1.2 Flashcards
The reason why our bodies require a continuous supply of oxygen
To break down food to release energy (respiration)
The gaseous waste product of respiration
CO2
The main components/features of the respiratory system
Ventilation, External Respiration, Transport of gases, Internal respiration, Cellular respiration
Ventilation definition
Getting air into and out of the lungs
External respiration definition
Gaseous exchange between the lungs + blood
Internal respiration definition
Exchange of gases between the blood in the capillaries + the body cells
Cellular respiration
The metabolic reactions + processes that occur in a cell to obtain energy from fuels like glucose
The passage of air through the respiratory system (from the outside)
Nostrils/nose/mouth, pharynx, larynx, trachea, bronchi, secondary bronchi, bronchioles, alveoli
What occurs at the alveoli
External respiration via diffusion
Diffusion
The movement of gas molecules from an area of high concentration/partial pressure to an area of low concentration/partial pressure
How the structure of alveoli aids diffusion
The thin walls are one cell thick - means a short diffusion pathway - there’s only 2 layers for the oxygen to pass through to reach the blood,They’re surrounded by an extensive capillary network - increases blood supply, A large surface area due to millions of them - increases rate of diffusion of oxygen
What does a greater concentration gradient do to the rate of diffusion
It increases it
How air is drawn into the lungs during inspiration
The pressure in the lungs is decreased as the volume of the thoracic cavity increases due to the contraction/relaxation of muscles
How air is forced out of the lungs in expiration
The pressure within the lungs increases as the volume of the thoracic cavity decreases due to the contraction/relaxation of muscles
Muscles which contract during inspiration at rest (inspiratory muscles)
Diaphragm + external intercostals
Muscles which contract during inspiration during exercise
Diaphragm, external intercostals, sternocleidomastoid, scalenes + pectoralis major
The type of process of expiration at rest
Passive
Muscles which relax during expiration
Diaphragm + external intercostals
Muscles which contract when you expire during exercise
Internal intercostals + abdominals
The movement of the diaphragm during inspiration
It contracts - so is pulled flat
The movement of the diaphragm during expiration
It relaxes - so rises to a dome-shaped position
The movement of the ribcage during inspiration
It moves upwards + outwards
The movement of the ribcage during expiration
It falls (moves inwards + downwards)
Tidal volume
The volume of air breathed in or out per breath
Inspiratory reserve volume (IRV)
The volume of air that can be forcibly inspired after a normal breath
Expiratory reserve volume (ERV)
The volume of air that can be forcibly expired after a normal breath
Residual volume
The volume of air that remains in the lungs after maximal expiration
Minute ventilation
The volume of air breathed in or out per minute
Expiration
Moving air out of the lungs
Inspiration
Taking air into the lungs
The effect of exercise on tidal volume
It increases it
Why there is always a residual reserve volume
There’s always some air in the alveoli, bronchi + trachea which are permanently held open
The effect of exercise on IRV
It decreases it
The effect of exercise on ERV
It slightly decreases it
The effect of exercise on minute ventilation
It increases it by a lot
The effect of exercise on residual volume
There’s no effect
A spirometer
A device used to measure the volume of air inspired + expired by the lungs
Spirometer trace
A chart produced by measurements from a spirometer
Partial pressure
The pressure exerted by an individual gas when it exists within a mixture of gases
The main examples of gaseous exchange in the respiratory system
Getting oxygen into the lungs so it can diffuse into the blood for transportation to body cells + the removal of CO2 from the blood
The main terms used when describing gaseous exchange
Partial pressure + diffusion
The partial pressures of oxygen in different parts of the respiratory system and why they’re in that order
Highest in the air, then get progressively lower as it moves from the alveoli to the blood + then to body cells (tissues) as gases flow from an area of high pressure to an area of low pressure
Concentration/diffusion gradient
It’s the difference between partial pressures
What does the concentration gradient explain
How gases flow from an area of high concentration to an area of low concentration
Why the partial pressure of oxygen in the capillary blood vessels is lower than that of the alveoli
Oxygen is removed from the blood in the capillaries by working muscles
The diffusion pathway of oxygen
Alveoli then blood then muscles
The diffusion pathway of CO2
Muscles then blood then alveoli
Diffusion occurs until…
The pressures of the gases are even so equilibrium is reached
The partial pressure of CO2 in the blood entering the alveolar capillaries compared to that of the alveoli
The blood in the alveolar capillaries has a higher partial pressure of CO2 than that of the alveoli
The 3 factors involved in the regulation of pulmonary ventilation
Neural, chemical + hormonal control
Pulmonary ventilation
Breathing
Neural control involves…
The brain + nervous system
Chemical control is concerned with…
Blood acidity
How the neural + chemical control systems work together to regulate breathing
When blood acidity (CO2 concentration) is high in the blood, the medulla oblongata is stimulated + sends impulses through the nervous system to increase breathing
The 2 systems of the nervous system which control breathing
Sympathetic + parasympathetic
The effect of the sympathetic nervous system on breathing
It prepares your body for exercise by increasing breathing rate
The effect of the parasympathetic nervous system on breathing
It decreases breathing rate
Why the 2 nervous systems cause opposite effects
They use different activating chemicals
Where the respiratory centre is located
In the medulla oblongata
What the medulla oblongata controls in relation to breathing
Depth + rate of breathing
The control systems used by the medulla oblongata to control breathing
The neural + chemical control systems
The 2 main areas of the respiratory centre of the medulla oblongata
Inspiratory + expiratory centre
The role of the inspiratory centre of the medulla oblongata
It controls inspiration + expiration
The role of the expiratory centre of the medulla oblongata
Stimulating the expiratory muscles during exercise
How the inspiratory centre works
It sends out nerve impulses via the phrenic nerve to the inspiratory muscles (diaphragm + external intercostals) + causes them to contract - they’re stimulated for about 2 seconds + then the impulses stop to allow passive expiration to occur due to the elastic recoil of the lungs
What the respiratory centre responds to
Impulses sent by receptors
Why the blood becomes acidic during exercise
There’s an increase in lactic acid production + the plasma concentration of CO2
How changes in blood acidity are detected
By using chemoreceptors
Where chemoreceptors are found
In the carotid artery + aortic arch
How chemoreceptors respond to an increase in blood acidity
They send impulses to the inspiratory centre to increase ventilation until blood acidity returns to normal.
How the expiratory centre works
It sends impulses down the intercostal nerve to stimulate more inspiratory muscles - causes an increase it rate, depth + rhythm of breathing
Muscles stimulated by the expiratory centre
The sternocleidomastoid, scalenes + pectoralis minor
The different receptors involved in control of breathing
Baroreceptors, proprioceptors, chemoreceptors + stretch receptors
The type of receptor which sends impulses to the expiratory centre
Stretch receptors
The types of receptors which send impulses to the inspiratory centre
Chemoreceptors, baroreceptors + proprioceptors
What are proprioceptors
Sensory receptors which detect movement
Where are proprioceptors located
In joints + muscles
What do baroreceptors detect
A decrease in blood pressure during exercise
Where are baroreceptors found
In the aorta + carotid arteries
What do stretch receptors prevent
Over-inflation of the lungs
How exercise affects the amount by which the lungs are stretched
It increases it
How do the stretch receptors prevent over inflation of the lungs
They send impulses to the expiratory centre to stimulate the expiratory muscles so expiration occurs
The hormone involved in hormonal regulation of pulmonary ventilation
Adrenaline
What type of hormone is adrenaline
A stimulant
Where is adrenaline made
The adrenal gland in the kidneys
What stimulates the release of adrenaline
Impulses from the brain during exercise and in anticipation of exercise (the increased need for oxygen + removal of CO2)
The physical effect of the release of adrenaline in anticipation of exercise
Increased breathing rate
The effect of smoking on the trachea + bronchi
Causes irritation
How smoking leads to a smokers cough
Smoke damages the ciliated cells lining the trachea, bronchi + bronchioles + the cilia on them which prevents them being able to push mucus out of the lungs - causes excess mucus in lung passages so smokers cough to try to remove the mucus from their lungs
Cells which have cilia on their surfaces
Ciliated cells
What are cilia
Microscopic, hair-like projections
The role of cilia
To sweep away fluids and particles
COPD (chronic obstructive pulmonary disease)
A chronic + debilitating disease + covers a collection of disease
An example of a COPD disease
Emphysema
The main cause of emphysema
Smoking
What is emphysema
A long-term progressive disease of the lungs
A symptom of emphysema
Shortness of breath
How smoking damages alveoli
It causes the walls of the alveoli to break down so the alveoli join together - forms larger air space - reduces efficiency of gas exchange - increases the risk of COPD
How smoking affects oxygen transport
Carbon monoxide from smoke combines with haemoglobin in red blood cells more readily than oxygen - reducing the blood’s oxygen carrying capacity - causing breathlessness
