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3. Table of Contents
1. Definition & Diagram
2. Respiratory Tract
3. Functions
4. Respiration In Humans
5. Conclusion/Respiration Steps
6. Frequently Asked Questions(FAQ)

4. B2T

5. B2T
The respiratory tract in humans is made up of the following parts:
o External nostrils – For the intake of air.
o Nasal chamber – Lined with hair & mucus to filter the air and remove dust/dirt.
o Pharynx – passage behind the nasal chamber & serves as the common passageway for both air
+ food.
o Larynx – Also known as the soundbox as it helps in the generation
of sound and thus helps us in communicating.
o Epiglottis – Flap-like structure - covers the glottis & prevents the
entry of food into the windpipe.
o Trachea – Long tube passing through the mid-thoracic cavity.
o Bronchi – The trachea divides into left & right bronchi.
o Bronchioles – Finer channels.
o Alveoli – Balloon/Bag-like structures.
o Lungs – Sac-like structures - covered by a double-layered membrane known as pleura.

6. B2T
 Inhalation and Exhalation
 Exchange of Gases between Lungs and Bloodstream
 Exchange of Gases between Bloodstream and Body
Tissues
 The vibration of the Vocal Cords
 Olfaction or Smelling

7. B2T
There are two types of respiration processes in humans:
1. External Respiration, that involves the inhalation and exhalation of
gases.
2. Internal Respiration, that involves the exchange of gases between
blood and body cells.

8. B2T
Respiration involves the following steps:
i. Breathing or pulmonary ventilation by which atmospheric air is drawn in and
CO2 rich alveolar air is released out.
ii. Diffusion of gases (O2 & CO2 ) across alveolar membrane.
iii. Transport of gases by the blood.
iv. Diffusion of O2 & CO2 between blood and tissues.
v. Utilisation of O2 by the cells for catabolic reactions and resultant release of
CO2 (cellular respiration as dealt in the Chapter 14).

9. B2T
Frequently Asked Questions(FAQ)
1) What is the human respiratory system?
2) What are the important respiratory system parts in
humans?
3) What is the respiratory tract made up of ?
4) What is the main difference between breathing and
respiration in humans?
5) Why do the cells need oxygen?
6) What are the different types of respiration in humans?
The air that we inhale has the following composition:
•Nitrogen – 78%
•Oxygen – 21%
•Carbon dioxide – 0.03 – 0.04%