6.16: Control of lung function

Question 1

5 regions of the cardiovascular centre of the medulla

Question 2

The dorsal respiratory group is responsible for

Answer 2

Controlling inspiration
Set the rate of inspiration

Question 3

The ventral respiratory group is responsible for

Answer 3

Expiratory centre
Inactive during quiet breathing
Inhibit apneustic centre

Question 4

Function of the apneustic centre

Answer 4

Stimulates activity in DRG
Inhibited by pulmonary afferents

Question 5

Function of the pneumotaxic centre

Answer 5

Inspiratory off switch
Regulates depth and frequency

Question 6

Two types of respiratory groups

Answer 6

Dorsal -inspire
Ventral - expire

Question 7

Role between dorsal and ventral groups

Answer 7

Inhibit one another

Question 8

What nerve is the main cause for breathing Innervation and it’s origins

Answer 8

Phrenic nerve
C3/4/5

Question 9

Where is the dorsal respiratory group located?

Answer 9

Dorsomedial medulla in the ventrolateral nucleus of the solitary tract

Question 10

Where is the apneustic centre located?

Answer 10

Lower part of the pons

Question 11

Where is the pneumotaxic centre located?

Answer 11

Upper part of the pons

Question 12

What effect does the pneumotaxic centre have on the dorsal respiratory group?

Answer 12

Inhibitory

Question 13

What effect does the apneustic centre have on the dorsal respitatory group?

Answer 13

Stimulatory

Question 14

What effect does the dorsal respiratory group have on the ventral respiratory group?

Answer 14

Inhibitory

Question 15

What effect does the ventral respiratory group have on the DRG and AC?

Answer 15

Inhibitory

Question 16

Do action potentials at a low frequency stimulate the AC or the PC?

Answer 16

AC

Question 17

When the action potentials fire at a higher frequency, are the AC or PC stimulated?

Answer 17

PC

Question 18

What effect does the PC have on the action potentials and what is this effect followed by?

Answer 18

Causes a cessation (stop)

Follwed by a period of latency before the AC then stimulates the DRG again to increase the action potential frequency

Question 19

What motor and sensory innnervation does the phrenic nerve provide?

Answer 19

Motor Innervation to the diaphragm
Sensation to the central tendon aspect of the diaphragm

Question 20

What action do the external intercostal muscles contribute to?

Answer 20

Inspiration

Question 21

What action do the internal intercostal muscles contribute to?

Answer 21

Expiration

Question 22

If there are gaps in the capillaries of normal circulation, then why are they described as ‘continuous’?

Answer 22

These gaps between capillary endothelial cells are filled with H2O

Question 23

What is the blood brain barrier and why is it important?

Answer 23

The purpose of the blood-brain barrier is to protect against circulating toxins or pathogens that could cause brain infections, while at the same time allowing vital nutrients to reach the brain

Question 24

Why is the blood brain barrier considered to have continuous capillaries?

Answer 24

Tight junctions between capillary endothelial cells formed by nervous cells to prevent unnecessary leakage of molecules

Question 25

Is dissolved carbon dioxide able to pass through the lipid bilayer and therefore the blood brain barrier (BBB)?

Answer 25

Yes

Question 26

How does this CO2 that is now in the CSF as it crossed the BBB from the capillaries, initiate activation of the DRG?

Answer 26

CO2 reacts with water to form a carbonate ion (HCO3-) and a proton Protons enter the medulla and interact with the afferent fibres in medulla These take signal straight to dorsal respiratory group to be able to determine what type of rate and rhythm should be created

Question 27

Where are irritant receptors found?

Answer 27

Embedded within and beneath airway epithelium (larynx, trachea, bronchi, and intrapulmonary airways)

Question 28

What is the role of the irritant receptor?

Answer 28

Detects foreign mattter Leads to cough which involves forceful expiration against a closed glottis with sudden glottal opening and high velocity expulsion of air

Question 29

Where are pulmonary stretch receptors found?

Answer 29

Past the secondary bronchi

Question 30

How are stretch receptors activated?

Answer 30

Excessive inflation of lungs

Question 31

What do the stretch receptors do once they are activated?

Answer 31

Send afferent signals to respiratory centres and stimulate pneumotaxic VRG Inhibit inspiration and stimulate expiration

Question 32

Where are J-receptors found

Answer 32

Alveolar walls in close proximity to the capillaries

Question 33

What is the role of a J-receptor?

Answer 33

Because of their location they respond readily to chemicals in pulmonary circulation, distension of pulmonary capillary walls and accumulation of interstitial fluid Increases breathing frequency as a response to these factors send action potentials via vagus nerve leading to bronchoconstriction and increased respiratory rate

Question 34

What happens when you reach the CO2 threshold for breathing?

Answer 34

Accumulation of H+ beyond the blood brain barrier activates the DRG - the struggle phase

Question 35

What happens when you reach the O2 threshold for blackout?

Answer 35

You blackout

Question 36

What happens to the 3D structure of proteins if the level of acidity of the blood is not tightly regulated enough?

Answer 36

It is altered -> denatured

Question 37

Is a base anionic or cationic?

Answer 37

Anionic, also a molecule that reversibly binds to protons

Question 38

Why does an acid have a low pH compared to a base?

Answer 38

It dissociates with H+, which creates a decreased pH as the higher the concentration of H+, the lower the pH Whereas a base binds to the H+ and would decrease the concentration

Question 39

What is the formula for calculating pH

Answer 39

-log10[H+]

Question 40

What is the difference between alkalaemia and alkalosis?

Answer 40

Alkalaemia refers to a higher-than-normal blood pH, whereas alkalosis describes the circumstances that will decrease [H+] and increase pH

Question 41

What is meant by a ventilatory disturbance and how is this corrected?

Answer 41

Minor change in breathing that changes the pH which is then corrected by the kidneys which are slow responses

Question 42

What is meant by a metabolic disturbance and how is this corrected?

Answer 42

Any non-lung cause of a change in the pH that is subsequently corrected for by the lungs which are fast responses

Question 43

What type of reaction is required to correct acidosis?

Answer 43

Alkolitic response

Question 44

Where are the peripheral chemoreceptors found?

Answer 44

Bifurcation of carotid arteries in region called carotic bodies in the carotid sinus and aortic bodies in the aortic arch They are found very close to the baroreceptors

Question 45

What is the role of the peripheral chemoreceptors?

Answer 45

To stimulate breathing in response to hypoxia

Question 46

Which part of the brain is responsible for the emotional responses?

Answer 46

Limbic system - composed of the hypothalamus, amygdala, thalamus, hippocampus

Question 47

How can the movement of a muscle lead to an increase in breathing?

Answer 47

Efferents from pirmary motor cortex to gross skeletal musculature partly innervates medulla by sending volitional instructions to it as it will inevitably be necessary Proprioceptive afferents from muscle spindles and golgi tendon organs also innervate medulla on way to brain Demonstrated by cycling someone's legs

Question 48

What is the cold shock ventilator response?

Answer 48

Immersion in cold water (<10 degrees Celsius) causes a large and fast fall in skin temperature, detected by the superficial sensory nerve endings in the skin which evokes muscle spasms and hyperventilation

Question 49

Which the respiratory center coordinates a response to prevent pulmonary damage seondary to over‐inflation?

Answer 49

Pneumotaxic centre

Question 50

Which receptors are most likely to identify the inhalation of smoke in a house fire?

Answer 50

Irritant receptors

Question 51

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

Answer 51

Specialised medullary/pontine nucleii

Question 52

How many respiratory nuclei are found in the medulla oblongata

Answer 52

Four

Question 53

What center and group control inspiration

Answer 53

Dorsal respiratory group Apneustic center

Question 54

What group and centre is responsible for expiration

Answer 54

Ventral respiratory group Pneumotaxic center

Question 55

What kind of pattern does a respiratory pacemaker display

Answer 55

Ramp potential

Question 56

6 stimuli of inspiration

Answer 56

Central H+ concentration Juxtacapillary oedema Motor control Limbic system Peripheral O2 concentration Peripheral proprioceptors and skin thermoreceptors

Question 57

3 stimuli of Expiration

Answer 57

Airway stretch receptors Limbic system Motor control

Question 58

What receptors stimulate coughing

Answer 58

Airway irritant receptors

Question 59

What is blood pH tightly regulated between

Answer 59

7.35-7.45

Question 60

Words ending in -osis refer to

Answer 60

Conditions precipitating a changing pH

Question 61

Words ending in -aemia refer to

Answer 61

Blood conditions at a snapshot in time

Question 62

Relationship between pH and proton concentration

Answer 62

Inversely and logarithmically proportional

Question 63

What is bloods ability to buffer acid like

Answer 63

Rapid and enormous

Question 64

Two types of pH disturbances

Answer 64

Respiratory Metabolic

Question 65

Relationship between compensatory responses and the original aetiology

Answer 65

Response Usually opposite of original