Human Physiology Part II Full Chapter Revision For NEET 2026 with Physics Wallah

Human Physiology Part II can be challenging for NEET aspirants because it combines muscle contraction, skeletal structure, nerve impulses and hormonal regulation. Remembering the mechanisms, functions and differences between these concepts is essential for effective revision.

Human Physiology Part II for NEET 2027 covers locomotion and movement, neural control and chemical coordination with key concepts, tables and frequently asked questions. PW supports NEET preparation through structured learning resources and revision practice, helping students strengthen their understanding and revisit important topics before the exam.

Human Physiology Part II Overview

Human Physiology Part II connects locomotion and movement with neural and chemical coordination. Muscles generate movement through actin–myosin interaction, while bones and joints provide support and mobility. The nervous system controls rapid responses through electrical impulses, and hormones regulate slower processes such as growth, metabolism, reproduction, calcium balance, and water conservation.

Locomotion And Movement

Movement is a basic property of living organisms. It may occur without displacement of the entire body, such as movement of a hand while the body remains stationary. Locomotion is movement that shifts an organism from one place to another.

Therefore:

• Not all movements are locomotion.

• All locomotion is movement.

• Locomotion is a specific type of movement.

Movement helps organisms search for food, capture prey, escape predators, transport materials, and change location. It occurs in plants, animals, and unicellular organisms such as Amoeba and Paramecium.

Types Of Movement

Movement can be classified according to whether it involves muscles and whether it occurs under conscious control.

• Muscular Movement: Involves muscles.

• Non-Muscular Movement: Does not involve muscles.

• Voluntary Movement: Usually under conscious control, such as skeletal muscle movement.

• Involuntary Movement: Occurs without conscious control, such as heartbeat and movement of food through the digestive tract.

Mechanism Of Muscle Contraction

Muscle contraction occurs when contractile proteins interact within muscle fibres, allowing the muscle to generate force and shorten.

Sliding Filament Theory

The sliding filament theory explains muscle contraction.

Muscle contraction occurs by the sliding of thin filaments over thick filaments.

• Thick filaments mainly contain myosin.

• Thin filaments mainly contain actin.

• During contraction, actin slides over myosin, shortening the sarcomere.

Motor Unit And Neuromuscular Junction

A motor unit consists of one motor neuron and all the muscle fibres connected to it. Contraction begins when a signal from the central nervous system reaches the motor neuron.

The sequence is:

1. The motor neuron releases acetylcholine.

2. Acetylcholine excites the muscle fibre.

3. An action potential is generated.

4. Calcium ions are released into the sarcoplasm.

5. Calcium binds to troponin.

6. The masking effect of the troponin–tropomyosin complex is removed.

7. Myosin binds to actin.

8. An actomyosin cross-bridge forms.

9. The muscle contracts.

The formation of the actomyosin cross-bridge is an essential step in muscle contraction.

Sarcomere And Muscle Bands

A sarcomere extends from one Z line to the next. The A band contains thick filaments, while the H zone is the central part of the A band where thin and thick filaments do not overlap.

During contraction:

• A band remains unchanged.

• I band becomes shorter.

• H zone becomes shorter.

• Sarcomere shortens.

The sarcoplasmic reticulum stores calcium ions. Skeletal muscle fibres are called syncytium because several myoblasts fuse to form one multinucleate fibre.

Skeletal System And Joints

The zygomatic bone is the cheekbone. It is a facial bone of the skull and belongs to the axial skeleton.

The scapula is a flat, triangular bone located between the second and seventh ribs. Its glenoid cavity forms part of the shoulder joint.

The clavicle directly articulates with the sternum, connecting the pectoral girdle to the axial skeleton. The pectoral girdle contains the clavicle and scapula. The pelvic girdle contains the ilium, ischium, and pubis.

A joint is a point of contact between two bones or between bone and cartilage. Muscles generate the force for movement. Bones do not generate the force.

Major Joint Types

Joints connect bones or other skeletal elements and differ in their structure and range of movement.

Sutures are immovable fibrous joints called synarthroses. Synovial joints, including hinge and ball-and-socket joints, allow considerable movement.

The first seven pairs of ribs are true ribs, the eighth to tenth pairs are false ribs, and the eleventh and twelfth pairs are floating ribs.

Neural Control And Coordination

A neuron contains dendrites, a cell body, and an axon. Nissl bodies, made of rough endoplasmic reticulum and ribosomes, occur in the cyton and are absent from the axon.

Afferent fibres carry sensory information, while efferent fibres carry motor information. The somatic nervous system controls skeletal muscles. The autonomic nervous system controls involuntary muscles.

Resting Potential And Action Potential

A resting neuron is polarised. Its interior is negative compared with the exterior.

• Inside: high potassium and low sodium

• Outside: high sodium and low potassium

The sodium–potassium pump actively transports three sodium ions out and two potassium ions into the neuron.

During depolarisation, sodium ions enter the neuron and the inner surface becomes positive. During repolarisation, potassium ions leave the neuron and the membrane returns towards its resting state. Excessive potassium loss may cause hyperpolarisation.

Synaptic Transmission

At a chemical synapse, an action potential reaches the axon terminal and promotes calcium entry. Synaptic vesicles then release neurotransmitters into the synaptic cleft. These chemicals bind to receptors on the postsynaptic membrane and produce excitatory or inhibitory potentials.

Chemical synapses are slower than electrical synapses. Transmission is unidirectional because the axon terminal releases neurotransmitters and the postsynaptic membrane contains the receptors.

The myelin sheath has gaps called nodes of Ranvier. Impulses jump between these nodes in a process called saltatory conduction. Saltatory conduction makes nerve impulse transmission faster.

Brain Regions and Their Functions

Different brain regions coordinate essential functions, including movement, balance, memory, emotion and the regulation of internal body conditions.

• Hypothalamus: thermoregulation, hunger, thirst, neurosecretion, and biological regulation.

• Medulla: respiration, cardiovascular reflexes, and gastric secretion.

• Cerebellum: posture, balance, and muscular coordination.

• Midbrain: integration of visual, tactile, and auditory inputs.

• Corpus callosum: connects the two cerebral hemispheres.

• Brainstem: midbrain, pons, and medulla.

• Association areas: memory, communication, and complex intersensory association.

• Hippocampus: converts short-term memory into long-term memory.

• Limbic system with hypothalamus: emotional and sexual behaviour.

Chemical Coordination And Integration

The hypothalamus controls the pituitary gland. The posterior pituitary stores and releases hormones made in the hypothalamus, including oxytocin and ADH. The anterior pituitary is connected to the hypothalamus through portal circulation.

Hormone Action

Protein hormones bind to membrane receptors and act through secondary messengers such as cyclic AMP. Lipid-soluble hormones enter cells, bind intracellular receptors, and interact with nuclear DNA.

Major Hormones and Their Functions

Different hormones regulate distinct physiological processes, and their functions are important for NEET examination preparation.

• FSH: Development of ovarian follicles and support of spermatogenesis.

• LH: Maintains the corpus luteum and supports testosterone secretion.

• Oxytocin: Uterine contraction and milk ejection.

• ADH: Water reabsorption and prevention of excessive urine formation.

• Glucagon: Glycogenolysis and maintenance of blood glucose.

• Insulin: Glycogenesis.

• Cortisol: Anti-inflammatory, immunosuppressive, gluconeogenic, lipolytic, and proteolytic effects.

• Thyroxine: Regulation of basal metabolic rate, water and electrolyte balance, and red blood cell formation.

• Calcitonin: Regulation of blood calcium.

• Parathyroid Hormone: Increases blood calcium and promotes bone resorption.

• Epinephrine: Increases heart rate and supports the fight-or-flight response.

• Melatonin: Regulation of the biological clock.

• Growth Hormone: Excess in adults causes acromegaly.

• Erythropoietin: Stimulates red blood cell formation.

Negative feedback maintains hormonal balance. For example, increased testosterone reduces further LH secretion.

Human Physiology Important Questions

Question 1. Read the given statements and identify the incorrect statement.

A. In Paramecium, cilia aid in movement. 

B. The tentacles of Hydra are used for both catching prey and movement. 

C. Female reproductive tracts have flagella that help in the movement of the ovum. 

D. Human leucocytes and macrophages are specialised cells that demonstrate amoeboid movement.

Question 2. Regarding cardiac muscle fibres, which of the following statements is false?

A. They are found in the myocardium of the heart. 

B. They are striated in appearance. 

C. They are involuntary in nature because their activities are not directly controlled by the nervous system. 

D. They are cylindrical and have a branching pattern.

Question 3. Read the following statements about skeletal muscles and select the correct answer.

Statement A: Each fascicle consists of numerous muscle fibres. Statement B: Each organised skeletal muscle contains numerous fascicles.

A. Both statements are correct. 

B. Both statements are incorrect. 

C. Only Statement A is correct. 

D. Only Statement B is correct.

Question 4. One myosin filament in the myofibril of a skeletal muscle fibre is surrounded by how many actin filaments?

A. Two 

B. Four 

C. Six 

D. Three

Question 5. Which of the following statements are incorrect about red muscle fibres?

(i) They contain more myoglobin. (ii) They contain more mitochondria. (iii) They contain more sarcoplasmic reticulum. (iv) They depend on anaerobic processes for energy. (v) They have a reddish appearance.

A. (i) and (ii) 

B. (iii) and (iv) 

C. (ii) and (iii) 

D. (iv) and (v)

Question 6. Match Column I with Column II and select the correct answer using the codes given below.

Options:

A. A–(iii), B–(iv), C–(i), D–(ii) 

B. A–(ii), B–(iv), C–(iii), D–(i) 

C. A–(ii), B–(i), C–(iii), D–(iv) 

D. A–(iii), B–(i), C–(iv), D–(ii)

Mastering Human Physiology Part II requires a clear understanding of muscle contraction, skeletal joints, neural impulses, and hormonal functions. Revise the important concepts, practise NEET-level MCQs, and use the related resources to strengthen your preparation. For dedicated guidance, classes, and comprehensive Biology revision, explore PW’s NEET 2027 preparation batches and take a confident step towards your medical entrance exam goals. 

Related Resources

• NEET 2027 Preparation Strategy

• Neural control and coordination

• Chemical coordination and integration

• Human physiology NEET notes

• NEET 2027 biology preparation