Lecture 1: Cells & Tissues

Question 1

What are the main types of nervous tissue cells?

Answer 1

• Neurons
• Glial Cells

Glial cells are split into:
PNS:

• satellite Cells
• Schwann Cells

CNS:

• Astrocytes
• Oligodendrocytes
• Microglia
• Ependymal Cells

Question 2

Whats the difference between neurons and glial cells?

Answer 2

Neurons are excitable and carry action potentials.

Glial cells are supportive and non-excitable, they have other functions

Question 3

How do neurons divide?

Answer 3

By Amitosis

Question 4

Can neurons grow back?

Answer 4

If you cut the axon it can grow back

But if you crush the cell body in the spine or ganglia then its permanent

Question 5

Whats the function of myelin?

Answer 5

Reduces loss of electrical signals as they pass down the axon, so they can travel further faster. (Also known as saltatory conduction)

Question 6

What do we call the spaces between myelin sheaths?

Answer 6

Nodes of Ranvier

Question 7

What forms the myelin sheath?

Answer 7

Schwann cells in the PNS

Oligodendrocytes in the CNS

Question 8

How do schwann cells produce a myelin sheath?

Answer 8

They wrap around the axon and extrude their cytoplasm.

So the cell membrane becomes the myelin sheath

Question 9

What are the different types of neurons?

Answer 9

Multipolar

• Motor neurons & interneurons
• Lots of dendrites

Bipolar:

• Olfactory or retinal nerve fibres
• One dendrite

Pseudounipolar

• Sensory Neurons
• Cell body sits off to the side of the axon

Question 10

Neurons are organised into different types/locations e.g. white vs gray matter or ganglia vs nuclei. What are they?

Answer 10

White matter: Myelinated axons
Grey Matter: Cell bodies/non-myelinated axon

Neuronal Cells bodies localised within the CNS are called nuclei, within the PNS they’re called Ganglia

Question 11

Divide Glial cells by PNS vs CNS:

Answer 11

PNS:

• Satellite Cells
• Schwann Cells

CNS:

• Ependymal cells
• Oligodendrocytes
• Microglia
• Astrocytes

Question 12

What do satellite cells do?

Answer 12

surround neuronal cell bodies in the PNS

Question 13

What do Ependymal cells do?

Answer 13

Type of Glial cell that line ventricles in the brain & central canal of spinal cord

Question 14

What do microglia do?

Answer 14

Type of glial cell in the CNS that phagocytose and form scar tissue

Question 15

What do astrocytes do?

Answer 15

Glial cells in the CNS that surround synapes and capillaries to buffer ions.
They contribute to the blood brain barrier

Question 16

How do the ventricles of the brain develop?

Answer 16

• Neural tube above 4th somite develops into 3 primary vesicles
  Forebrain (prosencephalon)
  Midbrain (mesencephalon)
  Hindbrain (rhombencephalon)
• From there into 5 secondary vesicles
  Telencephalon & Diencephalon
  Mesencephalon
  Myelencephalon & Metencephalon
• These 5 vesicles form the ventricles

Question 17

Which cavity forms which ventricle?

Answer 17

Telencephalon (part of forebrain) –> Lateral ventricles in cerebral hemispheres

Diencephalon (part of forebrain) contains 3rd ventricle

Mesencephalon (Midbrain) –> Cerebral Aqueduct

The two division of the rhombencephalon form the 4th ventricle

Question 18

Whats contained in the ventricles?

Answer 18

Lined by ependymal cells

Filled with CSF

Question 19

List the folds of the dura mater?

Answer 19

Falx Cerebri
Attaches to Crista Galli & dips between cerebral hemispheres

Tentorium Cerebelli
Seperates cerebellum form occipital lobes

Falx Cerebelli

Diaphragma Sellae

Question 20

What layer of meninges contains CSF?

Answer 20

The subarachnoid space between the pia mater and arachnoid mater

Question 21

Where is CSF produced/absorped?

Answer 21

Produced in the choroid plexus of the ventricles

Its absorbed by arachnoid villa

Question 22

List the layers of the head

Answer 22

Scalp 
- Skin
- Connective Tissue
- Aponeurosis
- Loose Connective Tissue
- Pericranium
Cranium
Meninges
- Dura
- Arachnoid
- CSF
- Pia

Question 23

What does the blood brain barrier do?

Answer 23

Maintains a stable homeostatic environment for the brain, preventing harmful amino acids/ions/blood cells from reaching the brain

Question 24

How is the blood brain barrier maintained

Answer 24

Endothelium- tight junctions
Thick Basal Lamina
Foot Processes of the Astrocytes

Question 25

Where are the different fold of dura mater?

Answer 25

Falx Cerebri is a verticle fold between the cerebral hemispheres

Diaphragma Sellae lines the Sella Turcica, wrapping around the pituitary gland

Tentorium Cerebelli is a horizontal fold dividing the cerebellum and cerebrum

Falx Cerebelli between cerebellar hemispheres