respiratory system Flashcards
what is the difference between breathing and respiration
Breathing is the movement of air in and out of the lungs.
Respiration is the exchange of gas in the lungs and cells and the release of energy.
what is the function of the respiratory system (2)
- bring oxygen into the body for the production of energy.
- remove carbon dioxide from the body which is a waste product from the energy-making process.
What happens when we breathe (3)
- air enters the mouth and nose and is humidified through the TURBINATES.
- the air passes through the pharynx, larynx, trachea, bronchi, bronchioles and alveoli.
- gas exchange takes place in the alveoli.
how does oxygen and carbon dioxide move in the lungs
Oxygen enters the lungs and enters the bloodstream.
Carbon dioxide from the body enters the lungs and is exhaled.
what are the requirements for gas exchange (4)
- large surface area - lots of alveoli packed in a small space
- rich blood supply - alveoli surrounded by capillaries
- moisture - lungs are moist due to mucous production
- thin walls - walls of alveoli and capillaries are only one cell thick
What happens during inhalation (3)
- the diaphragm contracts and becomes flat
- intercostal muscles contract and raise the rib cage
- chest cavity expands, air pressure decreases meaning air is sucked into the lungs
What happens during exhalation (3)
- the diaphragm relaxes and rises
- intercostal muscles relax and the rig cage collapses
- chest cavity shrinks, air pressure increases so air is forced out of the lungs.
what is the meaning of TOTAL LUNG CAPACITY, VITAL CAPACITY, TIDAL VOLUME, and RESIDUAL VOLUME
- Total lung capacity = the maximum amount of air in the lungs
- vital capacity = the maximum amount of air we can breathe in or out under heavy exercise (approx. 5L)
- tidal volume = the amount we normally breathe in and out in a resting state (0.5L)
- residual volume = amount of air left in the alveoli when you exhale.
how is breathing regulated (2)
Breathing is regulated by monitoring CO2 levels in the blood (normal homeostatic pH = 7.4)
High levels of CO2 determine the rate of breathing.
what happens when there is a rise in CO2 levels (6)
- excess CO2 in the blood makes it more acidic so the pH falls
- the drop in pH is detected by chemoreceptors in the arch of the aorta and carotid arteries in the neck.
- message is relayed to the medulla oblongata
- diaphragm and intercostal muscles increase contractions
- excess CO2 is exhaled and the pH rises again.
- The change in CO2 instructs the brain to slow breathing down.
how is CO2 removed
- CO2 diffuses out of the cell into the bloodstream to be removed.
- CO2 dissolves in blood plasma and red blood cells to form carbonic acid. The more CO2, the more acidic the blood.
how does oxygen bind to haemoglobin (4)
- at high oxygen concentrations, haemoglobin combines with oxygen to form oxyhemoglobin (e.g. in the lungs)
- At low oxygen concentrations, there is a dissociation back to haemoglobin and the oxygen is released. (e.g. in the tissues)
- As tissues become more active, the less oxygen they have. Therefore, the greater the dissociation.
- Oxyhaemoglobin formed in the lungs will combine to the maximum effect with haemoglobin. It is described as 100% saturated.
what does tar in cigarettes do (3)
- Coats the lining of the airways and stops the cilla from removing dust and particles
- triggers increased mucus secretions which accumulate in the lungs (smoker’s cough)
- coats the lining of the alveoli causes a thickened layer, reducing gas exchange and wearing away the alveoli wall.
what does nicotine in cigarettes do (2)
- causes an increase in blood pressure, heart rate, flow of blood to the heart and narrowing of arteries.
- may contribute to the hardening of the arterial walls, which may lead to a heart attack.
what does CO2 in cigarettes do (2)
- decreases the amount of oxygen carried in the red blood cells
- increases the amount of cholesterol that is deposited into the inner lining of the arteries which overtime causes them to harden.
