Cells and Tissues of the CNS (anatomy based)

Question 1

What makes up the CNS?

Answer 1

Brain and spinal cord

Question 2

What makes up the peripheral nervous system?

Answer 2

12 pairs of cranial nerves
33 spinal nerves

Question 3

Information carried by the nervous system can be motor or sensory. Name the two divisions of motor information.

Answer 3

Autonomic (sympathetic and parasympathetic)
Somatic

Question 4

How are impulses carried in neurons?

Answer 4

As action potentials

Question 5

Name the two types of cells in the nervous system.

Answer 5

Neurons
Glial cells

Question 6

Which cells are excitable; neurons or glial cells?

Answer 6

Neurons

Question 7

Which cells are bigger; neurons or glial cells?

Answer 7

Neurons

Question 8

Which cells are of greater quantity; neurons or glial cells?

Answer 8

Glial cells

Question 9

Neurons have a high metabolic rate and contain many mitochondria, RER and Golgi apparatus.
What can neurons produce?

Answer 9

Neurotransmitters

Question 10

Describe what happens to the neurotransmitter when produced by the neuron.

Answer 10

Travels down axon and is stored in the synaptic terminals.
The neurotransmitter will be released once an action potential reaches it.

Question 11

Perikaryon?

Answer 11

Cytoplasm in cell body of neuron

Question 12

Axoplasm?

Answer 12

Cytoplasm in the axon of a neuron.

Question 13

What happens if you lose a neuron?

Answer 13

They are not replaced. Neurons last your whole life, lose one, lost it forever.

Question 14

Name three common types of neurons.

Answer 14

Multipolar (typical neuron you would imagine).
Bipolar
Pseudounipolar

Question 15

Name two types of multipolar neuron.

Answer 15

Interneurons
Motor neurons

Question 16

Name two types of bipolar neurons.

Answer 16

Olfactory mucosa
Retinol nerve fibres

Question 17

Name a type of pseudounipolar neurons.

Answer 17

Sensory neurons

Question 18

In which crnails nerve would you find bipolar neurons?

Answer 18

CN I
CN II

->think about it, they tend to be olfactory mucosa and retinol fibres so would make sense it’s the olfactory and optic cranial nerves.

Question 19

Describe the direction of nerve impulses in multipolar neurons.

Answer 19

Impulse travels from the dendrite to cell cell body and then down the axon.

Question 20

Describe the direction of nerve impulses in pseudounipolar neurons.

Answer 20

Impulse travels down dendrite, bypasses cell body and goes straight down the axon.

Question 21

Where would you find the cell bodies of the multipolar neurons?

Answer 21

Always in the CNS (either brain or spinal cord)

Question 22

What does a myelin sheath do?

Answer 22

Increases the conduction of action potentials

Question 23

What is meant by saltatory conduction?

Answer 23

Action potential jumps from none node to another without having to travel through the entire neuron hence speeding up the rate of conduction.

Question 24

Which cells secrete the myelin sheath in:
1. CNS
2. PNS
?

Answer 24

1. Oligodendrocytes
2. Schwann cells

Question 25

If a neuron does not have a myelin sheath, what is this known as?

Answer 25

Non-myelinated neuron

Question 26

Why is Multiple Sclerosis (MS) caused?

Answer 26

Believed it is caused by patchy loss of the myelin sheath as the body's immune system attacks it's own tissues. These patchy myelin sheaths effect conduction of action potentials.

Question 27

Describe the arrangement of white and grey matter of the spinal cord.

Answer 27

Peripheral white matter H shaped grey matter in middle.

Question 28

What is found in : 1. white matter 2. grey matter

Answer 28

1. Myelinated axons 2. neuronal cell bodies

Question 29

Is the dorsal root motor or sensory?

Answer 29

Sensory

Question 30

Is the ventral root motor or sensory?

Answer 30

Motor

Question 31

What is the function of ascending tracts of the spinal cord?

Answer 31

Carry information up the spinal cord from the body to the brain.

Question 32

Do ascending tracts of the spinal cord carry motor or sensory information?

Answer 32

Sensory

Question 33

What is the function of descending tracts of the spinal cord?

Answer 33

Carry information down the spinal cord from the brain to the body.

Question 34

Do descending tracts of the spinal cord carry motor or sensory information?

Answer 34

Motor

Question 35

RECAP- where does the 1. dorsal ramus supply 2. ventral ramus supply

Answer 35

1. Posterior trunk 2. Anterior trunk and limbs

Question 36

If you see an area of the brain and it looks grey, what does that means about it's composition?

Answer 36

Lots of unmyelinated neuronal cell bodies ->myelinated cell bodies=white structure

Question 37

What is the name given to a collection of neuronal cell bodies, which is sitting outside of the central nervous system?

Answer 37

Ganglion

Question 38

What is the name given to a collection of neuronal cell bodies, which is sitting inside of the central nervous system?

Answer 38

Nucleus

Question 39

Which type of glial cell is the most populous within the CNS?

Answer 39

Astrocytes

Question 40

Describe astrocytes.

Answer 40

Look like an asteroid! Have central nucleus with many processes surrounding it- these are known as endfeet.

Question 41

What is the function of astrocyte endfeet?

Answer 41

They surround synapses and capillaries and help with potassium buffering.

Question 42

What is the function of microglia, another type of glial cell?

Answer 42

Phagocytosis and scar tissue formation.

Question 43

Which type of glial cell helps to maintain the blood brain barrier?

Answer 43

Astrocytes

Question 44

Why does the brain need microglia to enable phagocytosis when the rest of the body has other cells, like WBCs, that do this?

Answer 44

Blood brain barrier prevents white blood cells from moving in the capillaries of the brain so brain needs own cells for the process of phagocytosis.

Question 45

Where would you find ependymal cells, another type of glial cell?

Answer 45

Lining the ventricles of the brain Lining canal of spinal cord

Question 46

What is the function of oligodendrocytes? (another type of glial cell).

Answer 46

Secrete myelin sheath of axons in the CNS.

Question 47

Name the four types of glial cells in the CNS.

Answer 47

Astrocytes Microglial Ependymal cells Oligodendrocytes

Question 48

Name the two types of glial cells of the PNS.

Answer 48

Schwann cells Satellite cells

Question 49

What is the function of schwann cells?

Answer 49

Secrete myelin sheath of axons in the PNS.

Question 50

Where are satellite cells found?

Answer 50

Inside neuronal cell bodies

Question 51

What are more common- gliomas (tumours of glial cells) or neural brain tumours?

Answer 51

Glioma

Question 52

What is the blood brain barrier?

Answer 52

Protective mechanism creating a stable environment for the brain as prevents certain molecules from entering the brain.

Question 53

What does the blood brain barrier prevent coming into the brain?

Answer 53

Harmful amino acids and ions Glucose

Question 54

What makes up the blood brain barrier?

Answer 54

1. Endothelium- tight junction 2. Thick basal lamina 3. Foot processes of astrocytes

Question 55

Because of the blood brain barrier, what are the only substances that can go across the capillaries of the brain?

Answer 55

Lipid soluble substances e.g. water and oxygen.

Question 56

The brain needs glucose and amino acids, despite the blood brain barrier preventing them to flow into the brain. Therefore, how do these substances get into the brain?

Answer 56

Pump mediated transfer

Question 57

Which parts of the brain are not surrounded by the blood brain barrrier?

Answer 57

Hypothalamus Posterior pituitary ->both endocrine

Question 58

Due to the blood brain barrier, if wanting to use drugs which will affect the brain, what will need to be considered?

Answer 58

They will need to be able to pass over the BBB so will be lipid soluble or use suitable vectors to get them across.

Question 59

What does the cerebrum control?

Answer 59

'Seat of consciousness' e.g. initiates and coordinates movements, controls temperature.

Question 60

What does the cerebellum control?

Answer 60

Balance Coordination

Question 61

Name the three components of the brainstem.

Answer 61

Midbrain Pons Medulla

Question 62

What would be found in the brainstem?

Answer 62

Vital automatic centres e.g. cardio-respiratory centres

Question 63

What would you find in the subarachnoid space (space between arachnoid mater and pia mater)?

Answer 63

Cerebrospinal fluid

Question 64

Name the fold of dura mater which separates the two cerebral hemispheres.

Answer 64

Falx cerebri.

Question 65

Name the fold which separates the two cerebral hemispheres from the cerebellum.

Answer 65

Tentorium cerebelli.

Question 66

What are the ventricles of the brain?

Answer 66

Spaces within the brain- they are all connected

Question 67

Where do the lateral ventricles lie?

Answer 67

Cerebral hemispheres

Question 68

Where does the cerebral aqueduct lie?

Answer 68

Midbrain

Question 69

Where does the diamond shaped 4th ventricle of the brain lie?

Answer 69

Hindbrain

Question 70

What connects the lateral ventricles with the 3rd ventricle?

Answer 70

Interventricular foramen

Question 71

Where is the 3rd ventricle found?

Answer 71

Diencephalon

Question 72

What is found in the brain ventricles?

Answer 72

Cerebrospinal fluid

Question 73

What are meninges?

Answer 73

Coverings of the CNS

Question 74

Name the three layers of the meninges.

Answer 74

Dura mater Arachnoid mater Pia mater

Question 75

What is the function of CSF?

Answer 75

Maintains intracranial pressure Protects brain and spinal cord

Question 76

Where would you find CSF?

Answer 76

Brain ventricles Subarachnoid space

Question 77

What forms CSF?

Answer 77

A structure called the choroid plexus found in each ventricle

Question 78

Where is CSF absorbed?

Answer 78

By arachnoid villi into the sagittal sinus (this is the venous drainage for the brain).

Question 79

How does CSF leave the ventricular system and get to the subarachnoid space?

Answer 79

Leaves through three holes at the roof of the 4th ventricle.