Lecture 5

Question 1

Where is the best place to obtain a sample of cerebrospinal fluid?

Answer 1

Subarachnoid space, lumbar region

Question 2

How much CSF is produced a day?

Answer 2

120 mL

Question 3

Where is CSF produced?

Answer 3

Ventricles

Question 4

What kind of cells produce CSF?

Answer 4

Ependymal cells

Question 5

Where does CSF drain into?

Answer 5

Dural sinuses and dural lymph vessels

Question 6

What is the function of CSF?

Answer 6

Provides watery protective cushion for CNS, absorbs neuron metabolites during sleep

Question 7

What is it called if the ventricles fill with CSF because of a blockage somewhere?

Answer 7

Hydrocephalus (big head in a baby)

Question 8

Want ______ and _______ of CSF to match

Answer 8

Production and Drainage

Question 9

Ventricle should be _______

Answer 9

Symmetrical

Question 10

What is the choroid plexus?

Answer 10

-Wrinkly structure found inside the brain ventricles

Question 11

What is the choroid plexus composed of?

Answer 11

Ependymal cells (produces CSF)

Question 12

What does the cerebral aqueduct conect?

Answer 12

The 3rd ventricle to the 4th ventricle

Question 13

What is the flow of CSF through the ventricles?

Answer 13

L/R Lateral ventricles –> 3rd ventricle –> cerebral aqueduct –> 4th ventricle –> subarachnoid space –> dural sinuses

Question 14

What are the 6 stages of the developmental process?

Answer 14

1. Mitosis
2. Migration
3. Differentiation
4. Synaptogenesis
5. Apoptosis
6. Myelination

Question 15

In the mitosis stage, when do neurons stop dividing?

Answer 15

In the 5th prenatal month

*The only place neurons continue dividing throughout life is the olfactory bulb and hippocampus

Question 16

In the mitosis stage, what do neuroblasts (immature cells) divide into?

Answer 16

Neurons or glial cells

Question 17

What happens during the migration stage?

Answer 17

Neurons move to their correct locations

Question 18

When does migration end?

Answer 18

by the 7th prenatal month

Question 19

What can happen if neurons migrate to the wrong location?

Answer 19

Heterotopia (seizures)

Question 20

What is differentiation based on?

Answer 20

Neuron location

Question 21

When does differentiation occur?

Answer 21

Pre-natal

Question 22

What is synaptogenesis and what does it require?

Answer 22

Synapse formation, requires gene expression

Question 23

When does synaptogenesis occur?

Answer 23

Pre-natal to death

Question 24

What is apoptosis?

Answer 24

Programed cell death

*Neurons that don’t form synapses are removed

Question 25

When does myelination begin and when is it completed?

Answer 25

Begins: 4th pre-natal month (most by age 3) Ends: early 20s (reigns in impulsive behaviors)

Question 26

What increases myelination?

Answer 26

Stimulation of neurons

Question 27

Which 3 stages are involved in neural plasticity?

Answer 27

Synaptogenesis, apoptosis, and myelination

Question 28

What neuron types are seen in peripheral nerves?

Answer 28

1. Voluntary motor neurons (skeletal muscle) 2. Somatosensory neurons (skin, muscle, sub Q tissue) 3. Autonomic neurons (smooth and cardiac muscle)

Question 29

What are the three peripheral nerve plexuses?

Answer 29

1. Cervical plexus (C1-C4): innervates neck and diaphragm 2. Brachial plexus (C5-T1): innervates UE 3. Lumbosacral plexus (L1-S5): innervates LE and pelvic floor

Question 30

A typical peripheral nerve contains ______ (amount) of axons

Answer 30

Thousands

Question 31

What is every axon (myelinated or unmyelinated) surrounded by?

Answer 31

Endoneurium (thin sheath of connective tissue)

Question 32

Where is the endoneurium located in relation to the myelin sheath?

Answer 32

Endoneurium is external to the myelin sheath

Question 33

What is a fasicle?

Answer 33

Cluster of axons

Question 34

What is each fasicle surrounded by?

Answer 34

Perineurium (sheath of connective tissue)

Question 35

What is the entire peripheral nerve surrounded by?

Answer 35

Epineurium (somewhat thicker sheath of connective tissue)

Question 36

What increases blood flow to axons and fluid flow within axons?

Answer 36

Movement

Question 37

In an injured peripheral nerve, what happens first motor loss or loss of sensation?

Answer 37

Loss of sensation

Question 38

At what rate to axons regenerate in a peripheral nerve?

Answer 38

1 in/month

Question 39

What helps guide axons regrowth?

Answer 39

Schwann cells --> they secrete growth factor that forms tunnels to guide axons