Brainscape's Knowledge GenomeTM

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


See full index

PHGY 210 > Respiration V > Flashcards

Respiration V Flashcards

1
Q

What are the 3 causes of respiratory failure?

A

Respiratory failure occurs when the respiratory system is unable to do its job properly due to the failure of:
1. The gas exchanging capabilities of the lungs
2. The neural control of ventilation (the drive to breathe)
3. The neuromuscular breathing apparatus

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

What is arterial hypoxia (hypoxemia)

A

Deficient blood oxygenation (low PaO2 and low % Hb saturation)

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

What are the 5 causes of hypoxia?

A
  1. Inhalation of low PO2 (e.g. at high altitude)
  2. Hypoventilation - PaO2 decreases and PaCO2 increases.
  3. Ventilation/perfusion imbalance in the lungs
  4. Shunts of blood across the lungs - blood returns to systemic circulation deoxygenated
  5. O2 diffusion impairment (thickening of alveolar-capillary membrane, or pulmonary edema)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Is breathing voluntary or involuntary?

A

Both

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

What are the two major structures responsible for control of breathing?

A
  1. Cerebral hemispheres control voluntary breathing
  2. Brainstem (pons and medulla) controls involuntary breathing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the breaking point in respiration?

A

The breaking point is the point at which voluntary control of breathing is overriden by involuntary control due to arterial PCO2 getting too high and arterial PO2 getting too low.

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

What are the 3 basic elements in the respiratory control system? Describe their function.

A
  1. Sensors: gather information about lung volume (pulmonary receptors) and O2 and CO2 content (chemoreceptors)
  2. Controllers: information from the sensors is sent to the controller, in the pons and medulla, via afferent neural fibers. This peripheral information and inputs from higher structures of the nervous system are integrated.
  3. Effectors: neuronal impulses are generated and sent via spinal motoneurons to the effectors, the respiratory muscles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the pattern of respiration if you cut above the upper pons but keep the vagi intact.

A

Steady, regular rhythm.

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

Describe the pattern of respiration if you cut above the upper pons and cut the vagi.

A

Will take deep breaths at a regular rhythm.

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

Describe the pattern of respiration if you cut above the lower pons but keep the vagi intact.

A

Slow, deep breathing

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

Describe the pattern of respiration if you cut above the lower pons and cut the vagi.

A

Will take deep breath and hold it for as long as possible before exhaling.

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

Describe the pattern of respiration if you cut above the medulla but keep the vagi intact.

A

Irregular breaths

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

Describe the pattern of respiration if you cut above the medulla and cut the vagi.

A

Irregular breaths

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

Describe the function of respiratory neurons in the medulla

A

They generate the basic respiratory rhythmicity.

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

What are the two groups of neurons in the medulla? Describe their role.

A
  • Ventral respiratory group: generates basic rhythm. Contain pacemaker cells.
  • Dorsal respiratory group: receives sensory inputs.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the function of the upper pons in respiration? How do they affect the breathing pattern?

A

Cells located in the upper pons are responsible for turning off inspiration once an appropriate tidal volume has been reached. This leads to smaller tidal volume and increased breathing frequency

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

What happens when the upper pons are cut out of the respiratory system?

A

This causes the breathing to become deep and slow because they are responsible for turning off inspiration.

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

What is the effect of cutting off the upper pons and the vagus nerves?

A

It leads to a breathing pattern called apneuses, which is a large tidal breath up to lung capacity, holding it, then releasing it.

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

What is the role of the lower pons in respiration?

A

Cells located in the lower pons (called the apneustic center) send excitatory impulses to the respiratory groups of the medulla, thus promoting inspiration.

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

Where is the apneustic center?

A

The apneustic center refers to the cells located in the lower pons.

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

Chemoreceptors can detect […]

A

PO2, PCO2, and pH in arterial blood

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

What is the function of chemoreceptors?

A

They detect changes in the composition of arterial blood and send the information to the respiratory neurons, which change ventilation in response.

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

The activity of respiratory neurons will increase if chemoreceptors detect […] mm Hg of PaO2 or […] mm Hg of PaCO2.

A

< 60, > 40

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

The activity of respiratory neurons will decrease if chemoreceptors detect […] mm Hg of PaO2 or […] mm Hg of PaCO2.

A

> 100, < 40

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

What are the two types of chemoreceptors?

A

Central and peripheral

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

Where are central chemoreceptors located?

A

On the ventral surface of the medulla

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

What do central chemoreceptors detect and where?

A

They detect the PH of the cerebrospinal fluid (CSF) surrounding them (PCO2 and pH of the CSF are influenced by those of the arterial blood).

28
Q

The […] give rise to the main drive to breathe.

A

central chemoreceptors

29
Q

Describe the environment in which the central chemoreceptors get stimulated.

A

Central chemoreceptors sit in the brain ECF, through which CO2 easily diffuses from the blood vessels to the cerebrospinal fluid. The O2 reduces the CSF pH, thus stimulating the chemoreceptor.

H+ and HCO3- cannot easily cross the blood-brain barrier.

30
Q

What is hypercapnia?

A

Elevated CO2 in the blood

31
Q

Draw and describe the relationship between ventilation and hypercapnia.

A

When more CO2 is breathed in, this immediately leads to higher ventilation. Both tidal volume and frequency will increase.

32
Q

How can the sensitivity of central chemoreceptors be assessed?

A

The sensitivity of the central chemoreceptors can be assessed by performing a CO2 rebreathing test (breathe different CO2 mixtures).

33
Q

What are peripheral chemoreceptors sensitive to?

A

They are mainly sensitive to changes in PO2, but are also stimulated by increased PCO2 or decreased pH.

34
Q

Where are peripheral chemoreceptors located?

A

They are located in the carotid bodies and the aortic bodies.

35
Q

The aortic peripheral chemoreceptor nerve fiber is in the […] nerve

A

vagus (10th)

36
Q

The carotid peripheral chemoreceptor sensory nerve fiber is in the […] nerve

A

glossopharyngeal (9th)

37
Q

The carotid and aortic bodies are made up of […]

A

blood vessel structural supporting tissue and numerous nerve ends of sensory neurons of the glossopharyngeal (carotid) and vagus nerves (aortic)

38
Q

The afferent fibers of peripheral chemoreceptors project to the […]

A

dorsal group of respiratory neurons in the medulla

39
Q

How does the speed of the peripheral chemoreceptors response compare to that of the central chemoreceptors?

A

The peripheral chemoreceptors respond more slowly than central chemoreceptors.

40
Q

Draw and describe how the peripheral chemoreceptors change ventilation in response to decreased PO2 and decreased PCO2

A

During normocapnia (normal levels of CO2 in the blood), the alveolar PO2 can be reduced to about 60 mm Hg before appreciable changes in minute ventilation occur.

Increasing PCO2 increases ventilation at any PO2.

41
Q

What are the two major categories of sensors in the control of breathing?

A

Chemoreceptors and lung and other receptors.

42
Q

What are the 3 types of receptors in the lung that respond to mechanical stimuli? These can all be categorized as […] receptors.

A

pulmonary vagal.
1. Pulmonary stretch receptors
2. irritant receptors
3. Juxta-capillary or J receptors (C-fibers)

43
Q

Afferent fibers from the pulmonary vagal receptors travel in the […] nerves

A

vagus

44
Q

If the vagus nerve is sectioned, what is the result in terms of breathing pattern?

A

Slow, deep breathing

45
Q

Where are pulmonary stretch receptors located?

A

Pulmonary stretch receptors are located in the smooth muscles of the trachea down to the terminal bronchioles.

46
Q

Pulmonary stretch receptors are innervated by […]

A

large, myelinated fibres

47
Q

What provokes the activity of the pulmonary stretch receptors? How long does their activity last?

A

They discharge in response to the distension of the lung. Their activity is sustained as long as the lung is distended.

48
Q

The main reflex effect of stimulating the pulmonary stretch receptors is the […]

A

Hering-Breuer Inflation Reflex

49
Q

What is the Hering-Breuer inflation reflex?

A

This is a decrease in respiratory frequency due to a prolongation of expiratory time.

In other words, an increase in lung volume tends to inhibit the beginning of the next inspiratory effort (negative feedback mechanism)

50
Q

What types of individuals tend to have a more prominent and more weak Hering-Breuer reflex?

A

The HB reflex is weak in adults unless the tidal volume exceeds 1 L as in exercise, but is noticeable in infants and animals.

51
Q

Where are irritant receptors located?

A

The irritant receptors are located between airway epithelial cells in the trachea down to the respiratory bronchioles.

52
Q

What stimulates the activity of irritant receptors?

A

They are stimulated by noxious gases, cigarette smoke, histamine, cold air, and dust.

53
Q

Irritant receptors are innervated by […]

A

myelinated fibers

54
Q

What is the effect of the activation of the irritant receptors?

A

Their stimulation leads to bronchoconstriction and hyperpnea (increasing breathing depth). They are also important in reflex bronchoconstriction triggered by histamine release during an allergic asthmatic attack.

55
Q

Where are the juxta-capillary receptors located?

A

They are in the alveolar walls close to the capillaries.

56
Q

The juxta-capillary receptors are innervated by […]

A

non-myelinated fibers

57
Q

What stimulates the activity of the juxta-capillary receptors?

A

They are stimulated by a increase in pulmonary instititial fluid, like what may occur in pulmonary congestion and edema.

58
Q

What is the effect of the juxta-capillary receptors?

A
  • Rapid and shallow respiration
  • Intense stimulation causes apnea
  • These receptors may play a role in dyspnea (difficulty breathing) associated with left heart failure and lung edema or congestion
59
Q

During exercise, are you hyperventilating? Explain.

A

Generally, you do not hyperventilate because the metabolic rate increases linearly with minute ventilation. But this is only up for up to 50-65% of the maximum metabolic rate. After this, minute ventilation increases at a rate disproportionately greater than the change in metabolic rate (this is the inflection point)

60
Q

Draw and describe the relationship between minute ventilation and exercise level from rest to maximal exercise for a trained and untrained individual

A

The minute ventilation rises linearly until it reaches an inflection point past which hyperventilation starts.

In trained subjects, this inflection point where you start hyperventilating is delayed if you train.

61
Q

How do minute ventilation, arterial PO2, arterial PCO2, and arterial pH change with exercise?

A

Minute ventilation: rises linearly until inflection point
Arterial PO2: stays the same
Arterial PCO2: Starts consistent then decreases
Arterial H+: starts consistent then increases

62
Q

Explain why arterial PO2, arterial PCO2, and arterial pH are not the cause of increased ventilation during exercise.

A

Arterial PO2 stays constant, so it cannot be what signals to the brain to increase ventilation.

Arterial PCO2 goes down and [H+] goes up, so it can’t be what’s telling the brain to increase ventilation either. You would normally need more CO2 or lower pH.

63
Q

Describe the activity of the central chemoreceptors during exercise.

A

During exercise, there is an alkalotic pH increase in the medually ECF. This decreases the ventiolatory response. Therefore, the role of the central chemoreceptors is important at rest, but not so much during exercise.

64
Q

Describe the activity of peripheral chemoreceptors during exercise.

A

Although peripheral chemoreceptors are mainly sensitive to changes in PO2, they can also be stimulated by increased PCO2 and decreased pH.

During exercise, arterial pH does decrease (lactic acid) and PaO2 fluctuates subtly with arterial pulse waves. It is therefore possible that during exercise, these fluctuations in PaO2 increase the sensitivity of the peripheral chemoreceptors to CO2 and H+.

65
Q

Describe the role of peripheral mechanoreceptors in ventilation during exercise.

A

The pulmonary mechanoreceptors (muscle spindles, Golgi tendons, skeletal joint receptors) were though to play a role in the increase in minute ventilation during exercise.

However, the increase in minute ventilation generated by these mechanoreceptors is small compared to the large and abrupt increase observed during exercise.

66
Q

Describe the timing of the onset and recovery of breathing for exercise and why.

A

Minute ventilation starts increasing before the exercise has started. This control is believed to be neural. This is also why minute ventilation falls very abruptly at the end of exercise.

Humoral control is believed to be responsible for the ventilatory response during the exercise event.

67
Q

What are the values for the breaking point?

A

PO2 < 70 mm Hg and PCO2 > 50 mm Hg

PHGY 210 (36 decks)

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