Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Respiratory System > 12. Control of Breathing - Asleep > Flashcards

12. Control of Breathing - Asleep Flashcards

1
Q

What is apnoea and the apnoeic threshold?

A
  • Apnoea - cessation of breathing

* Apnoeic threshold - threshold over which CO2 level has to be to make sure we breath

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the difference between sleep and other non-responsive states (e.g. coma)?

A

Sleep is reversible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What do you use to measure sleep and what is the activity when awake?

A
  • Electroencephalogram (EEG)

* Awake - high frequency, low voltage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which stage is deep sleep?

A

Stage 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When do you dream?

A

• During REM sleep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens to muscle activity when you sleep?

A

Postural and ocular muscle activity falls

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which muscles are spared the functional paralysis during REM sleep?

A
  • Eye muscles
  • Diaphragm

(however it is still more difficult to breath during REM sleep)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe a hypogram in a healthy adult

A
  • Fall asleep and go up to Stage 4 (deep sleep)
  • After 90 minutes, REM sleep
  • Amount of deep sleep decreases and REM sleep increases as you go through the night
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does the level of blood gas differ in a sleep cycle with a patient who has difficulty breathing?

A

Blood gases different at the start compared to the end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What activity is activated if you suddenly breath in deeply?

A
  • Stretch receptor activity directly from the lungs
  • Chemosensitivity from the gases in the deep breath
  • Both influence the respiratory centre
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the 2 ways in which breathing is normally controlled?

A
  • Brainstem - reflex/automatic
  • Cortex - voluntary/behavioural

(chemosensitivity can be overridden by behavioural control)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which system does emotional control of breathing come from?

A

Limbic system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is breathing controlled during sleep?

A

• Brainstem
• No cortical control (motor cortex)
• Some input from the cortex unless you’re in deep sleep
- area in control of voluntary breathing, between shoulders and trunk, can be seen on PET scan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which area of the brainstem is responsible from the reflex control of breathing?

A
  • Rostral Ventrolateral medullary surface
  • Near the CSF
  • [H+] in the CSF detectable by respiratory nuclei, changing the firing rate (determined by PCO2)
  • Cluster of respiratory nuclei = Pre-Botzinger complex (vital for breathing)
  • Reciprocal inhibition - when one set fires, the other doesn’t
  • Also have early and late firing neurones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does breathing and blood gas change when sleeping?

A
  • Less input from respiratory centres
  • 10% reduction in ventilation
  • Shallower breathing (350mL, not 500mL)
  • Same breathing rate
  • Little change in SaO2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What gas levels drive your breathing?

A

More PCO2, not PO2

17
Q

What happens to SaO2 when sleeping?

A
  • Breathing/PaO2 can change a lot without changing SaO2 (due to ODC) when normally sleeping
  • SaO2 and PaO2 drop slightly during REM sleep
18
Q

Why is sleeping a challenge for people with lung disease?

A
  • REM sleep decreases SaO2 and PaO2
  • This is worse for lung disease patients as it decreases ventilation and O2 levels, and increases CO2 levels
  • Can cause respiratory failure
  • Recommended to increase O2 levels at night
19
Q

Why is necessary for CO2 levels to increase when sleeping?

A
  • Sensitivity to CO2 decreases when asleep
  • More CO2 required when sleeping to trigger breathing
  • If CO2 didn’t increase when sleeping => death
20
Q

How do you test someones ventilatory sensitivity to CO2?

A

• Keep people breathing in their own air
• More CO2 is expired than inspired
• VT = 500mL at 12 breath per minute at the beginning
- minute ventilation of 5 or 6
- maintains CO2 level
• Breathe in own CO2 => PaCO2 increases => try to breathe more (cycle repeats)
• Steep slope - people try to blow the CO2 off if they get sick (higher CO2 sensitivity)
• Flatter slope - people will retain CO2 more and slip into respiratory failure quicker

21
Q

What slope in ventilatory sensitivity is more beneficial to someone doing an elite performance sport?

A
  • Steeper slope
  • Brisk CO2 response
  • Favours certain exercises
22
Q

Why does CO2 sensitivity change when sleeping?

A
  • Less cortical input going to the respiratory centres
  • Causes sensitivity to CO2 to decrease and CO2 levels to rise
  • Increases blood gas range before we wake ourselves up (allowing brain to sleep which is important)
  • If we were very sensitive during sleep, a slight change in CO2 would wake us up
23
Q

What is hypercapnia and what is the significance of it in sleep?

A
  • Abnormally elevated CO2 levels in sleep

* Triggers a reflex which increases breathing and access to O2 during sleep

24
Q

What is the condition in which CO2 doesn’t exceed the apnoeic threshold in sleep?

A
  • Central Sleep Apnoea
  • aka Congenital Central Hypoventilation Syndrome (CCHS)
  • Treated with artificial ventilation
25
Q

Why are the upper airways badly designed for breathing?

A

• Designed for eating and drinking
• Tongue at the front and pharyngeal constrictor muscles around the back
• No cartilage rings until the larynx
• Muscular tube is good for swallowing but bad to breath through
• Muscles relax when sleeping
- negative intraluminal pressure (ILP) and positive extraluminal pressure (ELP) pressing on muscular tube
• More ELP if fat around the neck

26
Q

How does a recessed jaw affect breathing?

A
  • Smaller airway

* More likely to suffer from sleep apnoea, especially with fat around the neck

27
Q

What happens when the airways block when sleeping?

A
  • Oxygen levels fall
  • Carbon dioxide levels rise
  • Nothing wrong with chemosensitivity => hypoxia or hypercapnia wakes you up
28
Q

What is the difference between obstructive and central sleep apnoea?

A
  • Obstructive - no airflow, still trying to breath (mechanical problem)
  • Central - chemosensitivity problem, very rare

Patients are tired throughout the day due to disrupted sleep

29
Q

How can sleep apnoea affect cardiac conditions?

A
  • Generates massive pressures in the chest

* Exacerbates cardiac conditions

30
Q

How can heart failure affect breathing?

A
  • Pulmonary oedema

* Exacerbates hyperventilation and difficulty breathing

31
Q

How do you test the integrity of a metabolic controller?

A

Ventilatory response to a ramp increase of PaCO2

32
Q

How does hypoxia and hypercapnia change ventilatory sensitivity?

A
  • Hypoxia (low O2 reaching tissues) - increases ventilatory sensitivity to CO2
  • Hypercapnia - increases ventilatory sensitivity to hypoxaemia
33
Q

How do you determine whether a response is central (won’t breath) or peripheral (can’t breath) in origin?

A

Distinguished by measuring mouth occlusion pressure or diaphragm EMG during CO2 stimulation

Respiratory System (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions