BIO 225 ch13 part 3 notes

These flashcards cover key concepts from Chapter 13 of the peripheral nervous system, focusing on motor innervation, reflexes, and key definitions.

What is included in the peripheral nervous system (PNS)?

The peripheral nervous system includes all components outside the brain and spinal cord, including nerves and receptors.

How many pairs of spinal nerves are there?

There are 31 pairs of spinal nerves.

What neurotransmitter is released at the neuromuscular junction?

The neurotransmitter released at the neuromuscular junction is acetylcholine.

What happens to calcium ions at the axon terminal during action potential propagation?

Calcium ions enter the axon terminal when voltage-gated calcium channels open, facilitating neurotransmitter release.

What role do somatic motor neurons play?

Somatic motor neurons innervate skeletal muscle, enabling voluntary movement.

What is the difference between somatic reflexes and autonomic reflexes?

Somatic reflexes involve skeletal muscle, while autonomic reflexes involve smooth muscle, cardiac muscle, or glands.

What are the five components of a reflex arc?

The five components of a reflex arc include: sensory receptor, sensory neuron, integration center, motor neuron, and effector.

What is the primary motor cortex responsible for?

The primary motor cortex is responsible for initiating voluntary muscle movements.

What are central pattern generators?

Central pattern generators are neural circuits that produce rhythmic outputs, often involved in repetitive behaviors like walking.

What is the function of the cerebellum in motor control?

The cerebellum fine-tunes and coordinates muscle movements for smooth execution.

What is alpha-gamma coactivation?

Alpha-gamma coactivation refers to the simultaneous activation of alpha motor neurons and gamma motor neurons to maintain muscle spindle activity during muscle contraction.

What are the two types of innervation fibers in muscle spindles?

The two types of innervation fibers in muscle spindles are gamma efferent fibers (sensory) and alpha efferent fibers (motor).

What type of muscle fibers are extrafusal muscle fibers?

Extrafusal muscle fibers are the regular contractile skeletal muscle cells responsible for muscle contraction.

What is the purpose of neurotransmitter release into the synaptic cleft?

Neurotransmitter release into the synaptic cleft allows for communication between neurons and muscle cells or glands.

What is the effect of sodium ions entering muscle cells?

The entry of sodium ions into muscle cells depolarizes the cell, leading to muscle contraction.

What is an inborn reflex?

An inborn reflex is a reflex action that is naturally occurring without prior learning or experience.

What is a learned reflex?

A learned reflex is a reflex action that is developed through experience or practice, such as stopping at a red light.