The nevous system Flashcards
The nervous system
the nervous system is a communication system between the body’s internal cells and organs and the external world
it receives and processes and coordinates a response to information
it is divided into two main divisions central and peripheral NS
Central NS (CNS)
is comprised of the brain (organises and intergrates info) and spinal cord (highway for info).
This divisons major funtion is to transmit and receive information to and from the PNS
Peripheral NS (PNS)
carries messages to and from the CNS.
It is further divided into Autonomic and Somatic NS
Autonomic NS
self regulation of the bodys organs, visceral muscles and glands which occurs involuntarily (unconcious) eg. controls breathing, heart rate and other important involuntary movements
It is further divided again into sympathetic NS and parasympathetic NS
Somatic NS
carries sensory (afferent) info that is received at sensory receptor sites in the body (skin, joints, tendons) and carries messages along sensory neural pathways by sensory neurons to the CNS.
Carries and motor (EFFERENT) information from the CNS. Motor information is carried along motor neural pathways by motor neurons to skeletal muscles (attached to the skeleton) to control their activity.
Sympathetic NS
fight or flight response, it prepares the body for action
pupils dilate, heart rate and blood pressure increase as well as breathing
Parasympathetic NS
maintains the bodys internal environment in a steady, balanced state of funtioning
counterbalces the sympathetic NS activation by returning the body to a state of calm.
homeostasis
increased saliva, sweat glands reduce production and pupils contract
Spinal reflex
unconsious, involuntary and automatically occuring response to a certain stimuli without any involvement of the brain.
the spinal cord responds to the message directly, causing an increased reaction just before sensory info in the brain is received
it is an adaptive response
Neurons
an individual cell that is specialised to receive, process and or transmit infomation
they carry messages in the form of action potentials to the appropriate parts of the NS to interprete and form a response.
Neurotransmitter
a chemical sunstance that is produced by a neuron and is then carried to other neurons. neurotransmitters in the pre synaptic neuron work by attatching (binding) to receptor sites of the post synaptic neuron, that specialised to recieve that specific neurotransmitter.
they either have a excititory effect (increase the chance of post synaptic neuron firing) or inhibitory effect (decrease the chance of the post synaptic neuron firing)
they have a distinct shape which binds to the receptor sites in the denrites of the post synaptic neuron (lock and key process)
Parkinsons disease
is a chronic and degenerative neurological condition that affects both motor and non motor funtions
motor symptoms inclue - tremors, muscle stiffness, unstable posture, bradykinesia (slowness of movement)
non-motor symptoms include - slower cognitive funtions, reduced sense of smell
there is no known cure but there is treatment to manage motor symptoms
Role of dopamine in Parkinsons disease
dopamine (neurotransmitter) is produced in the substantia nigra in the brain. when diseased or damaged, the amount of dopaminebeing produced is reduced. dopamine sends messages that allow smooth and coordinated funtion of the bodys muscles and movement. there for resulting in tremors, muscle stiffness and unstable posture.
Consious responses to stimuli
reaction involves awareness voluntary or intentional reaction purposful or goal directed more complex response tend to vary and can be learnt can be controlled
Unconsious response to stimuli
reaction does not involve awareness involuntary and unintentional simple responses which doesnt require it to be learnt may not be able to control eg. spinal reflex
Neuron structures - dendrites
branches, that receive info from other neurons, then carry from synapse to the soma.
Neuron structures - soma
‘cell body’ controls maintenance and receives messages from other neurons
Neuron structures - axon
extends from soma, carries info towards cells that communicate with that neuron
Neuron structures - myelin sheath
coating around axom, protects from chemical and physical interference to impulses that travel along it, and insulates
Neuron structures - axon terminals
end of axon branch, it transmits messages to next neuron they have terminal buttons that secrete the neurotransmitter.
Glutamate
GABA
glutamate = your mate. is excititory (increases chance of the post synaptic neuron to fire)
GABA is inhibitory (decreases chance of post synaptic neuron to fire)
Process of neural transmition with reference to glutamate. exam question
terminal buttons from the pre-synaptic neuron release neurotransmitters (glutamate).
glutamate is then released into the synapse which then acts as a key, it has a specific shape that binds with the corresponding shape of a receptor site in the dendrites of the post synaptic neuron which acts as the lock.
glutamate is excititory which means it increases the chance of the post synaptic neuron to fire (4 marks)
Stress/ stressor
a state of biological & psychological arousal produced by internal or external stressors that are perceived by the individual as challenging or that exerts the individuals ability and resources to cope, it is a subjective experience.
a stressor is stimuli that causes or produces stress can be internal or external
Acute stress
brief and specific to the demands of a particular situation.
Chronic stress
ongoing demands, pressures and worries that are long lasting, with what seems like little hope of letting up.
Eustress
a positive response to a stressor, may feel like enthusiasm or excited or alert
short term and provides the body with energy to complete whats needed to acheive the goal with peak performance.
Distress
a negative psychological response to a stressor, like anxiety or anger.
short term but may be present from weeks to years, prolonged stress can have serious and debilitating effects of physical and mental health
Daily pressures - stress
little problems of everyday living. events that annoy or bother us that can make us upset or angry
eg. boredom, sleeping in, losing things
Life events - stress
a stressor in everyday life that forces the individual to adapt to new circumstances
eg. break up, death of loved one, starting new career
Major stress
involves an event that is extraordinarily stressful or disturbing for almost everyone involved.
eg. winessing a crime, workplace accident, having a terminal illness
Catastrophes - stress
an event that causes widespread damage or suffering
stressor of a massive proportion
eg. bushfire, cyclones
Acculturative stress
stress people (immigrants or refugees) experience in trying to adapt to new culture when living in it for a period of time eg. language differences, adapting to new customs, racial discrimination
models of stress - biological
fight flight freeze response - an involuntary physical response to sudden and immediate threat (stressor)
fight and flight - sympathetic NS - increased heart rate and blood pressure, increased breathing and dilated pupils.
freeze - parasympathetic NS - body movements and vocalisation stops, heart rate slows and blood pressure drops, tense muscles become still and collapse
Role of cortisol - biological
if a stressor needs to be dealt with over a prolongued period of time, additional physiological resources are required.
a brain to body response pathway is activated called the HPA-axis
the HPA-axis puts into motion a slower but long lasting chain of reaction including the release of cortisol.
this energises the body by increasing energy supplies
anti inflammatory by blocking white blood cells that contribute to that.
General adaption syndrome - stage one
SCARE
stage 1 - alarm reaction - shock counter shock
stressor is perceived, body temporarily enters state of shock & the bodys ability to deal with stressor is lowered.
a state of counter shock follows - sympathetic NS is activated & the fight or flight response.
the body is now prepared to deal with stress or
body systems involved in changes occuring with stress
perception amygdala hypothalamus sympathetic NS adrenal glands and adrenal cortex
General adaption syndrome - stage 2
SCARE
stage 2 - resistance
if stressor remains the bodys level of resistance is higher than normal
