section b: animal physiology Flashcards
(415 cards)
how do cells get their energy
by oxidising foods such as glucose, this is called respiration
if cells are to respire aerobically, what do they need
a continuous supply of oxygen from the blood, and carbon dioxide to be removed.
what is breathing
the mechanism that moves air into and out of the lungs, allowing gas exchange to take place.
what is the gas exchange system
the lungs, ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes of the thorax
where does gas exchange take place
in the lungs
where are the lungs
enclosed in the chest or thorax by the ribcage and a muscular sheet of tissue called the diaphragm.
what causes the movement of air into and out of the lungs
the actions of the lungs and diaphragm
describe the process of breathing in
the intercostal muscles and the diaphragm contract
thorax volume increases because the muscles pull the sternum up and out, so the pressure decreases, drawing air in.
describe the process of breathing out
intercostal muscles and diaphragm relax.
thorax volume decreases because the ribcage and sternum drop in and down, so the diaphragm moves up, increasing pressure, and forcing air out.
what happens to the air when we breathe in
it enters our nose or mouth and passes down the windpipe or trachea. the trachea splits into two tubes, the bronchi, and each bronchus divides into smaller and smaller bronchioles, which ends at alveoli where gas exchange takes place
what do the walls of the trachea and bronchi contain
rings of gristle or cartilage
what do the rings of cartilidge do
support the airways and keep them open when we breathe in
what is the inside of the thorax seperated from the lungs by
two thin, moist membranes called the pleural membranes
purpose of the pleural membranes
they make a continuous and airtight seal around the lungs. the pleural cavity is filled with a thin layer of pleural fluid, which acts as lubrication, so that the surfaces of the lungs don’t stick to the inside of the chest wall when we breathe.
explain mucus and it’s role in the airway
some cells in the lining between the trachea and the larger airways are lined with a layer of cells that secrete mucus, which traps particles of dirt or bacteria that are breathed in.
explain cilia and it’s role in the airway
the tiny hair-like structures beat backwards and forwards, sweeping the mucus and trapped particles out towards the mouth. this means they don’t reach the lungs, so they prevent infection.
what is ventilation
the moving of air in and out of the lungs
what is required in ventilaiton
a difference in air pressure - the air moves from a place where it is high to one where it is low.
where is deoxygenated blood pumped from and to
from respiring tissues of the body where it has given up some of its oxygen to the cells, and gained carbon dioxide, to the heart, to the lungs, and passes through the capillaries surrounding the alveoli.
what are the alveoli and the blood separated by
two cell walls: the cells making up the walls of the alveolus, and the capillary wall itself. this is the distance of less than a thousandth of a millimetre.
explain how the gas exchange within the alvelous works
the air in the alvelous has a higher concentration of oxygen than the blood entering the capillary network . this means oxygen can diffuse across the wall of the alveolus and into the blood. at the same time, there is more carbon dioxide in th air than in the lungs. this means there is a diffusion gradient for carbon dioxide in the other direction, so it diffuses the other way, out of the blood and into the alveolus.
what is the result of the gas exchange within the alveolus
the blood which leaves the capillaries and flows back to th heart has gained oxygen and lost carbon dioxide. the heart then pumps the oxygenated blood round the body again, to supply thee respiring cells.
why is it important for the gas exhange system to be clean and clear
the alveoli need to be free from dirt particles and bacteria, and have as big a surface area as possible with the blood.
give three diseases smoking is associated with
lung cancer, bronchitis and emphysma.