Biopsychology

Created by

Faith Naughton

Cards (138)

What is the nervous system?
> a specialized network of cells in the human body and is our primary internal communication system.
> Consists of the central nervous system and the peripheral nervous system.
> Communicates using electrical and chemical signals.
> two main functions = collect, process and respond to information in the environment & co-ordinate the working of different organs and cells in the body.
What is the central nervous system?
> Consists of the brain and the spinal cord and is the origin of all complex commands and decisions
> brain: Centre of all conscious awareness - divided into two hemispheres
> spinal cord: extension of the brain - passes messages to and from the brain and connects nerves to the PNS. Also responsible for reflex actions such as pulling your hand away from a hot plate.
What is the peripheral nervous system?
> Sends information to the CNS from the outside world, and transmits messages from the CNS to muscles and glands in the body
> transmits messages, via millions of neurons, to and from the CNS.
> subdivided into: autonomic nervous system & somatic nervous system
What is the 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
what is the automatic nervous system?
Transmits information to and from internal bodily organs. It is 'autonomic' as the system operates involuntary (i.e. automatic). It has two main divisions: the sympathetic and parasympathetic nervous system.
What is the endocrine system?
> works alongside the nervous system to control vital functions in the body.
> One of the body's major information systems that instructs glands to release hormones directly into the bloodstream.
> These hormones are carried towards target organs in the body.
> Communicates via chemicals
What is a gland?
An organ in the body that synthesizes substances such as hormones
What is a hormone?
> A biochemical substance that circulates in the blood but only affects target organs.
> They are produced in large quantities but disappear quickly.
> Their effects are very powerful
What is the fight of flight response?
> The way an animal responds when stressed
> The body becomes physiologically aroused in readiness to fight an aggressor or, in some cases, flee
What is adrenaline?
> a hormone produced by the adrenal glands which is part of the human body's immediate stress response system.
> adrenaline has a strong effect on the cells of the cardiovascular system - stimulating heart rate, contracting blood vessels and dilating air passages.
Fight or Flight response:
> stressor perceived, hypothalamus activates pituitary gland - triggers activity in sympathetic branch of autonomic NS
> The ANS changes from normal resting state (parasympathetic) to physiologically aroused sympathetic state.
> stress hormone adrenaline released from adrenal medulla - triggers physiological changes in body - creates the physiological arousal necessary for response
Fight or Flight response: sympathetic and parasympathetic
> happens in an instant when threat is detected - acute response & automatic reaction
> once threat past, parasympathetic NS work in opposition to sympathetic NS - reduced activities of the body that were increased by actions of sympathetic branch -> rest and digest response.
Two glands and their hormones:
Adrenal gland: adrenaline
Thyroid gland: thyroxine
Biological changes of sympathetic response:
> increases heart rate
> increases breathing rate
> Dilates pupils
> Inhibits digestions
> Inhibits saliva production
Biological changes of parasympathetic response:
> decreases heart rate
> decreases breathing rate
> constricts pupils
> stimulates digestion
> stimulates saliva production
What is a neuron?
The basic building blocks of the nervous system, neurons are nerve cells that process and transmit messages through electrical and chemical signals
What are sensory neurons?
> carry messages from the PNS to the CNS
> long dentrites
> short axons
What are relay neurons?
> connect the sensory neurons to the motor and other relay neurons
> short dentrites
> short axons
What are motor neurons?
> connect the CNS to effectors such as muscles and glands
> short dentrites
> long axons
What % of neurons are located in the brain?
80%
What are the three types of neurons?
> relay neurons
> sensory neurons
> motor neurons
What do neurons vary in?
> size
> from less than a millimeter to up to a metre long
structure of a neuron: cell body, dentrites and axon 
> cell body (soma) includes nucleus which contains the genetic material of cell
> dentrites (branched-like structures) carry nerve impulses from neighbouring neurons towards cell body
> axon carries impulses away from cell body down length of neuron - covered in fatty layer of myelin sheath (protects axon and speeds up electrical transmission of impulse)
structure of a neuron: myelin sheath, nodes of Ranvier, terminal buttons
> Myelin sheath = fatty - protects axon and speeds up electrical transmission of impulse
> If myelin sheath was continuous it would slow down electrical impulse - so it's segmented by gaps called nodes of Ranvier.
> nodes of Ranvier speed up the tranmission of impulse by forcing it to 'jump' across gaps along axon
> terminal button is at end of axon - communicate with next neuron in the chain across synapse
Where are motor neurons located?
may be in central nervous system (CNS) but have long dentrites which form part of the peripheral nervous system (PNS)
Where are sensory neurons located?
outside the CNS, in the PNS, in clusters known as ganglia
Where are relay neurons located?
relay neurons make up 97% of all neurons - mainly located in brain and visual system
Electrical transmission - the firing of a neuron
> when neuron in resting state, the inside of cell = negatively charged compared to outside
> when neuron activated by stimulus, the inside of cell = positively charged for split second, causing an action potential to occur
> this creates an electrical impulse that travels down the axon towards the end of the neuron
What is a synaptic transmission?
The process by which neighbouring neurons communicate with each other by sending chemical messages accross the gap (the synapse) that seperates them
What is a neurotransmitter>
> brain chemicals released from synaptic vesicles that relay signals accross the synapse from one neuron to another.
> Neurotransmitters can be broadly divided into those that perform an excitatory function and those that perform an inhibitory function
What can neurotransmitters be divided into?
> those that perform excitatory function
> those that perform an inhibitory function
What does excitation mean?
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
What does inhibition mean?
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
Synaptic transmission - chemical transmission
> neurons communicate with each other within groups known as neural networks.
> Each neuron is seperated from the next by a tiny gap called a synapse
> signals within neurons are transmitted electrically. However, signals between neurons are transmitted chemically across the synapse
> when the electrical impulse reaches the end of the neuron (presynaptic terminal) it triggers the release of neurotransmitter from tiny sacs called synpatic vesicles.
Synaptic transmission - neurotransmitter 
> chemicals that diffuse across synapse to the next neuron in the chain
Once a neurotransmitter crosses the gap, it's taken up by a postsynaptic receptor site on the dentrites of the next neuron
>The chemical message is converted back into an electrical impulse and the process of transmission begins again in the other neuron.
> travels in one-direction -> neurotransmitters are released from the presynaptic neuron terminal and received by postsynaptic neuron (at receptor site)
>Each neurotransmitter has its own specific molecular structure and function.
Axon and dentrite directions
> axons take signals to the synapse
> dentrites take signals away
Synaptic transmission - excitation and inhibition 
> neuorotransmitters have either an excitatory of inhibitory effect on neighbouring neuron
> Inhibition: serotonin causes inhibition in the receiving neuron, resulting in the neuron becoming more negatively charged and less likely to fire
> Excitation: adrenaline (element of stress response, both a hormone and a neurotransmitter) causes excitation of the postsynaptic neuron by increasing its positive charge and making it more likely to fire
Synaptic transmission - summation
> whether a postsynaptic neuron fires is decided by process of summation
> If net effect on the postsynaptic neuron is inhibitory then the postsynaptic neuron is less likely to fire
> If net effect is excitatory it is more likely to fire, i.e. the inside of the postsynaptic neuron momentarily becomes positively charged. Once the electrical impulse is created it travels down the neuron
> therefore, 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.
What is localisation of function?
The theory that different areas of the brain are responsible for specific behaviours, processes or activities.
What is the motor area? 
A region of the frontal lobe involved in regulating movement