Question

i) identify the components of the reflex arc
sensory (afferent) neurons
interneurons
motor (efferent) neurons
module 1: neural communication & the endocrine system
ii) label a neuron. describe the functions of each part below
neuron diagram
iii) what is a glial cell?

Explanation:

(i) Describe the components of the reflex arc

A reflex arc is a neural pathway for reflex actions. Its components are:

1. Receptor: Detects stimulus (e.g., skin receptor for touch/pain).
2. Sensory (Afferent) Neuron: Transmits sensory info from receptor to CNS.
3. Interneuron (in CNS): Processes info, connects sensory and motor neurons (in spinal cord/brain).
4. Motor (Efferent) Neuron: Transmits motor commands from CNS to effector.
5. Effector: Muscle/gland that responds (e.g., muscle contracts to move).

(ii) Label a neuron & describe each part (assuming typical neuron parts: dendrites, cell body, axon, myelin sheath, nodes of Ranvier, axon terminals)

• Dendrites: Branch-like, receive signals from other neurons.
• Cell Body (Soma): Contains nucleus, processes signals, maintains neuron.
• Axon: Long fiber, transmits electrical impulses (action potentials) away from soma.
• Myelin Sheath: Fatty layer (by glial cells) around axon, insulates, speeds impulse.
• Nodes of Ranvier: Gaps in myelin, allow saltatory conduction (faster impulse).
• Axon Terminals: End of axon, release neurotransmitters to communicate with next cell.

(iii) What is a glial cell?

Glial cells (neuroglia) are non - neuronal cells in nervous system. They support neurons:

• Astrocytes: Support, nourish neurons, form blood - brain barrier.
• Oligodendrocytes (CNS)/Schwann Cells (PNS): Produce myelin sheath.
• Microglia: Immune - like, remove debris/damaged cells.
• Ependymal Cells: Line CNS cavities, produce cerebrospinal fluid.

Answer:

s:
(i) Components of reflex arc: Receptor, Sensory Neuron, Interneuron, Motor Neuron, Effector.
(ii) Neuron parts & functions: Dendrites (receive signals), Cell Body (processes signals), Axon (transmits impulses), Myelin Sheath (insulates, speeds), Nodes of Ranvier (saltatory conduction), Axon Terminals (neurotransmitter release).
(iii) Glial cells: Non - neuronal nervous system cells that support, insulate, nourish, and protect neurons (e.g., astrocytes, oligodendrocytes, microglia, ependymal cells).