Nerve 2

Question 1

What are the 4 types of neuronal endings?

Answer 1

Synapse 
Motor end plate
Muscle end plate
Muscle spindle fibres
Sensory endings

Question 2

What are synapses?

Answer 2

Synapses are regions at the end of some axons that transmit the nerve impulse from one neuron to another

Question 3

What are gap junctions for?

Answer 3

To allow ions and electrical charge to flow through

Question 4

What is a motor end plate?

Answer 4

Several neuromuscular bulbs that sit within a trough on the muscle fibre surface

Question 5

What is a neuromusclar junction?

Answer 5

A chemical synapse formed by the contact between a motor neuron and a muscle fibre

Question 6

What occurs at the neuromuscular junction?

Answer 6

Motor neuron is able to transmit a signal to the muscle fibre causing muscle contraction

Question 7

Examples of some toxins that act on neuromuscular junctions?

Answer 7

Botulinum toxin 
tetanus toxin 
nerve gas 
latrotoxin 
snake venom

Question 8

What does botox do?

Answer 8

blocks acetylcholine release at neuromuscular junction which inhibits contraction

Question 9

What is a muscle spindle?

Answer 9

acts as a proprinoceptors providing the CNS with data about the musculoskeletal system

Question 10

What is the role of the muscle spindle?

Answer 10

To maintain posture and regulate the activity of opposing muscle groups involved in motor actvivities such as walking

Question 11

What causes the changes in the length of the muscle fibre?

Answer 11

Body movements are detected by muscle spindles and the sensory nerves relay this information to the spinal cord

Question 12

What is the stretch reflex?

Answer 12

When the impulse tells the muscle to contract with greater force in order to decrease the speed at which the muscle is being stretched.

Question 13

What does the oligondendrocyte do?

Answer 13

Forms the the myelin sheath for several axons insulating the axons and facilitating nerve impulses

Question 14

What is the most numerous cell of the CNS?

Answer 14

Astrocytes

Question 15

What are the two types of astrocytes?

Answer 15

Fibrous (white matter)

Protoplasmic (grey matter)

Question 16

What are the functions of the astrocytes?

Answer 16

Blood brain barrier
Restraint of spread of electrical disturbance by absorption of K+ ions around synapses, unmyelinated axons and nodes of ranvier

Question 17

What are ependymal cells?

Answer 17

Low columnar epithelial- like cells, lacking basement membranes, which line the cavities of the CNS

Question 18

What are microglia?

Answer 18

Originate from blood monocytes- small elongated cells with irregular processes. When activated they become small macrophage cells and antigen presenting cells of the CNS mediating immune defence activity

Question 19

What are the glial cells of the CNS?

Answer 19

Oligondendrocytes
Astrocytes
Ependymal cells
Microglia

Question 20

What are the glial cells of the PNS?

Answer 20

Schwann Cells

Satellite cells

Question 21

What are schwann cells?

Answer 21

Enclose all axons of nerves of the PNS producing myelin sheaths around large diameter axons.

Question 22

What are satellite cells?

Answer 22

Aggregated sensory or automatic neuronal bodies, where they enclose each perikaryon and regulate its microenvironment

Question 23

What are the meninges?

Answer 23

The membranous covering of the brain and spinal cord

Question 24

What are the three layers of the meninges?

Answer 24

Dura mater
Arachnoid
Pia mater

Question 25

What are the functions of the meninges?

Answer 25

Provide a supportive framework for the cerebral and cranial vasculature Acting with cerebrospinal fluid to protect the CNS from mechanical damage Involved in cerebral pathology as a common site of infection and intracranial bleeds

Question 26

What is the dura mater?

Answer 26

Dense CT continuous with periosteum of skull

Question 27

What is the arachnoid mater?

Answer 27

2 components: a layer in contact with dura mater and a system of trabeculae connecting the layer with the pia mater. The cavity between the trabeculae is the subtracted space filled with CSF

Question 28

What is the pia mater?

Answer 28

Loose CT containing many blood vessels and covered vy squamous cells. Very thin and tightly adhered to the surface of the brain and spinal cord

Question 29

What is the choroid plexus?

Answer 29

The choroid plexus is a collection of cells that produce the cerebrospinal fluid in the ventricles of the brain.

Question 30

What does the choroid plexus consist of?

Answer 30

Modified ependymal cells

Question 31

How many choroid plexuses are there and where are they?

Answer 31

Four choroid plexus in the brain and one in each ventricle

Question 32

What is the functions of the cerebrospinal fluid?

Answer 32

``` Bouyancy Protection Preventation Homeostasis Clearing waste ```

Question 33

What is hyrdocephalus?

Answer 33

Abnormal accumulation of CSF " water on the brain"