Autonomic Nervous System Overview

What type of axon is used by postganglionic neurons?

Which type of adrenergic receptor is primarily involved in the excitation of cardiac muscle cells?

In which area are nicotinic receptors located?

Which of the following neurotransmitters is released by all neurons in the parasympathetic nervous system?

What is the primary effect of binding norepinephrine to alpha 2 receptors?

Which nerve plexus is responsible for innervating the lower limbs?

What effect does binding epinephrine to beta 2 receptors in smooth muscle cells generally cause?

Which type of receptor is responsible for binding acetylcholine in muscle and gland cells stimulated by the parasympathetic division?

Autonomic Nervous System Overview

Preganglionic neurons use class B axons to transmit signals from the CNS, synapsing with postganglionic neurons.
Postganglionic neurons use class C axons.

Neurotransmitters

Acetylcholine (ACh) is the neurotransmitter released by all parasympathetic neurons.
Norepinephrine (NE) is the primary neurotransmitter of the sympathetic nervous system (fight-or-flight response).

Receptors

Cholinergic receptors: bind to acetylcholine.
- Nicotinic receptors: Found on all postganglionic neurons in both sympathetic and parasympathetic systems, the adrenal medulla, and skeletal muscle.
- Muscarinic receptors: Found on muscles and glands innervated by the parasympathetic division, as well as sweat glands and some blood vessels.
Adrenergic receptors: bind to norepinephrine and epinephrine (adrenaline).
- Alpha receptors: Found on most cells, except cardiac muscle cells.
  - Alpha 1: Binding with NE leads to excitation.
  - Alpha 2: Binding with NE leads to inhibition.
- Beta receptors: Found on cardiac, smooth, and skeletal muscle cells, as well as in the liver, kidneys, and adipose tissue.
  - Beta 1: Found in cardiac muscle, liver, and kidney cells; binding with epinephrine (E) leads to excitation.
  - Beta 2: Found in smooth muscle of blood vessels in the heart and skeletal muscles; binding with epinephrine leads to relaxation and inhibition.
  - Beta 3: Found on adipocytes; binding with epinephrine leads to excitation, stimulating lipolysis.

Nerve Plexuses

Brachial plexus: Innervates the upper limbs.
Sacral plexus: Innervates the lower limbs and some hip structures.
Ventral rami combine to form nerve plexuses, from which peripheral nerves branch.

Explore the intricacies of the autonomic nervous system as you learn about its structure, neurotransmitters, and receptors. This quiz covers the roles of preganglionic and postganglionic neurons, as well as the function of various receptors that respond to neurotransmitters. Test your knowledge on how these components interact in both sympathetic and parasympathetic systems.