PSL301: Respiratory 4 Flashcards Preview

PSL301 > PSL301: Respiratory 4 > Flashcards

Flashcards in PSL301: Respiratory 4 Deck (37):
1

What is responsible for feedback regulation of breathing?

Chemoreceptors sense pCO2 and pO2 levels
-> chemoreflex

2

In response to chemoreflex, what changes?

ventilation

3

Graph of arteriole pCO2 and ventilation rate is in what shape? What is it called?

hyperbola downards
metabolic hyperbola

4

What does the shape of the metabolic hyperbola depend on?

rate of production of CO2 by metabolism

5

How is CO2 and O2 monitored?

chemoreceptors

6

2 types of chemoreceptors

1. central
2. peripheral

7

Central chemoreceptors are located...

in medulla oblongata & other brain tissue

8

Central chemoreceptors detect...

[H+] in cerebrospinal fluid

caused by increased pCO2 in cerebral capillaries

9

peripheral chemoreceptors are located in...

carotid (mainly) & aortic arteries

10

peripheral chemoreceptors detect...

[H+] in blood
low plasma O2

caused by increased plasma CO2 & decreased plasma O2

11

what increases sensitivity of peripheral chemoreceptors?

decreased pO2

12

The sensitivity of __ is dependent on pO2 levels

peripheral chemoreceptors

13

After medulla receives info from chemoreceptors, how does it respond?

via somatic motor neurons that go to intercostals and diaphragm

14

How long does it take for central chemoreceptors to respond?

5 min

15

How do central chemoreceptors send signal?

H+ blocks K+ channels, and causes depolarization in the chemoreceptor

16

an increase in H+ is associated with...

increased plasma pCO2

17

Relationship between pCO2 and ventilation

linear; proportional

18

__ chemoreflex provides most of our drive to breathe

central

19

when is central chemoreflex not used?

during emergencies

20

why is hyperventilating before diving dangerous?

- increase pO2
- this decreases sensitivity of peripheral chemoreceptors to high pCO2
- will not easily send signal to respiratory control centers

21

How is peripheral chemoreceptor activity modulated by low O2?

1. O2 enters the glomus cell in carotid
2. low pO2 causes K+ channels to close
3. cell depolarization
4. Ca++ gates open and enter cell
5. Ca++ cause exocytosis of dopamine
6. bind to dopamine receptor on sensory neuron
7. sends AP to medulla
8. increase ventilation

22

What NT does O2 need to send signals to medulla?

dopamine

23

what cell must O2 enter to send signals to medulla?

glomus cell

24

Where does the conversion to bicarb take place in the brain?

cerebrospinal fluid

25

Relationship between H+, HCO2-, pCO2 is called...

Henderson-Hasselbalch equation

26

Henderson-Hasselbalch equation

24 pCO2 / [HCO3-]

27

Normal value for [H+]

40 nmol/L

28

Normal value for pCO2

40 mmHg

29

Normal value for [bicarb]

24 mmol/L

30

How much acid is removed by respiratory system per day? What is removed?

10 000 mmol carbonic acid

31

How much acid is removed by renal system per day? What is removed?

100 mmol of fixed acids

32

Things that may cause respiratory acidosis

- lung disease
- overdose of sedatives

33

things that may cause metabolic acidosis

- methanol poisoning
- ketoacidosis
- diarrhea

34

things that may cause respiratory alkalosis

- hyperventilation
- aspirin poisoning

35

things that may cause metabolic alkalosis

- vomitting

36

Compensation for acidosis

1. increased respiratory rate
2. kidney secretes H+ as NH4+ / combined with buffers
3. kidney generate bicarb
4. buffer systems absorb H+

37

Compensation for alkalosis

1. decreased respiratory rate
2. kidney get rid of bicarb
3. buffer systems release H+