Autonomic and Somatic Nervous Systems

These flashcards cover key concepts from the lecture on the autonomic and somatic nervous systems, including divisions, neurotransmitters, functions, and anatomical details.

What are the two divisions of the Peripheral Nervous System (PNS)?

Afferent division and Efferent division.

What does the Efferent division of the PNS consist of?

The Autonomic nervous system and the Somatic nervous system.

What neurotransmitter is released by parasympathetic postganglionic fibers?

Acetylcholine (ACh).

What neurotransmitters are released by sympathetic postganglionic fibers?

Norepinephrine (NE) and Epinephrine (E).

What is the main function of the Somatic Nervous System?

It controls skeletal muscles.

What is dual innervation in the context of the autonomic nervous system?

It refers to the innervation of an organ by both sympathetic and parasympathetic branches.

What type of muscle is innervated by the autonomic nervous system?

Smooth muscle, cardiac muscle, and glands.

Where do sympathetic preganglionic fibers originate?

Thoracic and lumbar regions of the spinal cord.

What effect does sympathetic stimulation have on the heart?

Increases heart rate and force of contraction.

What is the primary function of the autonomic nervous system?

To regulate involuntary bodily functions.

Name a major effect of parasympathetic stimulation.

Decreases heart rate and facilitates digestion.

What is the role of the adrenal medulla in the sympathetic nervous system?

It secretes catecholamines (epinephrine and norepinephrine) into the bloodstream.

What is a neuromuscular junction?

The synapse where a motor neuron communicates with a skeletal muscle fiber.

How does acetylcholine affect muscle contraction?

It binds to receptors on muscle cells, triggering contraction.

What happens to acetylcholine after it has acted at the neuromuscular junction?

It is broken down by acetylcholinesterase.

What is the major distinction between autonomic and somatic nervous systems?

Autonomic is involuntary and controls smooth/cardiac muscles and glands, while somatic is voluntary and controls skeletal muscle.