23 - ANS Flashcards
The ______ can change visceral function rapidly and intensely:
– Heart rate can be increased to twice normal within 3-5 seconds
– Arterial pressure can be doubled within 10-15 seconds
– Sweating can begin within seconds
ANS
In the ANS, terminal ends of these fibers usually have enlarged varicosities where neurotransmitter and large numbers of _______ are stored.
Mitochondria
The efferent activity of the ANS is largely regulated by reflexes (not spinal reflexes). A ________ reflex is located in the major systemic arteries sensing blood pressure. If BP decreases, sensory impulses to the vasomotor center of the brainstem decrease. Heart rate increases and vascular resistance increases.
Baroreceptor
The ANS pathways consist of two ______ in sequence.
Neurons
The ANS preganglionic neuron cell bodies are located within the ______, its axons are ________ and its neurotransmitter is _______.
CNS
Myelinated
ACh
The ANS postganglionic neuron cell bodies are located in the ________ ________, its axons are not ________, and its neurotransmitter is ______ in the parasympathetic system and ________ (usually) in the sympathetic system.
Peripheral ganglia
Myelinated
ACh
Norepinephrine
In the ANS, (PARASYMPATHETIC/SYMPATHETIC) glands cause secretion of large amounts of sweat. (CHOLINERGIC/ADRENERGIC) to most sweat glands, which means they are sympathetic neurons using ACh. There are a few (CHOLINERGIC/ADRENERGIC) fibers in palms and soles. This is actually a parasympathetic function distributed via sympathetic fibers.
Sympathetic
Cholinergic
Adrenergic
In the ANS, (PARASYMPATHETIC/SYMPATHETIC) glands strongly stimulates the lacrimal, nasal, salivary and GI glands of upper tract. Note that glands of lower GI tract are mostly stimulated via the _______ system.
Parasympathetic
Enteric
In the heart, (PARASYMPATHETIC/SYMPATHETIC) stimulation increases heart rate and strength of contraction.
Sympathetic
In the heart, (PARASYMPATHETIC/SYMPATHETIC) stimulation decreases heart rate and strength of contraction.
Parasympathetic
In the systemic blood vessels, (PARASYMPATHETIC/SYMPATHETIC) stimulation constricts most blood vessels while (PARASYMPATHETIC/SYMPATHETIC) stimulation has almost no effect.
Sympathetic
Parasympathetic
In arterial pressure, (PARASYMPATHETIC/SYMPATHETIC) stimulation decreases pumping of heart but has little effect on blood pressure.
Parasympathetic
In arterial pressure, (PARASYMPATHETIC/SYMPATHETIC) stimulation results in acute increase in arterial pressure but little effect long term.
Sympathetic
In general, the (PARASYMPATHETIC/SYMPATHETIC) stimulation inhibits most of the endodermal structures (GI, Respiratory, Endocrine, Auditory, Urinary).
Sympathetic
In general, the (PARASYMPATHETIC/SYMPATHETIC) stimulation excites most of the endodermal structures.
Parasympathetic
In the eyes, (PARASYMPATHETIC/SYMPATHETIC) stimulation results in pupil constriction and lens focusing.
Parasympathetic
In the eyes, (PARASYMPATHETIC/SYMPATHETIC) stimulation results in pupil dilation.
Sympathetic
In the GI tract, (PARASYMPATHETIC/SYMPATHETIC) stimulation results in a strong stimulation that inhibits peristalsis. The GI tract is normally not dependent on this type of stimulation.
Sympathetic
In the GI tract, (PARASYMPATHETIC/SYMPATHETIC) stimulation promotes peristalsis and relaxes sphincters.
Parasympathetic
The cell body of each sympathetic preganglionic neuron lies in the intermediolateral horn of the ______ _____ (CNS).
Spinal cord
The sympathetic preganglionic fiber can synapse with postganglionic neurons upward or downward in the paravertebral chain, interconnected with _______ nerves.
Spinal
T/F. The sympathetic preganglionic fiber can pass for variable distances through the chain and then through one of the sympathetic nerves to synapse in a peripheral sympathetic ganglion.
True
All preganglionic nerves are (CHOLINERGIC/ADRENERGIC).
Cholinergic
Postanglionic sympathetic fibers pass through the ______ rami, are type C fibers, and make up about 8 percent of the fibers in the average nerve.
Gray
(PREGANGLIONIC/POSTGANGLIONIC) sympathetic fibers innervate muscle to constrict blood vessels, piloerect hair, and change heart rate and force of contraction.
Postganglionic
The ________ sympathetics supply the face and thoracic viscera and are considered postsynaptic.
Cervical
The cervical sympathetic postganglionics are from what ganglia?
Superior, middle, and inferior cervical ganglia
T1-T5 paravertebral ganglia
The cervical sympathetic postganglionics exit the chain as direct fibers and travel downwards to enter the thorax as cardiopulmonary _________ nerves.
Splanchnic
The cardiopulmonary ________ nerves travel on their own and do not accompany other nerves or vessels. They function in coronary artery dilation, increase heart rate, and bronchodilation.
Splanchnic
The thoracic sympathetic chain lies against the neck of ribs and costovertebral junctions. They are made up of 12 thoracic ganglia pairs, the first one is often fused with inferior cervical ganglion going to the head and is referred to as the ________ ganglion collectively.
Stellate
Splanchnic nerves are composed of preganglionic fibers and visceral sensory fibers. They supply the abdominal viscera and synapses in the prevertebral ganglia. All preganglionic neurons are _________.
Cholinergic
This splanchnic nerve is from T5-T9 and synapses in the celiac ganglion.
Greater
This splanchnic nerve is from T10-T11 and synapses in the superior mesenteric ganglion.
Lesser
This splanchnic nerve is from T12 and synapses in the aorticorenal ganglion.
Least
This splanchnic nerve is from L1-2 and synapses in the superior and inferior mesenteric ganglion.
Lumbar
Put the following steps of post-ganglionic neurotransmitter synthesis of norepinephrine in order:
A. Hydroxylation of dopamine to norepinephrine
B. Hydroxylation of tyrosine to dopa
C. Transport of dopamine into the vesicles
D. Decarboxylation of dopa to dopamine
E. Once the neuron is stimulated, NE is released, where it binds to receptors depending on affinity
- B
- D
- C
- A
- E
After its release, norepinephrine is broken down in the cleft and recycled via the norepinephrine transporter. Then its taken up into circulation. With recycling, small amounts are returned to vesicles. Most is metabolized by ________ ________ to dihydroxyphenylglycol, which is released into circulation. It’s eventually broken down by _______, which is found in all tissues.
Monoamine Oxidase
COMT
Adrenergic receptors can be either _______ or _______.
Alpha (Alpha1 or Alpha2)
Beta (Beta1, Beta2, or Beta3)
Norepinephrine excites mainly _______ receptors but also _______ receptors to a lesser extent.
Alpha
Beta
Epinephrine excites both ______ and ______ receptors equally.
Alpha
Beta
Certain alpha receptors are ________, while others are _______.
Excitatory
Inhibitory
(ALPHA/BETA) receptors are associated with the following:
- Vasoconstriction
- Iris dilation
- Intestinal relaxation
- Intestinal sphincter contraction
- Pilomotor contraction
- Bladder sphincter contraction
- Inhibition of neurotransmitter release (alpha2)
Alpha
This type of beta receptor is associated with cardioacceleration, increased myocardial strength, and lipolysis.
Beta1
This type of beta receptor is associated with:
- Vasodilation
- Intestinal relaxation
- Uterus relaxation
- Bronchodilation
- Calorigenesis
- Glycogenolysis
- Bladder wall relaxation
Beta2
This type of beta receptor is associated with thermogenesis.
Beta3
Sympathetic preganglionic fibers are short and synapse with long postganglionic fibers via Ach and a _________ receptor. The postganglionic fibers release norepinephrine to adrenergic receptors.
Nicotinic
Parasympathetic preganglionic fibers are long and synapse with short postganglionic fibers via Ach and a ________ receptor. The postganglionic fibers release Ach to ________ receptors.
Nicotinic
Muscarinic
Muscarinic and nicotinic are both _________, however _______ deals with GPCR and ________ deals with ion channels.
Cholinergic
Muscarinic
Nicotinic
This drug blocks the synthesis and storage of norepinephrine.
Reserpine
This drug blocks the sympathetic beta1 and beta2 receptors.
Propranolol
This drug blocks mostly sympathetic beta1 receptors.
Metoprolol
Adrenergic beta receptor blockers (“Beta Blockers”) attenuate the actions of the _________ system. They decrease heart rate and force of contraction, and are antihypertensive. 13 are commonly prescribed.
Sympathetic
_______ _______ can have the following side effects:
- Fatigue
- Hypotension
- Bradycardia
- Associated with negative changes in blood lipid profiles
- Associated with higher glucose and insulin levels
Beta blockers
______ adrenergic receptor blocker of the sympathetic system will decrease blood pressure, because these receptors normally focus on vasculature and cause the contraction of _______ _______ cells.
Alpha
Smooth muscle
This is stimulated by the sympathetic system and secretes about 80 percent epinephrine and 20 percent norepinephrine hormones. The hormones last 5-10 times longer than neurotransmitter versions because there is no local intense reuptake and destruction.
Adrenal medulla
The secretory cells of the adrenal medulla are the ________ ________. They have rudimentary fibers that secrete epinephrine and norepinephrine.
Postganglionic neurons
Note that norepinephrine/epinephrine is active for only a few seconds when secreted by neurons, but when secreted into the blood (via the adrenal medulla) it remains active until destroyed by _______ in surrounding tissues, especially the liver.
COMT
Alarm or stress response occurs when there is a mass discharge of the entire _________ system (fright, fear, severe pain):
- Increased arterial pressure
- Rerouting of blood flow to active muscles
- Increased rates in cellular metabolism
- Increased blood glucose concentration
- Increased glycolysis in liver and muscle
- Increased muscle strength
- Increased mental activity
- Increased blood coagulation rate
Sympathetic
About 75 percent of all parasympathetic fibers are in the _______ nerve.
Vagus (CN X)
T/F. Most preganglionic fibers of the parasympathetic system pass all the way to the organ that is to be innervated.
True
__________ parasympathetic fibers are located in the wall of the organ and use Ach as their neurotransmitter.
Postganglionic
Some cranial nerves carry parasympathetic signals, which are…
Oculomotor (CN III)
Facial (CN VII)
Glossopharyngeal (CN IX)
Vagus (CN X)
The parasympathetic system has ________ nerves that pass through the spinal nerve _______ plexus on each side of S2 and S3. It supplies the colon, rectum, urinary bladder, and external genitalia.
Sacral
Sacral
Most parasympathetic nerves are __________ and synapse at the effector organ. There are very short _________ fibers.
Preganglionic
Postganglionic
The preganglionics of this cranial nerve come from the Edinger-Westphal nucleus to the ciliary ganglion, and its postganglionics go from the ciliary ganglion to the sphincter pupillae muscle.
Oculomotor nerve (CN III)
The motor function of this cranial nerve includes innervating the skeletal muscles of the eyes, including levator palpebrae superioris, superior rectus, medial rectus, inferior rectus, and inferior oblique.
Oculomotor nerve (CN III)
The parasympathetic function of this cranial nerve includes the constriction of pupillae of the iris and the ciliary muscles.
Oculomotor nerve (CN III)
The preganglionics of the cranial nerve go from the superior salivatory and lacrimal nuclei to the submandibular/sublingual ganglia. Its postganglionics go to the lacrimal gland, submandibular gland, sublingual gland, and mucous glands.
Facial nerve (CN VII)
The motor function of this cranial nerve is to provide innervation to the muscles of facial expression, as well as the muscles in the inner ear.
Facial nerve (CN VII)
The sensory innervation of this cranial nerve is to carry sensation of taste from the anterior 2/3 of the tongue.
Facial nerve (CN VII)
The parasympathetic innervation of this cranial nerve stimulates the submandibular and sublingual glands to increase the flow of saliva and stimulates the nasal mucosa.
Facial nerve (CN VII)
The preganglionics of this cranial nerve go from the inferior salivatory nucleus to the otic ganglion. The postganglionics go to the parotid gland.
Glossopharyngeal nerve (CN IX)
This cranial nerve functions to carry general sensation and sensation of taste from the posterior 1/3 of the tongue. It innervates the skeletal muscle to the stylopharyngeus muscle, and an injury to it can result in impaired swallowing.
Glossopharyngeal nerve (CN IX)
This is the longest nerve in the human body and it runs parallel to the esophagus, as well as innervates the esophagus.
Vagus nerve (CN X)
The vagus nerve passes posterior to root of lung on each side then pierces the diaphragm with the esophagus, then it becomes the _______ nerve and supplies viscera in the thoracic cavity.
Gastric
The vagus nerve does what to the heart?
Lowers heart rate
The ______ nerve does the following to the GI tract:
- Controls taste and saliva
- Increases stomach acidity (via release of histamine), digestive secretion, gut flow
- Role in controlling blood glucose balance
- Assists in releasing bile
Vagus
The vagus nerve promotes the general function and filtration of the ________.
Kidneys
For reproduction, the vagus nerve helps control ________.
Fertility
If there is a _______ nerve dysfunction, then the following can occur:
- Irritable bowel syndrome
- Anxiety
- Depression
- High or low heart rate
- Difficulty swallowing
- Esophageal reflux
- Migraines (association)
- Anxiety disorders
Vagus
________ + ________ = Acetylcholine
Acetyl-CoA
Choline
What is the enzyme used to form acetylcholine from acetyl-CoA and choline?
Choline acetyl-transferase
Acetylcholine can be broken down into _______ and _______ by the enzyme _________.
Choline
Acetate ion
Acetylcholinesterase
This is a poison from toadstools.
Muscarine
These receptors are found on all effector cells stimulated by postganglionic cholinergic neurons.
Muscarinic
These receptors are found in autonomic ganglia at synapses between preganglionic and postganglionic neurons. They are present in neuromuscular junctions in skeletal muscles.
Nicotinic
(MUSCARINIC/NICOTINIC) receptors have different subsets that can be stimulatory or inhibitory. They work through G-proteins.
Muscarinic
(MUSCARINIC/NICOTINIC) receptors work through ion channels.
Nicotinic
_______ _______ drugs because they bring to acetylcholine receptors (nicotinic or muscarinic).
Direct cholinergic
______ drugs inhibit cholinesterase (thus promoting acetylcholine to linger longer).
Indirect
Some chemical weapons are parasympathetic drugs such as _______ (indirect), and ______ ______.
Sarin
Tear gas
This drug is primarily used to treat glaucoma and an overdose is similar to nerve agents. It binds muscarinic and nicotinic receptors.
Carbachol
__________ drugs are not rapidly destroyed by cholinesterase. They include pilocarpine and methacholine. They act directly on muscarinic receptors.
Parasympathomimetic
Drugs that inhibit acetylcholinesterase are…
Neostigmine
Pyridostigmine
Ambenonium
Drugs that block cholinergic activity are…
Atropine
Homatropine
Scopolamine
