Autonomic Nervous System Review

A set of 65 practice flashcards covering the basic functions, subdivisions, neurotransmission, receptors, and pharmacology of the Autonomic Nervous System based on Part 1 of the lecture notes.

What are the two subdivisions of the Nervous System?

The Central Nervous System (CNS) and the Peripheral Nervous System (PNS)

Which components make up the Central Nervous System (CNS)?

The brain and spinal cord

What is the primary function of the Central Nervous System (CNS)?

It receives and interprets sensory info and initiates motor responses

What are the two types of nerves in the Peripheral Nervous System (PNS)?

Afferent nerves (sensory toward CNS) and efferent nerves (motor away from CNS)

How many pairs of cranial and spinal nerves are in the Peripheral Nervous System?

$12$ pairs of cranial nerves and $31$ pairs of spinal nerves

Which nervous system subdivision innervates skeletal muscle under voluntary control?

Somatic Nervous System

Which part of the brain controls the Somatic Nervous System?

Cerebral cortex

What structures are innervated by the Autonomic Nervous System (ANS)?

Cardiac muscle, smooth muscle of internal organs, and glands

What brain structures regulate the Autonomic Nervous System (ANS)?

Hypothalamus and medulla oblongata

What is the term for contraction without any stimulus, a characteristic of the ANS?

Autorhythmicity

How does the Autonomic Nervous System achieve homeostasis?

By increasing or decreasing the activity rate of organs

What are ganglia in the Autonomic Nervous System?

Collections of synapses between preganglionic and postganglionic nerves

Where does the preganglionic nerve emerge from in the ANS?

The spinal cord

What is the path of a postganglionic nerve?

It travels from the ganglion to the internal organ or gland

What is the purpose of neurotransmitters ($NT$) in the ANS?

They keep the impulse going and stimulate the organ or gland to produce action by binding to receptors

Which neurotransmitter is released from preganglionic nerve fibers in both divisions of the ANS?

$ACH$ (Acetylcholine)

What neurotransmitter is released by cholinergic postganglionic nerve fibers in the parasympathetic division?

$$ACH$$

What neurotransmitter is released by adrenergic postganglionic nerve fibers in the sympathetic division?

$NE$ (Norepinephrine)

What are the two subdivisions of the Autonomic Nervous System?

1. Sympathetic Nervous System (fight, fright, flight) and 2. Parasympathetic Nervous System (rest and digest)

Which organs are an exception and do not receive nerves from both ANS divisions?

Blood vessels

What happens during a sympathetic response regarding energy?

A large amount of energy is exerted physically and mentally

What does the adrenal medulla release to produce sympathetic responses?

Epinephrine ($EPI$) and some Norepinephrine ($NE$)

From what substance is Norepinephrine ($NE$) synthesized?

Dopamine ($DA$)

What is the role of Dopamine ($DA$) in the sympathetic nervous system?

It is a precursor to $NE$ and stimulates $alpha$, $beta$, and dopaminergic receptors based on dose

Where are sympathetic ganglia located in relation to the effector organ?

The ganglia are far from the effector organ

What type of receptor is found at the autonomic ganglion in the sympathetic division?

Nicotinic 1 or $N_n$ receptor

Where are $\alpha_1$ adrenergic receptors located?

Glands, smooth muscles, eyes, and most arteries and veins

What are the physiological effects of $\alpha_1$ receptor stimulation?

Smooth muscle contraction, vasoconstriction, increased BP, and dilation of pupils (mydriasis)

What is the primary effect of $\alpha_2$ receptor stimulation?

Decreases release of $NE$ (negative feedback), causes vasodilation, and lowers BP

Where are $\beta_1$ receptors primarily located?

On the heart

What three positive '+' effects does $\beta_1$ stimulation have on the heart?

Positive inotropic ($\uparrow$ force), positive chronotropic ($\uparrow$ heart rate), and positive dromotropic ($\uparrow$ conduction)

Where are $\beta_2$ receptors located?

Smooth muscle, lungs, uterus, skeletal muscle arteries, and coronary arteries

Which neurotransmitter stimulates $\beta_2$ receptors only?

Epinephrine ($EPI$)

What is the effect of $\beta_2$ stimulation on the bronchioles?

Bronchodilation

According to Figure 6.1, what is the enzymatic sequence for producing Norepinephrine?

$$Tyrosine \rightarrow DOPA \rightarrow DA \rightarrow NE$$

What enzyme metabolizes $NE$ back into inactive metabolites in the nerve ending?

$MAO$ (Monoamine Oxidase)

Does Norepinephrine ($NE$) stimulate $\beta_2$ receptors?

No, $NE$ does not stimulate $\beta_2$ receptors

What effect does sympathetic stimulation have on the GI tract?

Decreased motility and secretions

What medical term refers to the dilation of the pupil?

Mydriasis

How does sympathetic stimulation affect the urinary system?

Relaxation of the urinary bladder and contraction of the urinary sphincter, decreasing urination

What is the effect of a high rate of sympathetic nerve firing on blood vessels?

Vasoconstriction, which increases blood pressure but reduces blood flow

What is the effect of a low rate of sympathetic nerve firing on blood vessels?

Vasodilation, which decreases blood pressure but increases blood flow

What metabolic process occurs during sympathetic stimulation to provide energy?

Conversion of glycogen to glucose

What are drugs that mimic the sympathetic system called?

Sympathomimetics (adrenergics or adrenergic agonists)

What are drugs that work against the sympathetic system called?

Sympatholytics (adrenergic blocking drugs, inhibitors, or antagonists)

What is the Mechanism of Action (MOA) of $\alpha_1$ Adrenergic Agonists?

Stimulates $\alpha_1$ receptors, causing smooth muscle contraction and vasoconstriction to increase BP and reduce mucous membrane swelling

What is a common clinical use for $\alpha_1$ Adrenergic Agonists regarding the nasal passages?

Promoting decongestion by shrinking swollen mucous membranes

Which receptors are stimulated by generic Adrenergic Agonists such as Epinephrine?

$\alpha_1$, $\beta_1$, and $\beta_2$ receptors

What are the common uses for Adrenergic Agonists like Epinephrine?

Severe allergic reactions/anaphylaxis, shock, and cardiac arrhythmias

What is the standard dosage for an EpiPen auto-injector?

$$0.3\,mg$$

How do $\alpha_1$ Adrenergic Blocking drugs affect blood pressure?

They cause vasodilation of blood vessels, which decreases BP

What is Benign Prostatic Hyperplasia (BPH) and which drug class treats it?

A condition where $\alpha_1$ Adrenergic Blockers are used to relax smooth muscle and increase urine flow

What common suffix is associated with $\alpha_1$ Adrenergic Blocking drugs?

"-azosin"

What is orthostatic hypotension?

A side effect of $\alpha_1$ blockers where BP drops upon position changes, requiring patient caution

What is the effect of a low dose of Beta Adrenergic Agonists (like Dopamine) on the kidneys?

Stimulates dopaminergic ($d_1$) receptors, causing vasodilation and increased renal blood flow

What happens when Beta Adrenergic Agonists are given at a moderate dose?

They stimulate $\beta_1$ receptors, increasing force of contraction and cardiac output

What is the effect of high-dose dopamine administration?

It stimulates $\alpha_1$ receptors, causing vasoconstriction and an increase in blood pressure

What is the concentration of Dobutamine in a $20\,mL$ vial with $250\,mg$ total?

$$12.5\,mg\,mL^{-1}$$

Which drug class is used to treat asthma and preterm labor by relaxing smooth muscle?

$\beta_2$ Adrenergic Agonists

What are the side effects of $\beta_2$ Adrenergic Agonists?

Tachycardia, jittery feeling, tremors, and headache

What is the Mechanism of Action for Selective $\beta_1$ Blockers?

They block $\beta_1$ receptors, decreasing force of contraction, heart rate, and conduction

What common suffix is used for Beta Blockers?

"-olol"

What are the MOAs of Non-selective Beta Blockers?

They block both $\beta_1$ and $\beta_2$ receptors

Why are non-selective beta blockers contraindicated for asthma patients?

They block $\beta_2$ receptors, which can cause bronchoconstriction and trigger respiratory distress

What are common side effects and clinical monitoring needs for patients on beta blockers?

Drowsiness, bradycardia, monitoring serum lipid levels, and monitoring glucose levels in diabetics