The class will complete solve your doubt of human respiratory system.
Lecture by Babai Mukherjee , BSC nursing student.
The lecture will contain introduction , main organ involved , breathing process , gas exchange in alveoli, respiration types , key points, labelled diagram, frequently asked questions, conclusion, short notes which will boost your revision strategies
1. Introduction
Every living organism needs energy to survive. Humans get this energy from food, but energy is released only when food (mainly glucose) is broken down with the help of oxygen. This process is called Respiration.
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2. Human Respiratory System – Main Organs
1. Nostrils – Air enters through the nose, where hairs filter dust.
2. Nasal cavity – Warms and moistens the air.
3. Pharynx – Common passage for air and food.
4. Larynx (Voice box) – Produces sound.
5. Trachea (Windpipe) – Tube with rings of cartilage to prevent collapsing.
6. Bronchi – Two branches from the trachea, one to each lung.
7. Bronchioles – Smaller tubes inside the lungs.
8. Alveoli – Tiny air sacs where gas exchange takes place.
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3. Breathing Process
Inhalation (breathing in):
Diaphragm contracts & moves down
Chest cavity expands → air rushes into lungs
Exhalation (breathing out):
Diaphragm relaxes & moves up
Chest cavity contracts → air pushed out
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4. Gas Exchange in Alveoli
Oxygen from inhaled air diffuses into blood.
Carbon dioxide from blood diffuses into alveoli → exhaled.
This happens because of diffusion (movement from high concentration to low concentration).
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5. Respiration Types
1. Aerobic respiration (with oxygen) → Complete breakdown of glucose into CO₂ + H₂O + Energy (ATP).
Equation:
C₆H₁₂O₆ + O₂ → CO₂ + H₂O + Energy
2. Anaerobic respiration (without oxygen) → Partial breakdown, less energy.
Example: Muscle cells form lactic acid during heavy exercise → causes cramps.
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