Sub Topic: HUMAN BREATHING MECHANISM
Learning
Objectives:
At
the end of the lesson, student should be able to:
-
Identify the structure of the human respiratory system.
-
Identify the structure of the lung.
- Describe the process on inhalation and exhalation.
Lesson:
A. Human respiratory
system
1. The human respiratory
system consist of:
(i) diaphragm
(ii) ribs
(iii) breathing organs
(iv) intercostal muscles
2. The breathing organs
include the nasal cavity (nostril), the breathing channel (trachea,
bronchus and bronchiole)
and the lungs.
3. Alveolus, bronchiole and a part of the
bronchus are situated in the lungs.
4. In the
lungs, the bronchus branches to form many smaller channels called bronchiole. Each bronchiole ends with
an alveolus.
5. The function of the nasal cavity is to warm, moisten and filter fine particles like dust from the air that pass through it.
6. The trachea is a channel which branches into two. Each
branch is called bronchus
which enters the lungs.
7. Air is taken into our body through the
nose or mouth and then into the trachea.
8. Air is inhaled through the nasal cavity
and taken through the trachea, bronchus, bronchiole
and finally to the
alveolus.
9. The ribs protect the lungs and internal organs like the heart.
10. The diaphragm is a piece of muscle situated at the bottom of the
lungs.
11. The intercostal muscles
are situated between the ribs. There are two types of intercostals muscles, i.e. the internal intercostal muscle and the external intercostal muscle. The intercostal muscles contract and relax to
help the breathing
process.
12. Each alveoulus has a
very thin wall which is moist and contains a large networkof
blood capillaries.
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