Brainscape's Knowledge GenomeTM

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


See full index

CVR > Control Of Respiration > Flashcards

Control Of Respiration Flashcards

1
Q

Carbonic acid equilibrium

A

CO2 + H2O <—> H2CO3 <—> H+ + (HCO3)-

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

Carbonic acid equilibrium enzyme

A

Carbonic anhydrase

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

Requirement of respiration

A
  • Ensure haemoglobin is as close to full saturation with oxygen as possible
  • Efficient use of energy resource
    -Regulate PaCO2 carefully
    variations in CO2 and small variations in pH can alter physiological function quite widely
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Breathing is autonomic

A

No conscious effort for the basic rhythm
Rate and depth under additional influences
Depends on cyclical excitation and control of many muscles
-Upper airway, lower airway, diaphragm, chest wall
-Near linear activity
-Increase thoracic volume

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

Input signals to respiratory control centres

A

Central chemoreceptor a
Voluntary control (cerebrum)
Lung receptors; stretch, J receptors, irritant
Peripheral chemoreceptors: carotid, aortic
Muscle proprioceptors

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

Respiratory control centres- basic breathing rhythm

A

Medulla and pons

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

3 types of Lung receptors

A

Stretch
J receptors
Irritant

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

Pons

A

Pneumotaxic and apneustic centres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Medulla oblongata

A

Phasic discharge of action potentials
2 main groups:
1. Dorsal respiratory group (DRG)
2. Ventral respiratory group (VRG)

Each are bilateral, and project into the bulbo-spinal motor neuron pools and interconnect

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

When is DRG active

A

predominantly active during inspiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When is VRG active

A

active in both inspiration and expiration

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

Central pattern generator

A

Neural network (interneurons)
Located within DRG/VRG
-Precise functional locations not known
-Start, stop and resetting of an integrator of background ventilatory drive

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

What does desire to take a breath come from

A

PaCO2

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

Inspiration

A

Progressive increase in inspiratory muscle activation
-Lungs fill at a constant rate until tidal volume achieved
-End of inspiration, rapid decrease in excitation of the respiratory muscles

DRG and VRG prevent over inflation of the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Expiration

A

Largely passive due to elastic recoil of thoracic wall
-First part of expiration; active slowing with some inspiratory muscle activity
-With increased demands, further muscle activity recruited
-Expiration can be become active also; with additional abdominal wall muscle activity

DRG and VRG prevent over deflation of the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What % influence from PaCO2 on central chemoreceptors

A

60%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What % influence from PaCO2 on peripheral chemoreceptors

A

40%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Chemoreceptors

A

Stimulated by [H+] concentration and gas partial pressures in arterial blood
Brainstem [primary influence is PaCO2]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Peripheral chemoreceptors

A

Carotids and aorta [PaCO2, PaO2 and pH]
-Significant interaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Central chemoreceptors

A

Located in brainstem
Pontomedullary junction
Not within the DRG/VRG complex

Sensitive to PaCO2 of blood perfusing brain (also influenced by PaO2)
Blood brain barrier relatively impermeable to H+ and HCO3-
PaCO2 preferentially diffuses into CSF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Carotid bodies

A

Bifurcation of the common carotid
Glossopharyngeal (IX) cranial nerve afferents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Aortic bodies

A

Ascending aorta
Vagal (X) nerve afferents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Peripheral chemoreceptors

A

Responsible for [all] ventilatory response to hypoxia (reduced PaO2)

Generally not sensitive across normal PaO2 ranges

When exposed to hypoxia, type I cells release stored neurotransmitters that stimulate the cuplike endings of the carotid sinus nerve

Linear response to PaCO2

Interactions between responses

[Poison (e.g. cyanide) and blood pressure responsive]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are central chemoreceptors sensitive to

A

PaCO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are peripheral chemoreceptors sensitive to

A

PaO2, PaCO2 and pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What mediates the response to CO2 by central chemoreceptors

A

H+ produced during the carbonic acid equilibrium bind to receptors and increase ventilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Lung receptors

A

Stretch, J and irritant
Afferents; vagus (X)
Combination of slow and fast adapting receptors
Assist with lung volumes and responses to noxious inhaled agents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Stretch lung receptors

A

Smooth muscle of conducting airways
Sense lung volume, slowly adapting

29
Q

Irritant lung receptors

A

Larger conducting airways
Rapidly adapting [cough, gasp]

30
Q

J (juxtapulmonary capillary) lung receptors

A

Pulmonary and bronchial C fibres

31
Q

Nose, nasopharynx and larynx airway receptors

A

Chemo and mechano receptors
Some appear to sense and monitor flow
Stimulation of these receptors appears to inhibit the central controller

32
Q

Pharynx airway receptors

A

Receptors that appear to be activated by swallowing
- respiratory activity stops during swallowing protecting against the risk of aspiration of food or liquid

33
Q

Muscle proprioceptors

A

Joint, tendon and muscle spindle receptors
Intercostal muscles > > diaphragm
Important roles in perception of breathing effort

34
Q

If ascending up a hill….

A

Ascending; PiO2 falls (FiO2 remains constant)
Decreased PAO2
Decreased PaO2
Peripheral chemoreceptors fire (e.g carotid)
Activates increased ventilation (VA)
Increased PAO2
Increased PaO2

35
Q

PaCO2 and pH

A

The pH of the CSF is established by the ratio of pCO2 : [HCO3–].

The HCO3– levels remain relatively constant. CO2 freely diffuses across the blood brain barrier, from the arterial blood supply into the CSF. CO2 reacts with H2O, producing carbonic acid, which lowers the pH. This means that the pH of the CSF is inversely proportional to the arterial pCO2.

A small decrease in pCO2­ leads to an increase in the pH of the CSF, which stimulates the respiratory centres to decrease ventilation.
A small increase in pCO2 leads to a decease in the pH of the CSF, which stimulates the respiratory centres to increase ventilation.

36
Q

Ventral respiration group

A

the VRG sends inhibitory impulses to the apneustic centre, decreasing the duration of inspiration, leaving more time for longer expiration during forced expirations

37
Q

Dorsal respiratory group

A

initiates respiration and determines the basic rhythm of breathing by adjusting the frequency of inspiration. When it receives information regarding an increase in PaCO2, the DRG causes the diaphragm to contract (via the phrenic nerve) to increase the vertical length of the thoracic cavity, and through the intercostal nerves to the external intercostal muscles, which contract and cause the ribs to move up and out, increasing the lateral size of the thoracic cavity. This causes airflow into the lungs

38
Q

Apneustic centre

A

When O2 requirement is higher (eg during exercise) the apneustic centre of the pons is activated, stimulation excites the DRG in the medulla, prolonging the period of action potentials in the phrenic nerve, prolonging contraction of the diaphragm and so preolonging inspiration

39
Q

Pneumotaxic centre

A

To prevent over inflation of the lungs, the pneumotaxic centre is activated, which limits the burst of action potentials in the phrenic nerve, making the diaphragm contract less- stopping inspiration and allowing for expiration to happen

40
Q

When low PaO2 detected

A

afferent impulses travel via the Glossopharyngeal and vagus nerves to the medulla oblongata and pons in the brain stem. In order to restore PaO2, respiratory rate and tidal volume are increased to allow more oxygen to enter the lungs and diffuse into the blood. Also, blood flow is directed towards the kidneys and brain (as these organs are most sensitive to hypoxia), and cardiac output is increased to maintain blood flow

41
Q

Hypercapnia

A

Hypercapnia, also known as hypercarbia, is a condition that occurs when a person has too much carbon dioxide (CO2) in their bloodstream. It can cause confusion as increased CO2 levels cause the brain to reduce metabolism and spontaneous neural activity and enter a lower arousal state.

42
Q

In response to what stimuli cause chemoreceptors in the medulla to increase respiratory rate

A

Increase in carbon dioxide of cerebral spinal fluid

43
Q

Normal respiratory rate

A

10-12 breaths per minute

44
Q

Acid-base balance

A

CO2 +H20 <-> H2CO3 <-> (HCO3)- + H+
Carbonic anhydride enzyme

45
Q

Respiratory control of acid-base balance is

A

Rapid

46
Q

Renal control of acid base balance is

A

Slow

47
Q

Opioids

A

Depress control of respiration

48
Q

Amphetamines

A

Stimulate respiration

49
Q

Large respiratory reserve

A

Minute ventilation : 7.5 L/min
Can increase to 30L/min

50
Q

Flow of air

A

(Alveolar pressure - atmospheric pressure) / resistance

51
Q

Pneumotaxic centre

A

Inhibits inspiration- enables expiration

52
Q

Apneustic centre

A

Increases inspiration

53
Q

Pontine respiratory group

A

Pneumotaxic centre
Apneustic centre

54
Q

Dorsal respiratory group

A

Inspiration: contracts
Diaphragm
External intercostals

55
Q

Pre-Bötzinger complex

A

Rhythm generator of breathing (pacemaker cells)

56
Q

Ventral respiratory group

A

Inspiration and forced expiration
Contracts:
Internal intercostal muscles
Accessory muscles

57
Q

Central chemoreceptors

A

detect changes in PaCO2. The pH of the CSF is established by the ratio of pCO2 : [HCO3–].
• The HCO3– levels remain relatively constant.CO2 freely diffuses across the blood brain barrier, from the arterial blood supply into the CSF. CO2 reacts with H2O, producing carbonic acid, which lowers the pH. This means that the pH of the CSF is inversely proportional to the arterial pCO2.
• A small decrease in pCO2­ leads to an increase in the pH of the CSF, which stimulates the respiratory centres to decrease ventilation.
• A small increase in pCO2 leads to a decease in the pH of the CSF, which stimulates the respiratory centres to increase ventilation.
• The DRG (dorsal respiratory group) initiates respiration and

58
Q

What is main driver for respiration

A

CO2
chemoreceptors respond to small CO2 changes but large O2 changes

59
Q

Prolonged hypoxia

A

Type II sustenacular cells (supporting) ——> type I glomus cells (O2 sensing)

60
Q

Carotid sinus is innervated by

A

Glossopharyngeal nerve

61
Q

Aortic arch is innervated by

A

Vagus nerve

62
Q

Which nerve do pulmonary stretch and irritant receptors inhibit the respiratory centre by

A

Vagus nerve

63
Q

Irritant receptors

A

Larger conducting airways
Fast adapting- cough

64
Q

Stretch receptors

A

Lung inflation in smooth muscle
Slowly adapting
Inhibit inspiration (inflation)

65
Q

J receptors

A

Alveoli
Unmyelinated C fibres
Irritants, noxious agents, volume
Bronchoconstriction and shallow breathing

66
Q

Rapidly adapting stretch receptors

A

Airway epithelial cells that respond to rate of change of volume and irritants
Can cause bronchoconstriction and long deep breathing

67
Q

The central chemoreceptors, located in the ventral medulla help regulate the internal environment.

What do they respond to?

A

CSF pH

68
Q

Chemoreceptors regulate the internal environment by monitoring changes to various substances.

Changes in which of these substances stimulate the carotid chemoreceptors?

A

Oxygen, carbon dioxide and H+ ions

69
Q

The body uses a variety of chemoreceptors to regulate the internal environment.

Where are the main peripheral chemoreceptors located?

A

Carotid arteries and aortic arch

CVR (22 decks)

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