Biopsychology Flashcards
Nervous system
Consists of the central nervous system and peripheral nervous system. Communicates using electrical signals.
Central nervous system (CNS)
Consists of the brain and spinal cord and is the origin of all complex commands and decisions.
Peripheral nervous system (PNS)
Sends information to the CNS from the outside world, and transmits messages from the CNS to muscles and glands in the body
Somatic nervous system
Transmits information from receptor cells in the sense organs to the CNS. It also receives information from the CNS that directs muscles to act.
Autonomic nervous system
Transmits information to and from internal bodily organs. It is ‘autonomic’ as the system operates involuntarily. It has 2 main divisions: the sympathetic and parasympathetic nervous systems.
Endocrine system
Instructs glands to release hormones directly into the bloodstream. These hormones are carried towards target organs in the body.
Gland
An organ in the body that synthesises substances such as hormones.
Hormone
A biochemical substance that circulates in the blood but only affects target organs.
Fight or flight response
During stressful situations, the neurone of the sympathetic nervous system stimulate the adrenal medulla to secrete adrenaline, which prepares the body to deal with fear/stress/excitement.
Adrenaline
The stress hormones released from adrenal medulla into the bloodstream. Adrenaline triggers physiological changes in the body which creates the physiological arousal for fight or flight.
Sympathetic nervous system
Prepares the body for fight or flight. Heart rate, blood pressure and breathing rate increase.
Parasympathetic nervous system
Relaxes the body, and returns us to our ‘normal’ resting state. It slows down our heart rate and breathing rate, and reduces blood pressure.
Neuron
Nerve cells that process and transmit messages through electrical and chemical signals.
Sensory neurons
Carry impulses from PNS to CNS. They have long dendrites and short axons.
Relay neurons
Connect sensory neurons to the motor to other relay neurone. They have short dendrites and short axons.
Motor neurons
Connect CNS to effectors such as muscles and glands. They have short dendrites and long axons.
Structure of a neurone
- Cell body (soma) includes a nucleus, which contains genetic material.
- Dendrites protrude from cell body, and carry impulses from neighbouring neurone towards the cell body.
- Axon carries impulses away from the cell body down the length of the neurone.
- Myelin sheath protects axon and speeds up electrical transmission of the impulse - segmented into gaps called nodes of Ranvier, which speed up transmission of impulse by forcing it to ‘jump’ across the gaps along the axon.
- Terminal buttons communicate with next neurone across synapse.
Electrical transmission - the firing of a neurone
When a neuron is in a resting state the inside of the cell is negatively charged compared to outside.
- When a neurone is activated by a stimulus, the inside of the cell becomes positively charged for a split second causing an action potential to occur.
- This creates and electrical impulse that travels down the axon towards the end of the neuron.
Synaptic transmission
Neighbouring neurons communicate with each other by sending chemical messages across the gap (the synapse) that separates them.
Neurotransmitter
Brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another.
Excitation
When a neurotransmitter, such as adrenaline, increases the positive charge of the postsynaptic neuron. This increases the likelihood that the postsynaptic neuron will pass on the electrical impulse.
Inhibition
When a neurotransmitter, such as serotonin, increases the negative charge of the postsynaptic neuron. This decreases the likelihood that the postsynaptic neuron will pass on the electrical impulse.
Chemical transmission
When the electrical impulse reaches the end of the neurone (presynaptic terminal) it triggers the release of neurotransmitter from synaptic vesicles.
Summation
The excitatory and inhibitory influences are summed: if the net effect on the postsynaptic neuron is inhibitory then the postsynaptic neuron is less likely to fire. If the net effect is excitatory it is more likely to fire. Once the electrical impulse is created it travels down the neuron. The action potential of the postsynaptic neuron is only triggered if the sum of the excitatory and inhibitory signals at any one time reaches the threshold.
Localisation of function
The theory that different areas of the brain are responsible for specific behaviours, processes or activities.
Motor area
A region of the frontal lobe involved in regulating movement.
Somatosensory area
An area of the parietal lobe that processes sensory information such as touch.
Visual area
A part of the occipital lobe that receives and processes visual information.
Auditory area
Located in the temporal lobe and concerned with the analysis of speech-based information.