Control Of Breathing

Question 1

Dorsal Respiratory Group

Answer 1

Contain inspiratory neurons
Demonstrate rhythmic activity and stimulate inspiratory muscles
DRG = receive afferent input from lung receptors via vagus nerve

Question 2

Central Respiratory Group

Answer 2

Contains neurons with a degree of spontaneous rhythmic electrical pacemaker activity
Contains neurons that stimulate respiratory muscles to initiate:
Inspiration = inspiratory neurons
Expiration = expiratory neurons
Receive input from DRG and central chemoreceptors

Question 3

Pre-Botzinger complex

Answer 3

Upper end of VRG

Question 4

What is Pre-Botzinger complex?

Answer 4

Network of neurons display pacemaker activity

Self induced AP

Question 5

What does VRG and DRG form?

Answer 5

Central Respiratory rhythm generator

Question 6

What happens during normal quiet breathing?

Answer 6

Respiratory rhythm generator stimulates inspiratory neurons causing contraction of respiratory muscles

Question 7

What is expiration mostly?

Answer 7

Passive elastic recoil

Question 8

What does mutual inhibition of inspiratory and expiratory neurons result in?

Answer 8

Alternat stimulation of inspiratory and exploratory mucked

Question 9

Where does 2 regions of pons receive input from?

Answer 9

Cerebrum
Hypothalamus
Feed them into the Medullary respiratory centre

Question 10

What does sectioning of pons not alter but affect?

Answer 10

Alter: basic rhythmicity
Affects: breath duration

Question 11

When is Hering-Breuer Reflex?

Answer 11

Triggered when Tidal volume is large
E.g. during exercise
Prevents over Inflation of lungs

Question 12

What is Reflex if Hering-Breuer Reflex?

Answer 12

Tidal volume > 1 Litre
Pulmonary stretch receptors activated
AP travel via afferent nerves to primary RCC

Question 13

What is the effect of Hering-Breuer Reflex?

Answer 13

Inhibit inspiratory neurons

Stops inspiration, prevent over-inflation if lungs

Question 14

Why may PH change?

Answer 14

Extreme physiological situations

Question 15

What is Acidosis?

Answer 15

Proton accumulation

Question 16

Acidosis

Answer 16

Occurs after hard physical exercise producing lactic acid in the muscle
Lowers PH

Question 17

What are examples of metabolic acidosis?

Answer 17

Pathogen-physiological situations such as bicarbonate, HCO3-, loss in renal disease or in gut due to diarrhoea or diabetes

Question 18

What is hypoxia?

Answer 18

Deficiency in the amount of oxygen reaching the tissues

Question 19

What is hypercapnia?

Answer 19

Abnormally elevated carbon dioxide levels in the blood

Question 20

Small changes in PCO2

Answer 20

Marked changes in ventilation

Question 21

Increase in [H+]

Answer 21

Increase ventilation

Question 22

Pneumotaxic centre

Answer 22

Inhibit inspiration

Allow transition from inspiration to expiration

Question 23

Apneustic centre

Answer 23

Prolonged inspiration

It sends signal to VRG and DRG and trigger inspiration

Question 24

Central chemoreceptors

Answer 24

Sense any changes in PH of cerebrospinal fluid and interstitial fluid within CNS
Respond to PH through changes in partial pressure of CO2

Question 25

Dorsal Respiratory Group

Answer 25

Receive stretch receptor signals Send signal down to go an trigger inspiration via intercostal muscle and diaphragm Contains nucleus tractus solitarus

Question 26

Ventral Respiratory Group

Answer 26

Consist of expiratory and inspiratory neurons | Consist of pre-botzinger complex

Question 27

Pre-Botzinger complex

Answer 27

Pacemaker neurons Contr breathing Responding to hypoxia

Question 28

Hering-Breuer reflex

Answer 28

Initiated by lung expansion Excites stretch receptors in the airways Send signal to Medulla by the vagus nerve Shortens inspiratory times as tidal volume increases Accelerating the frequency of breathing Prevents overinflation of lungs

Question 29

What 2 regions does pons receive input from?

Answer 29

Cerebrum | Hypothalamus

Question 30

What does hypothalamus mediate?

Answer 30

Response to changes in temperature

Question 31

What does limbic system mediate?

Answer 31

Response to changes in emotional state

Question 32

The Hering-Breuer inflation reflex

Answer 32

Inspiration stretches airways Activates stretch receptors in bronchial smooth muscle Vagus nerve sends impulses to DRG Inspiratory neurons of DRG are inhibited Inhibits further inspiration, giving expiration time to occur

Question 33

Where are central chemoreceptors located

Answer 33

Ventrolateral surface of Medulla | Near the entry of vagus and glosso-pharyngeal nerves

Question 34

What is central chemoreceptors bathed in?

Answer 34

Cerebrospinal fluid

Question 35

What are examples of peripheral chemoreceptors

Answer 35

X vagus nerve | IX glossopharnygeal nerve

Question 36

Where are peripheral chemoreceptors located in?

Answer 36

Aortic and carotid bodies

Question 37

What does Glomus cells respond to?

Answer 37

Decrease PO2 Increase PCO2 and [H+] Main oxygen sensing cells in respiration

Question 38

What is protective involuntary factors of ventilation

Answer 38

Coughing/sneezing Inhaling noxious agents - cessation of ventilation Pain stimulates RCC Emotional: Laughing, crying, sighing Limbic system and RCC Other: swallowing Hiccups - involuntary spasmodic contractions of diaphragm

Question 39

What is voluntary factor of ventilation?

Answer 39

Hyperventilate, breath holding Brief period of time Chemical changes ultimately override voluntary input Other: speaking, singing, whistling