adaptations in lungs and breathing Flashcards
What is inspiration and when does it occur?
inhalation
when the air pressure of the atmosphere is greater than the air pressure inside the lungs = air is forced into the lungs
What is expiration and when does it occur?
exhalation
when the air pressure in the lungs is greater than that of the atmosphere = air forced out of the lungs
What happens during inspiration? (Diaphragm, intercoastal muscles, ribs, volume of thorax, pressure of the thorax compared to the outside)
Diaphragm muscles contract, causing it to flatten. External intercostal muscles = contract causing the Ribs to move upwards and outwards, which increases the volume of the thorax
the volume of thorax= increases causing a reduction in the pressure of the lungs,
pressure of the thorax compared to the outside= less than outside,so air is forced into the lungs
What happens during expiration? (Diaphragm, intercoastal muscles, ribs, volume of thorax, pressure of the thorax compared to the outside)
Diaphragm muscles relax and domes up.
External intercostal muscles = relax decreasing volume of the thorax causing the ribs to move downwards and inwards, which decreases the volume of the thorax.
due to having elastic tissue, the lung recoils
intercoastal muscles = contract
the volume of thorax= decreases causing an increase in the pressure of the lungs,
the pressure of the thorax compared to the outside= more than outside,so air is forced out of the lungs
What is the main cause of air being forced out
the recoil of the elastic tissue in the lungs
Which process is active and which is passive
inspiration = active
expiration = passive
Why do mammals need large volumes of oxygen to be absorbed and large volumes of co2 to be removed?
- they are relatively large organisms with a large volume of living cells
- they maintain a high body temperature which is related to them having high metabolic and respiratory rates
What are lungs?
a pair of lobed strucutres made up of a series of highly branched tubules (bronchioles) , which end up in tiny air sacs (alveoli)
Describe the structure and adaptations of the trachea
flexible airway supported by rings of cartilage, which prevents the trachea collapsing as the air pressure inside falls when breathing in
tracheal walls are made up muscle lined with ciliated epithelium and globet cells = produce mucus to trap dirt particles and have cilia that move the dirt-laden mucus towards the throat
cartilage is c-shaped to give flexibility
What is the bronchi and describe the structure and adaptation of the bronchi
two divisions of the trachea
produce mucus to trap dirt particles and have cilia that move the dirt-laden mucus towards the throat
supported by cartilage= prevents collapsing as the air pressure inside falls when breathing in
What is the bronchicles and describe the structure and adaptation of the bronchicles
series of branching subdivisions of the bronchi
walls are made of muscle lined with epithelial cells
muscle allows them to constrict so that they can control the flow of air in and out of the alveoli
What is the alveoli and describe the structure and adaptation of the alveoli (3 adaptations)
small air sacs at the end of the bronchioles
between alveoli there are some collagen (prevent collapsing) and elastic fibres= allow alveoli to stretch as they gill with air when breathing in
the alveoli are lined with epithelium
alveoli spring back during breathing out in order to expel the carbon dioxide-rich air
What the adaptations of the alveoli for gas exchange
- Red blood cells are slowed as they pass through pulmonary capillaries allowing more time for diffusion
- the distance between the alveolar air and red blood cells is reduced as the red blood cells are flattened against the capillary walls
- the walls of both alveoli and capillaries are very thin and therefore the distance over which diffusion tails place is very short
- alveoli and pulmonary capillaries have a very large total surface area
- breathing movements constantly ventilate the lungs and the action of the heart constantly circulates the blood around the alveoli. together these ensure that a steep concentration gradient of gases to be exchanged is maintained
- blood flow through the pulmonary capillaries maintains a concentration gradient
Describe the path by which oxygen goes from an alveolus to the blood
A high concentration of oxygen in the alveolus (i the lung) diffuses down the concentration, through the alveolus epithelium and through the endothelium of the capillary, to the blood where there is a low concentration of oxygen.
Describe how ventilation helps to maintain the difference in oxygen concentration between the alveoli and the lung capillaries
Ventilation removes the remaining gas in the alveoli, which has a low concentration of oxygen and a comparatively high concentration of carbon dioxide, and replaces it with fresh atmospheric air, with a high concentration of oxygen and low carbon dioxide.
