Neurons Part 2

Question 1

The impulses are generated at the

Answer 1

Axon hillock after it comes from the neuron

Question 2

Some axons are myelinated

Answer 2

Which is a insulated material, which is produced in the support cells

Question 3

Schwann cells wrap around the axon in pns and the cytoplasm squeezes out due too

Answer 3

Mylanation

Question 4

Nodes of Ranvier.

Answer 4

Schwann cells wrap around the axon in the PNS, but they don’t cover the entire length of the axon.
The spaces left between the Schwann cells are called Nodes of Ranvier.

Question 5

Cell body

Answer 5

Cell body contains the nucleus, which is transparent and houses the nucleolus (important for ribosome production).
The cytoplasm surrounds the nucleus and contains regular organelles but lacks centrioles (since neurons don’t divide after maturity).
The rough endoplasmic reticulum (RER) is called Nissl bodies, which are involved in protein synthesis for the neuron.
Neurofibrils are intermediate filaments in the cytoplasm, essential for maintaining the shape of the neuron and transporting materials.

Question 6

All axons branch profusely at their end forming hundreds to thousands of

Answer 6

Axon terminals

Question 7

Axon terminal contain

Answer 7

Axon terminals contain hundreds of tiny vesicles (membranous sacs).
These vesicles store chemicals called neurotransmitters.
When activated, the neurotransmitters are released into the extracellular space.
The extracellular space is the gap between neurons or between a neuron and its target cell.

Question 8

Synapse

Answer 8

An impulse that is transmitted from one neuron to another occurs at the synapse.

Question 9

Synaptic cleft

Answer 9

Axon Terminals: Each axon terminal is separated by a space called the synaptic cleft.
Neuronal Separation: Neurons never physically touch each other because of this synaptic gap.
Communication: Instead of direct contact, neurons communicate across the synaptic cleft via neurotransmitters.

Question 10

Squeezed out cytoplasm from schawn cells in the pns is called neurlima

Answer 10

Protection: It acts as a protective covering around the axon, supporting the myelin sheath.
Repair: If a neuron is injured, the neurilemma helps guide the regrowth of the axon and supports the regeneration process, allowing for repair of damaged neurons in the PNS.

Question 11

Oligodendrocytes (CNS):

Answer 11

Size: Oligodendrocytes have multiple arms (projections) that allow them to myelinate several axons at once.
No Neurilemma: Oligodendrocytes do not have a neurilemma, which is why they cannot facilitate axon regeneration after injury in the same way Schwann cells can.