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630: Medical Physiology > Breathing > Flashcards

Flashcards in Breathing Deck (32)
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1

What is breathing controlled by?

centers in the brainstem

2

What are the 4 components that control breathing

1) chemoreceptors for O2 and CO2
2) mechanoreceptors in the lungs and joints
3) control centers for breathing in the brainstem
4) respiratory muscles

3

Breathing is an involuntary process that is controlled by the _____ and _____ of the brainstem.

medulla

pons

4

What are the 3 brain stem centers that control the frequency of normal, involuntary breathing?

- medullary respiratory center
- apneustic center
- pneumotaxic center

5

What are the 2 groups of neurons that compose the medullary respiratory center?

- inspiratory center
- expiratory center

6

Afferent (sensory) information reaches the medullary inspiratory center via what 3 things?

- central chemoreceptors
- peripheral chemoreceptors
- mechanoreceptors (in the lungs, muscles, and joints)

7

Efferent (motor) information is sent from the medullary inspiratory center to which nerve?

To the phrenic nerve, which innervates the diaphragm

8

What is apneusis?

An abnormal breathing pattern with prolonged inspiratory gasps, followed by brief expiratory movement

9

Stimulation of the apneustic center _____ the inspiratory center in the medulla. What does this result in?

excites

Results in prolonging the period of APs in the phrenic nerve, and thereby prolonging the contraction of the diaphragm

10

The pneumotaxic center turns inspiration ___.

off

11

What structures are the most important for the minute-to-minute control of breathing?

the central chemoreceptors in the brainstem

12

Increases in arterial PCO2 produces _____ in PCO2 in the brain and the CSF, which _____ pH of the CSF. Central chemoreceptors detect this decrease in pH and signal the inspiratory center to _____ the breathing rate

increases

decreases

increase

13

Other than chemoreceptors, what other types of receptors are involved in the control of breathing?

- Lung stretch receptors
- Joint and muscle receptors
- Irritant receptors
- J receptors

14

Lung stretch receptors instruct the inspiratory center to _____ the breathing rate.

decrease

15

Joint and muscle receptors instruct the inspiratory center to _____ the breathing rate.

increase

16

Irritant receptors instruct the inspiratory center to _____ the breathing rate.

increase

17

J receptors instruct the inspiratory center to _____ the breathing rate.

increase

18

What 6 things increase in response to exercise?

- O2 consumption
- CO2 production
- ventilation
- CO
- pulmonary blood flow
- venous PCO2

19

What 2 things decrease in response to exercise?

- pH (sometimes)
- physiologic dead space

20

What 3 things are unaffected in response to exercise?

- Arterial PO2
- Arterial PCO2
- pH (sometimes)

21

What happens to V/Q in response to exercise?

It increases in the lungs

22

In response to exercise the O2-hemoglobin dissociation curve shifts to the ____. Which means P50 _____ and the affinity for O2 _____.

right

increases

decreases

23

What 4 things increase in response to high altitude?

- ventilation rate
- pH
- pulmonary resistance
- pulmonary artery pressure

24

What 2 things decrease in response to high altitude?

- alveolar PO2
- arterial PO2

25

In response to high altitude the O2-hemoglobin dissociation curve shifts to the ____. Which means P50 _____ and the affinity for O2 _____.

right

increases

decreases

26

Define hypoxemia

a decrease in arterial PO2

27

What are 5 examples in which arterial PO2 decreases, which causes hypoxemia?

- high altitude
- hypoventilation
- diffusion defect (fibrosis)
- V/Q defect
- right-to-left shunt

28

What is a useful tool for comparing causes of hypoxemia?

the A-a gradient

29

What is the A-a gradient?

the difference between the PO2 of alveolar gas and the PO2 of systemic arterial blood

A-a gradient = PAO2 - PaO2

30

In some cases of hypoxemia, the A-a gradient is _____. What does this signify?

increased, signifying a defect in O2 equilibrium