Human Body Organs & Systems – Detailed Notes
for NEET
This document provides a detailed overview of the human body systems and organs, covering
definitions, functions, mechanisms, examples, and diseases with causes. It is structured for NEET
preparation.
Circulatory System
Organs Heart, Blood, Blood Vessels
Functions Transport of oxygen, nutrients, hormones; removal of CO■ and waste.
Mechanism Right heart pumps deoxygenated blood to lungs; left heart pumps oxygenated blood to body.
Example During exercise, heart rate increases → more oxygen to muscles.
Diseases & Causes Heart attack (blocked arteries), Hypertension (high BP), Stroke (clot in brain).
Respiratory System
Organs Nose, Trachea, Lungs, Alveoli
Functions Gas exchange (O■ in, CO■ out).
Mechanism Air enters nose → trachea → bronchi → alveoli; diffusion of gases with blood capillaries.
Example Breathing rate increases during running for more oxygen.
Diseases & Causes Asthma (airway narrowing), Pneumonia (infection), COPD (smoking-related).
for NEET
This document provides a detailed overview of the human body systems and organs, covering
definitions, functions, mechanisms, examples, and diseases with causes. It is structured for NEET
preparation.
Circulatory System
Organs Heart, Blood, Blood Vessels
Functions Transport of oxygen, nutrients, hormones; removal of CO■ and waste.
Mechanism Right heart pumps deoxygenated blood to lungs; left heart pumps oxygenated blood to body.
Example During exercise, heart rate increases → more oxygen to muscles.
Diseases & Causes Heart attack (blocked arteries), Hypertension (high BP), Stroke (clot in brain).
Respiratory System
Organs Nose, Trachea, Lungs, Alveoli
Functions Gas exchange (O■ in, CO■ out).
Mechanism Air enters nose → trachea → bronchi → alveoli; diffusion of gases with blood capillaries.
Example Breathing rate increases during running for more oxygen.
Diseases & Causes Asthma (airway narrowing), Pneumonia (infection), COPD (smoking-related).
