Ventilation Control

Question 1

What stimulation does ventilation control need for inspiration

Answer 1

stimulation of skeletal muscle

Question 2

What two nerves stimulate skeletal muscle

Answer 2

Phrenic

Intercostal

Question 3

What does the phrenic nerve supply

Answer 3

the diaphragm

Question 4

What are the two respiratory centres in the brain

Answer 4

Pons and medulla

Question 5

What is ventilation control dependent on

Answer 5

signals from the brain

Question 6

What would happen if the spinal chord was severed above c3 - c5

Answer 6

breathing would cease

As supply the diaphragm

Question 7

What does dorsal respiratory group control

Answer 7

muscles of inspiration contractions

Question 8

What does the ventral respiratory group control

Answer 8

Muscles of expiration and some inspiratory to pharynx, larynx and tonuge

Question 9

What does the ventral respiratory do to the pharynx, larynx and tongue

Answer 9

maintain the tone of the muscle to ensure patency

Question 10

What is the function of the respiratory centres

Answer 10

set automatic rhythm of breathing

adjust the rhythm in response to a stimuli

Question 11

What is the automatic rhythm of breathing co-ordinated by

Answer 11

firing of smooth muscle

Action potential in then dorsal respiratory group

Question 12

What four factors can modulate the rhythm of breathing

Answer 12

Emotion
Voluntary override
Mechano sensory input from the thorax
Chemical composition of the blood

Question 13

Where does emotion come from

Answer 13

Via the limbic system in the brain

Question 14

When does the mechno sensory input from the thorax

Answer 14

as a safety mechanism performs a stretch reflex to prevent over inflamation from the lungs

Question 15

What makes up the chemical composition in the blood

Answer 15

CO2, pH, and O2

Question 16

What detects chemical composition

Answer 16

chemoreceptors

Question 17

What is the most significant input in altering the rhythm of breathing

Answer 17

chemical composition

Question 18

Where is the central chemoreceptors located

Answer 18

In the medula

Question 19

Where is the peripheral chemoreceptors located

Answer 19

carotid (neck) and aortic bodies

Question 20

What out out of the two receptors is the primary ventilation drive

Answer 20

Central

Question 21

What does central chemoreceptors respond directly to?

Answer 21

CO2 increasing [H+] in the CSF around the brain

Question 22

What triggers the raised [H+] levels in the CSF

Answer 22

raised PCO2 levels crossing across the blood brain barrier increasing the CSF [H+] levels

Question 23

Why cant CO2 directly cross the blood brain barrier

Answer 23

its impermeable

Question 24

How much does a 10% increase in PCO2 levels increase minute ventilation, and why is this

Answer 24

100%
The body is extremely sensitive to CO2
Linear relationship

Question 25

When arterial PCO2 drops what happens to the CSF [H+]

Answer 25

decreases - HYPERVENTILATION

Question 26

What do the peripheral chemoreceptors respond to

Answer 26

the H+ in the plasma and PO2

Question 27

When will peripheral chemoreceptors be stimulated

Answer 27

When PO2 levels fall below 60mmHg - hypoxic drive

Question 28

When is peripheral chemoreceptors more commonly stimulated

Answer 28

In people with a hypoxic drive

Question 29

How does H+ increase, increase ventilation

Answer 29

as H+ increase is accompanied by an increase in PCO2 (equation swings left)

Question 30

Can you override involuntary stimuli such as arterial PCO2?

Answer 30

No

Question 31

What are examples of ways you can control your breathing in voluntary override

Answer 31

Breath holding hyperventilation Breathing in high levels of CO2

Question 32

What is the result of breathing in high levels of CO2

Answer 32

increase PCO2, Partial pressure of CO2 has a small gradient therefore the overall partial pressure gradient is imparied

Question 33

What neural pathway allows a control over breathing

Answer 33

cerbral cortex to respiratoty motor neurons

Question 34

When in breathing inhibited

Answer 34

when swallowing to avoid aspiration of food

Question 35

Why do you expire after you swallow

Answer 35

to dislodge any food particles

Question 36

What is the affect of Barbiturates and opiods, gaseous anaesthetics have on the respiratory system (e.g. NO2)

Answer 36

``` depress peripheral chemoreceptors breath shallower (decrease tidal volume) and faster (increase respiratory rate) ```

Question 37

When would nitrous oxide cause you problems

Answer 37

if you are having an hypoxic drive -already low on oxygen

Question 38

When does the central pathway no longer become you primary drive

Answer 38

when you experience type 2 reparatory failure

Question 39

Why wouldnt you give pure oxygen to someone on hypoxic drive

Answer 39

as Oxygen needs have been satisfied and you stop breathing, retaining CO2 then ya die