control of ventilation

Question 1

eupnoea

Answer 1

normal quiet breathing

Question 2

hyperpnoea

Answer 2

increased ventilation

Question 3

tachypnoea

Answer 3

increased respiratory rate

Question 4

hyperventilation

Answer 4

overventilation (PaCO2 less than normal)

Question 5

hypocapnia

Answer 5

PCO2 less than normal

Question 6

hypercapnia

Answer 6

PCO2 greater than normal

Question 7

hypoxia

Answer 7

PO2 less than normal

Question 8

hyperoxia

Answer 8

PO2 greater than normal

Question 9

hypoxaemia

Answer 9

PO2 less than normal in blood

Question 10

asphyxia

Answer 10

hypoxia and hypercapnia

Question 11

dyspnoea

Answer 11

stressful breathing.

Question 12

apnoea

Answer 12

absence of breathing

Question 13

what controls ventilation

Answer 13

sensors -Chemoreceptors
Lung receptors
Other receptors send input to central controller
central controller - medulla oblongata and pons sends output
effector - respiratory muscles receive output from central controller

Question 14

pons respiratory centers

Answer 14

pneumotaxic center

apneustic center

Question 15

medullary respiratory center

Answer 15

dorsal respiratory group

ventral respiratory group

Question 16

what kind of neurons are dorsal respiratory group

Answer 16

Inspiratory neurons

Question 17

location of dorsal respiratory group

Answer 17

dorsomedial medulla

Question 18

function of - DRG dorsal respiratory group

Answer 18

DRG inspiratory neurons fire inducing muscle contraction and therefore inspiration

Question 19

what kind of neurons are ventral respiratory group

Answer 19

Both inspiratory and expiratory neurons

Question 20

when does - VRG ventral respiratory group become inactive

Answer 20

Both sets remain inactive during quiet breathing

Question 21

when does ventral respiratory group become active

Answer 21

Utilised when demand for ventilation is increased beyond normal (active expiration)

Question 22

what neurons display pacemaker like activity

Answer 22

ventral respiratory group
dorsal respiratory group
pre-bötzinger complex

Question 23

ventral respiratory group
dorsal respiratory group
pre-bötzinger complex can generate what types of breathing rythms

Answer 23

1. normal breathing (fast, low amplitude)

2. Sighs (slow, large

Question 24

what modifies the rhythm generated in the medulla

Answer 24

modified by neurons in the pons

Question 25

pneumotaxic centre function

Answer 25

sends signals to the DRG that help silence/inhibit the inspiratory neurons

Question 26

apneustic centre function

Answer 26

prevents the inspiratory neurons from being switched off

Question 27

causes of loss of function of the pneumotaxic centre and apneustic centre

Answer 27

depressant drugs on the respiratory centres cord injury damage to motor nerves (trauma, neurological disease) muscle diseases e.g. dystrophies dysfunction of the respiratory apparatus i.e. restriction and obstruction

Question 28

receptors in airways and lungs

Answer 28

stretch receptors irritant receptors j receptors

Question 29

chemoreceptors

Answer 29

peripheral | central

Question 30

stretch receptors function

Answer 30

there are nerve endings in the airway smooth muscle which are stimulated by stretch during inspiration

Question 31

where do the impulse of the stretch receptors travel to

Answer 31

impulses travel in the vagus nerve to inhibit the inspiratory centre

Question 32

Hering-Breuer inflation reflex

Answer 32

there are nerve endings in the airway smooth muscle which are stimulated by stretch during inspiration the nerve impulses travel in the vagus nerve to inhibit the inspiratory centre

Question 33

irritant receptors

Answer 33

nerve endings near the airway epithelial cells which are stimulated by noxious gases, cigarette smoke, dust and cold air

Question 34

where do the impulse of the irritant receptors travel to

Answer 34

travel in the vagus nerve causing reflex bronchoconstriction or coughing

Question 35

irritant receptors are involved in

Answer 35

asthma attacks

Question 36

j receptors function

Answer 36

nerve endings near the capillaries in the alveolar walls called juxtacapillary receptors which are stimulated by pulmonary congestion and oedema

Question 37

where do the impulse of the j receptors travel to

Answer 37

travel in the vagus nerve causing reflex apnoea or rapid shallow breathing

Question 38

irritant receptors are involved in

Answer 38

in the rapid shallow breathing and dyspnoea of pulmonary congestion and oedema

Question 39

chemoreceptors

Answer 39

Specialised cells that respond to changes in the chemical composition of the blood or other fluid

Question 40

location of peripheral chemoreceptors

Answer 40

Located near the heart in the carotid bodies - at the bifurcation of the common carotid arteries aortic bodies - above and below the aortic arch

Question 41

where do the impulses and info of peripheral chemoreceptors travel to

Answer 41

is carried via the vagus and glossopharyngeal nerves to the dorsal respiratory group

Question 42

what does peripheral chemoreceptors respond to

Answer 42

increased arterial CO conc decrease in pH decrease arterial O2 levels

Question 43

how does peripheral chemoreceptors correct the response made

Answer 43

send glossopharyngeal nerve to dorsal respiratory group - induce muscle contraction for inspiration inc. ventilation

Question 44

location of central chemoreceptors

Answer 44

medulla separate from the respiratory centres

Question 45

what stimulates central chemoreceptors

Answer 45

by an increase in brain extracellular fluid PCO2 and H+ but not by a decrease in PO2

Question 46

what is central chemoreceptors responsible for

Answer 46

responsible for 80% of the ventilatory response to increased PaCO2

Question 47

what is the central chemoreceptors response to arterial blood H+ like and why

Answer 47

poor response to arterial blood H+ because of the blood-brain barrier

Question 48

what chemoreceptor responds to all of the decreased PaO2

Answer 48

peripheral chemoreceptors

Question 49

what is responsible for most the of the response to increased arterial blood H+

Answer 49

peripheral chemoreceptors

Question 50

how can we measure ventilatory response to hypoxia and hypercapnia

Answer 50

changing the PaO2 and PaCO2 by inhaling hypoxic and hypercapnic gas mixtures

Question 51

when a graph is drawn to indicate the relationship between ventilation and PaCO2 what do we expect to see

Answer 51

steep upward graph at 30 PaCO2

Question 52

what does the graph steep line with ventilation and PaCO2 indicate

Answer 52

ventilation is sensitive to a very small change in PaCO2

Question 53

what does hypocapnia cause

Answer 53

increased neuromuscular excitability and tetany

Question 54

what does hypercapnia cause

Answer 54

depression of the nervous system and coma

Question 55

anaemic

Answer 55

the PaO2 is normal but the O2 content is < normal

Question 56

stagnant hypoxia

Answer 56

the PaO2 and O2 content are normal but O2 delivery to the tissues is reduced due to decreased blood flow

Question 57

histotoxic hypoxia

Answer 57

the PaO2, O2 content and delivery are normal but the tissues cannot use the O2 due to metabolic poisoning e.g. cyanide poisoning

Question 58

respiratory disorders are due to

Answer 58

decreased ventilation decreased alveolocapillary diffusion decreased transport

Question 59

respiratory disorders caused by decreased ventilation

Answer 59

neurological damage, muscular disorders, obstructive and restrictive pulmonary diseases etc

Question 60

respiratory disorders causes by decreased alveolocapillary diffusion

Answer 60

emphysema, oedema, fibrosis, atelectasis

Question 61

respiratory disorders causes by decreased transport

Answer 61

anaemia, carbon monoxide poisoning