Ch9 ANS 1 Flashcards
receptors of the ANS
- mechanoreceptors
- chemoreceptors
- nociceptors
- thermoreceptors
mechanoreceptors respond to
- pressure
- stretch
chemoreceptors respond to
chemical concentrations in the blood
nociceptors respond to
- stretch
- ischemia
different types of thermoreceptors in:
- hypothalamus
- skin
hypothalamus thermoreceptors respond to
very small changes in the temp of circulating blood
cutaneous thermoreceptors respond to
external temperature changes
visceral afferents synapse with
- visceral afferents in the spinal cord
- neurons that ascend to regions of the brainstem, hypothalamus, and thalamus
visceral nociceptive afferents synapse with
- somatosensory nociceptive afferents
- somatic efferents
visceral nociceptive afferents synapsing with somatosensory nociceptive efferents cause
referred pain
visceral nociceptive afferents synapsing with somatic efferents produce
muscle guarding
autonomic functions controlled in the medulla
- heart rate
- respiration
- vasoconstriction/vasodilation
How does the medulla regulate autonomic functions?
- signals to autonomic efferents in spinal cord
- signals conveyed by vagus nerve
autonomic functions controlled in the pons
regulation of respiration
How are the autonomic functions of the brainstem controlled?
- hypothalamus
- thalamus
- limbic system
What does the hypothalamus influence?
- cardiorespiratory
- metabolic
- water reabsorption
- digestive activity
How does the hypothalamus exert influence?
acts on
- pituitary gland
- control centers in brainstem
- spinal cord
How does the hypothalamus use visceral information?
maintains equilibrium in the body
Where is the majority of the visceral information conveyed?
limbic system
What is the role of the thalamus in the processing of visceral information?
- projects to the limbic system
limbic system
- in cerebrum
- involved in emotion, mood, motivation
autonomic responses of the limbic system
- activated areas produce responses
- increased HR due to anxiety, blushing, crying, etc.
classifications of autonomic efferents
- sympathetic
- parasympathetic
How many neurons in the pathway that connects the CNS to the autonomic effectors?
2
Where do the two neurons between CNS/efferents synapse?
peripheral ganglion
preganglionic neuron
extends from CNS to ganglion
postganglionic neuron
connects ganglion with effector organ
differences between somatic and autonomic system
- unconscious regulation due to hormones
- internal organs function independent of CNS input
- number of neurons
somatic pathways have __ neurons
1
autonomic pathways use ___ neurons
2: synapse outside the CNS
How is all CNS output delivered?
somatic or autonomic efferents
somatic efferents innervate
- only skeletal muscle
- frequently voluntary
autonomic efferents innervate
- all other body parts (other than muscle) that are innervated
autonomic neurons secrete these neurotransmitters
- acetylcholine (cholinergic)
- norepinephrine (adrenergic)
- epinephrine (adrenergic)
Which ANS neurons secrete acetylcholine?
- all ANS preganglionic neurons
- postganglionic neurons of parasympathetic system
What do the effects of a NT depend upon?
type of receptors activated by the NT
2 groups of cholinergic receptors
- muscarine (poison derived from mushrooms)
- nicotine (derived from tobacco)
How does nicotine work?
activates ACH receptors on skeletal muscle membrane and in limbic areas of the brain
- limbic system causes alertness/arousal » addiction
- improves performance on tasks that require careful, intense attention
NT released by most sympathetic postganglionic neurons
norepinephrine
Which part of the brain releases epi and norepi directly into the blood?
medulla
What are receptors called that bind norepinephrine and epinephrine?
adrenergic receptors
two groups of adrenergic receptors
α and β
