Patella |
Classification depends on shape, not the everyday meaning of size. A finger bone is a long bone even though it is shorter than many other bones. Long-bone shafts contain compact tissue around a central cavity, while ends include spongy tissue. Periosteum is the outer connective covering, and articular cartilage covers joint surfaces where appropriate.
4. Joints and movement
A joint is where bones meet. Functionally, joints differ in the movement they allow. Fibrous joints such as skull sutures usually allow little or no movement. Cartilaginous joints, including those between many vertebral bodies, allow limited movement. Synovial joints have a cavity and permit a wider range.
Synovial type | Typical movement | Example |
|---|---|---|
Hinge | Mainly bending and straightening | Elbow |
Ball-and-socket | Movement in several directions and rotation | Shoulder, hip |
Pivot | Rotation about an axis | Upper neck joint between atlas and axis |
Gliding or plane | Sliding between surfaces | Some intercarpal joints |
Saddle | Movement in two main directions with a saddle-like fit | Thumb carpometacarpal joint |
Condyloid | Movement in two main planes | Wrist radiocarpal joint |
A synovial joint includes articular cartilage, a capsule, a synovial lining and synovial fluid. Cartilage helps distribute load and reduce friction; fluid lubricates. Ligaments connect bone to bone, while tendons connect muscle to bone. A joint's structure permits some movements and limits others.
5. Muscle types, properties and functions
Muscle type | Main location | Control and function |
|---|---|---|
Skeletal | Attached to the skeleton | Usually voluntary movement and posture |
Smooth | Walls of internal organs and vessels | Involuntary control of internal processes |
Cardiac | Heart | Involuntary rhythmic contraction |
The principal muscle properties are excitability, responding to a stimulus; contractility, producing tension; extensibility, being stretched within limits; and elasticity, returning towards resting length. Producing tension does not always mean a muscle shortens: a muscle can maintain tension while its length stays similar or increases under control.
Skeletal muscle contributes to movement, posture, joint stability and heat production. It contains fibres organised into bundles and receives nerve and blood supply. In a basic diagram, label muscle belly and tendon, and show the tendon attaching across a joint rather than directly joining two bones without muscle.
6. Coordinated muscle action
An agonist is a main contributor to a movement; an antagonist opposes or controls it; synergists assist; fixators stabilise relevant parts. Roles depend on the task rather than being permanent labels.
During elbow flexion, the biceps and other flexors contribute to bending while the triceps acts as an opposing extensor. During controlled lowering, muscles may work while lengthening. Concentric action involves active shortening, eccentric action active lengthening and isometric action tension without appreciable joint movement. Holding a suitable position demonstrates isometric effort.
7. Heart structure and blood flow
The heart has four chambers: right atrium, right ventricle, left atrium and left ventricle. Valves promote one-way flow. The left ventricle has a thick muscular wall because it pumps blood through systemic circulation.
Follow this sequence for a labelled flow diagram:
Body → venae cavae → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → lungs → pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta → body.
The pulmonary circulation links heart and lungs; the systemic circulation links heart and the rest of the body. Arteries carry blood away from the heart and veins towards it. Do not define arteries as always oxygenated: the pulmonary artery carries relatively deoxygenated blood, and pulmonary veins carry oxygenated blood.
8. Blood vessels and blood
Arteries have walls adapted to pressure, veins return blood at lower pressure and often contain valves in the limbs, and capillaries provide thin exchange surfaces. Blood contains plasma, red blood cells, white blood cells and platelets. Red blood cells transport oxygen using haemoglobin; white cells contribute to defence and platelets to clotting.
During exercise, circulation redistributes delivery towards active tissues. Working muscles need oxygen and nutrients and produce heat and metabolic by-products. Blood delivery and breathing therefore increase together, although the exact response varies with effort, fitness and conditions.
9. Cardiac output and exercise response
Heart rate, HR is beats per minute. Stroke volume, SV is blood ejected by one ventricle per beat. Cardiac output, Q = HR × SV, expressed as volume per minute.
Worked resting example: HR = 72 beats/min and SV = 70 mL/beat.
Q = 72 × 70 = 5,040 mL/min = 5.04 L/min.
Worked exercise example: HR = 150 beats/min and SV = 110 mL/beat.
Q = 150 × 110 = 16,500 mL/min = 16.50 L/min.
These are illustrative values, not targets for every student. Acute exercise commonly increases heart rate, stroke volume and cardiac output. Longer-term training can change cardiovascular efficiency, but a single reading cannot diagnose fitness or illness.
10. Respiratory structures and breathing
Air travels through the nose or mouth, pharynx, larynx, trachea, bronchi, bronchioles and alveoli. Alveoli are small air sacs surrounded by capillaries. Their thin walls, large combined surface and moist interface support diffusion.
During quiet inspiration, the diaphragm contracts and moves down; the external intercostal muscles help expand the rib cage. Thoracic volume increases, pressure falls relative to the atmosphere and air enters. Quiet expiration is largely passive: muscles relax, elastic recoil reduces volume and air leaves. Forceful expiration recruits additional muscles.
In a respiratory diagram, label trachea, right and left bronchi, lungs, bronchioles, alveoli and diaphragm. Put the alveoli at the ends of small airways rather than drawing them inside the trachea.
11. Gas exchange and ventilation
At the lungs, oxygen diffuses from alveolar air into blood and carbon dioxide in the opposite direction, following partial-pressure gradients. At tissues, oxygen moves towards cells and carbon dioxide towards blood. Breathing, gas exchange and cellular respiration are related but distinct processes.
Tidal volume is air moved in one ordinary breath. Minute ventilation = tidal volume × breathing frequency. It includes air that does not participate directly in gas exchange.
Worked example: Tidal volume = 500 mL and frequency = 12 breaths/min.
Minute ventilation = 500 × 12 = 6,000 mL/min = 6.00 L/min.
If frequency rises to 18 breaths/min at the same tidal volume, ventilation = 500 × 18 = 9,000 mL/min = 9.00 L/min. In real exercise both depth and frequency may change.
A reliable approach to questions
Identify the body system and whether structure or function is required.
Use a labelled sequence for blood or air flow.
For comparisons, state a shared basis such as control, direction or joint movement.
Write formulas with units and convert mL to L when needed.
Link movement, oxygen delivery and breathing without treating one system as independent.
Connections that matter
Kinesiology applies joint structure and muscle action to movement analysis.
Fitness training depends on cardiovascular, respiratory and muscular responses.
Biology develops the cellular processes underlying gas transport and contraction.
Common mistakes
Calling tendons bone-to-bone connectors confuses them with ligaments.
Defining arteries only by oxygen content fails for pulmonary circulation.
Saying all contractions shorten muscles ignores eccentric and isometric actions.
Confusing ventilation with cellular respiration mixes air movement with energy-releasing cellular processes.
Revision checklist
I can describe skeletal functions, bones and joints.
I can explain muscle properties and coordinated action.
I can trace blood through the four heart chambers.
I can trace air and explain alveolar gas exchange.
I can calculate cardiac output and minute ventilation.
I can relate acute exercise to changes across systems.