Control of lung anatomy

Question 1

What 4 nuclei in the medulla controlling respiration?

Answer 1

dorsal

ventral
apneustic
pneumotaxic

Question 2

dorsal?

Answer 2

Inspiratory centre
Main ‘controller’ of inspiration
Set the ‘rate’

Question 3

ventral?

Answer 3

Expiratory centre
Inactive during quiet breathing
Inhibit apneustic centre

Question 4

Apneustic centre

Answer 4

Stimulates activity in DRG

Inhibited by pulmonary afferent

Question 5

Pneumotaxic centre

Answer 5

The ‘inspiratory off switch’

Regulates depth & frequency

Question 6

What inhibits and stimulates the dorsal centre?

Answer 6

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

Question 7

What innervates diapragm, intercoastal muscles, ribs muscles

Answer 7

C 3,4,5 =phenic nerve

Question 8

What is the difference between normal circulation and the blood brain barrier?

Answer 8

Normal - H2O filled gap junction but continous capillaries

BBB - tight junction between continuos capillaries

• charged / large molecules cannot pass BBB

Question 9

Carbon dioxide is highly lipid soluble so?

Answer 9

Can pass into the CSF it reacts to create HCO3- which dissociates into H+ which can interact with fibres in medulla

Question 10

What receptors are in the trachea?

Answer 10

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

Question 11

What are stretch receptors for in the bronchi?

Answer 11

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

Question 12

What are J-receptors in the bronchi for?

Answer 12

Sensitive to oedema and pulmonary capillary engorgement

Increases breathing frequency

Question 13

What happens when you hold your breath?

Answer 13

Carbon dioxide increases oxygen decreases

CO2 passes BBB to stimulate dorsal nuclei for inhalation before you reach the threshold for O2 blackout

Question 14

Understand pH mechanics and equation?

Answer 14

Refer back to PPT

Question 15

What is Alkalaemia?

Answer 15

Refers to high-than-normal pH of blood

Question 16

What is Acidaemia?

Answer 16

Refers to lower-than-normal pH of blood

Question 17

What is Alkalosis

Answer 17

Describes circumstances that will decrease [H+] and increase pH

Question 18

What is Acidosis?

Answer 18

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

Question 19

What allows a rapid response to change blood pH?

Answer 19

Changes in ventilation can stimulate a RAPID compensatory response to change CO2 elimination and therefore alter pH

Question 20

What allows a slow response to change blood pH?

Answer 20

Changes in HCO3- and H+ retention/secretion in the kidneys can stimulate a SLOW compensatory response to increase/decrease pH

Question 21

Where are peripheral cheoreceptors found?

Answer 21

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

Question 22

How can emotional changes lead to ventilation changes?

Answer 22

Higher brain centres and special senses lead to emotional response which are close to the respiratory control centre

Question 23

How is exercise linked to ventilation?

Answer 23

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

Question 24

What are the effects of skin afferents on ventilation?

Answer 24

’ cold shock response ‘

Causes inspiratory gasp/hyperventilation

central reflex of deep breathing so cannot hold breath in cold water