Cells and tissues of the nervous system

Question 1

PNS consists of nerves of (2)

Answer 1

• Cranial nerves
• Spinal nerves

Question 2

What fibres do spinal nerves carry (4)

Answer 2

• Afferent -Sensory
• Efferent - motor

Efferent- motor consist of :

1. Somatic motor
2. Autonomic motor

Autonomic consist of :

1. sympathetic
2. parasympathetic

Question 3

2 cell types making up the nervous system

Answer 3

Neurons Glia/ glial cells

Question 4

Are glial cells excitable

Answer 4

No, supporting cells that support neurons.

Question 5

Typical neuron consists of (4)

Answer 5

MULTIPLE DENDRITES, 1 CELL BODY, 1 AXON & SYNAPTIC TERMINALS

Question 6

What is the cytoplasm of the cell body of a neuron known a, and What is the cytoplasm of the axon of a neuron known as?

and what is the rough endoplasmic reticulum(rER) called?

Answer 6

cell body cyto-Perikaryon

Axon cyto- Axoplasm

rER- Nissl bodies

Question 7

Do neurons proliferate by mitosis

Answer 7

No, they proliferate by amitosis (unusual form of cell division in which the nucleus and cytoplasm divide by constriction without the formation of chromosomes)

Question 8

Are neurons or glia bigger

Answer 8

Neurons

Question 9

Axons may or may not be covered in a

Answer 9

Myelin sheath

Question 10

Purpose of a myelin sheath

Answer 10

Increase conduction speed by “saltatory conduction” where the action potential jumps fron on mylein sheath to other, without going striaght into each myelin sheath.

Question 11

Myelin sheath is formed by what type of glial cell -in the PNS -in the CNS

Answer 11

PNS - Schwann cells CNS - oligodendrocytes

Question 12

3 types of neurons

Answer 12

Multipolar - e.g. motor neurons

Bipolar olfactory mucosa, retinal nerve fibres

Pseudounipolar - e.g. sensory neurons

Question 13

What type of neurons are motor neurons

Answer 13

Multipolar

Question 14

What type of neurons are sensory neurons

Answer 14

Pseudounipolar

Question 15

Name 6 types of glial cells + which of these are in the CNS (4) and the PNS (2)

Answer 15

CNS: 1.Astrocytes 2. Oligodendrocytes 3. Microglial cells 4. Ependymal cells PNS: 1. Schwann cells 2. Satellite cells

Question 16

Most abundant glial cell in the CNS

Answer 16

Astrocytes

Question 17

2 functions of astrocytes

Answer 17

1. Provide structural and biochemical support to neurons
2. Forms part of BBB (due to its end feet projections)

Question 18

Function of microglia, and why do you need specific cells for this function?

Answer 18

Phagocytosis and scar tissue formation, because of the BBB

Question 19

What is the function of oligodendrocytes and Schwann cells?

Answer 19

Myelination

Question 20

Function of ependymal cells (a type of glial cell)

Answer 20

Linning the cavaties of the brain called: ventricles and they also line the central canal of the spinal cord.

Question 21

What is the function of satellite cells?

Answer 21

Unknow, but they surround neural cell bodies

Question 22

What is grey matter composed of

Answer 22

Cell bodies of neurons

Question 23

Focused collections of neuronal cell bodies are called in the CNS

Answer 23

nuclei

Question 24

1. Focused collections of neuronal cell bodies outside the CNS are called
2. what is the name given to bundle of axons connecting nuclei?

Answer 24

1- ganglia, e.g. DRG

2. Fibre tracts or nerve tracts

Question 25

Function of the BBB (brain blood barrier

Answer 25

SEMIPERMEABLE membrane allowing passage of water, some gases, and hydrophobic (O2, CO2) molecules by passive diffusion, as well as the selective transport (transport protein required) of molecules such as glucose and amino acids

Question 26

Circumventricular organs are those that lack a

Answer 26

BBB They have a highly permeable microvasculature

Question 27

Where are circumventricular organs found

Answer 27

Midline structures around the third and fourth ventricles

Question 28

Drugs entering brain have to be … … or use suitable … or else it can’t cross the BBB

Answer 28

lipid soluble vectors

Question 29

What special feature do astrocytes have

Answer 29

Long end feet projections that surround synapses & capillaries

Question 30

BBB consists of (3)

Answer 30

1. Tight junctions between endothelial cells
2. Thick basal lamina
3. Endfeet of astrocytes that surround endothelial cells

Question 31

name the 4 ventricles and indicate which part of the brain they lie?

Answer 31

1. (1st and 2nd )lateral ventricles - (2, L & R), c-shaped located in the cerebral hemispheres
2. 3rd ventricle- The interventricular foramen (formen of munro) connects the lateral ventricles and the 3rd. the 3rd ventricle lies in the diencephalon.
3. 4th ventricle lies behind the pons and medulla and in front of cerebellum ( lies in the hindbrain). The cerebral aqueduct lies in the midbrain and connects the 4th ventricle with the 3rd ventricle

Question 32

CSF is found where (3) and where is formed or produced and where it is absorbed?

Answer 32

1. brain cavaties (VENTRICLES)
2. CENTRAL CANAL OF SPINAL CORD
3. SUBARACHNOID SPACE

CSF is formed by the choroid plexus in each ventricle

CSF is absorbed by ararachnoid villi into saggital sinus ( venous channel in the brain).

Question 33

CSF protects the brain by providing…

Answer 33

buoyancy which prevents the weight of the brain from compressing the cranial nerve roots and blood vessels against the internal surface of the cranium

Question 34

3 layers of meninges

Answer 34

Dura Arachnoid Pia

Question 35

Which layer of the meninges is vascularised

Answer 35

Pia

Question 36

What direction does the impulse travel in the multipolar and the in the pseudounipolar neurons?

Answer 36

Multipolar neuron: from the denderite —- to cell body—– to Axon

Pseudounipolar neuron: denderite—- bypass the cell body striaght to axon

Question 37

Where does the cell body of the multipolar neuron lie?

Answer 37

1. Multipolar neurons: the cell bodies are stuitated in the CNS ( brain or spinal cord)
2. Pseudounipolar neurons: the cell bodies are situated at the doorsal root ganglia

Question 38

Collection of neural cell bodies in the spinal cord is called?

Answer 38

grey matter