Control of lung function

Question 1

What is the main function of medulla oblongata respiratory centres?

Answer 1

The control of ventilation arise from interactions of cranial regions, resulting in a rhythmic ventilation rate that provides the bod with sufficient oxygen volume, whilst facilitating adequate carbon dioxide removal

Question 2

Where are the respiratory centres located?

Answer 2

Medulla oblongata and pons

Question 3

What are the four main respiratory centres?

Answer 3

Dorsal respiratory group
Ventral respiratory group
Apneustic centre
Pneumotaxic centre

Question 4

What is the function of the dorsal respiratory group?

Answer 4

Involved in maintaining a constant breathing rhythm by stimulating the diaphgram and the intercostal muscles to contract
INSPIRATION

Question 5

Which respiratory group is mainly focussed on inspiration ?

Answer 5

Dorsal respiratory group

Question 6

What happens when the dorsal respiratory group activity decreases?

Answer 6

No longer stimulates diaphragm and intercostal to contract causing relaxation and expiration

Question 7

What is the main expiratory centre?

Answer 7

The ventral respiratory group

Question 8

Which centre causing forced expiration?

Answer 8

Ventral respiratory group

Question 9

Which respiratory centre inhibits the apneustic centre?

Answer 9

Ventral respiratory group

Question 10

Which respiratory centre stimulates the DRG?

Answer 10

Apneustic centre

Question 11

What is the function of the apneustic centre?

Answer 11

Controls the depth of inspiration, for deep breathing

Double cluster of neuronal Bodies stimulates the neurones in the DRG

Question 12

Which pontine respiratory centre inhibits the DRG?

Answer 12

Pneumotaxic centre

Question 13

Which respiratory centre controls frequency and depth, & enables relaxation post inspiration?

Answer 13

Pneumotaxic centre

Question 14

Which respiratory centre is classified as the inspiratory off switch?

Answer 14

Pneumotaxic centre

Question 15

Which plexus of sympathetic and parasympathetic motor & visceral nerve fibres innervate the lung?

Answer 15

Pulmonary plexus

Question 16

What is the pathway of nerve bundles taken during descent?

Answer 16

Nerve bundles descend parallel to the bronchial tissue & blood vessels

Question 17

Which nerve contributes to parasympathetic motor fibres of the airways?

Answer 17

Vagus nerve

Question 18

What is the effect of the vagus nerve on parasympathetic motor fibres on airways?

Answer 18

Regulates bronchoconstriction of airways. Autonomic excitatory cholinergic neves secrete acetylcholine into the bronchial smooth muscle & submucosal glands.

Bronchoconstriction & mucous production

Question 19

Which hormone causes airway bronchodilation?

Answer 19

Noradrenaline

Vasoactive intestinal peptides, neural nitric oxide

Question 20

Describe the pathway of sympathetic nerve fibreo the superior cervical ganglion?

Answer 20

Preganglionic neurones pass through the sympathetic chain of ganglia, synapsing with post ganglionic neurones the superior cervical ganglion

Question 21

Which pulmonary ganglion contains postganglionic sympathetic cell bodies?

Answer 21

Superior cervical ganglion

Question 22

Which nerves form the phrenic nerve?

Answer 22

C3, C4, C5

Question 23

Which nerve innervates the diaphragm contraction?

Answer 23

Phrenic nerve

Question 24

What is the primary muscle of respiration?

Answer 24

Diaphragm

Question 25

What is the effect of diaphragmatic contraction?

Answer 25

Reduced intrathoracic pressure

Question 26

Describe the endothelial arrangement of the blood brain barrier

Answer 26

Compact forming the blood barrier - continuous capillary structure with additional tight junctions

Question 27

What type of capillary forms the blood barrier?

Answer 27

Continuous capillary

Question 28

What type of junction supports the blood brain barrier?

Answer 28

Tight junctions

Question 29

Describe the relationship with proton concentration and carbon dioxide:

Answer 29

Proton concentration is proportional to carbon dioxide proportion

Question 30

Which enzyme is responsible for the activity of carbonic acid?

Answer 30

Carbonic anhydrase

Question 31

Carbonic acid dissociates into which two ions?

Answer 31

Bicarbonate ions | Hydrogen ions

Question 32

Can charged ions including hydrogen ion pass through the blood brain barrier?

Answer 32

No due to presence of tight junctions

Question 33

Why can carbon dioxide pass through the blood brain barrier?

Answer 33

Neutral molecule, lipid soluble, therefore can diffuse through the blood brain barrier into the cerebrospinal fluid within the subarachnoid space

Question 34

What does diffused carbon dioxide form within the CSF?

Answer 34

Carbonic acid --> Dissociates into hydrogen and bicarbonate ions

Question 35

What does an increased hydrogen ion concentration reflect within CSF?

Answer 35

Reflective on the amount of diffused carbon dioxide

Question 36

Which receptors detect hydrogen ion concentration within the medulla?

Answer 36

Central chemoreceptors

Question 37

Which nucleus is innervated by the chemoreceptors within the medulla?

Answer 37

Dorsal respiratory nucleus (Conducts transmission to centres within the medulla and pontine respiratory group)

Question 38

Where are irritant receptors located?

Answer 38

Embedded within and beneath the airway epithelium

Question 39

What do irritant receptors detect?

Answer 39

Inhaled particles water | Irritants

Question 40

What is the result from irritant receptor stimulation?

Answer 40

Leads to cough, forceful expiration (respiratory muscles contract forcefully, generate significant intrathoracic pressure), against closed glottis with sudden glottal opening and high velocity expulsion of air. Coughing is a productiee reflex, with the production of sputum

Question 41

Hyperinflation of lungs results in the activation of which receptors?

Answer 41

Stretch receptors

Question 42

Activation of stretch receptor inhibits which respiratory centres?

Answer 42

Dorsal respiratory group | Apneustic centre

Question 43

Activation of stretch receptors within the lung activates which respiratory centres?

Answer 43

Pneumotaxic centre | Ventral respiratory group

Question 44

What is inhibited and stimulated in terms of inspiration and expiration during stretch receptor afferent transmission?

Answer 44

Inspiration inhibited | Expiration stimulated

Question 45

What are J-receptors sensitive to?

Answer 45

Oedema | Pulmonary capillary engorgement

Question 46

Activation of J-receptors results in what?

Answer 46

Increased breathing frequency

Question 47

Which pulmonary fibres adjacent to capillary cells of the alveoli detect the accumulation of fluid within the interstitial space?

Answer 47

Pulmonary C-fibres

Question 48

What is pulmonary vessel engorgement?

Answer 48

Congestion of blood exceeding capacity

Question 49

What happens during the struggle phase of volitional apnoea?

Answer 49

Respiratory muscles contract autonomically, carbon dioxide is unloaded from the lungs (hyperventilation) removes central stimulus

Question 50

Why is volitional apnoea dangerous in terms of breathing thresholds?

Answer 50

The risk of oxygen threshold, blackout occurs before the carbon dioxide threshold for breathing

Question 51

What are acids?

Answer 51

Proton donors

Question 52

What is a proton?

Answer 52

Valency of +1 has no electrons or neutrons

Question 53

What is the relationship between pH and Hydrogen ion concentration?

Answer 53

pH = -Log10[H+] | A greater concentration of hydrogen ions logarithmic ally causes a lower pH

Question 54

What is the importance of acid-base balance in terms of proteins?

Answer 54

The acidity of blood is regulated to ensure that the tertiary structure of proteins are not stereochemically altered (Enzymes, hormones, protein channels).

Question 55

What is a base?

Answer 55

Anionic (negatively charged ions), molecule is capable of reversibly binding protons, reducing the available dissociated hydrogen ions present within the plasma

Question 56

What is the acid base relationship of carbonic acid?

Answer 56

𝑯𝟐𝑶+𝑪𝑶𝟐⇌𝐇𝟐𝐂𝐎𝟑⇌𝐇+ +𝐇𝐂𝐎𝟑− (Reversed reaction at pulmonary capillaries)

Question 57

Which enzyme is responsible for the formation of carbonic acid?

Answer 57

Carbonic anhydrase

Question 58

What does carbonic acid dissociate into?

Answer 58

Hydrogen ions | bicarbonate ions

Question 59

In order to maintain acid-base balance what is the fate of bicarbonate ions within erythrocytes?

Answer 59

Exchanged for chloride ions through the AE1 transporter, maintains resting potential

Question 60

What do hydrogen ions form within RBCs?

Answer 60

Protonate haemoglobin molecules forming haemoglobin acid

Question 61

What % of carbon dioxide is transported as bicarbonate ions?

Answer 61

70%

Question 62

The direct binding of carbon dioxide haemoglobin forms what molecule?

Answer 62

Carbaminohaemoglobin

Question 63

How is acidotic environments balanced?

Answer 63

Capacity to accommodate acid. pH detriment experienced was negligible, acidotic, capacity of different proteins had bicarbonate release into blood to reversibly neglect effect on proton concentration (neutralisation).

Question 64

What is alkalaemia?

Answer 64

Refers to elevated blood pH in respect to standard

Question 65

What is acidaemia?

Answer 65

Refers to lower than standard blood pH

Question 66

What is alkalosis?

Answer 66

Describes circumstances that will decrease hydrogen ion concentration and increase pH

Question 67

What is acidosis?

Answer 67

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

Question 68

Where are peripheral chemoreceptors located?

Answer 68

Within aortic arch and carotid sinus

Question 69

What are peripheral receptor sensitive to?

Answer 69

Concentration of hydrogen ions and carbon dioxide

Question 70

Stimulation of peripheral chemoreceptors results in transmission to which structure?

Answer 70

Medulla oblongata & pons

Question 71

How would acidosis affect ventilation?

Answer 71

Increased ventilation to expel carbon dioxide from circulation faster, removal from carbon dioxide reduced hydrogen ion concentration therefore increasing pH

Question 72

How does oxygenation influence respiratory rate?

Answer 72

Detected by peripheral chemoreceptors low blood oxygenation will stimulate increase in respiratory activity (Sense dissolved oxygen molecules not oxyhaemogloibin ) reduced partial pressure will increase oxygen dissociation

Question 73

Which cranial system exerts an influence on breathing rate by interacting with respiratory centres?

Answer 73

Limbic system

Question 74

How does increased basal temperature influence respiratory rate?

Answer 74

Increases respiratory rate

Question 75

What are the two main proprioreceptors in muscle?=

Answer 75

Muscle spindles | Golgi tendon organs

Question 76

What is inspiratory gasp?

Answer 76

Exposure to sudden temperature decline results in an inspiratory gasp directed by the apneustic centre (Water aspiration may occur  drowning). Systemic cold water leads to hyperventilation (Respiratory demand increases through shivering as basal metabolic rate increases) Thermoreceptors in skin detect temperature change <10℃