Respiratory System - Applied Anatomy and Physiology (Paper 1) Flashcards
Why do we need oxygen
To produce energy
What is respiration
The taking in of oxygen and removal of carbon dioxide
What is ventilation
Getting air into and out of the lungs
What is external respiration
Gaseous exchange between the lungs and blood
What is internal respiration
Exchange of gases between the blood in the capillaries and in body cells
What is cellular respiration
The metabolic reactions and processes that take place in a cell to obtain energy from fuels such as glucose
What is diffusion
The movement of gas molecules from an area of higher partial pressure to an area of lower partial pressure
What is gaseous exchange
The movement of oxygen from the air into the blood, and carbon dioxide from the blood into the air
What is crucially needed during inspiration
The pressure needs to be lower in the lungs than in the atmosphere. Done by increasing the volume in the thorax due to the muscles in the thorax contracting
What is needed for expiration
The pressure has to be higher in the lungs than the atmosphere. Done by decreasing volume of thorax due to the relaxation of inspiratory muscles in the thorax
What muscles are used during breathing at rest when inspiring
- diaphragm
- external intercostal muscles
What muscles are used during breathing at rest when expiring
- diaphragm relaxes
- external intercostals relax
What is tidal volume
The volume air breathed in or out per breath
What is inspiratory reserve volume
The volume of air that can forcibly be inspired after a normal breath
What is expiratory reserve volume
Volume of air that can be forcibly expired after a normal breath
What is minute ventilation
The volume of air inspired or expired per minute
How is minute ventilation calculated
Number of breathes (per min) x tidal volume
Why does tidal volume increase when exercising
More oxygen is required so we start breathing deeper. This means the tidal volume increases. This happens because we are using more of our inspiratory and expiratory reserve volumes.
What is residual volume
The amount of air that remains in the lungs after maximal expiration
What happens to tidal volume during exercise
Increases
What happens to inspiratory reserve volume during exercise
Decreases
What happens to expiratory volume reserve during exercise
Slight decrease
What happens to residual volume during exercise
Stays the same
What happens to minute ventilation during exercise
Big increase
What is a spirometer
A device that is used to measure the volume of air inspired and expired by the lungs
What is partial pressure
The pressure exerted by an individual gas when it exists within a mixture of gases
Why is the partial pressure in the alveoli (100mmHg) higher than in the blood (40mmHg)
This is because oxygen has been removed by the working muscles so it’s concentration in the blood is lower and therefore so is it’s partial pressure
What is the difference in partial pressure referred as
Concentration gradient
What three factors are involved in the regulation of pulmonary ventilation (breathing) during exercise
- neural control
- chemical control
- hormonal control
What is neural control
Involves the brain and the nervous system to regulate breathing
What is chemical control
Control concerned with the blood acidity to regulate breathing
What happens when the blood acidity is high
The brain is informed and it sends impulses through the nervous system to increasing breathing
What two systems controls pulmonary ventilation (breathing)
- sympathetic nervous system
- parasympathetic nervous system
what does the respiratory centre of the medulla oblongata control
rate and depth of breathing and uses neural and chemical control
what would stimulate the respiratory centre to increase respiratory rate
an increase in concentration of carbon dioxide
The respiratory centre has two main areas. What are they and what are they responsible for
- Inspiratory centre, responsible for inspiration and expiration
- Expiratory centre, stimulates the expiratory muscles during exercise
The inspiratory centre sends outs what via the phrenic nerve
Sends out nerve impulses to cause inspiratory muscles to contract
How long does the impulses from the inspiratory centre act for
Approximately 2 seconds then the impulses stop and passive expiration occurs due to the elastic recoil of the lungs
What does the respiratory centre mainly respond to
Changes in blood chemistry
What factors affect neural control of breathing
- mechanical factors
- baroreceptors
- stretch receptor
How do stretch receptors affect neural control of breathing during exercise
during exercise lungs are stretched more. These receptors prevent over-inflation of lungs by sending impulses to the expiratory centre and then down the intercostal nerve to the expiratory muscles so expiration occurs
How do baroreceptors affect neural control of breathing during exercise
which detect increases and decreases of pressure in the aorta and carotid arteries and results in an increase in breathing rate
How do mechanical factors affect neural control of breathing during exercise
Factors such as proprioceptors located in joints which provide feedback to the respiratory centre to increase breathing during exercise
What is cilia
Microscopic hair-like projections that help to sweep away fluids and particles
What is COPD
Chronic obstructive pulmonary disease
A chronic disorder and debilitating disease, the name is collective for a number of diseases such as emphysema
What is emphysema
A long term progressive disease of the lungs that causes shortness of breath caused by smoking
What does smoking cause damage to
- The alveoli as their walls break down and join together formimg larger air spaces than normal which reduces the efficiency of gaseous exchange.
- smoking affects transport oxygen as carbon monoxide from cigarettes combines to the haemoglobin in red blood cells much more readily than oxygen. This reduces the oxygen carrying capacity of the blood
In gaseous exchange between muscles why is it important that the partial pressure of oxygen is lower in the tissues than in the blood
- so diffusion can occur
- the ppO2 in the tissues is 40mmHg and the ppO2 in the blood is 100mmHg
- this lower ppO2 allows O2 to diffuse from the blood into the muscle until equilibrium
- the oxygen is then used in respiring cells
In gaseous exchange between the muscles, why is it important that the ppCO2 is lower in the blood than the tissues
- so diffusion can occur to exchange CO2 between the blood and tissues
- the ppCO2 in tissues is 46mmHg, the ppCO2 in the blood is 40mmHg
- the blood then transports the CO2 to the lungs to be expired
