of the Respiratory system

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24 Οκτ 2013 (πριν από 3 χρόνια και 7 μήνες)

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Functions

of the

Respiratory system

P6 M3


The respiratory system is

responsible
for:


getting oxygen in to our body


Getting carbon dioxide and other waste products out of our body


All living creatures need Oxygen in
combination with food to produce
energy and movement.


Every cell of the body needs
Oxygen to function


Respiration is the process by
which cells receive a constant
supply of oxygen and carbon
dioxide is removed.


The aim of the respiratory
system is to get:


Oxygen to the
bloodstream


so that the CV system can
deliver it to the muscles.


Carbon dioxide out of the
bloodstream


All endurance performance relies
on


Delivery of Oxygen into the
blood stream


Removal of Carbon Dioxide
out of the blood


Give a couple of specific
examples in your worksheet


When we exercise:
CO
2 dissolves within the
bloodstream and increases acidity levels. So the
respiratory centre in the brain speeds up the rate
of breathing to get rid of excess
CO
2.


So rate of breathing increases due to
CO
2 levels
rising. Not the cells demanding more
O
2.


Gases move through a process called diffusion


Gas moves from a high concentration to a low
concentration


Eg
: someone wearing perfume.


In the respiratory system


Two different types of
diffusion:


Diffusion of Oxygen into the blood
stream, attracted by haemoglobin


Diffusion of Carbon Dioxide out of
the blood
stream to be excreted
by
the lungs



The alveoli are in constant contact with the
capillaries


The air we breath in arrives in the alveoli,
rich in Oxygen


The blood arrives from the pulmonary artery
very low in oxygen


Following the principle of diffusion, the
Oxygen moves across the capillary wall
and into the blood stream


It is attracted by the haemoglobin into the
red blood cells


The blood returns to the heart to be pumped
to the rest of the body


The blood arrives in capillaries of the lungs with a high concentration
of Carbon Dioxide


The air in the alveoli has a low concentration of Carbon Dioxide

According to the principles of diffusion, the Carbon dioxide moves
across the wall of the capillaries and into the alveoli, so that it can
be expired.


Breathing is regulated by:



the
respiratory centre
,
located in the brain.


Receptors in the air
passages and lungs


Breathing in = Inspiration


Breathing out = Expiration


To breathe the thorax must
increase and then decrease in
size


The mechanics of
breathing

Overview

Inspiration


In order to breathe in the volume of the
chest cavity needs to increase.


This increase in size of the chest cavity,
causes a decrease in pressure within the
lungs


Boyle’s Law

states that a volume of gas is
inversely proportional to its pressure.


This means that the increase in volume in
the lungs causes a decrease in pressure.


Gases flow from a high pressure area to a
low pressure area


In this situation the ambient air is the high
pressure area and the lungs are the low
pressure area, so the air flows into the
lungs

Inspiration


Inspiration


Breathing in


Diaphragm contracts


It flattens and pulls down


This is an active process


External intercostal muscles contract


The sternum moves up and out, with the
lungs following


The lungs are attached to the pleural sac
(containing pleural fluid), which in turn is
attached to the thoracic cage


As the chest expands, the surface
tension, created by the film of pleural
fluid causes the lungs to be pulled
outwards, with the chest



These two actions cause
the volume of the thoracic
cavity to increase


According to Boyles Law
this increase in volume
causes a decrease in
pressure


Air flows into the lungs


As gas flows from high
pressure to low pressure.

Expiration


To breathe out


Expiration
:


Diaphragm relaxes


It moves back up and into the thoracic cavity


This is a passive process


The external intercostal muscles relax


The ribs/sternum moves down.


The lungs, sternum and rib cage are elastic structures that naturally 'spring'
back to their resting positions once the forces of the inspiratory muscles
are removed. So expiration is a passive process.


The volume of the thoracic cavity decreases causing the air to
move out of the lungs.


This is because air pressure in the lungs is now higher than atmospheric
pressure, according to Boyles Law, so the air is forced out of the lungs to
equate the pressure in and out of the body.

The muscles of breathing

Respiratory

volumes

Lung Volumes


Lung volumes:

refers to physical differences in lung volume, while
lung capacities represent different combinations of lung volumes,
usually in relation to inhalation and exhalation.


The average pair of human lungs can hold about 6
litres

of air, but
only a small amount of this capacity is used during normal breathing.


Spirometer trace


Respiratory
volumes


Tidal Volume


The volume of air inspired
or expired per breath
(
Approx

500ml at rest)




Expiratory Reserve Volume


The amount of space that is available to breathe out, once you have exhaled
normally


Eg
: Breathe out normally, then force out more air. This is your ERV.




Inspiratory Reserve Volume


The amount of space that is
available to draw in more air


Eg
; Breathe in normally, then
breathe in more. This extra
capacity is your IRV



Respiratory
volumes


Total Lung
Capacity


Take in as
much breath
as possible


This is your
total lung
capacity


ERV+IRV+TV
+RV (
Approx

6000ml)



Vital Capacity


Breathe in as much as you can,
and then force as much air out of
your lungs as possible.


This is your IRV+ERV+TV,
and is your Vital Capacity



Residual Volume


Breathe out as much as
possible


There is always
some air left in
your lungs


This is your RV
(
Approx

1200ml)


D
escribe

the
(1) Structure
with
all the parts named BELOW and
(2)
Function
(1
-
4 BELOW) of
the
respiratory
system.

2. Function
:

1. Gaseous exchange

2. Mechanisms
of breathing
(
inspiration and expiration
)

3. Lung
volumes:
e.g.
tidal

volume, vital capacity, residual
volume

4. Control
of breathing (
neural and
chemical
)

1. Structure
of the respiratory
system
:


N
asal cavity


Epiglottis


Pharynx


Larynx


Trachea


Bronchus


Bronchioles


L
ungs
(lobes, pleural membrane, thoracic
cavity,
visceral
pleura, pleural fluid,
alveoli)


Diaphragm


I
ntercostal
muscles (external and internal)

E
xamine

the respiratory system

and
explain

how it
works

and
how each part of the system is
designed to meet its
function