intro to nervous system

Question 1

name some support cells in PNS and CNS

Answer 1

In cns :

1. Oligodendrocytes : involved in myelination, can myelinate more than one neuron, can also send cytoplasm to unmyelinated neurons
2. Astrocytes : involved in BBB, supports nerve cells
3. Microglia : macrophages of the CNS, sweeps up debris

In PNS:

1. satellite cells: provide support, nourishment to neurons
2. Schwann cells: myelinate neurons to increase speed of AP, can only myelinate one neuron

Question 2

How does myelination affect AP

Answer 2

myelination allows for saltatory conduction in which action potentials can jump from one node of ranvier to another thus increasing the speed of conduction of action potentials

Question 3

Where is gray matter found

Answer 3

In CNS: found outside, with some subcortical nuclei within white matter
In PNS: found inside

Question 4

Function of gray matter?

Answer 4

Processing, decision making etc

Question 5

Describe sympathetic system. What is its function?

Answer 5

• involves fight or flight response
• responds in emergencies where blood flow to the gut is decreased thus decreased gut motility but increased to muscles)
• THORACOLUMBAR output : pre-ganglionic neurons found in T1-L2 region
  Functions:
• dilates pupils
• vasodilation of bronchial smooth muscle
• constricts vascular smooth muscle, BP increase
• increase heart rate, resp. rate, blood glucose levels

Question 6

Role of the sympathetic system in exercise?

Answer 6

sympathetic vasoconstriction shunts blood from skin and digestive viscera and directs it to heart, brain and muscles

Question 7

Describe the parasympathetic system. What are its functions?

Answer 7

• involves rest and digest system
• involved in homeostatic type activities in body (constricts pupils, glandular secretion, increase gut motility, elimination of wastes)
• CRANIOSACRAL output: pre-ganglionic neurons found at the brain stem and S1-S2

Question 8

How are sympathetic and parasympathetic systems similar, and different?

Answer 8

Similar : both have 2 neuron chain
Differ :
1. sympathetic system has its ganglia closer to vertebral column so its preganglionic is shorter and post-gang is longer
2. parasympathetic has its ganglia closer to organ so its pre-gang is longer but post-gang is shorter

Question 9

What are the neurotransmitters used in sympathetic

Answer 9

between pre and post ganglionic: acetylcholine

between post and effector: norepinephrine

Question 10

What neurotransmitters are used in parasympathetic?

Answer 10

between pre and post gang, and between post gang and effector : acetylcholine

Question 11

Name layers of dura mater

Answer 11

2 layers: outer periosteal layer and inner meningeal layer

Question 12

Function of dural septae

Answer 12

1. attaches brain to skull
2. prevents excessive movement of brain in the skull t avoid damage
3. separates brain into functional compartments that can freely communicate

Question 13

Name the three dural septae

Answer 13

1. falx cerebri : separates left and right hemispheres of cerebrum
2. falx cerebelli: divides left and right cerebellum
3. tentorium cerebelli : divides cerebrum and cerebellum

Question 14

Name all the potential and actual spaces between meninges.

Answer 14

epidural/ extradural space
subdural space
subarachnoid space