Reg Of Respiration

Question 1

What is the higher brain area to regulate Rhythmic breathing

Answer 1

Cerebral cortex

Question 2

Which parts of the brain are the respiratory centre in

Answer 2

Pons and medulla

Question 3

Which types of receptors go to the medulla/ pons (6)

Answer 3

Receptors Eg for pain to hypothalamus

Irritant receptors

Stretch receptors in lungs

Peripheral and central chemoreceptors

Proprioreceptors

Question 4

How do signals get from medulla to inspristory muscles or expiratory muscles

Answer 4

AFFERENT Motor neurones

Question 5

Which types of muscles are involved in inspiration which are attached to motor neurones from medulla

Answer 5

External intercostal

Diaphragm

Question 6

Which types of muscles allow expiration forced

Answer 6

Abdominal muscles

Internal intercostal muscles

Question 7

What system makes up the pons

Answer 7

Pontine respiratory group (PRG)

Question 8

What 3 things makes up the pons PRG

Answer 8

2 pneumotaxic centres

1 apreustic centre

Question 9

What are the 2 medullary neurones

Answer 9

DRG (dorsal)

VRG (ventral)

Question 10

Which medullary neurone is responsible for inspiration

Answer 10

DRG

Question 11

How does the DRG/VRG get inputs to change insp/exp

Answer 11

From craniofacial nerves IX (glossy pharyngeal) and X (vagus)

Which send impulses eg from chemoreceptors

Question 12

How does the DRG for inspiration send impulses to the diaphragm to contract

Answer 12

Down phrenic nerves

Question 13

Which nerves contact the intercostal muscles eg expiratory to contract in inspiration

Answer 13

Thoracic

Question 14

Which complex in the VRG links it to the DRG for rhythmic breathing

Answer 14

Pre botzinger complex

Question 15

What does VRG signalling do

Answer 15

Allow expiration mostly

And affects the pharynx, larynx

Question 16

What happens when DRG neural activity inhibits

Answer 16

Expiration can occur as inspiration muscles like diaphragm relax

Question 17

What do the apreustic centre in the pons do

Answer 17

Promotes inspiration via the DRG and also stimulating the inspiratory neurones eg phrenic

Question 18

The pneumotaxic centres inhibit apreustic stimulation of the DRG , which neurones does it inhibit to stop inspiration

Answer 18

T5 to the external intercostal

Phrenic to the diaphragm

Question 19

Which chemoreceptors are most sensitive to 02 levels

Answer 19

Peripheral chemoreceptors

Question 20

When would peripheral chemoreceptors start to increase ventilation

Answer 20

When levels of o2 are below 60 (usually 100)

Question 21

Where are peripheral chemoreceptors

Answer 21

Aortic arch

Carotid arteries (both internal and external)

Question 22

How do aortic arch chemoreceptors transmit info to the medulla

Answer 22

Via craniofacial nerve IX (glossopharyngeal)

Question 23

How does the carotid artery send impulses to the medulla

Answer 23

Via vagus X nerve

Question 24

What would happen when peripheral (aortic and carotid) chemoreceptors detected o2 low levels below 60

Answer 24

Impulses down the IX and X

Medulla DRG and VRG would be stimulated

Hyperventilation would occur to increase Po2 and decrease Pco2

Question 25

Which cells in the carotid chemoreceptors detect low Po2

Answer 25

Glomus cells

Question 26

What happens in glomus cells to cause impulse for low o2 down to the medulla

Answer 26

Low po2 closes the K channels in glomus cells This causes depolarisation Ca channels can open in depolarisation DA vesicles fuse and released DA binds to receptors on neurones AP sent down vagus to the medulla for hyperventilation

Question 27

Which receptors are better at detecting high pco2

Answer 27

Central chemoreceptors

Question 28

Where are central chemoreceptors found

Answer 28

At the csf / blood brain barrier

Question 29

How can pco2 be detected from the capillaries to the csf but H can’t

Answer 29

Pco2 can diffuse through blood brain barrier

Question 30

How is co2 levels detected in the csf indirectly via central chemoreceptors

Answer 30

They detect HCO3 and H levels from the splitting of carbonic acid when co2 reacts with h20

Question 31

What happens when high co2 senses indirectly via HCO or directly via co2

Answer 31

Impulses sent to medulla from the central chemoreceptors Causes hyperventilation via DRG and VRG

Question 32

How are central chemoreceptors adaptive

Answer 32

After many days of high co2 levels these become normal and hyperventilation stops

Question 33

What happens when low co2 levels are sensed via chemoreceptors

Answer 33

Hypoventilation

Question 34

What causes respiratory alkalosis

Answer 34

Increased ph due to hyperventilation removing co2 This means less co2 present to produce Hco3 and H This increases ph (alkalosis)

Question 35

What causes respiratory acidosis

Answer 35

Hypoventilation Increased co2 levels More co2 into HCO and H H reduces ph Causes respiratory acidosis

Question 36

What is metabolic acidosis

Answer 36

The increase of acids / decrease in ph due to exercise lactic acid rather than co2 levels

Question 37

Which chemoreceptors deal with metabolic acidosis (high co2)

Answer 37

Peripheral chemoreceptors

Question 38

Why aren’t central chemoreceptors affected by ph

Answer 38

They can’t sense ph as H can’t pass the blood brain barrier to the csf

Question 39

What happens when peripheral chemoreceptors sense metabolic acidosis via exercise

Answer 39

They send impulses down the vagus or IX to medulla Cause hyperventilation Reduces pco2 which counteracts the low ph

Question 40

Can peripheral sense co2 as much as central chemoreceptors?

Answer 40

No, weak stimuli sent from aortic or carotid

Question 41

What are stretch receptor connected to the DRG and VRG for

Answer 41

when inflation of lungs is too high during inspiration They cause inactivation of the DRG and activation of expiration via VRG

Question 42

What are irritant receptors connected to the medulla for

Answer 42

Detect stimuli like allergens or cold air to cause a cough

Question 43

Which nerve has impulses sent from irritant receptors

Answer 43

Vagus X

Question 44

Explain how a cough is produced from irritant receptors

Answer 44

When triggered via cold air etc Impulse sent down vagus to DRG DRG sends impulses down phrenic and thoracic to intercostal and diaphragm for inspiration This reduces pleural cavity pressure Air enters The larynx and glottis close after Abdomen muscles and expiratory muscles contract via VRG to cause expiration Glottis and larynx open Air is forced out fast and down narrow bronchi and trachea as they are collapsed

Question 45

What are proprioreceptors for

Answer 45

They increase Po2 and decrease pco2 before exercise has begun to meet demands Via induction of the DRG and VRG = hyperventilation