Respiratory System 5

Question 1

what controls and innervates breathing

Answer 1

innervated by smooth muscle and glands that are innervated by axons of lower motor neurons of autonomic nervous system
controlled by autonomic brainstem nuclei

Question 2

what controls and innervates breathing muscles

Answer 2

innervated by lower motor neurons of somatic nervous system
controlled by brainstem autonomic nuclei, cerebral cortex, and somatic nervous system

Question 3

how are the rate and depth of breathing altered

Answer 3

either through reflexes in the brainstem or controlled by the cerebral cortex

Question 4

define the respiratory center

Answer 4

autonomic nuclei in the brainstem that coordinate breathing
clusters of neurons in the pons and medulla oblongata which control rate and depth of breathing

Question 5

define the ventral respiratory group (VRG)

Answer 5

generates breathing rhythm and is an integrative center
has four main nuclei: botzinger, pre-botzinger, nucleus retro-ambiguous, and nucleus ambiguous

Question 6

define botzingner complex

Answer 6

a part of the ventral respiratory group
controls expiration by sending expiratory signals

Question 7

define pre-botzinger complex

Answer 7

a part of the ventral respiratory group
acts as pacemaker neurons
sets eupnea to roughly 12-16 breaths per minute

Question 8

define nucleus retro-ambiguous

Answer 8

a part of the ventral respiratory group
inspiratory and expiratory functions
controls mainly inspiratory signals

Question 9

define nucleus ambiguous

Answer 9

a part of the ventral respiratory group
posterior to other nuclei groups
controls some inspiratory process by controlling things like the uvula and pharynx muscles

Question 10

define the dorsal respiratory group (DRG)

Answer 10

main nuclei is nucleus of tractus solitarius (NTS)
receives peripheral signals from different receptors
sends signals to inspiration muscles

Question 11

what are the two pontine respiratory centers

Answer 11

pneumotaxic center and apneustic center

Question 12

define pneumotaxic center (parabrachial nucleus)

Answer 12

part of the pontine respiratory center
upper aspect of pons
smooths out transition between inspiration and expiration
fine tunes respiratory rate and depth

Question 13

define apneustic center

Answer 13

part of the pontine respiratory center
lower aspect of pons
controls prolonged inspiration

Question 14

how are breathing rate and depth determined

Answer 14

how long respiratory center is active
depth determined by how actively respiratory center stimulates respiratory muscles

Question 15

explain how quiet breathing occurs

Answer 15

begins when inspiratory neurons in the prebotinger complex of VRG fire to excite skeletal muscle causing them to contract which draws air in

Question 16

explain how the phrenic nerve works with the respiratory center

Answer 16

stems from VRG and DRG come together in the spinal cord
1 nerve comes out each at C3-C5 and come together to form the phrenic nerve which innervates the diaphragm

Question 17

explain how the intercostal nerves work with the respiratory center

Answer 17

stems from VRG and DRG come together in the spinal cord
1 nerve comes out each at T1-T11 and each go to intercostal and abdominal muscles

Question 18

what are the three chemical factors that influence breathing rate and depth

Answer 18

central chemoreceptors
peripheral chemoreceptors
muscle chemoreceptors

Question 19

define chemoreceptors and their function

Answer 19

chemical receptors that monitor concentrations of H+, PCO2 and PO2

Question 20

how do chemoreceptors work to control breathing rate and depth

Answer 20

chemoreceptors in medulla oblongata bring info to DRG which then talks to VRG
VRG triggers response

Question 21

what causes ventilation increase which is detected by chemoreceptors

Answer 21

increase in H+ of CSF
increase in blood H+ or PCO2

Question 22

what causes ventilation decrease which is detected by chemoreceptors

Answer 22

decrease in H+ or PCO2

Question 23

what do central chemoreceptors in medulla do

Answer 23

monitor pH (H+) changes of CSF

Question 24

what do peripheral chemoreceptors in aortic and carotid bodies do

Answer 24

monitor changes in CO2, H+, and O2 in the blood
carotid bodies send signals to glossopharyngeal nerve
aortic bodies send signals to vagus nerve
both end up at the respiratory center

Question 25

what is the major stimulus affecting breathing

Answer 25

blood CO2 levels

Question 26

why does declining PO2 levels only have a slight effect on ventilation

Answer 26

we have a huge reservoir of oxygen bound to hemoglobin
must drop below 60mmHg to become major stimulus for breathing

Question 27

explain how muscle chemoreceptors influence breathing rate and depth

Answer 27

skeletal muscles are sensitive to changes in H+ (pH) and K+ concentrations
decreased pH or increased K+ stimulates increase of breathing

Question 28

explain how muscle and joint proprioceptors influence breathing rate and depth

Answer 28

include internal receptors for mechanical stimuli; detect movement
signals have to go to spinal cord first
ex. muscle spindles, Golgi tendon organs, and joint pressure receptors

Question 29

explain how irritant receptors influence breathing rate and depth

Answer 29

when you have something in your airway, irritant receptors communicate with respiratory centers through the vagus nerve
causes decrease of airflow in and things like coughing to get irritant out

Question 30

explain how baroreceptors influence breathing rate and depth

Answer 30

found in pleura and smooth muscle of bronchioles
respond to stretch
hering-breuer reflex - prevents over inflation of lungs
turns on at >800 mL

Question 31

what does the hypothalamus do

Answer 31

increases ventilation is body is warm
decreases ventilation if body is cold

Question 32

what does the limbic system do

Answer 32

alters breathing rate due to things like pain and anxiety

Question 33

what does the frontal lobe (motor cortex) do

Answer 33

controls voluntary changes in breathing patterns