Transcript Functions - VUSCyear11PE

Respiratory System
Chapter 12
Pg. 284
Functions
The functions of the respiratory system are:
 Brings air from the atmosphere into the lungs.
 Transfers O2 into the blood.
 Removes CO2 from the blood.
 Expels heat and water vapour (in the air breathed out).
 Allows the vocal cords to create speech (as air is breathed out).
Structure
Mechanics of Breathing
• Breathing: the movement of air into and out of the
respiratory system in order to extract oxygen from the
atmosphere and bring it into the body
• Each minute you breathe you move approx 7-8L of air
in and out of your lungs.
• The design of the lungs, blood and blood system ensure
that oxygen is absorb into the bloodstream and pump
around the body by the heart.
Structure
 Breathing in: inspiration
 The diaphragm* contracts and move downwards making the chest cavity larger.
 As the chest cavity becomes larger, the air pressure inside it becomes lower,
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sucking air in.
Breathing out: expiration
The diaphragm relaxes and the chest cavity goes back to its ‘resting’ size.
Breathing out is a passive process but last longer than breathing in.
The intercostal* muscles also aid the process by allowing the ribs to return to
their ‘resting’ position.
*Diaphragm is an involuntary muscle
*Intercostal muscles are found between the ribs.
Respiration and Exercise
 When you begin to exercise you use more energy from your
body, which comes from the combination of oxygen and food
stored in the cells.
 Therefore, when exercising you need to breathe more rapidly
and more deeply.
Respiration Rate – the amount of times you breathe per minute
(avg. 12-18 times/min)
Tidal Volume – the amount of air breathed in and out with each
breath (avg. 0.5L)
Ventilation – amount of air breathed in per minute
= tidal volume x respiratory rate
0.5L x 15 breaths = 7.5L
Vital Capacity – the maximum amount of air you can breathe
out after breathing in
Respiration and Exercise:
 Respiration will increase immediately – up to 35 times/minute.
 As you exercise, the level of CO2 in your body increases.Your
brain detects this and stimulates the increase in your respiratory
rate.
 Tidal volume will increase from 0.5L up to 5L per breath.
 Ventilation will increase from 7.5L up to 150L per minute.
VO2 Max
V=Volume, O2=Oxygen
 The maximum amount of oxygen that can be breathed in,
transported to, and used by your working muscles.
 A good measure of aerobic endurance (how efficient your
circulatory, respiratory and muscular systems are whilst
exercising).
 The actual figure is the largest amount of oxygen you can use per
minute and is determined by your maximum heart, stroke
volume and arteriovenous oxygen difference.
 Page 289, table 12.1
Passageway of Air
 Air breathed in through nostrils
 Air passes through your pharynx
 At the end of the pharynx there are 2 openings: one leads to
the larynx, the other to the oesophagus. Air travels down the
larynx, food travels down the oesophagus.
 Air then passes into the trachea (windpipe) which then
divides into 2 bronchi, which then branch into bronchial
tubes.
 Air moves through the bronchial tubes, which are part of the
lungs. The bronchial tubes branch into smaller bronchioles,
which connect to the alveoli.
Gaseous exchange: O2 and waste
transfer
 Gaseous exchange = The transfer of oxygen through the
alveoli to the red blood cells. Oxygen passes rapidly through
the lining of the alveoli and into the red blood cells in the
capillaries, which add oxygen to the blood. Carbon dioxide is
removed from the blood and enters the alveoli.