ANS Flashcards
What is the autonomic nervous system ?
Nervous system that controls many involuntary functions of the body
Is the autonomic nervous system a part of the CNS or PNS?
PNS
True or false
ANS effects organs which are under voluntary control
False
Involuntary control
True or false
The ANS is important for maintaining homeostasis
True
Because it controls organs that participate in homeostatic control
What are the usual effectors of ANS?
Cardiac muscle
Smooth muscle
Glands
True or false
Skeletal muscles are effectors of the ANS
False
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 !!
Divisions of the ANS
Sympathetic division (thoracolumbar)
Parasympathetic division (craniosacral)
The thoracolumbar division of the ANS is also called
Sympathetic division
The craniosacral division of the ANS is also called
Parasympathetic division
In the sympathetic division, cell bodies of the preganglionic neurons are from ________________ + _____________
THORACIC spinal cord + LUMBAR spinal cord
In the parasympathetic division, cell bodies of the preganglionic neurons are from ________________ + _____________
BRAIN + SACRAL spinal cord
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
Which is supplied directly by preganglionic fibers?
A. Adrenal cortex
B. Liver
C. Spleen
D. Adrenal medulla
D. Adrenal medulla
Most important nerve in parasympathetic nervous system?
Vagus nerve (cranial nerve 10)
Vagus nerve runs with ____________ artery and branches everywhere.
Carotid
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
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
True or false
Every organ is innervated by BOTH sympathetic and parasympathetic systems
False
What are some of the organs that are innervated by BOTH sympathetic and parasympathetic systems
Heart
Digestive tract
Pupil of eye
Salivary glands
What are some of the organs that are innervated by ONLY sympathetic innervation
Adrenal medulla
Sweat glands
Most blood vessels
Which ANS system prepares the body for Fight/Flight (activity)
Sympathetic system
Excitation of sympathetic centers will cause :
Excitation of parasympathetic centers will cause :
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
- Acetylcholine
- Norepinephrine (noradrenaline)
- 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 
Make sure you know this all
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