Control of Breathing: Lecture 3

Question 1

If we have an unchanged/equal metabolic rate and pick up our breathing what will happen?

Answer 1

hyperventalating aka breathing to much
- O2 will increase
- CO2 will decrease

Question 2

if the ventilation is unchanged/equal and we increase metabolic rate without picking up our breathing what will happen?

Answer 2

hypoventilation aka not breathing enough
- O2 will decrease
- CO2 will increase

Question 3

What will happen to O2 and CO2 when we increase metabolic rate and pick up our breathing aka increase ventilation?

Answer 3

O2 and CO2 will remain steady

Question 4

Where is breathing generated?

Answer 4

level of the medulla, in the brain stem

Question 5

What are the 2 groups in the medullary respiratory centre called?

Answer 5

1. Dorsal respiratory group (DRG)
2. Ventral respiratory group (VRG)

Question 6

What kind of neurons do the dorsal respiratory group and the ventral respiratory group both control?

Answer 6

Inspiratory neurons

Question 7

Which respiratory group controls expiratory neurons?

Answer 7

ventral respiratory group

Question 8

Why do we need more neurons for inspiration?

Answer 8

because we have to activate our inspiratory muscles, we need to tell the diaphragm what to do via the phrenic nerve

Question 9

Where is the Pre-Botzinger complex?

Answer 9

within the medulla

Question 10

What does the Pre-Botzinger complex do?

Answer 10

generates the respiratory rhythm
- size and frequency of the breath

Question 11

What are the 3 types of receptors that control the respiratory pattern?

Answer 11

1. Mechanoreceptors
2. Metaboreceptors
3. Pulmonary receptors

Question 12

What do mechanoreceptors do?

Answer 12

detect changes in pressure or displacment of a structure and sends this information to the medulla

Question 13

What are examples of changes that the mechanoreceptos would pick up on?

Answer 13

• lung and chest wall
• peripheral muscles

Question 14

What do metaborcepetors do?

Answer 14

detect local changes in metabolic byproduct concentration and sends this information to the medulla

Question 15

What are examples of changes that the metaborcepetors would pick up on?

Answer 15

• changes in lactate or hydropgen

Question 16

What do pulmonary receptors do?

Answer 16

dectects chnage in the strecth of the lung

Question 17

What are chemical controls/chemoreceptors?

Answer 17

sense fluxations of O2 and CO2 in the blood to maintain our breathing

Question 18

What are the 2 types of chemoreceptors?

Answer 18

1. Peripheral receptors
2. Central Medullary receptors

Question 19

What are the 2 peripheral chemoreceptors?

Answer 19

1. Carotid
2. Aortic

Question 20

True or False
The carotid and aortic chemoreceptors both respond to changes in the arterial blood gas concentration or partial pressures and send signals to the medulla

Answer 20

True

Question 21

Which body plays a larger role and is more sensitive?

Answer 21

carotid

Question 22

True or False
The carotid body is much more dominant, aka its more important

Answer 22

True

Question 23

The peripheral carotid chemoreceptor is predominantly for a sensor for what?

Answer 23

Oxygen

Question 24

How much can we increase and decrease PO2 with almost no change in our minute ventilation?

Answer 24

+20 or -40 mmhg of PO2, 60 mm Hg

Question 25

When would the carotid peropheral chemoreceptor become active?

Answer 25

after the arterial PO2 reaches about 60 or lower, sending a signal to increase our breathing

Question 26

True or False When the PaO2 decreases the receptors increase their rate of discharge

Answer 26

True

Question 27

True or False When the rate of firing (excitatory stimuli) increases our ventilation increases, meaning what exactly?

Answer 27

True, meaning increased ventilation is directly proportional to ventilation

Question 28

What kind of feedback is being used with the peripheral chemoreceptors?

Answer 28

Negative feedback, bring us back to breathing aka back to homeostasis

Question 29

If we have an increase of H+, can that also stimulate the carotid chemoreceptor?

Answer 29

yessir

Question 30

What are the 2 scenarios where there is an increase of H+ in the cell?

Answer 30

1. Diarrhea - loss of lactic acid or HCO3- 2. Maximal exercise - where H* exceeds HCO3- buffering capacity

Question 31

Where are central chemoreceptors located?

Answer 31

in the medulla

Question 32

What do central chemoreceptors do?

Answer 32

- sense changes within the brain's extracellular fluid or the cerebral spinal fluid - respond to changes of H+ (pH) in the medulla

Question 33

Can hydrogen pass the blood-brain barrier?

Answer 33

no, not alone as a hydrogen moelcule

Question 34

Can carbon dioxide pass the blood-brain barrier?

Answer 34

yes, it can

Question 35

When the cerebrospinal fluid senses hydrogen where is the hydrogen coming from?

Answer 35

it is the hydrogen from the arterial CO2

Question 36

The CO2 in the blood leads to increased what?

Answer 36

ventilation via the bicarbonate equilibrium

Question 37

The central chemoreceptors respond to what?

Answer 37

CO2 fluctuations, via an increased Hydrogen in the cerebral spinal fluid

Question 38

Low O2 is sensed by which sensors?

Answer 38

carotid peripheral chemoreceptors

Question 39

High CO2 is sensed by which sensors?

Answer 39

central chemoreceptors