RESPIRATORY SYSTEM
PHYSICAL EDUCATION CLASS
COORDINATED BY MRS BLESSING TITILOYE
Week: Nine
Class: SS1
Lesson Title: Respiratory system
Period: I-II
Duration: 80
Minutes
Learning
Objectives: Students should be able to know:
i. Structure and functions of the lungs
ii. International and external respiration
iii. Mechanism of breathing
iv. An aerobic and anaerobic respiration
Respiratory System
There are two processes of respiration
1) Breathing or external
respiration.
2) Internal respiration
or tissue respiration.
External respiration is
the exchange of gases between the lungs and the atmosphere is the taking in of
oxygen and the sending out of carbon(iv)oxide
Internal respiration is
otherwise known as tissue respiration. It is the actual oxidation of organic
molecules (glucose) in the cells of the tissue for the liberation of energy.
Glucose is absorbed and
stored in the liver after digestion through the hepatic portal vein. The
process is called dialysis. The glucose is delivered by the circulatory system
to every cell in the body, this is called assimilation. During respiration
oxygen intake in the alveoli combines with haemoglobin of the red blood cells
to form oxyhaemoglobin. The oxygen is taken to the cells where glucose is
always present, oxidation is then brought about by enzymes and oxygen of the
oxyhaemoglobin. This oxidation liberates the energy in the glucose for various
vigorous physical activities, carbon(iv)oxide and water are formed as waste
products and are carried back by the blood for elimination. The Site of this
respiration in the cell is the mitochondria. This reaction occurs in two
stages.
1. Anaerobic
reaction
2. Aerobic reaction
Mechanism of Breathing
The lungs cannot inflate or deflate by themselves, they a helped by two actions. Firstly, by the circular and radial muscles of the diaphragm which when contract flattens and move the diaphragm down so that the volume of the chest cavity is increased from top to bottom. And secondly by the intercostal muscles between the ribs which pull the ribs up and outwards. Through these actions, the volume and circumference of the whole chest cavity is increased, and because of reduced pressure in the chest cavity, air rushes in through the nostrils by the pressure of the air outside. This is called inhalation or inspiration. The opposite action which is expiration or exhalation is due to the elasticity of the lungs. The stretched lungs tend to return to their original size.
What is internal or tissue respiration?
Tissue respiration is the oxidation of glucose in the cells to liberate energy and water are formed as waste products.
Anaerobic reaction
(without oxygen) fundamental chemical change that takes place a voluntary
muscle contracts, is the breakdown of glycogen to produce carbon(iv)oxide, water
and energy in form of heat energy. This energy is taken up and stored by
phosphate salts the tissue fluid and muscle fibres. This is why it is possible
for the muscles to continue to contract even though the supply of oxygen
inadequate. Anaerobic contraction continues due to the accumulation of high
energy phosphates within the muscles. A T.P (Adenosine Triphosphate) is made up
of two other phosphatic salts. Adenosine diphosphate (ADP) and creatine
phosphate (CP) i.e. Adenosine diphosphate (A.D + creatine phosphate = Adenosine
Triphosphate). A.D.p. = A. T.p.
What is anaerobic in relation to physical activity?
Anaerobic respiration
is:
1.
The release of energy in the absence of
oxygen the energy from A. T. P
2.
The amount of energy released is
short-lived
3.
The energy released is mainly used for a
short burst e.g 100m dash or weight lifting
4. The races that can be sustained by
anaerobic respiration are 50m. 75m, 100m, 200m, 400m and 110m hurdles
What is aerobic in relation to physical activity?
Aerobic respiration is:
1.
The release of energy in the presence of
oxygen
2.
The amount of energy released is much
3.
The energy released is mainly used for
long duration and enduring exercise e.g. 1,500m race. Races that can be
sustained by aerobic respiration are 1,500m, 3,000m, 5,000m, 10,000m and
marathons
Major functions of respiratory system
1.
It makes oxygen constantly available in
the body.
2.
It carries away carbon(iv)oxide from the
body.
3.
It helps in vocalization (making of
sounds - for talking and singing)
4.
It helps to exert pressure (e. g, during
defecation, urination and childbirth).
5.
It helps in excretion of water and heat.
The Organs of Respiration
These organs are:
1. The mouth
2.
The pharynx
3.
The nose and nostrils
4. The larynx and trachea
5.
The lungs
6.
The ribs
7.
The diaphragm
Functions of the lungs
1. They expand to accommodate air
2. Each lung contains millions of alveoli
3. The actual exchange of oxygen for carbon
(iv)oxide takes place inside
4. They deflate to expel the air
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