autonomic nervous system

Question 1

in regulation of blood pressure, what senses blood pressure

Answer 1

baroreceptors

Question 2

what nerve are aortic baroreceptors connected to

Answer 2

afferent cranial nerve X (vagus)

Question 3

what nerve are carotid baroreceptors connected to

Answer 3

afferent cranial nerve IX (glossopharyngeal)

Question 4

when a threshold firing rate is reached, what happens to cause a decrease in blood pressure

Answer 4

parasympathetic innovation along efferent cranial nerve X (vagus), as well as an inhibition in sympathetic stimulation, causes heart rate to decrease and vessel diameter to increase

Question 5

why does vessel diamater increase in order to lower blood pressure

Answer 5

lower total peripheral resistance, and a lower stroke volume and cardiac output

Question 6

what is the normotensive maintaining of blood pressure called

Answer 6

baroreflex

Question 7

what happens when there is a very small increase in blood pressure

Answer 7

corresponding increase in baroreceptor firing so causes blood pressure to return to normal

Question 8

what is the effect on baroreceptors if you are hypertensive

Answer 8

firing rate set point is higher, so whilst small changes in blood pressure still affect baroreceptor firing rate correspondingly, there is always higher blood pressure

Question 9

autonomic regulation of GI function: nerve

Answer 9

cranial nerve X (vagus)

Question 10

autonomic regulation of GI function: what is the cephalic response

Answer 10

where stimuli of sight, smell and taste enough to stimulate GI function before ingestion of food

Question 11

autonomic regulation of GI function: what causes the cephalic response

Answer 11

pancreas primes body by releasing insulin, release of gastric juices in stomach

Question 12

autonomic regulation of GI function: role of mechanoreceptors in stomach

Answer 12

detect distension of stomach wall and duodenum; send signals via cranial nerve X (vagus) to brain; as more food is consumed, mechanoreceptor firing increases, increasing the feeling of bloatedness (this is blunted in obesity)

Question 13

autonomic regulation of GI function: what happens when enough food has reached the intestine, including role of chemoreceptors

Answer 13

release of gut hormones in GIT, chemoreceptors on intestine signal via cranial nerve X (vagus) to stop eating

Question 14

autonomic regulation of GI function: chemoreceptors in lean vs obese people

Answer 14

in lean people, more chemoreceptors to respond to gut hormones; in obesit people these chemoreceptors are not present so requires more food to stop eating

Question 15

autonomic regulation of respiration: components of medullary respiratory centre

Answer 15

consists of ventral and dorsal group

Question 16

autonomic regulation of respiration: role of ventral group

Answer 16

coordinated rhythmicity

Question 17

autonomic regulation of respiration: role of dorsal group

Answer 17

insipration and control of diaghram

Question 18

autonomic regulation of respiration: role of pontine respiratory centre

Answer 18

rate and pattern of breathing

Question 19

autonomic regulation of respiration: role of aortic chemoreceptors when increased respiration

Answer 19

respond to drop in O2, drop in pH and increase in CO2; send to brainstem

Question 20

autonomic regulation of respiration: role of central chemoreceptors when increased respiration

Answer 20

respond to drop in pH and increase in CO2; send to brainstem

Question 21

autonomic regulation of respiration: role of mechanoreceptors in lungs

Answer 21

Hering-Breuer reflex prevent overinflation of lung, so reduce respiration

Question 22

autonomic regulation of respiration: which respiratory centre section innovates accessory muscles

Answer 22

C1-C3

Question 23

autonomic regulation of respiration: which respiratory centre section innovates diaphragm

Answer 23

C3-C5

Question 24

autonomic regulation of respiration: which respiratory centre section innovates intercostal muscles

Answer 24

T1-T11

Question 25

autonomic regulation of respiration: which respiratory centre section innovates abdominal muscles

Answer 25

T6-L1

Question 26

autonomic regulation of micturition (bladder): parasympathetic innovation

Answer 26

afferent signals results in signals being sent from mechanoreceptors to brain via parasympathetic innovation between S2-S4, causing contraction of detrusor muscle

Question 27

autonomic regulation of micturition (bladder): sympathetic innovation

Answer 27

sympathetic innervation between T10-T12, causing contraction of internal sphinctor

Question 28

autonomic regulation of micturition (bladder): overall control

Answer 28

governed by voluntary control of external sphincter due to activation of somatic motor nerves between S2-S4

Question 29

central regulation of autonomic function: higher brain centres

Answer 29

inputs via cranial nerves IX and X up the nucleus tractus solitarius to hypothalamus; signals sent down to dorsal motor nucleus of cranial nerve X or intermediolateral cell column to control output