Cells and organization of the nervous system

Question 1

what does the central nervous system consists of

Answer 1

1. brain - neurons and glia
2. spinal cord - neurons and glia

Question 2

what does the peripheral nervous system consists of

Answer 2

1. peripheral nerves - neurons and glia
2. ganglia - neurons and glia

Question 3

2 general features of neurons

Answer 3

1. cells specialised for transmission of information
2. four morphological types

Question 4

3 general features of glia

Answer 4

1. support for neurons
2. five basic types
   - 4 in CNS
   - 1 in PNS
3. each type has a specific function

Question 5

4 structural components of neurons

Answer 5

1. dendrites
2. cell body
3. axon
4. axon terminals

Question 6

2 features of dendrites

Answer 6

1. receive input
2. send info to cell body

Question 7

2 features of the cell body

Answer 7

1. contains nucleus and organelles
2. sums input

Question 8

2 features of the axon

Answer 8

1. carries electrical impulses
2. may or may not be myelinated

Question 9

2 features of axon terminals

Answer 9

1. end (terminus) of axon
2. neurotransmitter release

Question 10

a group of cell bodies in the CNS

Answer 10

nucleus (plural is nuclei)

Question 11

a bundle of axons in the CNS

Answer 11

tract

Question 12

a group of cell bodies in cerebral cortex or spinal cord

Answer 12

grey matter

Question 13

bundle of axons in cerebral cortex or spinal cord

Answer 13

white matter

Question 14

group of cell bodies

Answer 14

ganglion (plural ganglia)

Question 15

bundle of axons

Answer 15

nerve

Question 16

4 functional zones of neurons

Answer 16

1. input zone
2. summation zone
3. conduction zone
4. output zone

Question 17

describe the input zone of a neuron

Answer 17

• made up of dendrites and cell body
• receives chemical signals from other neurons

Question 18

describe the summation zone of a neuron

Answer 18

• structure is called a axon hillock
• summation of inputs

Question 19

describe the conduction zone of a neuron

Answer 19

• located at the axon, may be quite long
• carry electrical signals between brain areas, to and from spinal cord, or from peripheral sensory receptors and to effector cells

Question 20

describe the output zone in the neuron

Answer 20

• located in the axon terminals
• contact with input zone of other neurons or effectors
• release of neurotransmitter (chemical signal)

Question 21

what is the axon hillock

Answer 21

anatomical location where inputs are summated before action potential

Question 22

what are the 4 morphological types of neurons

Answer 22

1. Multipolar
2. Bipolar
3. Unipolar
4. Anaxonic (axonless)

Question 23

feature of the multipolar neuron

Answer 23

multiple processes emanate from the cell body

Question 24

feature of the bipolar neuron

Answer 24

2 processes emanate from the cell body

Question 25

features of the unipolar neuron

Answer 25

- one process emanates from the cell body - the branches into dendrite and axon

Question 26

features of anaxonic neuron

Answer 26

- has non distinct axon - all processes look alike

Question 27

what are the 4 different glia cells in the CNS

Answer 27

1. astrocytes 2. microglia 3. ependymal cells 4. oligodendrocytes

Question 28

what type of glia cell is found in the PNS

Answer 28

Schwann cells

Question 29

3 features of astrocytes

Answer 29

1. supply nutrients to neurons 2. cover blood capillaries 3. injury response

Question 30

2 features of microglia

Answer 30

1. immune cells of the CNS 2. engulf microorganisms and debris

Question 31

2 features of ependymal cells

Answer 31

1. line fluid filled spaces of brain and spinal cord 2. have cilia to circulate Cerebral Spinal Fluid

Question 32

2 features of oligodendrocytes

Answer 32

1. support nerve fibres 2. ensheath them with myelin

Question 33

3 features of Schwann cells

Answer 33

1. support peripheral nerve fibres 2. ensheath them with myelin 3. similar to oligodendrocytes in CNS

Question 34

what is a myelin sheath

Answer 34

a protective layer made of a fatty substance called myelin that wraps around certain nerve fibers in the brain and spinal cord, as well as other parts of the nervous system CNS - oligodendrocytes PNS - Schwann cells

Question 35

what are the gaps between myelin called

Answer 35

Nodes of Ranvier

Question 36

what is the function of a myelin sheath

Answer 36

increases conduction velocity by acting as an insulator, preventing signal leakage and allowing impulses to "jump" between gaps in the sheath called Nodes of Ranvier, a process known as saltatory conduction

Question 37

what is the difference between Schwann cells and oligodendrocytes

Answer 37

- Schwann cells are found in the PNS, forming myelin around individual axons - oligodendrocytes are found in the CNS and can myelinate multiple axons.

Question 38

what is a synapse

Answer 38

a junction between neurons where communication occurs between the neurons the part of neurotransmission that is carried out through a chemical signal

Question 39

what does pre-synaptic and post-synaptic neurons means

Answer 39

pre-synaptic neurons are the neurons before the synaptic cleft and post-synaptic neurons are after. entirely depends on what synapse you are looking at

Question 40

what is afferent/ascending

Answer 40

SENSORY AFFERENT information goes into the brain goes up sensing something from the environment

Question 41

what is efferent/descending

Answer 41

MOTOR EFFERENT response that come from the brain goes down responding to something with an appropriate action