2.2 Cells of the Nervous System

Question 1

What is the CNS and what does it consist of?

Answer 1

Central Nervous System

Consists of:

• cerebral hemispheres
• brainstem
• cerebellum
• spinal cord

Question 2

What is the PNS and what does it consist of?

Answer 2

Peripheral Nervous System

Consists of:
- nerve fibres originating from the CNS

Question 3

What is the telencephalon?

Answer 3

The cerebral hemispheres

Question 4

What are gyri?

Answer 4

ridges on the surface of the cerebral hemispheres

Question 5

What are sulci?

Answer 5

valleys on the surface of the cerebral hemispheres

Question 6

What are the four lobes of the cerebral hemispheres?

Answer 6

1. Frontal
2. Parietal
3. Temporal
4. Occipital

Question 7

What is the role of the frontal lobe?

Answer 7

responsible for executive functions such as personality

Question 8

What is the role of the parietal lobe?

Answer 8

contains the somatic sensory cortex responsible for processing tactile information

Question 9

What is the role of the temporal lobe?

Answer 9

Contains important structures such as the hippocampus (short term memory), the amygdala (behaviour) and Wernicke’s area (auditory perception & speech)

Question 10

What is the role of the occipital lobe?

Answer 10

Processing of visual information

Question 11

What does the brainstem consist of (in descending order)?

Answer 11

1. Midbrain
2. Pons
3. Medulla

Question 12

What is the role of the brainstem?

Answer 12

multitude of important functions (e.g. control of respiration & heart rate) and are the target or the source of all cranial nerves

Question 13

Where is the cerebellum located?

Answer 13

the dorsal region of the CNS, and attached to the brainstem

Question 14

What is the role of the cerebellum?

Answer 14

motor coordination, balance, and posture

Question 15

What is the role of the spinal cord?

Answer 15

acts as a conduit for neural transmission but can coordinate some reflex actions

Question 16

What is a mature neuron?

Answer 16

A non-dividing excitable cell whose main function is to receive and transmit information in the form of electrical signals.

Question 17

What is the most abundant cell type in the brain?

Answer 17

Astrocytes

Question 18

What is the role of astrocytes in the brain?

Answer 18

Main function is as structural cells.

Play an important role in cell repair, synapse formation, neuronal maturation, and plasticity.

Question 19

What are the four morphologies of neurons?

Answer 19

1. Unipolar - single axonal projection
2. Pseudo-unipolar - single axonal projection that divides into two
3. Bipolar - two axonal projections from cell body
4. Multipolar - numerous projections from cell body

Question 20

What are three examples of multipolar neurones?

Answer 20

1. Pyramidal cells - pyramid-shaped cell body with three axonal projections
2. Purkinje cells - GABA neurons found in the cerebellum
3. Golgi cells - GABA neurons found in the cerebellum

Question 21

What is the role of neurons?

Answer 21

Excitable cells of the CNS

Responsible for electrical transmission

Question 22

What are three important features of neurons?

Answer 22

1. Heterogeneous morphology
2. Non-diving cells
3. Have common features (soma, axons, dendrites)

Question 23

What is the soma?

Answer 23

Cell body (perikaryon) of the neuron.

• contains nucleus & ribosomes
• neurofilaments -> structure & transport

Question 24

What is the axon?

Answer 24

• long process (aka nerve fibre), originates from axon at hillock
• can branch off into collaterals
• usually covered in myelin

Question 25

What are dendrites?

Answer 25

- highly branched cell body - NOT covered in myelin | - receive signals from other neurons

Question 26

What are the differences between oligodendrocytes and Schwann cells?

Answer 26

Oligodendrocytes are the myelin producing cells of the CNS Schwann cells are the myelin producing cells of the PNS Each oligodendrocyte is capable of meylinating a number of axons Each Schwann cell only myelinates a single axonal segment

Question 27

What are microglia?

Answer 27

specialised cells that perform immune functions (i.e like neronal macrophages)

Question 28

What are ependyma?

Answer 28

Epithelial cells that line the fluid filled ventricles regulating production and movement of cerebrospinal fluid

Question 29

What are the 4 major physiological ions?

Answer 29

potassium (K+) sodium (Na+) chloride (Cl-) calcium (Ca2+)

Question 30

Why is there an ionic imbalance between the extracellular fluid and intracellular fluid?

Answer 30

unequal distribution of major physiological ions

Question 31

How do ions cross the cell membrane?

Answer 31

transportation by channels and pumps | cell memebranes impermeable to these ions

Question 32

Neuronal cells have a .... charge inside compared to the outside

Answer 32

negative

Question 33

What is the average RMP of a neuronal cell?

Answer 33

-40 to -90mV