Nervous System & Synaptic Transmission

Question 1

Central Nervous System

Answer 1

Brain and Spinal Cord

Question 2

Peripheral Nervous System

Answer 2

All nerves in the body outside of CNS

Question 3

Somatic NS

Answer 3

Transmits and recceives info from the senses and directs muscles to react and move (voluntary movement)

Question 4

Autonomic NS

Answer 4

• Controls involuntary, vital functions of the body
• Has 2 antagonistic systems - para/sympathetic (fight each other for control)

Question 5

Sympathetic NS

Answer 5

• Involved with responses to deal with emergencies
• Responds to perceived threat - neurons go to all organs and produce physiological changes
• Fight or Flight

Question 6

Parasympathetic NS

Answer 6

• Restores normal physiological functioning
• Involved with energy conservation and digestion
• Rest and Digest

Question 7

Neurons

Answer 7

• Carry info as electrical impulses
• Info received by terminals in dendrites

Question 8

Sensory Neurons

Answer 8

• Receive info from receptor cells
• Action Potential travels towards CNS
• 2 axons
• Cell body in the middle

Question 9

Motor Neurons

Answer 9

• Controls muscles to responds
• Action potential travels away from CNS
• 1 axon
• Cell body at the beginning

Question 9

Relay Neurons

Answer 9

• Transmit info
• Action Potential travels through CNS
• 0 Axons
• Cell body at the beginning

Question 9

Reflex Actions

Answer 9

• Automatic, rapid responses that do not involve conscious areas of brain
• Consist of 3 neurons
• Protective responses that occur in response to certain stimuli

Question 10

Synaptic Tansmission

Answer 10

• Communication between neurons at synapses
• Electrical messages called action potentials are translated into chemical messages (neurotransmitters)

Question 11

Synapse

Answer 11

Gap between neurons that AP must diffuse across to reach postsynaptic terminal

Question 12

Steps of Synaptic Transmission

Answer 12

1) AP arrives at presynaptic terminal
2) AP causes vesicles containing NTs to form
3) Vesicles fuse with presynaptic membrane, releasing NTs into synapse - exocytosis
4) NTs diffuse across synaptic cleft
5) NTs bind to receptors on postsynaptic membrane (either excitatory or inhibitory)
6) NTs that don’t diffuse across cleft are involved in reuptake to be used for future APs

Question 13

Excitatory & Inhibitory Post-Synaptic Potentials (EPSP & IPSP)

Answer 13

• Different hormones carry different messages - either positive or negative
• AP become postsynaptic potential
• Total for both EPSP and IPSP is summed up in summation, which decides if AP is created after the synapse
• EPSP = AP will be created
• IPSP = AP will not be created

Question 14

Temporal Summation

Answer 14

Very quick firing of one presynaptic neuron

Question 14

Spatial Summation

Answer 14

Lots of small signals at different synapses

Question 15

Process of Summation

Answer 15

• AP released when presynaptic potential is above threshold
• After threshold reached, there is a refractory period where membrane potential drops below resting state - fatigue if no rest

Question 16

Depolarising

Answer 16

Cell membrane is becoming more positive, toward threshold

Question 17

Repolarising

Answer 17

Cell membrane going back to resting state potential