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respiratory system - Coggle Diagram
respiratory system
gaseous exchange
in the blood vessels = the blood arrives through the capillaries that surround the alveoli is said to be deoxygenated, as oxygen has been used up at the tissues for respiration, and the waste product carbon dioxide is being carried in the blood
in the alveoli/ lungs = the air inspired into the alveoli is oxygen rich at sea level and has very low levels of carbon dioxide. this presents gases either side of the double membrane that have different pressures
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diffusion = gaseous exchange is the movement of gases across a membrane is achieved by diffusion
- gas will diffuse from an area of high partial pressure to an area of low partial pressure
- the difference between high and low partial pressure is known as the diffusion gradient
- the steeper the diffusion gradient, the greater the rate of gaseous exchange
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respiratory regulation
Respiratory control centre = a control centre in the medulla oblongata responsible for respiratory regulation
- it receives information from the sensory nerves and sends direction through motor nerves to change the rate of muscle contraction
Inspiratory centre = stimulates inspiratory muscles to contract at rest and during exercise
Expiratory centre = inactive at rest but will stimulate additional expiratory muscles to contract during exercise
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at rest
- the inspiratory centre is responsible for the rhythmic cycle of breathing
- nerve impulses are generated and stimulate the inspiratory muscles causing them to contract via: the intercostal nerve to the external intercostals, and phrenic nerve to the diaphragm
during exercise
- an increase in breathing depth is needed to meet the demand rates of O2 delivery and CO2 removal
- sensory nerves relay information to the RCC, response by both the inspiratory and expiratory centre
- the RCC can also pick up on chemical changes
chemoreceptors = picks up on the increase/decrease in blood acidity, CO2 concentration and O2 concentration
Neural stimuli:
thermoreceptors = inform the body on an increase in blood temperature
proprioceptors = inform the body on motor movement in muscles and joints
baroreceptors = informs the body of blood pressure and lung inflation
two main functions
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Gaseous exchange:
- external respiration = the movement of oxygen into the blood stream and carbon dioxide into the lungs
- internal respiration = the release of oxygen to respiring cells for energy production and collection of waste products
structure
1) air is drawn into the nose and travels down the trachea
- the trachea has a mucous membrane which moistens, warms and filters the air before going into the lungs
2) the trachea then divides into the left and right bronchi
3) the bronchi is then divided into smaller bronchioles which hold the alveoli at the end
4) the alveoli is a single cell thick and carries the most amount of capillaries in the body
- this is where gaseous exchange takes place
- oxygen moves from the alveoli into the blood stream and carbon dioxide moves from the bloodstream into the alveoli to be expired
gas transport
Blood = 45% cells, 55% plasma
Oxygen can be transported in two ways:
- haemoglobin (97%)
- blood plasma (3%)
Carbon dioxide can be transported in three ways:
- dissolved in water and carried as carbonic acid (70%)
- haemoglobin (23%)
- blood plasma (7%)
the Bohr shift
- a move in the oxyhaemoglobin dissociation curve to the right caused by increased acidity in the blood stream
during exercise, muscle tissue will:
- increase in temperature
- increases the production of carbon dioxide
- increase production of lactic acid and carbonic acid
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minute ventilation
- the volume of air inspired or expired per min
- breathing rate x tidal volume = minute ventilation
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