BL11 L21 Nervous Tissue Structure And Function

Question 1

How can the nervous system be divide?

Answer 1

Central nervous system
Peripheral nervous system

Question 2

What makes up the CNS?

Answer 2

Brain
Spinal cord
Relay neurones

Question 3

What is the PNS composed of?

Answer 3

Cranial nerves
Spinal nerves
Motor and sensory neurones
Some relay neurones

Question 4

Where is grey matter in the brain and spinal cord?

Answer 4

Brain- peripheral in areas called nuclei
Spinal cord- centrally in butterfly shape

Question 5

What does grey matter consisted of?

Answer 5

Nerve cell bodies
Dendrites
Axon terminals
Non myelinated axon
Neuroglia - support cells

Question 6

Where is white matter in the brain and spinal cord?

Answer 6

Brain- central
Spinal cord- peripheral

Question 7

What does white matter consist of?

Answer 7

Myelinated material

Question 8

Types of neurones

Answer 8

Motor
Sensory
Integrative/relay
Anaxonic

Question 9

Location of motor neurones

Answer 9

CNS to periphery

Question 10

Function of motor neurones

Answer 10

Sends signals to effector tissues

Question 11

Location of sensory neurones

Answer 11

Periphery to CNS

Question 12

Function of sensory neurones

Answer 12

Sends environmental signals to integrative centre

Question 13

Location of integrative neurones

Answer 13

CNS

Question 14

Function of integrative neurones

Answer 14

Collate all information

Question 15

Types of integrative neurones

Answer 15

• Pyramidal cell
• Interneurons - synaptic information flow in brain + reflex arc
• Purkinje cell - involved in sending signals to other parts of the brain

Question 16

Anaxonic neurone structure

Answer 16

No axon

Question 17

Location of anaxonic neurones

Answer 17

Retina

Question 18

Function of anaxonic neurones

Answer 18

Acts as relays

Question 19

What are the majority of nerves in the CNS?

Answer 19

Interneurones

Question 20

What neurone cell bodies are located outside the CNS?

Answer 20

Motor- postsynaptic autonomic neurone
Sensory - Pseudounipolar + bipolar

Question 21

What neurones are restricted to the CNS?

Answer 21

Integrative- purkinje + pyramidal cells

Question 22

Shape of grey matter in spinal cord

Answer 22

Butterfly
Centrally

Question 23

Function of nissl body

Answer 23

Synthesis and segregation of proteins
Main site of protein synthesis in neuronal cytoplasm

Question 24

Process of neurotransmitter synthesis release

Answer 24

• immature vesicles constrain only enzymes
• as it moves along the axon it synthesises the neurotransmitter
• after neurotransmitter is released, the vesicle can either be - recycled through clathrin-coated endocytosis or lost to neurolemma

Transport using microtubules

Question 25

Two fates of vesicle after neurotransmitter release

Answer 25

-Recycled through clathrin-coated endocytosis -Lost to neurolemma

Question 26

How are vesicles transported?

Answer 26

Microtubules

Question 27

Types of synapse

Answer 27

Axosomatic Axodendritic Axoaxonic Dendro-dendritic Axo-axonal

Question 28

What is axosomatic synapse?

Answer 28

Direct connection to plasma membrane of nerve or cell

Question 29

What is axodendritic synapse?

Answer 29

Axon terminal synapses with dendritic spine

Question 30

What is axoaxonic synapse?

Answer 30

Synapse at the axonic bouton

Question 31

What is the axonic bouton?

Answer 31

Small swellings at terminals of axons Involved in axoaxonic synapse

Question 32

What causes schizophrenia?

Answer 32

Mutation in myelination

Question 33

Do myelinated or non-myelinated nerves conduct faster?

Answer 33

Myelinated Saltatory conduction- Can jump between nodes of ranvier

Question 34

How does diameter of axon impact the speed of conduction?

Answer 34

Larger diameter = faster conduction

Question 35

What is the cause of multiple sclerosis?

Answer 35

Degeneration of myelin sheath

Question 36

Symptoms of MS

Answer 36

- fatigue - diplopia - dysarthria - slurred speech - Paraesthesia - mobility issues - urinary retention - constipation

Question 37

Diplopia meaning

Answer 37

Vision problems

Question 38

Dysarthria meaning

Answer 38

Slurred speech

Question 39

Paraesthesia meaning

Answer 39

Numbness and tingling sensations

Question 40

What is dendro-dendritic synapse?

Answer 40

Between dendrites of two different neurones

Question 41

What is axo-axonal synapse?

Answer 41

Between axon of two different neurones

Question 42

Parts of peripheral nerves

Answer 42

Endoneurium Perineurium Epineurium Paraneurium

Question 43

What connective tissue is endoneurium?

Answer 43

Loose connective tissue

Question 44

What connective tissue is Perineurium?

Answer 44

Specialised connective tissue - transport proteins

Question 45

Fascicle meaning

Answer 45

Bundle of structures

Question 46

What connective tissue is Epineurium?

Answer 46

Dense irregular connective tissue

Question 47

Function of Epineurium

Answer 47

Separates different types of nerves Fills spaces between fascicles

Question 48

Function of endoneurium

Answer 48

Surrounds single nerve cells/axon

Question 49

Function of Perineurium

Answer 49

- maintains ionic con. around nerve - Surrounds cluster of axons (fascicle)

Question 50

Function of Paraneurium

Answer 50

Fascia that separates nerves from surrounding structures

Question 51

Structure of neurovascular bundle of PNS

Answer 51

- Each exon is surrounded by **endoneurium** - Many of these together forms a **fascicle** - Each fascicle is surrounded by **perineurium** - Fascicles are grouped + get surrounded by **epineurium**

Question 52

What types of nerve fibres are in peripheral nerves?

Answer 52

All three- motor, sensory and integrative

Question 53

What is myelin produced by in the CNS?

Answer 53

Oligodendrocytes

Question 54

What is myelin produced by in the PNS?

Answer 54

Schwann cell

Question 55

What does damage in myelin in CNS cause?

Answer 55

Multiple sclerosis

Question 56

What does damage to myelin in the PNS cause?

Answer 56

Guillain-Barre syndrome Fatal

Question 57

How does myelination occur in the PNS

Answer 57

Schwann cell - axon sitting in a groove is surrounded by Schwann cell - the mesaxon membrane surrounds the axon - extensions of this membrane wrap around the axon, forming a multiple layered membrane - cytoplasm is extruded from the Schwann cells to compact them and form myelin

Question 58

How does myelination occur in CNS?

Answer 58

-oligodendrocytes - same process as Schwann cells wrapping around the axon

Question 59

Difference between CNS and PNS myelination

Answer 59

- CNS uses oligodendroytes - wrap around more than one axon simultaneously - PNS uses Schwann cells - wrap around one axon

Question 60

What does tolluidine blue stain and what colour?

Answer 60

Fats Blue

Question 61

What do unmyelinated cells look line in histology?

Answer 61

Double layered White circle with two blue circles around

Question 62

What do myelinated cells look like in histology?

Answer 62

One thick coloured layer

Question 63

Unmyleinated nerve cells structure

Answer 63

- Individual axons are engulfed by cytoplasm of Schwann cell

Question 64

What are glia?

Answer 64

Support cells in the CNS

Question 65

What are the four support cells/glia in the CNS?

Answer 65

- oligodendocytes - Astrocytes - microglial cells - ependymal cells

Question 66

Astrocytes function

Answer 66

- **regulate nerve impulses** by releasing glutamate - contribute to **blood-brain barrier** - **biochemical support** - **transport of nutrients** from blood to nerve cells

Question 67

Astrocytes structure

Answer 67

Star-like structure Perineural feet - contain gap junctions

Question 68

Microglial cell structure

Answer 68

- Large cells - Have elongated nucleus

Question 69

Microglial cell function

Answer 69

**Resident macrophage** - immune function - remove damaged nerve cells - sense increased K+ ions - bad for the brain

Question 70

Ependymal cell location

Answer 70

Line the spinal canal

Question 71

What do ependymal cells look like?

Answer 71

Columnar epithelia cells Apical surface have cilia and microvilli

Question 72

What do the cilia and microvilli do in ependymal cells?

Answer 72

Cilia- move through ventricles to the spinal cord Microvilli- absorb CSF for removal of pathogens by presenting them to Astrocytes and microglial cells

Question 73

What does the modified tight junction between ependymal cells do?

Answer 73

Control fluid release into brain

Question 74

What controls fluid release into brain?

Answer 74

Modified tight functions between ependymal cells