13.1 Neurons: Types, Reflex Arcs, and Checkpoint Review

Flashcards covering neuron types, reflex arc components and sequence, and a couple of clinical notes (CMT1/CMT2) based on the provided lecture notes.

What are the three main types of neurons?

Sensory (afferent) neuron, interneuron, and motor (efferent) neuron; interneurons are located in the CNS.

Where are interneurons located?

In the central nervous system (brain and spinal cord) only.

What does a sensory neuron do?

It carries sensory information into the CNS (toward the brain/spinal cord).

What does a motor neuron do?

It carries information out of the CNS to an effector (muscle, gland, or organ) to trigger a response.

What is an effector?

A muscle, gland, or organ that responds to motor neuron signals.

What does 'inter' in interneuron mean?

'Inter' means between; an interneuron is between two other neurons.

What are the five basic components of a reflex arc (in order, excluding the initial stimulus)?

Sensory receptor, sensory neuron, interneuron, motor neuron, and effector.

What is the purpose of reflexes?

Survival; they are involuntary and fast, often bypassing the brain for speed.

Do reflexes involve the brain in the initial response?

Usually not; the reflex arc bypasses the brain for speed, though the brain may process the signal afterward.

Describe the patellar (knee-jerk) reflex arc.

A stretch stimulus to the knee causes the quadriceps to contract via a reflex through the spinal cord and motor neuron, producing leg extension.

Which part does CMT1 damage?

The myelin sheath around axons.

Which part does CMT2 affect?

The axon itself.

Why do interneurons often have short axons in the brain?

Because they are in the CNS and form many local connections, so long axons are not needed.

What is the direction of information flow for sensory vs motor neurons?

Sensory neurons carry information toward the CNS; motor neurons carry information away from the CNS to effectors.