Neuronal communication

Question 1

CNS

Answer 1

Brain (100 billion neurones)

Spinal Chords

Question 2

PNS

Answer 2

Peripheral Nervous System

Somatic Nervous system (SNS)- Afferent nerves relay sensory info to CNS
Efferent relay motor commands from CNS to muscles

Autonomic Nervous System (ANS)
-Regulates internal organs of the body

Question 3

Golgi complex

Answer 3

Process and bundle molecules like proteins and lipids as they are synthesised within the cell

Question 4

Soma

Answer 4

cell body does most of metabolic work

Question 5

Axon

Answer 5

Thin fibre of constant diameter

Myelin sheath - nodes of ranvier

Question 6

Dendrites

Answer 6

Branching fibres that get narrower towards the end

Specialised synaptic receptors

Great surface area

Question 7

Purkinje cell

Answer 7

Receives inputs from 200,000 parallel fiber that convey information from the pontine nuclei

Question 8

Multipolar neurone

Answer 8

The dendrites recieve signals at synapses with several hundred other neurones

Local communication - mostly within the brain

Question 9

Motor neurone

Answer 9

Soma in spinal cord

Recieves excitation from other neurons through its dendrites

Conducts impulses along its axon to a muscle - can be over a meter long

Efferent

Question 10

Efferent neurone

Answer 10

Takes info away from CNS

Question 11

Sensory Neurone

Answer 11

specialised to be highly sensitive to a particular type of sensory stimulation

Sensory input - cell body - CNS

Afferent neurone

Question 12

Afferent neurone

Answer 12

takes info to CNS

Question 13

Neuroglial cell

Answer 13

Supporting cells

3:1 outnumber neurones

Do not participate in communication

Help define synaptic contacts and maintain signalling abilities of neurones

• Remove waste and pruning
• Uptake ions and send back to axons

Question 14

what builds myelin sheath in PNS?

Answer 14

Schwann cell

Question 15

What builds myeline sheath in CNS ?

Answer 15

Oligodendrocytes

Question 16

Radial glia

Answer 16

Guide neuronal migration in embryonic development

Primary stem and progenitor cell

Question 17

Neuronal membrane

Answer 17

Separates fluid inside the cell from outside

Large protein molecules in membrane control movement of ions (pumps)

Movement of ions across the neuronal membrane causes electrical signals

Question 18

Resting potential

Answer 18

Sodium-potassium pump:

3 sodium out/ 2 potassium in

Question 19

Receptor potentials

Answer 19

Sensory neurones activated by external stimuli

Amplitude in proportion to sensory stimuli magnitudes

Question 20

Synaptic potentials

Answer 20

Communication between neurones at synaptic contacts

Amplitude depends on number of synapses activated

Question 21

Electrical synapse

Answer 21

small gap junction - around 3.5 nm

aligned paired channels extremely efficient

Question 22

chemical synpase

Answer 22

bigger synaptic cleft

presynaptic vesicles are filled with neurotransmitters

neurotransmitters synthesised within presynaptic terminals

Question 23

vesicles merging

Answer 23

full fusion - all neurotransmitter released

kiss and run - partial fusion

Question 24

Auto receptors

Answer 24

feedback to presynaptic neuron
too much transmitter - less production and release
too little tranmitter - increase release

Question 25

Hetero receptors

Answer 25

excitatory or inhibitry messages from other neurons - transmitter release

Question 26

Criteria of neurotransmitter

Answer 26

Must be present in the presynaptic neurone Must me Ca2+ dependent, released in response to presynaptic depolarisation Specific receptors must be present on the postsynaptic neurons

Question 27

Types of synapses

Answer 27

Axodendritic synapses - Axon synapses on the postsnaptic dendrites of other neurones Axosynaptic - axon to presynaptic terminal of another neurone

Question 28

Agonist

Answer 28

neurotransmitter enhancer

Question 29

Antagonist

Answer 29

neurotransmitter blocker

Question 30

Resting membrane potential

Answer 30

-70mv positive sodium ions outside positive potassium ions inside and negative proteins polarised

Question 31

sodium potassium pump

Answer 31

2 sodium in, 3 potassium out

Question 32

what causes a neurone to fire?

Answer 32

environmental stimulus causes sodium channels to open This increases charge inside cell Once cell voltage reaches around -55mv, action potential occurs Voltage gate channels open causing cell to depolarise Positive charge moves down the cell

Question 33

repolarisation

Answer 33

potassium channels open and potassium leaves cell down electrochemical and concentration gradient goes to far at firs - hyperpolarisation sodium potassium pump returns neurone to resting potential