VM 704- (Physiology) ANS Organization & Receptors

What are the central components of the autonomic reflex arc?

1. Spinal cord grey matter

2. Hypothalamus

3. Medulla

What are the peripheral efferent neurons called?

Visceral motor neurons

Are sensory neurons afferent or efferent neurons?

Afferent neurons

What are the 2 main ways we can organize the 2 divisions of the autonomic nervous system?

1. Anatomically (brain or spinal cord)

2. Functionally

What are the 2 divisions of the autonomic nervous system?

1. Parasympathetic

2. Sympathetic

Where does blood flow in the parasympathetic division of the ANS (which organs)?

Kidneys and stomach (rest and digest)

What are the nerves involved in cranio-sacral outflow in the parasympathetic division of the ANS?

CN III, VII, IX, X

Which nerve is a major source of preganglionic neurons?

The vagus nerve

What kind of metabolism is associated with the sympathetic division of the ANS?

Catabolism

What is the nerve involved in thoraco-lumbar outflow in the sympathetic division of the ANS?

The spinal cord (T1-L2)

Where are the preganglionic cell bodies in the sympathetic division of the ANS?

In the lateral horn of the spinal cord

What is the difference between nAChRs N1 and N2?

N1 receptors are found on skeletal muscle, while N2 receptors are found on ganglia.

What kind of neurotransmitter does the postganglionic neuron release in the sympathetic division of the ANS?

Norepinephrine

What kind of neurotransmitter does the postganglionic neuron release in the parasympathetic division of the ANS?

Acetylcholine (ACh)

Which of the 2 divisions of the ANS regulate the enteric nervous system (gut function)?

Both sympathetic and parasympathetic

Do both the sympathetic and parasympathetic division have some input at the same time in most organs?

Yes

Which organs only have sympathetic innervation?

1. Sweat glands

2. Blood vessels

____ is released onto ____ receptors in sympathetic postganglionic neurons of the sweat glands and blood vessels.

ACh; M3

Which muscarinic ACh receptor is inhibitory?

M2

Which muscarinic ACh receptor is excitatory?

M3

What are the effects that the M3 receptor has on the body?

Contraction of urinary bladder, contraction of smooth muscle in airways

What happens to blood vessels when they receive NO (nitric oxide)?

They relax (vasodilation)

What neurotransmitters bind to adrenergic receptors?

Epinephrine, norepinephrine, dopamine

What is the role of the alpha-1 adrenergic receptor?

Vasoconstriction

What is the role of the alpha-2 adrenergic receptor?

CNS inhibition, presynaptic inhibition

What is the role of the beta-1 adrenergic receptor?

Excites contractile cells and conductile tissue

What is the role of the beta-2 adrenergic receptor?

Relaxation of smooth muscle

What is the effect of sympathetic-adrenal medulla specialization?

Instead of binding to a receptor, epinephrine is released freely into the systemic circulation.

What kinds of neurons use adrenergic signaling?

Sympathetic postganglionic neurons

What are the 4 types of autonomic drugs?

1. Sympathetic agonists

2. Sympathetic antagonists

3. Parasympathetic agonists

4. Parasympathetic antagonists

Is the alpha-2 receptor inhibitory or excitatory?

Inhibitory

Is the alpha-1 receptor inhibitory or excitatory?

Excitatory

Is the beta-1 receptor excitatory or inhibitory?

Excitatory