Physiological control of respiration

Question 1

involves the inward and outward movement of air
into the lungs

Answer 1

Respiration

Question 2

The rate of respiration regulates the partial pressures of ___ and ___ in the blood

Answer 2

oxygen (PaO2)
carbon dioxide (PaCO2)

Question 3

___ from the brain are responsible for rhythmic discharge

Answer 3

Nerve impulses

Question 4

This rhythmic discharges from the brain are regulated by changes in arterial __

Answer 4

PaO2, PaCO2 and hydrogen ion (H+)
concentration

Question 5

Respiration is controlled through ___

Answer 5

neuronal feedback loops

Question 6

These feedback loops are comprised of the
control centre, sensors, and effectors, namely:

Answer 6

• Control centre:
• respiratory nuclei in the cerebral cortex and brainstem.
• Sensors:
• mechanoreceptors
• peripheral and central chemoreceptors.
• Effectors:
• muscles of respiration

Question 7

The ___, ____, and ____ comprise the neural control of respiration

Answer 7

cerebral cortex, medulla and pons

Question 8

responsible for
voluntary control of breathing

Answer 8

cerebral cortex

Question 9

responsible for automatic breathing

Answer 9

medulla and pons

Question 10

The nerve impulses arising from respiratory neurons in these areas regulate the activity of respiratory muscles, by activating motor neurons in the ___ and ___ spinal cord that eventually innervate respiratory muscles

Answer 10

cervical
thoracic

Question 11

The physical changes in the lungs are then sensed by the ____ and central and peripheral ____ to further adjust the breathing

Answer 11

mechanoreceptors
chemoreceptors

Question 12

The higher centre of the brain responsible for control of respiration is the ____

Answer 12

cerebral cortex

Question 13

The ___ is responsible for initiating any voluntary muscular movement, including that responsible for respiration

Answer 13

primary motor cortex

Question 14

Controlled exhalation is regulated from the ___ portion of the primary motor cortex

Answer 14

inferior

Question 15

The ___ portion of the primary motor cortex is responsible for initiating the voluntary contraction and relaxation of the internal and external intercostal muscles

Answer 15

superior

Question 16

Diaphragm control from the higher centre is also located within the ___ portion of the motor cortex

Answer 16

superior

Question 17

The respiratory centre is comprised of four main anatomical areas, namely:

Answer 17

the dorsal respiratory group (DRG)
ventral respiratory group (VRG)
apneustic centre
pneumotaxic centre

Question 18

area of brain responsible for the respiratory pattern generation and where coordination of various voluntary and involuntary demands on respiratory activity occurs.

Answer 18

medulla

Question 19

The medullary respiratory centre is composed of two groups of neurons that are concentrated in two anatomical areas

Answer 19

inspiratory centre (dorsal respiratory group)

expiratory centre (ventral respiratory group)

Question 20

The DRG is located next to the ___ near the
root of cranial nerve IX

Answer 20

nucleus tractus solitarius

Question 21

the DRG has sensory afferents from peripheral
chemoreceptors via the ___ nerve and ___
nerve

Answer 21

glossopharyngeal
vagus

Question 22

functions in both quiet or forced respiration and contains neurons that control lower motor neurons innervating the external intercostal muscles and the diaphragm

Answer 22

DRG

Question 23

This group of neurons primarily control the timing of the respiratory cycle

Answer 23

DRG

Question 24

Motor output is sent to the diaphragm from the DRG via the ___

Answer 24

phrenic nerve

Question 25

a network of neurons located ventrally in the brain stem extending from the spinal cord to the pons medulla junction

Answer 25

VRG

Question 26

The VRG expiratory centre is primarily responsible for ___

Answer 26

expiration

Question 27

These neurons are primarily inactive during quiet breathing because expiration is normally a passive process

Answer 27

VRG

Question 28

The VRG comprises the following respiratory neurons:

Answer 28

* Caudal ventral respiratory group * Rostral ventral respiratory group * Pre-Bötzinger complex * Bötzinger complex

Question 29

responsible for the modification of rhythmic discharges from the medullary neurons

Answer 29

apneustic and the pneumotaxic centres

Question 30

They regulate the depth and rate of respiration in response to sensory stimuli or input from other centres in the brain

Answer 30

apneustic and the pneumotaxic centres

Question 31

The pneumotaxic centre located in the ____ interacts with the medullary respiratory centre (dorsal respiratory group) to reduce the depth of inspiration

Answer 31

upper pons

Question 32

An increase in __ output increases the rate of respiration by shortening the duration of each inhalation

Answer 32

pneumotaxic

Question 33

The apneustic centre is located in the __

Answer 33

lower part of the pons

Question 34

During forced breathing, the apneustic centres respond to sensory input from the ___ nerves regarding the amount of lung inflation

Answer 34

vagus

Question 35

There are two types of respiratory chemoreceptors, namely

Answer 35

peripheral, and central chemoreceptors

Question 36

are the main influencer of respiration.

Answer 36

Peripheral chemoreceptors

Question 37

Peripheral chemoreceptors are located in the ____ and ___

Answer 37

carotid (at the bifurcation of the carotid artery) and aortic bodies (on the aortic arch

Question 38

The afferent impulses from the carotid bodies are carried via the ___ nerve, whereas those from the aortic bodies are carried via the ___ nerve

Answer 38

glossopharyngeal vagus

Question 39

he only chemoreceptors in the body that respond to hypoxaemia

Answer 39

aortic and carotid bodies

Question 40

stimulates both aortic and carotid bodies

Answer 40

High PaCO2

Question 41

the ___ are only responsible for 20% of the body’s response to hypercapnia

Answer 41

peripheral chemoreceptors

Question 42

______ only stimulates the carotid bodies.

Answer 42

Low pH

Question 43

Low blood pressure leads to ____of the carotid and aortic bodies, subsequently increasing their neuronal output

Answer 43

hypoperfusion

Question 44

Central chemoreceptors are located in the ___, on the ventral surface, however, separate from the VRG

Answer 44

medulla

Question 45

They detect chemical changes in the medulla

Answer 45

Central chemoreceptors

Question 46

Central chemoreceptors are stimulated by a drop in ___

Answer 46

cerebrospinal fluid (CSF) pH

Question 47

CO2 then reacts with water, catalysed by ____ enzyme to form carbonic acid (H2CO3)

Answer 47

carbonic anhydrase (CA)

Question 48

stimulate the respiratory centre through the lung stretch receptors and muscle spindles

Answer 48

Mechanoreceptors

Question 49

The lung stretch receptors are located in the ____ and they are stimulated by overinflation of the lung

Answer 49

bronchial smooth muscle

Question 50

occurs when the steady lung inflation results in an increase in the duration of expiration

Answer 50

Hering–Breuer inflation reflex

Question 51

a decrease in the duration of expiration as a result of marked lung deflation is called the

Answer 51

Hering–Breuer deflation reflex

Question 52

During exercise there is a change in respiration and this change is initiated by ___ activity

Answer 52

muscle spindle

Question 53

These receptors are located in the airway epithelium

Answer 53

Irritant receptors

Question 54

Irritant receptors cause ___ and stimulate ___as a protective mechanism in response to inhalation of noxious gases

Answer 54

bronchoconstriction ventilation

Question 55

Chemicals such as ___ also stimulate Irritant receptors, thereby, activating rapidly adapting receptors in the trachea causing coughing, bronchoconstriction and secretion of mucus

Answer 55

histamine

Question 56

non-myelinated C-fibres in the alveolar walls and located in close proximity to pulmonary vessels

Answer 56

Juxtacapillary receptors (J-receptors)

Question 57

They are activated by hyperinflation of the lung, dyspnoea, bradycardia and hypotension

Answer 57

Juxtacapillary receptors (J-receptors)

Question 58

Intravenous or intracardiac administration of ___ also leads to the activation of J receptors, producing a reflex response termed pulmonary chemoreflex

Answer 58

capsaicin

Question 59

produced by receptors in the heart

Answer 59

Bezold–Jarisch reflex

Question 60

Ventilation is stimulated by activation of

Answer 60

pain recepors

Question 61

Ventilation is stimulated by an increase in ___

Answer 61

core temperature

Question 62

The fact that pain and emotional stimuli results in hyperventilation, suggests that afferents from the ___ and ___ send signals to the respiratory neurons in the brainstem

Answer 62

limbic system hypothalamus