Respiratory Flashcards
(47 cards)
Mechanics of breathing for inspiration at rest
Diaphragm actively contracts and flattens and External intercostal muscles actively contract
Which moves the ribcage and sternum upwards and outwards
Thoracic Cavity Volume increases
Lung air pressure decreases below atmospheric air (outside)
Air rushes into lungs
Mechanics of breathing for expiration at rest
Diaphragm passively relaxes and is pushed upwards and external intercostal muscles passively relax
Which moves ribcage and sternum downwards and inwards
Thoracic cavity volume decreases
Lung air pressure increases above atmospheric air (outside)
Air pushed out of lungs
Mechanics of breathing for inspiration at exercise
Diaphragm actively contracts harder than at rest and flattens with more force and External intercostals actively contract harder than at rest. Sternocleidomastoid contracts, scalenes contract and pectoralis minor actively contract
Which moves the ribcage and sternum upwards and outwards more than at rest
Thoracic Cavity Volume increases more than at rest
Lower air pressure in lungs than at rest
More air rushes into lungs than at rest
Mechanics of breathing for expiration at exercise
Diaphragm relaxes and is pushed upwards with more force and External intercostal muscles actively relax. Internal intercostals actively contract, Rectus abdominis/ obliques actively contract
Which moves ribcage and sternum downwards and inwards more than at rest
Thoracic cavity volume decreases more than at rest
Higher air pressure in lungs than at rest
More air pushed out of lungs than at rest
What is the respiratory control centre
The RCC receives information from sensory nerves to change the rate at which the respiratory muscles contract. It is located in the medulla oblongata.
There are two centres within the RCC
- The inspiratory centre (IC)
- The expiratory centre (EC)
When are the inspiratory and expiratory centre are actioned?
The IC stimulates inspiratory muscles to contract at rest and during exercise
The EC is inactive at rest, but will stimulate additional expiratory muscles to contract during exercise to force air out when expiring.
How are the muscles stimulated at rest and what does this cause
Nerve impulses are generated
Stimulate the inspiratory muscles causing them to contract via the…
Intercostal nerve which stimulates the external intercostal muscles
The phrenic nerve which stimulates the diaphragm
This causes the thoracic cavity volume to increase which lowers the lung air pressure which means air will be inspired.
After approximately 2 seconds – stimulation will stop and the inspiratory muscles will relax passively
How are the muscles stimulated during exercise
There is a rising demand for O2 and CO2 removal therefore, breathing rate and depth of breathing must be increased.
Sensory nerves relay the information to the RCC where a response will be initiated by the IC and the EC
What are the 4 sensory nerves and what do they detect
Chemoreceptors detect an increase in CO2/ acidity/ lactic acid or detect a decrease in O2/ pH
Proprioceptors detect an increase in motor activity or movement
Baroreceptors detect and increase in pressure and stretch of lung walls and potential infection
Thermoreceptors detect an increase in blood temperature
Inspiratory centre
Information is sent to the RCC (located in the medulla oblongata)
This stimulates the IC
Increased stimulation or force of contraction of diaphragm via phrenic nerve
Increased stimulation or force of contraction of external intercostals via the intercostal nerve
Recruitment or stimulation of additional inspiratory muscles e.g. SCM or scalenes or pectoralis minor
Causes rest of mechanics of breathing
Expiratory centre
EC stimulated by baroreceptors
Expiration becomes active
Recruitment of expiratory muscles e.g. internal intercostals/ obliques / rectus abdominis
This causes rest of mechanics of breathing
What are the 2 sites of gaseous exchange
Internal site - Between the muscles and the capillaries (bloodstream)
External site - Between the alveoli and the capillaries (bloodstream)
External site - ppO2
The ppO2 in the alveoli is high and the ppO2 in the capillary blood is low. Oxygen diffuses down the diffusion gradient from the alveoli into the capillary blood
What is the order of neural control
Chemoreceptors, proprioceptors and thermoreceptors inform the IC
To increase stimulation of diaphragm via the phrenic nerve and the external intercostals via the intercostals nerve to contract with more force than at rest
The IC recruits additional inspiratory muscles e.g. scalenes and SCD to contract
Allowing the thoracic cavity to have a greater increase in volume than at rest. This increases the depth of inspiration
External site - ppCO2
The ppCO2 in the capillary blood is high and the ppCO2 in the alveoli is low. The CO2 diffuses down the concentration gradient from capillary blood into the alveoli
Internal site - ppO2
The ppO2 in the capillary bed is high and the ppO2 in the muscle cell is low. The O2 diffuses down the concentration gradient from capillary bed into the muscles
Internal site - ppCO2
The ppCO2 of the capillary bed is low and the ppCO2 of the muscle cells is high. CO2 diffuses down the concentration gradient from the muscles to the capillary
Changes at the External site during exercise
Steeper gradient due to faster diffusion
PPO2 in alveoli = higher
PP02 in capillary blood = lower
PPCO2 in capillary blood = higher
PPCO2 in alveoli = lower
Changes at the Internal site during exercise
PPO2 in capillary blood = higher
PPO2 in muscle cells = lower
PPCO2 in muscle cells = higher
PPCO2 in capillary bed = lower
What is the oxygen dissociation curve
Oxygen dissociation curve shows the relationship between dissociation of oxygen within respiratory tissues.
Dissociation is the release of oxygen from haemoglobin for gaseous exchange
Also takes into account the pp02 against how saturated the haemoglobin is.
General overview of shifting dissociation curve
The oxygen dissociation curve can be shifted right or left by a variety of factors. A right shift indicated decreased oxygen affinity of haemoglobin allowing more oxygen to be available to the tissues
What are the factors affecting the oxygen dissociation curve
pH
CO2
Temperature
Organic Phosphates
O2
How does pH affect oxygen dissociation curve
Decrease pH shifts the curve right and increase pH shifts curve left.
Due to higher hydrogen ion concentration causes alteration in amino acid residues that stabilises deoxyhaemoglobin in the T state that has a lower affinity for oxygen.
How does CO2 affect oxygen dissociation curve
Decrease CO2 shifts curve left and increase CO2 shifts curve right.
Accumulation of CO2 causes carbamino compounds to be generated which bind to oxygen and form carbaminohaemoglobin which stabilises deoxyhaemoglobin in the T state
Accumulation of CO2 causes increase H+ ions concentrations and decrease in pH will shift curve right