Biopsychology Flashcards
What are the functions of the nervous system? + What is it?
Primary internal communication system, based on chemical and electrical signals
Functions:
- collects, processes and responds to information in an environment
- co-ordinate working of different organs/cells in the body
What are the two sub-systems of the nervous system?
Central nervous system (CNS)
Peripheral nervous system (PNS)
What is the CNS made up of?
The brain and spinal cord
What are the functions of the brain and the spinal cord?
Brain- centre of all conscious awareness
Spinal cord- extension of the brain which passes messages to and from the brain and connects the nerves to PNS. Also responsible for reflex actions.
What is the PNS made up of?
Millions of neurones
What are the two sub-systems of the PNS?
Autonomic nervous system (ANS): responsible for vital functions like breathing, heart rate, digestion
Somatic nervous system (SNS): responsible for muscle movement and receives info from sensory receptors
What is the role of the PNS?
Transmit messages through neurones to and from the CNS.
What are the two sub-systems of the ANS?
Sympathetic nervous system
Parasympathetic nervous system
What is the role of the endocrine system?
Instructs glands to release hormones directly to the blood stream, which are carried to their target organs.
What are some of the main glands in the body?
Hypothalamus, Pituitary, Thyroid, Ovaries, Testes
What is the main gland and its function?
Pituitary gland
Located in the brain and controls the release of hormones from all other endocrine glands.
What is the fight or flight response?
- Stressor is perceived
- Hypothalamus activates the pituitary gland which results in activity in Sympathetic nervous system.
- ANS goes from parasympathetic state to physiologically aroused sympathetic state
- Adrenaline triggers physiological changes in the body for fight or flight
- Happens immediately as soon as a threat it detected
- Once the threat has passed, the parasympathetic nervous system returns the body to resting state. The parasympathetic system works opposite to the sympathetic nervous system.
What is adrenaline?
A stress hormone released from adrenal medulla that triggers physiological changes in the body -> fight/flight response.
What are the biological changes which happen during both the parasympathetic and sympathetic response?
Parasympathetic:
- Decreases heart rate
- Decreases breathing rate
- Constrics pupils
- Stimulates digestion
- Stimulates saliva production
- Relaxes rectum
Sympathetic:
- Increases heart rate
- Increases breathing rate
- Dilates pupils
- Inhibits digestion
- Inhibits saliva production
- Contracts rectum
What are the 3 types of neurone?
- Sensory
- Motor
- Relay
What is the role of a sensory neurone?
Carry messages from the PNS to the CNS
They have long dendrites and short axons
What is the role of a relay neurone?
Connect sensory neurones to motor or other relay neurones
They have short dendrites and short axons
What is the role of a motor neurone?
Connect the CNS to effectors like muscles and glands
They have short dendrites and long axons
What is the structure of a neurone?
- Cell body: has a nucleus
- Dendrites (carry impulses to other neurones to cell body)
- Axon (carry impulses away from cell body + communicate with other neurones (they are terminal buttons)
- Myelin sheath (on axon, protects axon and speeds up transmission of impulse)
- Nodes of Ranvier (between parts of myelin sheath to speed up electrical transmission)
What is the charge of the inside of cells when neurones are at resting state?
Negative (positive on outside)
What happens when a neurone is activated by a stimulus?
Inside of a cell becomes positively charged which causes an action potential to occur, creating an electrical impulse that travels along the axon to the neurones end.
What is each neurone separated by?
Synapses
How are signals within neurones transmitted differently to signals between neurones?
Signals within neurones: transmitted electrically
Signals between neurones: transmitted chemically across synapse
What happens when the electrical signal reaches the end of a neurone? + what is the name for this?
The Presynaptic Terminal
Triggers the release of neurotransmitter from synaptic vessels (tiny sacs)
What is a neurotransmitter?
Chemicals that diffuse across synapse to the next neurone in the chain
What happens after a neurotransmitter has crossed the synapse?
It is taken up by a postsynaptic receptor site on the dendrites of the next neurone, where it is converted into an electrical impulse.
What is specific about each neurotransmitter?
It has its own specific molecular structure, so can only fit into one particular postsynaptic receptor site
What does an excitatory neurotransmitter do?
Increases the positive charge of the postsynaptic neurone, which increases the likelihood of the postsynaptic neurone will pass on the electrical impulse
What does an inhibitory neurotransmitter do?
Increases the negative charge of the postsynaptic neurone, which decreases the likelihood of the postsynaptic neurone will pass on the electrical impulse
What is summation?
Action potential of a postsynaptic neurone is only triggered if the sum of the excitatory and inhibitory signals at one time are greater than each other.
What is the process of the reflex arc?
Knee jerk reflex-> a reflex arc
A stimulus (hammer) hits the knee, this is detected by sense organs in the PNS which send a message along a sensory neurone
Message reachers the CNS and connects with a relay neurone which transfers a message to a motor neurone. This carries a message to an effector (muscle), causing the muscle to contract and therefore the knee moves.
