Introduction
Human Physiology is a core unit in Class 11 Biology that explains how the human body functions at the system level. It covers the anatomical structures, physiological mechanisms, and biochemical processes that maintain homeostasis. For NEET aspirants, Unit V forms the basis of several high-weightage questions in Biology. This unit builds on prior knowledge of biomolecules and the cell, and leads into medical-level understanding needed for advanced topics in Class 12.
Chapter-Wise Overview
Chapter 14: Breathing and Exchange of Gases
Explains respiratory anatomy, mechanism of breathing, gas exchange, and transport.
Key Concepts:
- Human respiratory system: nasal cavity to alveoli
- Mechanism of inspiration and expiration
- Oxygen-Hemoglobin dissociation curve
- Regulation of respiration by respiratory centers
Important NEET Topics:
- Lung volumes: tidal volume, vital capacity
- CO₂ transport as bicarbonate
- Disorders: Emphysema, Asthma
Quick Table – Lung Volumes:
| Volume | Approx. Value | Description |
| Tidal Volume (TV) | 500 mL | Air during normal breath |
| Vital Capacity (VC) | 4500 mL | Max air exhaled after max inhalation |
Chapter 15: Body Fluids and Circulation
Describes the circulatory system, heart structure, cardiac cycle, and ECG.
Key Concepts:
- Blood composition: RBCs, WBCs, plasma
- Structure and function of heart chambers
- Cardiac cycle: systole, diastole
- ECG and interpretation
Important NEET Topics:
- Double circulation
- Blood pressure values: systolic/diastolic
- Disorders: Hypertension, atherosclerois
NEET MCQ Tip: ECG wave P-QRS-T – identify and label
Chapter 16: Excretory Products and Their Elimination
Covers structure and function of the nephron, urine formation, and excretory disorders.
Key Concepts:
- Kidney structure and nephron anatomy
- Glomerular filtration, tubular reabsorption, secretion
- Role of ADH in osmoregulation
- Juxtaglomerular apparatus (JGA)
Important NEET Topics:
- Counter-current mechanism
- Dialysis and kidney failure symptoms
Quick Table – Nitrogenous Wastes:
| Organism Type | Waste Product | Example |
| Ammonotelic | Ammonia | Fish |
| Ureotelic | Urea | Humans |
| Uricotelic | Uric acid | Birds |
Chapter 17: Locomotion and Movement
Discusses skeletal muscles, bones, joints, and types of movement.
Key Concepts:
- Sarcomere structure (Z line, M line, A band, I band)
- Sliding filament theory: actin-myosin interaction
- Bone types: long, short, flat
- Joints: fibrous, cartilaginous, synovial
Important NEET Topics:
- Muscle contraction: ATP role, calcium ions
- Disorders: Myasthenia gravis, arthritis, osteoporosis
Diagram-Based MCQ: Label the sarcomere correctly in muscle contraction models
Chapter 18: Neural Control and Coordination
Explores CNS, PNS, and regulation of nerve impulses.
Key Concepts:
- Structure of neuron: dendrites, axon, synapse
- Impulse conduction: depolarization, repolarization
- Reflex arc: pathway and significance
- Parts of the brain: cerebrum, cerebellum, medulla
Important NEET Topics:
- Synapse types: electrical vs. chemical
- Nerve impulse direction and neurotransmitters
- Disorders: Epilepsy, Alzheimer’s
Common MCQ Confusion: Difference between sympathetic and parasympathetic responses
Chapter 19: Chemical Coordination and Integration
Describes endocrine glands and hormonal functions.
Key Concepts:
- Glands: pituitary, thyroid, adrenal, pancreas, gonads
- Hormonal regulation: feedback loops (positive & negative)
- Hormone types: steroidal, peptide
Important NEET Topics:
- Insulin function and diabetes mellitus
- Hypo- and hyperthyroidism
- Hormone chart: source, target organ, function
Quick Table – Important Hormones:
| Hormone | Gland | Function |
| Insulin | Pancreas | Lowers blood glucose |
| Thyroxine | Thyroid | Increases metabolism |
| Cortisol | Adrenal cortex | Stress response |
FAQs
What is human physiology in Class 11 Biology?
It is the study of how different systems in the human body function to maintain life processes such as digestion, respiration, circulation, excretion, and control mechanisms.
How many chapters are in Unit V of Class 11 Biology?
There are seven chapters in Unit V – from Chapter 16 to Chapter 22 – covering all major physiological systems.
Why is this unit important for NEET?
Human Physiology is one of the highest-weighted sections in NEET Biology. Many direct and application-based questions are asked from these chapters.
Which chapter covers muscle contraction?
Chapter 20: Locomotion and Movement discusses muscle structure and contraction mechanisms in detail.
What are some common NEET questions from this unit?
NEET frequently tests:
- Enzyme roles in digestion
- Oxygen dissociation curve
- ECG interpretation
- Nephron structure
- Hormonal feedback loops
NEET Relevance Snapshot
| Chapter | Key NEET Topics |
| Digestion and Absorption | Digestive enzymes, absorption sites |
| Breathing | Lung volumes, O₂/CO₂ transport |
| Circulation | Heart cycle, blood groups, ECG |
| Excretion | Nephron function, osmoregulation |
| Locomotion | Muscle contraction, bone disorders |
| Neural Control | Synapses, impulse transmission |
| Chemical Coordination | Hormones, feedback loops |
Conclusion
Unit V: Human Physiology is not only foundational to biology but also a crucial scoring area in NEET. Understanding the structure and function of body systems, along with related disorders and mechanisms, helps bridge basic biology to clinical understanding. Students preparing for NEET should master this unit through NCERT reading, diagrams, and consistent MCQ practice.
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