A-level PE: respiratory system

inspiration at rest

- dome shaped diaphragm contracts - moves downward - increases volume -decrease pressure - external intercostal muscles contract lifting in rib cage.

residual volume

Amount of air remaining in the lungs after a forced exhalation. remains the same during exercise.

expiratory reserve volume

Amount of air that can be forcefully exhaled after a normal breath.slight decrease during exercise.

tidal volume

Amount of air that moves in and out of the lungs during a normal breath. increases during exercise.

internal respiration

Exchange of gases between cells of the body and the blood

Inspiration during exercise

External intercostals, pectoralis minor, scalene, and sternocleidomastoid muscles assist because of the demand of oxygen during exercise.

passage of air

Nose - Larynx - Trachea - Bronchi - Bronchioles - Alveoli

What are stretch receptors?

Protect against excess lung inflation. Decrease respiratory rate and volume. sends impulses down the intercostal nerve to the expiratory muscles to make expiratory happen.

What are propioceptors?

these sensors movement when exercising in joints and muscles. they increase breathing rate, sympathetic.

What are chemoreceptors?

they detect a rise in blood acidity due to lactic acid, found in the carotid artery and aortic arch. increase breathing rate until blood acidity is back to normal. sympathetic.

why is there a slight rise in minute ventilation before exercise?

adrenaline is released just before exercise

hormonal regulation

adrenaline made in the kidneys is transported in the blood and is released when we exercise.

oxygen diffusion pathway

alveoli, blood, muscles

hormonal regulation

breathing rate increases in preparation for exercise for the demand to take in more oxygen and remove carbon dioxide.

expiration at rest

everything goes back to normal, increase pressure, decrease volume, passive process.

external respiration

exchange of gases between lungs and blood

Gaseous exchange

getting oxygen from the air into the lungs so that it can diffuse into the blood and be transported to the cells of the body, which in other words means the removal of carbon dioxide from the blood.

gaseous exchange in muscles

in the capillary membranes surrounding the muscle, the partial pressure of oxygen is 40mmhg and it is 100mmhg in the blood, this lower partial pressure allows oxygen to diffuse from the blood into the muscles until equilibrium is reached

Effects of smoking on the respiratory system

irritation to the trachea and bronchi cilia is damaged and mucus gets built up which leads to a smokers cough alveoli walls are broken, less diffusion/ gaseous exchange can take place increase in the chance of COPD carbon monoxide in cigarettes attaches to haemoglobin in the blood which means blood will carry less oxygen.

hormonal regulation

just before exercise the brain send impulses down the renal gland which responds and sends adrenaline into the blood ready for the increase in need of oxygen and carbon dioxide.

carbon dioxide diffusion pathway

muscles, blood, alveoli

gaseous exchange in muscles

on the other hand, the partial pressure of carbon dioxide in the blood is lower in the tissues, so diffusion takes place and carbon dioxide moves into the blood to be transported to the lungs.

features of alveoli

one cell thick, excellent blood supply and large surface area so that more diffusion can take place.

expiratory centre

sends out nerve impulses via the intercostal nerve to the expiratory centre to the abdominals and internal intercostals

inspiratory centre

sends out nerve impulses via the phrenic nerve to the inspiratory muscles (diaphragm and external intercostals)

minute ventilation

the amount of air breathed in and out in one minute= number of breaths times tidal volume. big increase during exercise.

inspiratory reserve volume

the amount of air that you can forcibly breath in after a normal breath. decreases during exercise.

Gaseous exchange in alveoli

the bigger the gradient the faster the diffusion will be. oxygen will diffuse from the alveoli into the blood until the pressure in both is equal.

cellular respiration

the metabolic reactions that take place in cells to create energy

What are baroreceptors?

these detects blood pressure in the aorta which increases out breathing rate so increases blood pressure. sympathetic.