Biopsychology

Question 1

The nervous system

Answer 1

Network of cells and our primary communication system, divided into the central nervous system and the peripheral nervous system

Divided into central and peripheral

Question 2

2 main functions of NS

Answer 2

1) To collect, process and respond to information in the environment
2) To co-ordinate the working of different organs and cells in the body

Question 3

Structure and functions of CNS

Answer 3

• CNS= brain and spinal cord
• brain is centre of all conscious awareness
• cerebral cortex (highly developed in humans) distinguishes our higher mental functions from animals
• spinal cord is extension of the brain; responsible for reflex actions
• spinal cord passes messages to and from brain + connects nerves to PNS

Question 4

Structure and functions of PNS

Answer 4

• PNS transmits messages, via millions of neurons, to and from nervous system
• PNS is split into the automatic nervous system the somatic nervous system
• ANS governs vital functions in body such as breathing, heart rate, digestion, sexual arousal and stress responses
• SNS controls muscle movement and receives information from sensory receptors

Question 5

The endocrine system

Answer 5

Works alongside the NS to control vital functions in the body through the action of hormones

-slower than NS but has widespread and powerful effects

Question 6

Glands

Answer 6

Organs in the body that control hormones

• The major endocrine gland is the pituitary, located in the brain
• called ‘master gland’ bc it controls release of hormones from all the other endocrine glands in the body

Question 7

Hormones

Answer 7

Secreted in the bloodstream and affect any cell in the body that has a receptor for that specific hormone

-e.g. thyroxine produced by thyroid gland affects cells in the heart and also cells thought the body, which increase metabolic rates. This in turn affects growth rates

Question 8

The endocrine system and the ANS work together

E.g. fight or flight

Answer 8

• When stressor is perceived, hypothalamus triggers activity in sympathetic branch of ANS. ANS changes from normal resting state (parasympathetic state) to physiologically aroused state
• Stress hormone adrenaline is released from adrenal medulla into bloodstream
• Adrenaline triggers physiological changes in target organs in the body and causes, e.g. increased heart rate, dilation of pupils, decreased production of saliva. Called ‘fight or flight’
• Once threat has passed, parasympathetic NS returns body to resting state. This acts as a ‘brake’ and reduces activities of the body that were increased by sympathetic branch

Question 9

Motor neurons

Answer 9

• Connect CNS to effectors such as muscle and glands

- Short dendrites and axons

Question 10

Sensory neurons

Answer 10

• Carry messages from PNS to the CNS

- Long dendrites and short axons

Question 11

Relay neurons

Answer 11

• Connect sensory neurons to motor neurons or other relay neurons
• Short dendrites and axons

Question 12

Cell body (soma)

Answer 12

Includes a nucleus which. Contains the genetic material of the cell

Question 13

Dendrites

Answer 13

Branch-like structures that protrude from the cell body. Carry nerve impulses from neighbouring neurons towards the cell body

Question 14

Axon

Answer 14

Carries the electrical impulse away from the cell body down the neuron

• covered in a fatty layer of myelin sheath that protects the axon
• gaps in the axon (nodes of Ranvier) speed up the transmission of the impulse

Question 15

Terminal buttons

Answer 15

At the end of the axon, communicate with the next neurons in the chain across synapse

Question 16

Electric transmission

The firing of a neuron

Answer 16

• When neuron is in resting, inside of the cell is negatively charged compared to outside
• When neuron activated, inside of cell becomes positively charged for split second, causing an action potentials to occur
• This creates an electrical impulse that travels down axon towards end of the neuron

Question 17

Synapse

Answer 17

A tiny gap where one neuron (presynaptic) can send a chemical message to an adjacent neuron (postsynaptic)

Question 18

Signal transmission

Answer 18

Transmitted electrically within neurons but chemically between neurons (across the synapse)

Question 19

The events that occur at the synapse

Answer 19

• When electrical impulse reaches presynaptic terminal, triggers release of neurotransmitter from synaptic vesicles
• Once neurotransmitter crosses gap, it’s taken up by postsynaptic receptor site on the next neuron
• Chemical message converted back into electrical impulse and process of electric transmission begins

Question 20

Neurotransmitters

Answer 20

Chemicals that diffuse across the synapse to the next neuron in the chain

Question 21

Examples of neurons

Answer 21

• Acetylcholine (ACh) founds where a motor neuron meets the muscle, causing muscles to contract
• Serotonin affects moods and social behaviours, involved as a cause of depression

Question 22

Adrenaline

Answer 22

Generally excitatory, increasing the positive charge of the postsynaptic neuron, making it more likely the neuron will fire

Question 23

Seratonin

Answer 23

Generally inhibitory, increasing the negative charge of the postsynaptic neuron, making it less likely to fire

Question 24

Dopamine

Answer 24

Equally likely to have excitatory or inhibitory effects on the next neuron will fire

Question 25

Summation

Answer 25

Excitatory and inhibitory influences are summed and must reach a certain threshold in order for the action potential of the postsynaptic neuron to be triggered

If the net effect of the neurotransmitters is inhibitory then the postsynaptic neurons is less likely to fire. It is more likely to fire if the net effect is excitatory

Question 26

Synaptic transmission

Answer 26

Process by which one neuron communicates with another

Question 27

Process of synaptic transmission

Answer 27

-Information is passed down the axon of the neuron as action potential

Once the action potential reaches the end of the axon it needs to be transferred to another neuron or tissue

It must cross over the synaptic gap between the presynaptic neuron and post-synaptic neuron

At the end of the neuron (in the axon terminal) are the synaptic vesicles, which contain neurotransmitters

• When the action potential reaches these synaptic vesicles, they release their contents of neurotransmitters
• Neurotransmitters then carry the signal across the synaptic gap
• They bind to receptor sites on the post-synaptic cell, thereby completing the process