Cells and Tissues of the Nervous System

Question 1

Divisions of the peripheral nervous system

Answer 1

Sensory (afferent) division

Motor (efferent) division

Question 2

Divisions of the motor (efferent) division

Answer 2

Somatic motor

Autonomic

Question 3

Divisions of the autonomic system

Answer 3

Sympathetic

Parasympathetic

Question 4

Two types of neural cells

Answer 4

Neurones

Glial cells

Question 5

What are neurones?

Answer 5

Structural and functional unit

Excitable cells

Question 6

How are impulses carried in neurones?

Answer 6

As action potentials

Question 7

What are glial cells?

Answer 7

Non excitable supporting cells

Much smaller than neurones

Question 8

Structure of neurones

Answer 8

Multiple dendrites
One axon
The axon branches at the end with the synaptic terminal
Impulse transmission is by an action potential which can only travel in only one direction from cell body to synaptic terminal
Nucleus is loose chromatin with a prominent nucleolus

Question 9

Cell organelles found in neurones

Answer 9

Mitochondria
rER (Nissl bodies)
Diffuse Golgi apparatus

Question 10

Features of neurones

Answer 10

High metabolic rate
Long living and amniotic
Does not regenerate if dies (axons can)

Question 11

What is the cytoplasm of the cell body in a neurone called?

Answer 11

Perikaryon

Question 12

What is the axon of a neurone called?

Answer 12

Axoplasm

Question 13

Can axons regenerate?

Answer 13

Yes

Question 14

Can cell bodys regenerate?

Answer 14

No

Question 15

Function of myelin sheath

Answer 15

Increase conduction speed in axons by ‘saltatory conduction’

Question 16

What is saltatory conduction? Why is it beneficial?

Answer 16

Where the action potential jumps from node to node

Helps to speed up the rate in which conduction happens, especially in long axons

Question 17

How is the myelin sheath formed in the PNS?

Answer 17

Schwann cells

Question 18

How is the myelin sheath formed in the CNS?

Answer 18

Oligodendrocytes

Question 19

In myelinated axons, what is formed?

Answer 19

A mesaxon

Question 20

What is multiple sclerosis (MS)?

Answer 20

Patchy loss/scarring of myelin sheath (demyelination) => nerve conduction across affected axons abnormal

Question 21

Pathology of MS

Answer 21

Antigens of myelin sheath are abnormal and so the body’s immune system attacks, leading to patchy loss of myelination

Question 22

What is seen on MRIs of MS?

Answer 22

Whitish plaques of demyelination

Question 23

Types of neurones

Answer 23

Multipolar
Bipolar
Pseudounipolar

Question 24

What type of neurone is your typical neurone?

Answer 24

Multipolar

Question 25

What type of neurones are sensory neurones?

Answer 25

Pseudounipolar neruones

Question 26

Features of pseudounipolar neurones

Answer 26

Cell body with one projection | Sensory neurones

Question 27

Features of multipolar neurones

Answer 27

Interneurons | Motor neurones

Question 28

Where are bipolar neurones found?

Answer 28

Retina

Question 29

Are bipolar neurones common or rare?

Answer 29

Rare

Question 30

Dorsal = ?

Answer 30

Sensory

Question 31

Ventral = ?

Answer 31

Motor

Question 32

Where do the cell bodies sit?

Answer 32

Dorsal route ganglions

Question 33

What colour are axons in the CNS? Why?

Answer 33

Grey | They are myelinated

Question 34

What colour are lots of cell bodies together in the CNS?

Answer 34

Grey

Question 35

What is a collection of white matter called?

Answer 35

Tracts

Question 36

What is a collection of bodies outside the NS called?

Answer 36

Ganglion

Question 37

What is a collection of bodies inside the NS called?

Answer 37

Nucleus

Question 38

What may different tracts carry?

Answer 38

Different modalities

Question 39

In the PNS what do myelinated axons form?

Answer 39

Nerves

Question 40

In the PNS, what do cell bodies form?

Answer 40

Ganglia

Question 41

What are glial cells?

Answer 41

The supportive cells of the CNS

Question 42

What do glial cells do?

Answer 42

They surround neurones and provide support for and insulation between them

Question 43

What are the 6 types of glial cells?

Answer 43

``` Satellite cells Schwann cells Astrocytes Oligodendrocytes Microglia Ependymal cells ```

Question 44

Which types of glial cells are found in the PNS?

Answer 44

Satellite cells | Schwann cells

Question 45

What types of glial cells are found in the CNS?

Answer 45

Astrocytes Oligodendrocytes Microglia Ependymal cells

Question 46

Which is there more of, glial cells or neurones?

Answer 46

Glial cells

Question 47

Function of satellite cells

Answer 47

Surround neuronal cell bodies

Question 48

Function of schwann cells

Answer 48

Myelination in PNS

Question 49

Function of astrocytes

Answer 49

Have end feet Surround synapses and capillaries Help in K+ buffering

Question 50

Function of oligodendrocytes

Answer 50

Myelination in CNS

Question 51

Function of microglia

Answer 51

Phagocytosis | Scar tissue formation

Question 52

Function of ependymal cells

Answer 52

Line ventricles

Question 53

What does CSF stand for?

Answer 53

Cerebrospinal fluid

Question 54

What is CSF?

Answer 54

Fluid inside the cavity of the brain (the ventricles) and central canal of the spinal cord

Question 55

Where is CSF present?

Answer 55

Ventricles Surrounding the brain Spinal cord between the pia and arachnoid

Question 56

Where is CSF formed?

Answer 56

Choroid plexus in each ventricle

Question 57

Where is CSF absorbed?

Answer 57

By arachnoid villi into sagittal sinus (venous channel in brain)

Question 58

What is the blood brain barrier?

Answer 58

A protective mechanism that helps maintain a stable environment for the brain and prevents harmful amino acids and ions present in the bloodstream and blood cells from entering the brain

Question 59

Layers of the BBB

Answer 59

1. endothelium - tight junction 2. thick basal lamina 3. foot processes of astrocytes

Question 60

Where is the BBB absent?

Answer 60

Circumventricular organs - parts of hypothalamus - posterior pituitary

Question 61

How many hemispheres does the brain have?

Answer 61

2

Question 62

What is the brainstem made up from?

Answer 62

Mid brain Pons Medulla

Question 63

How many parts does the diencephalon have?

Answer 63

2

Question 64

Two parts of the diencephalon?

Answer 64

Thalamus | Hypothalamus

Question 65

Function of brainstem

Answer 65

Vital centres e.g. cardioresp | Pathway for fibre tracts

Question 66

Function of cerebellum

Answer 66

Balance and coordination

Question 67

How are ventricles formed?

Answer 67

Cavity of neural tube persisting in the adult brain

Question 68

What ventricles are present in the brain?

Answer 68

``` Lateral ventricles Interventricular foramen Cerebral aqueduct 3rd ventricle 4th ventricle ```

Question 69

What cavity is found in the telencephalon?

Answer 69

Lateral ventricles

Question 70

What cavity is found in the diencephalon?

Answer 70

III ventricle

Question 71

What cavity is found in the midbrain?

Answer 71

Cerebral aqueduct

Question 72

What cavity is found in the hindbrain?

Answer 72

IV ventricle

Question 73

Parts of the lateral ventricles

Answer 73

Anterior horn Posterior horn Inferior horn

Question 74

Layers of the protection of the brain

Answer 74

``` Skin Subcutaneous tissue Epicranial aponeurosis Loose areolar tissue Pericranium Skull bones / cranium Meninges CSF ```

Question 75

What are the dural folds?

Answer 75

Falx cerebri Tentorium cerebelli Falx cerebelli Diaphragma sellae

Question 76

What structure is the diaphagma sellae related to?

Answer 76

Pituitary gland

Question 77

What are the 3 meninges?

Answer 77

Dura matter Pia matter Arachnoid matter

Question 78

Which meninge is the most outmost?

Answer 78

Dura mater

Question 79

Which meninge is found in the most inner?

Answer 79

Pia mater

Question 80

Features of dura mater

Answer 80

Tough Fibrous Has dural folds

Question 81

Features of pia mater

Answer 81

Vascularised | Dips into the folds of the brain

Question 82

What is the subdural space?

Answer 82

A potential space which is transversed by blood vessels penetrating into the CNS

Question 83

What is the subarachnoid space?

Answer 83

A potential space that contains CNS

Question 84

Function of the BBB

Answer 84

Maintains homeostasis in the brain parenchyma