Control of Lung Function

Question 1

What are the four centers in the brain that control lung function called?

Answer 1

1. Dorsal Respiratory Group
2. Ventral Respiratory Group
3. Apneustic Center
4. Pneumotaxic Center

Question 2

What is the Dorsal Respiratory group responsible for?

Answer 2

it is the main controller of inspiration

Question 3

Which group in the medulla sets the rate for inspiration?

Answer 3

The dorsal respiratory group

Question 4

Which group in the medulla is the expiratory center?

Answer 4

The ventral Respiratory group

Question 5

What does the ventral respiratory group Inhibit?

Answer 5

The Dorsal and The Apenustic

Question 6

what does the Apneustic center do?

Answer 6

Stimulates the Dorsal Respiratory group

Question 7

What is the pneumotaxic center known as?

Answer 7

The inspiratory off switch

Question 8

What does the pneumotaxic center do?

Answer 8

Regulates depth and frequency of breathing

Question 9

What does the pneumotaxic center inhibit?

Answer 9

The dorsal respiratory group

Question 10

Why is the pneumotaxic center especially important?

Answer 10

Prevents pulmonary damage and over inflation of the lungs

Question 11

Which two centers make up the pontine respiratory group?

Answer 11

The apnuestic center and the pneumotaxic center

Question 12

Which muscles does the Dorsal Respiratry group Innervate?

Answer 12

The external Intercostals

Question 13

Which muscles are involved with expiration?

Answer 13

Internal intercostals

Question 14

Which muscles are involved with inspiration?

Answer 14

External Intercostals

Question 15

Aside from the external intercostals, what else is involved with inspiration?

Answer 15

The diaphragm - It moves down during inspiration to reduce pressure in the lungs, which allows the flow of air into the lungs

Question 16

Aside from the internal intercostals, what else in involved with inspiration?

Answer 16

Accessory Respiratory Muscles

Question 17

Which anatomical structure(s) create the primary drive to breathe?

Answer 17

Specialised medullary/pontine nucleii

Question 18

What inhibits the apneustic center?

Answer 18

Pulmonary afferents

Question 19

What type of gap junctions do normal capillaries have?

Answer 19

H2O Filled Gap Junctions

Question 20

What type of junctions are found in the Blood Brain Barrier?

Answer 20

Tight junctions

Question 21

Why can charged or large molecules not pass through the blood brain barrier?

Answer 21

Due to the presence of tight junctions

Question 22

Why can Carbon Dioxide pass the Blood Brain Barrier?

Answer 22

CO2 is highly lipid soluble and therefore can pass the blood brain barrier

Question 23

Why are the tight junctions found in the brain?

Answer 23

Certain nervous cells like astrocytes pack the H2O filled junctions which make them tight junctions

Question 24

Levels of Oxygen are sensed by what on the surface on the medulla oblongata?

Answer 24

Central Chemoreceptors

Question 25

Where are central chemoreceptors found?

Answer 25

In the medulla oblongata

Question 26

what do central chemoreceptors respond to?

Answer 26

Hydrogen ion concentration from the dissociation of CO2 within the surrounding tissue and the CSF, NOT BLOOD

Question 27

Why do central chemoreceptors not response to changes in the blood?

Answer 27

The diffusion of the ions such as H+ and HCO3- from the blood is poor due to the tight junctions between the cells which forms the blood brain barrier

Question 28

Where are peripheral receptors located>

Answer 28

Around the aortic arch and the carotid sinus (Aortic and Carotid Bodies)

Question 29

Afferent neurones from the peripheral chemoreceptors are via which two nerves?

Answer 29

Glossopharyngeal and the Vagus nerve

Question 30

What enzyme is responsible for converting H2O and CO2 into H2CO3 and then H+ and HCO3-?

Answer 30

Carbonic anhyrase

Question 31

What happens when central chemoreceptors found in the medulla detect a reduced blood pH?

Answer 31

They cause the respiratory centers to increase the rate and depth of breathing

Question 32

How does the partial pressure of Carbon Dioxide change going from Rest into Exercise?

Answer 32

Does not change

Question 33

Why does the transition from rest to exercise not impact the partial pressure of CO2?

Answer 33

The overall affect is no change

Question 34

What are irritant receptors?

Answer 34

Afferent receptors found within the beneath airway epithelium

Question 35

What does activation of irritant receptors lead to?

Answer 35

Cough

Question 36

What does a cough involve?

Answer 36

which involves forceful expiration against a closed glottis with sudden glottal opening & high velocity expulsion of air

Question 37

What does excessive inflation of the lungs activate?

Answer 37

Pulmonary Stretch Receptors

Question 38

What does activation of the stretch receptors do?

Answer 38

Inhibits Inspiration and Stimulates expiration

Question 39

When stretch receptors are activated, which centers are activated and which are inhibited?

Answer 39

Apneustic and Dorsal and inhibited, and Ventral is stimulated

Question 40

What are J receptors sensitive to?

Answer 40

Pulmonary capillary engorgement and Oedma

Question 41

What does stimulation of the J receptors lead to?

Answer 41

Increased breathing Frequency

Question 42

What is Volitional Apnoea?

Answer 42

Cessation of breathing

Question 43

What is meant by chloride shift?

Answer 43

Where one chloride ion is exchanged into red blood cell for one bicarbonate ion out the red blood cell

Question 44

What is an acid

Answer 44

A proton donor

Question 45

A greater H+ concentration refers to what in terms of pH?

Answer 45

A low pH

Question 46

Why must the acidity of the blood be tightly regulated?

Answer 46

marked changes will alter the 3D structure of proteins (enzymes, hormones, protein channels)

Question 47

What transporter is involved in chloride shift?

Answer 47

AE1 Transporter

Question 48

Whatis the ability of the blood to react to changes in H+ ion conc known as?

Answer 48

buffering capacity

Question 49

What is meant by alkaemia?

Answer 49

A higher than normal pH of blood

Question 50

What is meant by acidaemia?

Answer 50

A lower than normal pH of blood

Question 51

What is alkalosis?

Answer 51

Describes circumstances that will decrease [H+] and increase pH

Question 52

What is acidosis?

Answer 52

Describes circumstances that will increase [H+] and decrease pH

Question 53

What stimulates a rapid compensatory response to affect pH?

Answer 53

Changes in ventilation

Question 54

What stimulates a slow compensatory response to affect pH?

Answer 54

Changes in HCO3- and H+ retention/secretion in the kidneys

Question 55

What is needed to correct an acidaemia?

Answer 55

Alkalosis

Question 56

What are baroreceptors?

Answer 56

Receptors which are sensitive to changes in blood pressure

Question 57

What receptors are involved in the control of alveolar ventilation during exercise?

Answer 57

Central chemoreceptors

Question 58

What triggers the change in ventilation due to emotional change?

Answer 58

The respiratory control center

Question 59

Efferents from primary motor cortex to gross skeletal musculature partly innervate what?

Answer 59

the medulla

Question 60

What innervates the medulla on the way to the brain during exercise?

Answer 60

Proprioceptive afferents from the muscle spindles and golgi tendon organs

Question 61

What effect does cycling someones legs have?

Answer 61

Increases ventilation - This shows that the afferent nerves from muscles and tendons also innervate the medulla on the way to the brain, as just through shortening and lengthening of the muscle fibres is enough to create an increase in ventilation

Question 62

What effect does immersion in cold water have on ventilation?

Answer 62

Results in an inspiratory gasp and hyperventilation

Question 63

What pH range is the blood pH tightly regulated between?

Answer 63

7.35 and 7.45

Question 64

What do peripheral chemoreceptors do?

Answer 64

They respond to changes in blood molecule concentrations (like oxygen and carbon dioxide) and help maintain cardiorespiratory homeostasis

Question 65

Why does the partial pressure of carbon dioxide and oxygen not change during normal exercise?

Answer 65

use of oxygen increases and prouction of CO2 increases, however this is compensated for by corresponding increases in ventilation such that blood gas levels remain in normal limits

Question 66

In what circumstance might the partial pressure of oxygen or carbon dioxide change?

Answer 66

During strenuous exercise, when the production of lactic acid results in an acideamia