Autonomic System 1 Flashcards by Jhaunte Braithwaite

What are the 3 components of the autonomic nervous system?

Sympathetic nervous

Parasympathetic nervous

Enteric nervous system

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Explain the patterns of ganglion in the autonomic nervous system

Parasympathetic nervous- preganglionic neuron delivers ACh to ganglion and post ganglion ic neuron delivers ACh to various organ

Sympathetic- preganglionic neuron delivers ACh to ganglion and post ganglion ic neuron delivers ACh to various organ

Sympathetic- preganglionic neuron delivers ACh to ganglion and post ganglionic neuron delivers norepinephrine to various organs

Sympathetic- preganglionic neuron delivers ACh to ganglion and adrenal medulla sends epinephrine to various organs

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What are the functions of autonomic nervous system function on smooth muscle ?

Blood vessels—> blood pressure, body temperature

Gastrointestinal tract—> digestion

Bladder—> mictruition

Bronchial tree—> bronchial construction/dilation

Eye(upper eyelid, iris, ciliary body) —> pupillary dilation /constriction

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How is the heart affected by the autonomic system?

Heart rate, heart contractility

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What are the glands affected by the autonomic nervous system ?

Endocrine glands

Pancreas and adrenal glands—> metabolism

Exocrine glands

lacrimal glands—> lacrimation (tearing)
sweat glands —> sweating
salivary glands —> salivation

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What are the functions of the sympathetic nervous system?

“Fight or flight”

Stressful situations

increase in blood flow in the skeletal muscles
increase in heart rate
increase in blood pressure
increase in blood sugar level
pupillary dilation (mydriasis)

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What are the functions of the parasympathetic nervous system ?

“Rest and digest”

Conservation and restoration of body energy

Decrease in heart rate

Increase in activity of gastrointestinal tract

Papillary construction (myosis)

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Describe sympathetic division anatomy

Origin in the thoracolumbar segments (T1-L2)

Short preganglionic neurons

Long postganglionic neurons

Sympathetic ganglia located near the central nervous system

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Describe the parasympathetic division anatomy

Origin in the brain stem and sacral segments of the spinal cord (S2-S4)

Long preganglioninc neurons

Short preganglionic neurons

Parasympathetic ganglia located near the target organs

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Describe the vagus nerve

Parasympathetic fibers
Innervation of the thoracic and abdominal vscer

Vagomoty: a surgical operation in which one or more branches of the vagus nerve are cut, typically to reduce the rate of gastric secretion (e.g. in treating peptic ulcers)

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Contrast the origins of sympathetic and parasympathetic

Sympathetic origin: T1-L2 spinal cord segments (lateral horn)

Parasympathetic origin: brain stem (autonomic motor nuclei of III, VII, IX, and X cranial nerves), and sacral spinal cord segments S2-S4

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Contrast the Ganglia location of sympathetic and parasympathetic

Sympathetic-

Paravertebral sympathetic ganglion chain
Collateral ganglia (prevertebral)

Parasympathetic-
-ganglion located near or embedded within the target tissue

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Contrast cholinergic preganglionic fibers in sympathetic and parasympathetic fibers

Sympathetic- short cholinergic preganglionic fiber

Parasympathetic- long cholinergic preganglionic fiver

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Contrast adrenergic fibers in sympathetic and parasympathetic fibers

Long adrenergic postganglionic fibers

Short cholinergenic postganglionic fiber

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Contrast the ratio of preganglionic fibers to post ganglionic fibers in sympathetic and parasympathetic fibers

Sympathetic: Ratio of preganglionic fibers to postganglionic fibers is 1:20

Parasympathetic: ratio of preganglionic fibers to postganglionic fibers is 1:3

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Briefly contrast the activity of sympathetic and parasympathetic fibers

Sympathetic -activity often involves massive discharge of the entire system

Parasympathetic- activity normally to discrete organs

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Contrast the primary neurotransmitter of sympathetic and parasympathetic nervous system

Sympathetic- primary neurotransmitter of the postganglionic neurons is norepinephrine

Parasympathetic- primary neurotransmitter of the postganglionic neurons is acetylcholine

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What are the characteristics of the parasympathetic and sympathetic nervous system?

Disynaptic pathway

Preganglionic neuron is myelinated (faster transmission)

Origin of preganglionic neuron is in the central nervous system

Origin of the postganglionic neuron is the autonomic ganglia, in the peripheral NS

Preganglionic neuron releases Acetylcholine as neurotransmitter, which binds to cholinergic nicotinic receptors (nicotinic neuronal subtype Nn)

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What are the exceptions to the rule?

Adrenal medulla: directly innervated by preganglionic sympathetic fibers

Sweat glands:
Innervated by cholinergic sympathetic postganglionic neurons

Receptors on the sweat glands are cholinergic muscarinic: M3

Renal Vasculature smooth muscle:

Innervated by dopaminergic sympathetic postganglionic neurons

Receptors on the renal vasculature are dopaminergic: D1

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What is the function of chromaffin cells in the adrenal gland?

Preganglionic sympathetic axons synapse on chromaffin cells: Ach binds to Nn receptors

Chromaffin cells releases catecholamines into the CIRCULATION: 80% epinephrine(E), 20% Norepinephrine (NE)

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Explain cholinergic transmission in the presynaptic nerve

Acetyl CoA is synthesized in the mitochondria
Choline transported into the neuronal terminal by a sodium-dependent carrier (CHT1)
ACh is synthesized in the cytoplasm from Acetyl-CoA and choline, a reaction catalyzed by choline acetyltransferase (ChAT)
ACh transported into vesicles by a the vesicular ACh transporter (VAChT)
ACh released occurs when an action potential reaches the terminal and triggers calcium influx through voltage-gated calcium channels

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Explain cholinergic transmission in the synapse

Released ACh:

ACh binds to cholinergic receptors: nicotinic or muscarinic in the postsynaptic membrane
ACh binds to presynaptic M2 ACh receptors, which inhibit Ach release
Acetylcholinesterase (AChE) splits ACh into choline and acetate

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Explain adrenergic transmission in the presynaptic nerve

Presynaptic nerve

Tyrosine is transported into the adrenergic neuron by system L
tyrosine is then converted to L-DOPA by the enzyme tyrosine hydroxylase
DOPA is converted to dopamine by DOPA decarboxylase
Vesicular monoamine transporter (VMAT) translocate dopamine into synaptic vesicles
Intravesicular dopamine-B-hydroxylase converts dopamine to NE

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Explain andrenergic transmission in the synaptic cleft

Norepinephrine (NE):

released NE binds adrenergic receptors: alpha or beta on the postsynaptic membrane
Released NE binds to presynaptic a2 autoreceptors which inhibits NE release
Termination of the action of NE results from diffusion away from the receptor site and reuptake into the nerve terminal, mediated by the Na+-dependent NE transporter(NET)

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What are the types of cholinergic receptors?

Nicotinic (ion channel linked) (muscle type-Nm and neuronal type Nn) Muscarinic receptors (G-protein linked)(M1, M2,M3)

What are the types of nicotinic receptors at the skeletal muscle (NMJ)?

Nicotinic muscle subtype Nm- function: skeletal muscle contraction Use ligand gated Sodium/potassium channels

Explain the subtype, function of nicotinic receptors of the brain

Nicotinic neuronal subtype (Nn)- function: neuronal development learning and memory Signal mechanism: ligand gated Sodium/potassium channels

Explain the subtype, function of nicotinic receptors of the adrenal medulla

Nicotinic neuronal subtype Nn Chromaffin cells releases Catecholamines to bloodstream Ligand-gated Sodium/potassium channels

Explain the subtype, function of nicotinic receptors of the autonomic ganglion

Nicotinic neuronal subtype Nn Postganglionic neuron activation Ligand-gated Sodium/potassium channels

Give the function of M1 muscuranic receptors in the brain

Brain (neurons) function: higher cognitive functions ``` Signal mechanism Gq-protein- linked: Increased IP3 increased DAG Increased Ca2+ ```

Explain the function of autonomic ganglia (neuron)

Uses M1 muscuranic receptors like the brain Autonomic ganglia (neurons) Function/effect: stimulates enteric nervous system Signal mechanism Gq-protein-linked: Increased IP3 Increased DAG Increased Ca2+

Explain the role of M2 in presynaptice nerve terminal

M2 receptor neurons Function: inhibition of ACh release Signal mechanism: Gi -protein linked: Decreased cAMP

Explain the function of M2 muscuranic receptors on the heart

Heart (mainly in the atria) Decreased heart rate Decreased contractility of atria Signal: Gi-protein-linked results in decreased cAMP

Explain the function of M3 muscuranic receptors on exocrine glands

Increased exocrine secretions (lacrimal, sweat, salivary, gastric acid) Signal mechanism Gq-protein-linked: Increased IP3 Increased DAG Increased Ca2+

Explain the function of M3 muscuranic receptors on pancreatic B cells

Increased insulin release Gq-protein-linked: Increased IP3 Increased DAG Increased Ca2+

Explain the function of M3 muscuranic receptors on gastrointestinal smooth muscles

Increased gut peristalsis Gq-protein-linked: Increased IP3 Increased DAG Increased Ca2+

Explain the function of M3 muscuranic receptors on detrusor muscle

Increased bladder contraction Gq-protein-linked: Increased IP3 Increased DAG Increased Ca2+

What role does M3 muscuranic receptors play in the functioning of the eye?

Eye: pupillary sphincter muscle, ciliary muscle Function: pupillary constriction and accommodation Gq-protein-linked: Increased IP3 Increased DAG Increased Ca2+

What is the function of M3 muscarinic receptors in the bronchial smooth muscle?

Bronchial constriction Gq-protein-linked: Increased IP3 Increased DAG Increased Ca2+

What is the function of M3 muscarinic receptors in endothelial cells?

Endothelium NO-mediated vasodilation Gq-protein-linked: Increased IP3 Increased DAG Increased Ca2+

What are the adrenergic receptors ?

a-receptors : G-protein linked( had type a1 and a2) B-receptors: G-protein linked( B1, B2, B3)

What is the function of a1 receptors in the vascular smooth muscle ?

Located in vascular smooth muscle Causes vascular smooth muscle contraction Signal: Gq-protein linked

What is the function of a1 receptors in the eye

Eye: dilator papillae muscle Function: pupillary dilation Signal: Gq-protein linked

What is the function of a1 receptors in intestinal and bladder sphincter smooth muscle?

Intestinal and bladder contraction Signal: Gq-protein linked

What is the function of A2 receptors in presynaotic nerve terminals?

Decreased norepinephrine release Signal: Gi-protein linked

What is function of a2 receptors in pancreatic B cells?

Pancreatic B cells Decreased insulin receptors Gi-protein-linked

What is the function of B1 receptors for the heart ?

Increased heart rate Increased contractility Signal mechanism: Gs protein linked Increased cAMP

What are the functions of B1 receptors on the kidney (Juxtaglomerular cells)?

Increased renin release Signal mechanism: Gs protein linked Increased cAMP

What is the function of B1 receptor for adipocytes?

Increased lypolysis Signal mechanism: Gs protein linked Increased cAMP

What is the function of B2 receptors in bronchial smooth muscle?

Causes bronchial dilation Signal mechanism: Gs protein linked Increased cAMP

What is the function of blood vessels of skeletal muscle ?

Vasodilation Signal mechanism: Gs protein linked Increased cAMP

What is the function of B2 receptors in uterine smooth muscle (myometrium) ?

Decreased uterine tone Signal mechanism: Gs-protein linked Increased cAMP

What is the function B3 receptors on brown adipose tissue ?

Thermogenesis Increased lypolysis Signal mechanism: Gs-protein linked Increased cAMP

What is the function of the autonomic nervous system on skin?

Sweat glands- secretion Piloerector muscle -contraction. No parasympathetic response

What is the impact of the autonomic nervous system on Blood vessels ?

Skin - sympathetic-constriction Skeletal muscle- sympathetic-dilation Viscera- sympathetic- construction Parasymoathetic- none

What is the function of the autonomic nervous system in the SA node ?

Parasympathetic- decreased heart rate. Sympathetic- increased heart rate

What is the impact of the the autonomic nervous system on the AV node?

Parasympathetic- Decrease conduction velocity Sympathetic- increase conduction velocity

What is the function of the autonomic nervous system of the Atria?

Parasympathetic- decrease contractility Sympathetic- increase contractility

What is the function of the autonomic nervous system on the ventricle?

Parasympathetic- little effect Sympathetic- increase contractility

What is the function of the autonomic nervous system on the lungs ?

Bronchioles parasympathetic- constriction Sympathetic- dilation Glands- parasympathetic-secretion Sympathetic- decreased secretion

What is the function of the autonomic nervous system in the gastrointestinal tract?

Wall muscles= parasympathetic- contraction sympathetic- relaxation Sphincters= parasympathetic-relaxation sympathetic- contraction Glands= parasympathetic-stimulation sympathetic- inhibition