Control of lung anatomy Flashcards
What 4 nuclei in the medulla controlling respiration?
dorsal
ventral
apneustic
pneumotaxic
dorsal?
Inspiratory centre
Main ‘controller’ of inspiration
Set the ‘rate’
ventral?
Expiratory centre
Inactive during quiet breathing
Inhibit apneustic centre
Apneustic centre
Stimulates activity in DRG
Inhibited by pulmonary afferent
Pneumotaxic centre
The ‘inspiratory off switch’
Regulates depth & frequency
What inhibits and stimulates the dorsal centre?
P inhibits
A stimulates
- only D or V can be stimulated at one point so they can inhibit each other too. V also inhibited A to stop it from stimulating D
What innervates diapragm, intercoastal muscles, ribs muscles
C 3,4,5 =phenic nerve
What is the difference between normal circulation and the blood brain barrier?
Normal - H2O filled gap junction but continous capillaries
BBB - tight junction between continuos capillaries
- charged / large molecules cannot pass BBB
Carbon dioxide is highly lipid soluble so?
Can pass into the CSF it reacts to create HCO3- which dissociates into H+ which can interact with fibres in medulla
What receptors are in the trachea?
Irritant receptors :
Afferent receptors embedded within and beneath airway epithelium
Leads to cough: which involves forceful expiration against a closed glottis with sudden glottal opening & high velocity expulsion of air
What are stretch receptors for in the bronchi?
Excessive inflation of lungs activates pulmonary stretch receptors
Afferent signals to respiratory centres inhibit DRG and apneustic centre and stimulate pneumotaxic VRG
Inspiration inhibited & expiration stimulated
What are J-receptors in the bronchi for?
Sensitive to oedema and pulmonary capillary engorgement
Increases breathing frequency
What happens when you hold your breath?
Carbon dioxide increases oxygen decreases
CO2 passes BBB to stimulate dorsal nuclei for inhalation before you reach the threshold for O2 blackout
Understand pH mechanics and equation?
Refer back to PPT
What is Alkalaemia?
Refers to high-than-normal pH of blood
What is Acidaemia?
Refers to lower-than-normal pH of blood
What is Alkalosis
Describes circumstances that will decrease [H+] and increase pH
What is Acidosis?
Describes circumstances that will increase [H+] and decrease pH
- An acidosis will need an alkalosis to correct
An alkalosis will need an acidosis to correct
What allows a rapid response to change blood pH?
Changes in ventilation can stimulate a RAPID compensatory response to change CO2 elimination and therefore alter pH
What allows a slow response to change blood pH?
Changes in HCO3- and H+ retention/secretion in the kidneys can stimulate a SLOW compensatory response to increase/decrease pH
Where are peripheral cheoreceptors found?
Positioned near the carotid baroreceptors (sensitive to changes in blood pressure)
- in structures called carotic bodies - found in aortic arch before blood goes to the brain
How can emotional changes lead to ventilation changes?
Higher brain centres and special senses lead to emotional response which are close to the respiratory control centre
How is exercise linked to ventilation?
Efferents from primary motor cortex to gross skeletal musculature partly innervate medulla
Proprioceptive afferents from muscle spindles & golgi tendon organs innervate medulla on way to brain
What are the effects of skin afferents on ventilation?
’ cold shock response ‘
Causes inspiratory gasp/hyperventilation
central reflex of deep breathing so cannot hold breath in cold water
