Biopsychology - Neurons And Synaptic Transmission

Question 1

Introduction to neurones

Answer 1

NS contains about 100 billion neurones
80% of neurones are in the brain
Neurons enable communication within the NS
Signals are transmitted electrically within neurones and chemically between neurones

Question 2

Structure of a neurone

Answer 2

Cell body: contains the nucleus with genetic material
Dendrites: branch-like structures that receive information
Axon: carries nerve impulses away from cell body
Myelin sheath: insulates and protects the axon
Nodes of Ranveir: gaps in myelin sheath that speed up impulse transmission
Terminal buttons: send impulses to next axon across synapse

Question 3

Types of neurones

Answer 3

Sensory neurons: carry messages from peripheral to CNS
Motor neurons: carry nerve impulses from CNS to effectors
Relay neurons: found in brain + spinal cord, connect sensory and motor neurones

Question 4

Receptors and effectors

Answer 4

Receptors: cells that detect changes in the environment (stimuli)
E.g. Skin detecting temp, tongue detecting taste
Effectors: organs or cells that produce a response to stimuli
E.g. muscles contracting, glands releasing hormones

Question 5

The reflex action

Answer 5

Automatic, involuntary response to a stimulus
Involves receptors, sensory neurones, relay neurones, motor neurones, and effectors

Question 6

Synaptic transmission info

Answer 6

Process by which neurones communicate with each other
Neurons separated by a tiny gap called synapse
Electrical messages converted to chemical signals
Neurotransmitters carry information across synapse

Question 7

Synaptic transmission process (VRRERRS)

Answer 7

V: Vesicles containing neurotransmitters
R: Release of neurotransmitters into synaptic cleft
R: Receptors on post:synaptic neurone receive neurotransmitters
E: Enzymes break down remaining neurotransmitters
R: Re-uptake of excess neurotransmitters
R: Replenishment of vesicles with new/reused neurotransmitters
S: Summation of signals

Question 8

Excitation and inhibition

Answer 8

Excitation: increases likelihood of neuron firing
Inhibition: decreases likelihood of neuron firing
Summation: total effect of excitatory and inhibitory influences
Determines whether neuron will fire and pass on electrical impulse

Question 9

Importance of neurotransmitters

Answer 9

Chemical messengers in synaptic transmission
Different types have various effects on neurons
Can be excitatory or inhibitory
Imbalances can lead to neurological and mental health disorders