Cells of the nervous system and neuromuscular junction

Question 1

What are the roles of the frontal,temporal,parietal and occipital lobe?

Answer 1

Frontal-higher processing,feelings,emotions
Temporal-sound hearing
Occipital- visual processing
Parietal -motor and sensory processing

Question 2

What does the brainstem consist of?

Answer 2

Midbrain, pons, medulla (descending order)

Question 3

What is the role of the cerebellum?

Answer 3

Motor coordination, balance and posture

Question 4

What are the 4 components of the CNS?

Answer 4

Cerebral hemispheres, brainstem, cerebellum and Spinal cord

Question 5

what are the 4 types of neuron morphology

Answer 5

unipolar, pseudo-unipolar, dipolar, multipolar

Question 6

what are the three types of multipolar neurons

Answer 6

pyramidal, purkinje and golgi (both of which are GABA neurons found in the cerebellum)

Question 7

what are the 3 components of a neuron

Answer 7

soma, axon, dendrites

Question 8

what is one key difference between an axon and a dendrite

Answer 8

axons are usually covered in myelin and dendrites are not

Question 9

how many axons do neurons have

Answer 9

ONE

Question 10

What is the most abundant cell type in the CNS

Answer 10

Astrocytes

Question 11

What are the three functions of an astrocyte

Answer 11

cell repair (synthesis neurotrophic factors), homeostasis (neurotransmitter removal and uptake) , structural cells (blood brain barrier)

Question 12

What is the function of an oligodendrocyte

Answer 12

produces myelin

Question 13

what are the two differences between a oligodendrocyte and a schwaan cell

Answer 13

oligodendrocyte-CNS , schwaan-PNS.

oligodendrocyte myelinates parts of many axons. Schwaan cells only myelinate a segment of one axon.

Question 14

what is the function of a microglial cell

Answer 14

immune function- similar to a macrophage

Question 15

what is the function of the ependymal cell

Answer 15

epithelial cells- line fluid filled ventricles to control the movement and regulate the production of CFS

Question 16

what are the 5 types of neuroglia cells

Answer 16

astrocytes, oligodendrocyte, schwaan cell, microglial, ependymal

Question 17

what are the 4 major ions that affect resting membrane potential?

Answer 17

K+, Na+, Cl-, Ca2+

Question 18

how do ions travel across the neuron’s cell membrane?

Answer 18

by channels and pumps

Question 19

which ions are of high concentration OUTSIDE of the neuronal cell?

Answer 19

Na+, Cl-

Question 20

which ion is there a high concentration of INSIDE of the neuronal cell?

Answer 20

K+

Question 21

Which ion has a high concentration gradient?

Answer 21

Ca2+

Question 22

What is the RMP usually ?

Answer 22

-70mv (between -40 to -90)

Question 23

Is the outside or the inside of the neuronal cell more negative?

Answer 23

inside. charges are concentrated around the membrane

Question 24

if the RMP is more negative ( eg -90mV), is the neuronal cell more or less excitable?

Answer 24

Less

Question 25

At RMP are VGSC and VGKC open or closed?

Answer 25

closed

Question 26

what happens during membrane depolarisation?

Answer 26

opening of VGSC, Na+ influx

Question 27

what happens during membrane repolarisation?

Answer 27

opening of VGKC, k+ efflux. VGKC are slower at opening

Question 28

how is the ion gradient restored?

Answer 28

using Na+-K+-ATPase (pump)

Question 29

what happens during resting configuration?

Answer 29

Na+ enters vestibule (leaves cell) and upon phosphorylation- ions are transported through protein

Question 30

what happens during active configuration?

Answer 30

Na+ removed from cell- K+ enters the vestibule (cell)

Question 31

why does myelin prevent AP from spreading?

Answer 31

it has high resistance and low capacitance ( ability to store charge)

Question 32

whats the term for when AP 'jumps' from one node of ranvier to another?

Answer 32

saltatory conduction

Question 33

what are the 4 steps of neurotransmission that occur at the synapse?

Answer 33

1) propagation of an action potential 2) neurotransmitter release from vesicles 3) activation of post-synaptic receptors 4) neurotransmitter reuptake

Question 34

what happens to the neurotransmitter once it dissociates from the receptors?

Answer 34

- metabolised by enzymes in synaptic cleft | - recycled by transporter proteins

Question 35

what are the two types of communication between nerve cells?

Answer 35

autocrine(same cell) and paracrine(nearby cell)

Question 36

what are the 3 types of synpatic organisation?

Answer 36

- axodendritic synapse - axosomatic synapse - axoaxonic synapse

Question 37

at the neuromuscular junction is chemical communication unidirectional or bidirectional?

Answer 37

unidirectional

Question 38

what is the neurotransmitter at the neuromuscular junction and what are the post synaptic receptors on the skeletal muscle?

Answer 38

acetylcholine (ACh) | nicotinic ACh receptors (nAChR)

Question 39

what must happen to the end plate potential (EPP) for an AP to be generated ?

Answer 39

increase. need lots of miniature EPP to generate an AP.

Question 40

what is the sarcolemma?

Answer 40

cell membrane of muscle cell

Question 41

Describe the excitation-contraction coupling?

Answer 41

nAChR activation-> depolarisation->AP. It then moves down T-tubules. Sarcoplasmic reticulum releases Ca2+ following depolarisation. Muscle contraction (myofibril)

Question 42

what is the sarcoplasmic reticulum's location, function and effect?

Answer 42

location: surrounds myofibrils-contractile units of muscle function: Ca2+ storage and release following sarcolemma depolarisation effect: myofibril contractions and muscle contraction

Question 43

what occurs during the disorder botulism?

Answer 43

botulinum toxin: irreversible disrupts stimulation-induced ACh release form presynaptic nerve terminal ( acts on proteins which then prevent fusion of vesicles)

Question 44

what occurs during the disorder Myasthenia Gravis and what are the effects?

Answer 44

autoimmune disorder where antibodies directly bind to MUSCLE TYPE nicotinic acetylcholine receptors. causes fatigable weakness

Question 45

what occurs during the disorder Lamber-Eaton myastenic syndrome (LEMS)?

Answer 45

autoimmune disorder where antibodies directly bind to VGCC on the presynaptic terminal. prevent calcium entry. causes fatigable weakness.