enjoy Biology

2. In your Body
Created by D.T Nyalunga
University of Johannesburg
Copyrights (2012)

4. Why do we have to breathe?
You have to breathe because all
the cells in your body require
oxygen. Without oxygen, your body
wouldn’t move. It would be like a
parked car without a battery.

5. The cycle of breathing
Air Co2 from
Exhaled out
lungs
Nose air Trachea Co2
lungs
O2 O2
O2

7.  The must be a large surface area, in man this is created by the
presence of the alveoli. (We focus on it later.)
 The must a thin moist layer for the diffusion of gases,
 The surface must be adequately ventilated. For effective
mechanism of inhalation and exhalation Camphell & Reece (2010).
 The gaseous exchange must be richly supplied with blood
vessels, for transport
 The organ must be properly protected , in man the lungs are
situated in an airtight chest cavity and are well protected by the
ribs and sternum Mader s.s (2008).

8. Organ Function
1.Nasal passage For Inhalation (Oxygen) and exhalation
(carbon dioxide).
2.pharynx Contain epiglottis which closes the food
passage when breathing
3.Trachea C-shaped cartilage rings, for moistening
the air and trapping dust.
4.Bronchi and bronchioli Convey air to the lungs
5. Lungs Its moist to facilitated the diffusion of
gases, between lungs and the blood
capillaries.

9. The breathing system

10. The lungs are two grey, spongy, elastic organs situated in the chest
cavity. They are protected by the ribs and sternum. The lower
section consist of diaphragm, surrounded by a double membrane
called pleura membrane. The right lung is divided into three while
the left is divided into two.

11. The lungs and the alveolus

12. Transportation of oxygen and
carbon dioxide in the alveolus.
We, and all respiring organisms, need oxygen to live. When we breathe in air, alveoli in our
lungs exchange carbon dioxide for oxygen, as shown here in this diagram

13. Oxygen can only be transported in two ways.
1. A small percentage is conveyed in solution in the
blood plasma.
2. Most of the oxygen transported in a form of
oxyhaemoglobin.
Carbon dioxide can be transported in three ways.
1. Small percentage is transported in a solution in
the blood plasma.
2. Some transported as carbamino haemoglobin.
3. Most carbon dioxide is transported as
Bicarbonate Ions in the erythrocytes.

14. Pulmonary Diseases
1Bronchitis cigarette smoke and other pathogens irritants the movement of
cilia. Which lines the bronchial tubes. Thus mucus blocks the bronchial tubes
and then infections develops.

15. 2.Emphysema repeated coughing due to aveola bust. when a lot of alveola
destroyed the heart does not get enough oxygen, therefore it could result to
cardiac arrest.

16. 3. Asthma causes by irritants such as smoke, pollen, dust and allergies. The air
ways become narrow which make breathing difficult.

17. 4. Cancer is the most known respiratory diseases which affects our life
daily. Hence there many types of cancer but it is known that smoking is
the most cause of cancer.

18. PNEUMONIA