Autonomic Nervous System Flashcards
Contrast somatic nervous system pathways and autonomic nervous system pathways: receptors
- SNS: skeletal muscle
- ANS: smooth and cardiac muscle and many glands
Contrast somatic nervous system pathways and autonomic nervous system pathways: sensory input
- SNS: special senses (vision, hearing, etc) and somatic senses (skin receptors)
- ANS: interoreceptors (sensory receptors found in organs, ex blood vessels)
Contrast somatic nervous system pathways and autonomic nervous system pathways: control of motor output
- SNS: voluntary control (mostly through cerebral cortex, ex primary motor area)
- ANS: involuntary control (limbic system, hypothalamus, medulla, pons, or just reflex through spinal cord)
Contrast somatic nervous system pathways and autonomic nervous system pathways: motor neuron pathway (somatic neurons/ autonomic)
- SNS: single motor neuron, possibly interneuron and single motor neuron back out to trigger effector
- ANS: 2 motor neurons; pre and post ganglionic motor neurons (sensory neuron brings info in, maybe interneuron, then pre ganglionic and post ganglionic motor neuron
Contrast somatic nervous system pathways and autonomic nervous system pathways: neurotransmitters and hormones released
- SNS: ACh
- ANS: ACh and norepinephrine (symp. or parasymp.)
Contrast somatic nervous system pathways and autonomic nervous system pathways: effectors
- SNS: skeletal muscle (voluntary action)
- ANS: smooth or cardiac muscle and glands
Parasympathetic division of ANS
- origin of pre ganglionic neurons in CNS
- parasympathetic ganglia (name and location / how close to target)
- neurotransmitter released from pre ganglionic neurons
- neurotransmitter released from post ganglionic neurons
- type of response produced
- “rest and digest”
- craniosacral outflow: pre ganglionic neurons from brain stem nuclei or second to fourth sacral nerves
- ganglia= terminal ganglia: on walls of visceral organs (closer to organs to stimulate effectors; short second pathway/ post ganglionic neuron)
- ACh released from pre and post ganglionic neurons and AChesterase from post
- response is SLUDD: salivation, lacrimation (tears), urination, digestion, defecation
Sympathetic division of ANS
- origin of pre ganglionic neurons in CNS
- sympathetic ganglia (name and location / how close to target)
- neurotransmitter released from pre ganglionic neurons
- neurotransmitter released from post ganglionic neurons
- type of response produced
- “E” situations: exercise, emergency, excitement, embarrassment
- thoracolumbar outflow: pre ganglionic neurons from thoracic nerves and first 2-3 lumbar nerves
- ganglia= sympathetic trunk ganglia: either side of vertebral column (closer to origin point) and prevertebral ganglia: anterior to vertebral column and close to abdominal arteries
- ACh released from pre ganglionic neurons and norepinephrine released from post ganglionic neurons (and COMT and MAO to inactivate)
- response is fight or flight: state of readiness (pupil and airway dilation, increased blood flow, etc)
Explain what is meant by cholinergic neurons and identify three types of ANS neurons that are cholinergic
- nerve cell that uses ACh as a neurotransmitter
- all pre ganglionic neurons
- all parasympathetic post ganglionic neurons
- sympathetic post ganglionic neurons for most sweatglands
Explain what is meant by cholinergic receptors, describe the two types (muscarinic and nicotinic receptors) and identify their major locations
- receptors that are activated by binding to ACh
- muscarinic: depolarization or hyperpolarization depending on target; effectors via parasympathetic
- nicotinic: depolarization and excitation of target; post ganglionic cell bodies and motor end plates
Identify the enzyme that inactivates ACh
acetylcholinesterase
Explain what is meant by adrenergic neurons and give their major location
- release norepinephrine and epinephrine (adrenaline) as neurotransmitter or hormone
- most sympathetic post ganglion neurons (minus sweat glands)
Explain what is meant by adrenergic receptors, identify their major locations, and describe two types (alpha and beta receptors) and briefly describe subtypes of each
- receptors respond to NE
- alpha and beta receptors respond to NE
- alpha and beta 1 = excitation
- alpha and beta 2 = inhibition
Enzymes that inactivate norepinephrine
-catechol-o-methyltransferase (COMT) and monoamine oxidase (MAO) breakdown NE
Explain how drugs can selectively activate or block cholinergic and adrenergic receptors by acting as antagonists or agonist
- antagonist: bind and block receptor; prevents neurotransmitter activity (ex. beta blockers used to block adrenergic beta receptors for heart conditions)
- agonist: bind and activate receptor; stimulates neurotransmitter (ex. nicotine stimulates nicotine receptors the same way ACh would, nicotine= agonist)
