Chapter 14 - The Autonomic Nervous System Flashcards
Somatic Motor Division - Somatic motor neurons directly innervate ——– muscles, ——- control; acetylcholine (ACh); excitatory/inhibitory?
skeletal muscles
voluntary control
Excitatory
Visceral Motor Division (ANS) - Autonomic motor neurons innervate —— & ——– muscles , and glands; ——- control
Smooth & cardiac
Involuntary Control
2 neurons are involved in Visceral Motor Division
Preganglionic neurons
Postganglionic neurons
——— neuron: Cell body in the PNS autonomic ganglion; axon synapses on the target cell; often ACh and norepinephrine; EXCITATORY & INHIBITORY
Postganglionic neuron
Cell body in the CNS; Synapses on the other ganglionic neuron
Preganglionic neuron
Autonomic Nervous System Divisions
Sympathetic Nervous System
Parasympathetic Nervous System
Sympathetic or parasympathetic where Preganglionic axons are LONG and postganglionic axons are SHORT
Parasympathetic Nervous System
Sympathetic or Parasympathetic where preganglionic axons are SHORT, and postganglionic axons are LONG
Sympathetic Nervous System
——- Division is where cell bodies of preganglionic neurons originate in thoracic and upper lumber spinal cord
Thoracolumbar Division
Sympathetic ganglia are generally near the…
Spinal cord
——- Division is where cell bodies of preganglionic neurons are located within nuclei of cranial nerves in the brainstem and the sacral region of the spinal cord
Craniosacral Division
Parasympathetic ganglia are near or within—-
Target organs
Clusters of neuron cell bodies that house millions of synapses
Ganglia
Actions of the parasympathetic nervous system directly ——– those of the sympathetic nervous system
ANTAGONIZE
Sympathetic neurons ——– heart rate
Increases
Parasympathetic neurons ———- hear rate
Decreases
——— nervous system prepares the body for emergency situations
Sympathetic Nervous System
——— nervous system maintains homeostasis when body is engaged in physical work (Ex: standing)
Sympathetic nervous system - Temporarily initiates changes in heart rate and blood vessel diameter to encounter effect of gravity on blood pressure, which can drop and cause you to fall
——- nervous system mediates the body’s visceral responses to emotion
Sympathetic nervous system
Classes of Sympathetic Neurotransmitters
The preganglionic axon communicates with postganglionic neurons at an excitatory synapse using a neurotransmitter called
Acetylcholine (ACh)
Sympathetic Nervous System - The postganglionic axon releases ———– (Noradrenaline), ———– (Adrenaline), or ——–
Norepinephrine
Epinephrine
Acetylcholine (ACh)
Classes of Sympathetic Receptors
———– Receptors bind to norepinephrine and epinephrine; include different types of ——- receptors & ——– receptors
Adrenergic receptors
Alpha & Beta receptors
——– receptors: found in the ———- of certain sympathetic target cells in the pancreas and adipose tissue; most in the plasma membrane of ———- sympathetic neurons, where ———- occurs, and slows or cancels the action potential, prevent excessive activity by damping or shutting off sympathetic response
Alpa 2 receptors
plasma membrane of certain sympathetic target cells
preganglionic sympathetic neurons
hyperpolarization occurs
When Alpa 2 receptors are ——– bound to norepinephrine, the preganglionic neuron releases —–, exciting the —— neuron
are not bound
ACh
postganglionic neuron
When Alpa 2 receptors are ——– bound to norepinephrine, the preganglionic neuron hyperpolarizes, decreasing —— release, and ——— neuron activity
Are bound
ACh
postganglionic neuron activity
—— receptors - Membranes of Cardiac muscle cells and certain cells of the kidneys
Beta 1 receptors
—— receptors - Membranes of smooth muscles in bronchioles, urinary bladder, blood vessels of skeletal muscles, liver and pancreas cells and salivary glands
Beta 2 receptors
—– receptors - Cells of adipose tissue, smooth muscles in walls of digestive tract
Beta 3 receptors
The sympathetic Nervous System’s most basic function is to—-
- Ensure survival
- Maintain homeostasis during times of physical or emotional stress
The Parasympathetic Nervous System’s most basic function is to—
Maintain homeostasis when body is at rest
Most drugs target the sympathetic nervous system in two ways
Antagonists
Agonists
Antagonist effects + what receptors are targeted
Alpha1 + Beta1
Block the receptor and prevent norepinephrine from binding to it
Agonist effects + what receptors are targeted
Alpha2 + Beta2
Bind the receptor and Mimic the effects of norepinephrine
Sympathetic tone dominant in
blood vessels and keeps them partially constricted at all times
parasympathetic tone is dominant in
heart and digestive system
keeps the heart rate at an average of 72 beats/minute
—— ——— is when most organs are innervated by neurons from both SNS and PSNS
Dual innervation
SNS: dominant during exercise or emergency
PSNS: regulate same organs when the exercise or emergency has finished
