ANS Flashcards by Wadhha Alajmi

What is the autonomic nervous system ?

Nervous system that controls many involuntary functions of the body

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Is the autonomic nervous system a part of the CNS or PNS?

PNS

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True or false
ANS effects organs which are under voluntary control

False

Involuntary control

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True or false
The ANS is important for maintaining homeostasis

True

Because it controls organs that participate in homeostatic control

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What are the usual effectors of ANS?

Cardiac muscle
Smooth muscle
Glands

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True or false
Skeletal muscles are effectors of the ANS

False

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What is the difference between the somatic motor reflex and the autonomic motor reflex ?

In the efferent pathway:
Somatic reflex has ONE set of neurons
Autonomic reflex has TWO sets of neurons (pre + post)

Also autonomic reflex consists of an autonomic ganglion !!

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Divisions of the ANS

Sympathetic division (thoracolumbar)
Parasympathetic division (craniosacral)

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The thoracolumbar division of the ANS is also called

Sympathetic division

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The craniosacral division of the ANS is also called

Parasympathetic division

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In the sympathetic division, cell bodies of the preganglionic neurons are from ________________ + _____________

THORACIC spinal cord + LUMBAR spinal cord

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In the parasympathetic division, cell bodies of the preganglionic neurons are from ________________ + _____________

BRAIN + SACRAL spinal cord

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What is sympathetic chain and what is its importance ? (Picture is important for understanding)

Preganglionic neurons synapse at the sympathetic chain ganglia with postganglionic neuron

NOTE:⚠️

Splanchnic nerves: preganglionic neurons enters and leaves the sympathetic chain ganglion WITHOUT synapsing in it. It synapses at different ganglions with postganglionic neurons.
Adrenal medulla are innervated directly by PREganglionic fibers of the sympathetic nervous system

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Which is supplied directly by preganglionic fibers?
A. Adrenal cortex
B. Liver
C. Spleen
D. Adrenal medulla

D. Adrenal medulla

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Most important nerve in parasympathetic nervous system?

Vagus nerve (cranial nerve 10)

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Vagus nerve runs with ____________ artery and branches everywhere.

Carotid

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Difference between sympathetic and parasympathetic : where do the preganglionic and postganglionic fibers synapse ?

Sympathetic: synapse occurs outside of organ
- preganglionic : OUTSIDE of organ
- postganglionic: OUTSIDE of organ

Parasympathetic: synapse occurs at organ
- preganglionic : OUTSIDE of organ
- postganglionic: INSIDE of organ

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what do you understand from this picture

1- Adrenal medulla is responsible for making epinephrine and norepinephrine (adrenaline and noradrenaline) , which both play a role in the body’s fight or flight.

2- Adrenal medulla is innervated DIRECTLY from PREganglionic fibers

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True or false
Every organ is innervated by BOTH sympathetic and parasympathetic systems

False

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What are some of the organs that are innervated by BOTH sympathetic and parasympathetic systems

Heart
Digestive tract
Pupil of eye
Salivary glands

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What are some of the organs that are innervated by ONLY sympathetic innervation

Adrenal medulla
Sweat glands
Most blood vessels

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Which ANS system prepares the body for Fight/Flight (activity)

Sympathetic system

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Excitation of sympathetic centers will cause :

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Excitation of parasympathetic centers will cause :

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PNS or SNS

SNS

PNS or SNS

PNS

ANS can have both positive and negative effects on its effector organs. Why?

Because both PNS and SNS continuously transmit action potentials (signals) at low rate through their nerve fibers

Explain this image

Blood vessels are normally kept at a certain diameter due to LOW rate firing from the sympathetic fibers = normal blood flow However, if the rate increases and now we have a HIGHER firing rate from the sympathetic fibers, the diameter of the blood vessels decreases = VASOCONSTRICTION = REDUCED blood flow If we STOP the firing from the sympathies fibers, the diameter of blood vessels increase = VASODILATION = increases blood flow to organ

Which causes vasodilation? A. High firing rate of SNS B. Low firing rate of SNS C. No firing of SNS

C. No firing of SNS

Examples of sympathetic system in action

Blood flow to muscle in exercise - vasoconstriction of blood vessels of all organs except heart and brain Liver - stimulates glycogenolysis (glycogen to glucose), releasing glucose into the blood to provide muscles with energy

Examples of parasympathetic system in action

GI tract - causes increased blood flow, motility and secretion of GI tract Heart and lungs - reduces heart rate and contracts air tubes (bronchioles) in lung

Which of the following not an action of the PNS? A. Reduce heart rate B. Glycogenolysis C. Increased GI blood flow D. Bronchiole constriction

B. Glycogenolysis

neurotransmitters of the ANS

1. Acetylcholine 2. Norepinephrine (noradrenaline) 3. Non-adrenergic non-cholinergic (NANC)

Transmission of signals using acetylcholine as the neurotransmitter is said to be ____________________.

Cholinergic

Transmission of signals using norepinephrine (noradrenaline) as the neurotransmitter is said to be ____________________.

Adrenergic

Acetylcholine is released by:

- ALL preganglionic fibers (SNS and PNS) - MOST parasympathetic postganglionic fibers - SOME sympathetic postganglionic fibers

Norepinephrine (noradrenaline) is released by:

MOST sympathetic postganglionic fibers

What are some non-adrenergic non-cholinergic (NANC) neurotransmitters

ATP VIP NO (But NOT acetylcholine or norepinephrine)

Fill in the neurotransmitters

We said that - ALL sympathetic PREganglionic fibers release ACh. - MOST sympathetic POSTganglionic fibers release NE. HOWEVER, SOME sympathetic POSTganglionic fibers release ACh !! What do these fibers innervate?

What effect is seen there is both sympathetic and parasympathetic innervation of effectors?

Antagonistic effect

Example of antagonistic effect?

SNS increases heart rate PNS reduces heart rate

NE causes excitation to some tissues while it inhibits other tissues. Why?

Due to the presence of different receptors

Two types of adrenergic receptors

α - adrenergic receptors β - adrenergic receptors

Two types of cholinergic receptors

Nicotinic Muscularinic

What happens when NE binds to α-receptor

Increase in cytoplasmic calcium Ca++ levels

What is the second messenger of α-receptor?

Calcium

What happens when NE binds to β-receptor?

Production of cyclic adenosine monophosphate (cAMP)

What is the second messenger of β- receptor?

cAMP

(Idk if important) Stimulation of α - adrenergic receptors causes what physiological effect?

Vasoconstriction in viscera and skin

(Idk if important) Stimulation of β - adrenergic receptors causes what physiological effect?

Increased heart rate and contractility

Which acetylcholine receptor is found at the synapse between preganglionic and postganglionic fibers

Nicotinic Receptors

What kind of receptor is a nicotinic receptor

Ligand gated

What occurs as a result of simulation of nicotinic receptors by acetylcholine

Excitation (Due to depolarization )

Nicotinic receptors have __________________ effect

Excitatory

What type of receptor is muscarinic receptors]

G–protein-coupled receptors

Muscarinic receptors have __________________ effect and __________________ effect

Excitatory and inhibitory effects

Muscarinic receptors have both excitatory and inhibitory effects. When does each occur

Inhibition: - Hyperpolarization - K+ channels opened Excitation: - Depolarization - K+ channels closed

Which muscarinic receptor effect causes reduced heart rate

Inhibition (hyperpolarization)

Which muscarinic receptor effect causes increased heart rate

Excitation (depolarization)

Which part of the brain contains control centers for cardiovascular, pulmonary, urinary, reproductive , digestive systems?

Medulla oblongata

The brain stem, specifically the medulla oblongata and pons, mainly control ــــــــــــــــــــــــــــــ and _____________________

Vascular system and respiration

What parts of the brain stem control vascular system and respiration

Medulla oblongata and pons

What is controlled by the hypothalamus

Cardiovascular system Body temperature Body water secretion of ADH and signals to initiate thirst Feeding (hunger and satiety centers) Excitement and rage Endocrine function

What is the role of the POSTERIOR hypothalamus on the cardiovascular system

Increases in blood pressure and heart rate

What is the role of the ANTERIOR hypothalamus on the cardiovascular system

Decreases in blood pressure and heart rate

What part of the hypothalamus detects changes in blood temperature and causes several mechanisms for temperature regulation

ANTERIOR hypothalamus

Which nucleus in the hypothalamus is responsible for excitement and rage

Perifornical nucleus

Reflex effects of sensory inputs to brain centers: What type of sensory receptor is in the lung

Stress receptor

Reflex effects of sensory inputs to brain centers: What reflex occurs when lung stretch receptor is stimulated

Inhalation is inhibited And heart rate increases

Reflex effects of sensory inputs to brain centers: What type of sensory receptors are in the aorta

Chemoreceptor Baroreceptor

Reflex effects of sensory inputs to brain centers: What type of sensory receptor is in the heart

Stretch receptor

Reflex effects of sensory inputs to brain centers: What type of sensory receptor is in the GI tract

Stress receptor

Reflex effects of sensory inputs to brain centers: What reflex occurs when aorta chemoreceptors are stimulated

Increase breathing and heart rate

Reflex effects of sensory inputs to brain centers: What reflex occurs when Aorta baroreceptors are stimulated

Decrease in heart rate

Reflex effects of sensory inputs to brain centers: What reflex occurs when heart stretch receptor is stimulated

Increase volume of urine excretion Decrease in heart rate

Reflex effects of sensory inputs to brain centers: What reflex occurs when GI stretch receptor is stimulated

Feeling of satiety

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