Cells and Tissues of the Nervous System

Question 1

What is the functional unit of the nervous system?

Answer 1

the neuron

Excitable, carries AP’s, lit

Question 2

What are glial cells?

Answer 2

Non-excitable supporting cells of the NS

Smaller and more numerous than neurons

Question 3

Three types of neurons?

Answer 3

• Multipolar: INTERNEURONS/ MOTOR NEURONS (typical neuron)
• Bipolar (retinal & olfactory)
• Pseudounipolar: ALL SENSORY NEURONS (typical except cell body is further along axon off in the GANGLIA, instead of at dendrites)

Question 4

What is the metabolic rate of a neuron like compared to other cells?

Answer 4

Got a high metabolic rate

Question 5

Do adult neurons proliferate?

Answer 5

No, they are long lived but are amitotic so don’t go through mitosis

Question 6

Type of conduction enabled by the myelin sheath? Effect on rate?

Answer 6

• Saltatory conduction

- Speeds up rate, AP’s jump between nodes of Ranvier

Question 7

Cells of the nervous system that produce the myelin sheath?

Answer 7

• Schwann cells in the PNS

- Oligodendrocytes in the CNS

Question 8

Effect of MS on the myelin sheath?

How does it appear on MRI?

Answer 8

Immune mediated inflammatory disease causing degeneration of the myelin sheath - abnormal conduction of AP’s.

Appears as white plaques of demyelination on MRI

Question 9

Function of Astrocytes and where they’re found in the nervous system?

Answer 9

• Surround synapses and capillaries, help in K ion buffering
• Found in CNS

Question 10

Function of Ependymal cells and where they are in the nervous system?

Answer 10

• Line ventricles of the brain (produce CSF)

- Found in CNS

Question 11

Function of microglia and where they are in the nervous system?

Answer 11

• Phagocytosis and scar tissue formation

- Found in the CNS

Question 12

Function of the blood brain barrier?

Answer 12

• Maintain a stable environment for the brain

- Stop passage of harmful amino acids, ions, blood cells and other toxins from entering the brain

Question 13

Structure of the blood brain barrier?

Answer 13

• Tight junctions between the endothelium of blood vessels
• Thick basal lamina
• Foot processes of astrocytes line the capillaries

Question 14

What can pass through the blood brain barrier?

Answer 14

• Lipid soluble molecules, oxygen and water can diffuse right through
• Water soluble molecules (glucose/AA’s) are pump mediated

Question 15

Where is the blood brain barrier absent?

Answer 15

In a few circumventricular (surrounding the ventricles) organs

(Parts of hypothalamus, posterior pituitary)

Question 16

Constituents of the brainstem?

Answer 16

• Midbrain
• Pons
• Medulla

Question 17

Layers of the meninges from outer to inner?

Answer 17

• Dura mater
• Arachnoid mater
• Pia mater

Question 18

Where is the CSF contained in the meninges?

Answer 18

Subarachnoid space

between arachnoid and pia mater

Question 19

Which layer of the meninges has dural folds?

Answer 19

Dura mater

Question 20

Which layer of the meninges is vascularized and dips into the folds of the brain?

Answer 20

Pia mater

Question 21

Where is the cerebrospinal fluid?

Answer 21

• In the cavities of the brain (ventricles)
• In the central canal of the spinal cord
• Subarachnoid space of the meninges

Question 22

Where is CSF produced?

Where is it absorbed?

Answer 22

• Produced by the choroid plexus in each ventricle

- Absorbed by arachnoid villi into the saggital sinus (venous channel in brain)

Question 23

What is one of the functions of CSF?

Answer 23

Aides in the maintenance of intracranial pressure

Question 24

What are the types of glial cells?

Answer 24

• Ependymal cells
• Microglia
• Oligodendrocytes
• Astrocytes
• Schwann cells
• Satellite cells

Question 25

Name the ventricles of the brain?

Answer 25

• Lateral ventricles on either side
• 3rd ventricle
• 4th ventricle

Question 26

What connects the 3rd and 4th ventricle?

Answer 26

The cerebral aqueduct