Natalie - Control of Breathing

Question 1

What are the two aspects of respiratory control

Answer 1

Involuntary

Voluntary

Question 2

Which control is used most of the time

Answer 2

Involuntary control used most often

Question 3

Why is involuntary control used most open

Answer 3

Its most efficient way to breath

Question 4

In general what happens when we exert conscious control

Answer 4

Breathing changes

Question 5

What three things does voluntary control of respiratory rate depend on?

Answer 5

Conscious and unconscious thought

Emotional state

Anticipation

Question 6

How does conscious and unconscious thought affect respiratory rate?
(2)

Answer 6

e.g. rage or fear

Affect respiratory rate by stimulating centres in the hypothalamus

Question 7

How can emotional state affect respiratory rate

Answer 7

Depression can slow down RR

Question 8

How can anticipation affect RR?

Answer 8

If anticipating strenuous exercise

This can cause automatic increase in RR, along with increased cardiac output by sympathetic stimulation

Question 9

How much control do you have over voluntary breathing

Answer 9

Breathing cannot be consciously suppressed

Can only hold your breath until you lose consciousness then brain takes over

Question 10

What are the central controllers of the brain

Answer 10

Pons

Medulla

Question 11

Explain the pathway of control
(3)

Answer 11

Information from various sensors is fed to the central controller

The output of which goes to the respiratory muscles

By changing ventilation, the respiratory muscles reduce negative feedback of the sensors

Question 12

What are the five receptors of the lung?

Answer 12

Chemoreceptors

Baroreceptors

Stretch receptors

Sensations

Physical or chemical stimuli

Question 13

What are chemoreceptors

Answer 13

Receptors sensitive to the PCO2, pH or PO2 of the blood or cerebro-spinal fluid

Question 14

What are baroreceptors

Answer 14

Receptors that detect changes in blood pressure in aortic or carotid sinuses

Question 15

What are stretch receptors

Answer 15

Receptors that respond to changes in the volume of the lungs and prevent overstretch

Question 16

How do sensations act as sensors

Answer 16

Sensations of pain, changes in body temperature or abnormal gut sensations

Question 17

How do physical or chemical stimuli act as sensors

Answer 17

Physical or chemical stimuli in the nasal cavity, larynx or bronchial tree

Question 18

What does the medulla oblongata do?

Answer 18

Sets pace of breathing

Question 19

What centres are found in the medulla oblongata?

Answer 19

Respiratory rhythmicity centers

Question 20

What does the pons do?

Answer 20

Controls breathing pattern (inhalation and exhalation)

Question 21

What centres are found in the pons?

Answer 21

Apneustic and pneumotaxic centers

Question 22

What happens in the apneustic centers
(4)

Answer 22

Breathing where long inspirations are interrupted by occasional expirations = snoring sound

Not normally used

Should be switched off

We are not sure why these exist

Question 23

What happens in the pneumotaxic centre?

Answer 23

Breathing pattern shows a normal balance between inspiration and expiration

Question 24

What are the effectors of respiration

Answer 24

Respiratory muscles

Question 25

The inspiratory centres of the brain are influenced by input from where?

Answer 25

The nerves and receptors that monitor the composition of the CSF

Question 26

What does stimulation of the chemoreceptors lead to? (2)

Answer 26

Increase in depth Increase in rate of breathing

Question 27

How does oxygen chemoreceptors work?

Answer 27

Oxygen: - monitored by carotid and aortic bodies - Arterial PO2 must be < 60 mmHg to activate chemoreceptors - Haemoglobin saturation still 90% at 60mmHg of O2 - Normally it is 100 mmHg and 97% saturated

Question 28

Why does oxygen concentrations not control breathing?

Answer 28

Because it takes large drop in oxygen levels to cause a dramatic change in breathing

Question 29

Why is carbon dioxide the main regulator?

Answer 29

CO2 diffuses 20x faster than oxygen

Question 30

What happens if input from pons is disrupted?

Answer 30

Breathing becomes irregular

Question 31

What are found in apneustic and pneumotaxic centres?

Answer 31

Paired nuclei that adjust the output of the respiratory rhythmicity centres

Question 32

Why are pneumotaxic centres most important

Answer 32

Their activities regulate the respiratory rate and depth of breathing in response to input from other centres in the brain

Question 33

Where is concentrations of CO2 monitored

Answer 33

Monitored by receptors in the medulla oblongata = respiratory rhythmicity centres

Question 34

What can the centres of the medulla oblongata be divided into?

Answer 34

Dorsal respiratory group (DRG) Ventral respiratory group (VRG)

Question 35

When does DRG function

Answer 35

Functions in every respiratory cycle whether quiet or forced breathing

Question 36

When does VRG function

Answer 36

VRG only functions during forced breathing

Question 37

What happens in quiet breathing (6)

Answer 37

Inspiration occurs Dorsal respiratory group inhibited Inspiratory muscles relax Passive expiration occurs Dorsal respiratory group active Inspiratory muscles contract

Question 38

What happens in forced breathing? (9)

Answer 38

Inspiration occurs - Dorsal respiratory group and inspiratory center of VRG inhibited. -Expiratory center of VRG active. -Inspiratory muscles relax -Expiratory muscles contract Active expiration occurs -Expiratory center of VRG inhibited -DRG and inspiratory center of VRG active Inspiratory muscles contract Expiratory muscles relax

Question 39

How do lungs help regulate pH

Answer 39

Through carbonic acid-bicarbonate buffer system

Question 40

How do kidneys help regulate pH

Answer 40

Through renal compensation

Question 41

How do the lungs regulate pH?

Answer 41

Changing respiratory rates changes partial pressure of CO2

Question 42

When do respiratory acid base disorders result

Answer 42

Result when abnormal respiratory function causes rise or fall in CO2 in ECF - acidosis - alkalosis

Question 43

What are metabolic acid-base disorders

Answer 43

Generation of organic or fixed acids Anything affecting concentration of bicarbonate ions in ECF

Question 44

What is hypercapnia

Answer 44

High carbon dioxide

Question 45

What does hypercapnia cause?

Answer 45

Respiratory acidosis

Question 46

What does hypocapnia do?

Answer 46

Respiratory alkalosis

Question 47

When does respiratory acidosis occur?

Answer 47

When the lungs cannot remove all of the carbon dioxide produced by the body Body fluids become excessively acidic

Question 48

What disease cause acidosis

Answer 48

A consequence of any lung disease that prevents removal of carbon dioxide

Question 49

What are the symptoms of respiratory acidosis? (4)

Answer 49

Shortness of breath Easy fatigue Chronic cough Wheezing

Question 50

What causes respiratory alkalosis

Answer 50

Any lung disease that leads to shortness of breath may result in respiratory alkalosis

Question 51

What is respiratory alkalosis

Answer 51

The pH is high and carbon dioxide levels are low

Question 52

What are the symptoms of respiratory alkalosis

Answer 52

Light-headedness Dizziness Numbness of the hands and feet

Question 53

What are some treatments for alkalosis

Answer 53

Breathing into a paper bag (re-breathing of carbon dioxide)