autonomic nervous system Flashcards
autonomic response: explain the regulatory role of the autonomic nervous system and explain the role in the fight-flight stress response
in regulation of blood pressure, what senses blood pressure
baroreceptors
what nerve are aortic baroreceptors connected to
afferent cranial nerve X (vagus)
what nerve are carotid baroreceptors connected to
afferent cranial nerve IX (glossopharyngeal)
when a threshold firing rate is reached, what happens to cause a decrease in blood pressure
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
why does vessel diamater increase in order to lower blood pressure
lower total peripheral resistance, and a lower stroke volume and cardiac output
what is the normotensive maintaining of blood pressure called
baroreflex
what happens when there is a very small increase in blood pressure
corresponding increase in baroreceptor firing so causes blood pressure to return to normal
what is the effect on baroreceptors if you are hypertensive
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
autonomic regulation of GI function: nerve
cranial nerve X (vagus)
autonomic regulation of GI function: what is the cephalic response
where stimuli of sight, smell and taste enough to stimulate GI function before ingestion of food
autonomic regulation of GI function: what causes the cephalic response
pancreas primes body by releasing insulin, release of gastric juices in stomach
autonomic regulation of GI function: role of mechanoreceptors in stomach
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)
autonomic regulation of GI function: what happens when enough food has reached the intestine, including role of chemoreceptors
release of gut hormones in GIT, chemoreceptors on intestine signal via cranial nerve X (vagus) to stop eating
autonomic regulation of GI function: chemoreceptors in lean vs obese people
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
autonomic regulation of respiration: components of medullary respiratory centre
consists of ventral and dorsal group
autonomic regulation of respiration: role of ventral group
coordinated rhythmicity
autonomic regulation of respiration: role of dorsal group
insipration and control of diaghram
autonomic regulation of respiration: role of pontine respiratory centre
rate and pattern of breathing
autonomic regulation of respiration: role of aortic chemoreceptors when increased respiration
respond to drop in O2, drop in pH and increase in CO2; send to brainstem
autonomic regulation of respiration: role of central chemoreceptors when increased respiration
respond to drop in pH and increase in CO2; send to brainstem
autonomic regulation of respiration: role of mechanoreceptors in lungs
Hering-Breuer reflex prevent overinflation of lung, so reduce respiration
autonomic regulation of respiration: which respiratory centre section innovates accessory muscles
C1-C3
autonomic regulation of respiration: which respiratory centre section innovates diaphragm
C3-C5
autonomic regulation of respiration: which respiratory centre section innovates intercostal muscles
T1-T11
autonomic regulation of respiration: which respiratory centre section innovates abdominal muscles
T6-L1
autonomic regulation of micturition (bladder): parasympathetic innovation
afferent signals results in signals being sent from mechanoreceptors to brain via parasympathetic innovation between S2-S4, causing contraction of detrusor muscle
autonomic regulation of micturition (bladder): sympathetic innovation
sympathetic innervation between T10-T12, causing contraction of internal sphinctor
autonomic regulation of micturition (bladder): overall control
governed by voluntary control of external sphincter due to activation of somatic motor nerves between S2-S4
central regulation of autonomic function: higher brain centres
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
