Download Structure Of The Lungs

Structure of the Lungs
Structure of the Lungs
Larynx
Trachea
Right
Bronchus
Intercostal
Muscles
Alveoli
Left Bronchus
Bronchioles
Diaphragm
Put these Words into the
Correct Order
Trachea
Alveoli
Bronchioles
Pharynx
Alveolar Ducts
Larynx
Bronchi
Nose, nasal cavity and mouth
Put these Words into the
Correct Order
Nose, nasal cavity and mouth
Pharynx
Larynx
Alveolar Ducts
Trachea
Bronchi
Bronchioles
Alveoli
Inspiration and Expiration
•Both inspiration and expiration are
caused by changes in air pressure in
the lungs
•The changes in pressure are caused
by muscular action
of the intercostal
muscles and
diaphragm
Inspiration
Air comes in
External
intercostals
contract
Lung Expands
Diaphragm has
contracted
Diaphragm and external intercostals contract
causing the rib cage to move upwards and outwards
reducing pressure inside the pleural membranes and
resulting in air rushing into the lungs
Expiration
Air flows out
Rib cage falls
Diaphragm
relaxes
Expiration is caused by an increase in pressure on
the pleural membrane from the falling ribs and
returning diaphragm. Also, the alveoli recoil (after
being stretched during inspiration) forcing out air.
Respiratory Volumes at Rest
Define and give values for the following:
•Tidal Volume
•Vital Capacity
•Minute Volume
•Inspiratory Reserve
•Expiratory Reserve
•Residual Volume
Gaseous Exchange at the Lungs
Oxygenated blood back
to the heart
R.b.c.’s with high
O2 conc. and
plasma with low
CO2 conc.
CO2 diffuses
out of plasma
Air to and from
rest of lung
Deoxygenated
blood from
the heart
O2 diffuses
into r.b.c.
Blood plasma with a
R.b.c.’s with a low O2 high CO content
2
content
Tissue Respiration
•There is a high oxygen content in the
red blood cells passing through
capillaries to muscles and a low carbon
dioxide content in the blood plasma
•There is a low oxygen content in
muscle tissue and a high carbon dioxide
content
•What do you think happens?
Inspiration During Exercise
•Same as for at rest, but:
•The Sternocleidomastoid
and Pectoralis Minor
contract to raise the first rib
and sternum (increasing
volume of thorax)
•External Intercostal
Muscles Contract again
increasing the size of the
thorax
Expiration During Exercise
•Same as for expiration at
rest, but:
•Abdominal muscles
contract forcing air out of
the lungs
•The Internal Intercostal
muscles aid gravity by
contracting and reducing
the size of the thorax
Lung Volumes During Exercise
•At rest, breathing rate is around 12 per
minute. With heavy exercise this can get up to
60-70 per minute.
•At rest tidal volume is 500ml. In Heavy
exercise this can go up to vital capacity (4 or 5l)
•Stretch receptors signal when the tidal volume
is getting too big.
•Control mechanisms are most important in
sleep and in exercise.
•With exercise the lung volume after expiration
goes below Functional Residual Capacity.
The Respiratory Centre
•There are two mechanisms for
controlling breathing rates and volumes: 1. Nervous regulation (medulla oblongata)
2. Chemical regulation
Nervous Regulation
•Breathing rates are controlled
by the medulla oblongata
•Inspiration by the apneustic
centre
•Expiration by the
pneumotaxic centre
Chemical Regulation
•Peripheral chemoreceptors in the
carotid arteries and the aorta respond to
chemical changes in the blood.
•There are 3 chemical controls: 1. Partial pressure of oxygen
2. Partial pressure of carbon dioxide
3. Hydrogen ion (H+) concentration
Gaseous Exchange at the
Lungs During Exercise
•Greater partial pressure of CO2 in the
blood and a lower partial pressure of O2
than at rest
•Therefore, an increased diffusion
gradient, resulting in more Oxygen
passing into the blood and more carbon
dioxide passing out of the blood
Tissue Respiration During
Exercise
•Higher pCO2 in the muscles and lower p02
than at rest leading to an increased diffusion
gradient
• Accelerated dissociation of oxy-haemoglobin
due to a decreased
partial pressure of
oxygen in the tissue
capillaries
Effect of Altitude on the
Respiratory System
•At altitude air is thinner
•Thinner air means less air resistance, so
athletes who sprint, jump, or cycle will perform
better at high-altitude venues.
•But thinner air also means less oxygen, so the
pace of hard endurance training and
competition--which depends on high rates of
oxygen consumption--gets slower at altitude.
Effect of Altitude on the
Respiratory System
•If you live at altitude for several weeks, your
body adapts to the shortage of oxygen.
•The most important adaptation for the endurance
athlete is an increase in the number of red blood
cells
•Red blood cells carry oxygen from your lungs to
your muscles. More red cells means your blood
can carry more oxygen, which partly makes up for
the shortage of oxygen in the air.