WEEK 2 COMPLETED SET Flashcards
what is the nervous system
a vast network of nerve pathways and structures that mediate all aspects of being human eg. motor, cognitive, sonrory, perceptual, emotional and behavioural activity
what is a neuron
cell of the NS specialised for receiving and transmitting electrochemical signals
anatomy of a neutron from top to bottomq
dendrites, cell body, nucleaus, axon hillock, axon, node of ranvier, myelin sheath, collateral branches and terminal buttons
what is a gilial cell
important cells variety of shapes sizes and roles, play a supportive role to neurons, repair injury, clear up debris, prevent some substances from entering the brain, insulate neuron axons (mylein sheath)
what is a resting potential
in its resting state the fluid environment outside the axon is more positively charged than the inside- electrical potential of -60mV
what are graded potentials
electrical charges caused by neural signals arriving from the axons of other cells- can be inhibitory or excitatory
excitatory potentials
membrane potential become more positive, closer to the threshold more likely to fire
inhibitory potentials
membrane potentials become more negative and further away from threshold less likely to fire
when will a cell fire
when potentials are added together at the axon hillock if the threshold of excitation of -55mV
characteristics of action potentials
all or nothing, uniform in size, travel in one direction, takes1-2ms, can fire
what is an absolute refractory period
brief period of time when another AP cannot occur
processes involved in synaptic transmission
- NTs are encased in vescicles in the axon terminals
- when an AP is triggered in presynaptic neuron, NTs are released into the synaptic cleft
- the NTs attach to receptors and produce a graded potential in the post synaptic neuron
- the NT is inactivated (released from receptor) and taken back into the pre-synaptic cell (rey-take) or broken down by enzymes in the synaptic cleft or drift away
excitatory NTs..
cause depolarisation (an excitatory GP), increasing probability of AP
inhibitory NTs…
cause hyper polarisation reduces probability of an AP
glutamate
the main excitatory transmitter in CNS involved in learning, memory and transfer of sensory input- alcohol and memory enhancers interact with some glutamates receptors
gaba
the main inhibitory transmitter- dampens neural activity, involved in learning memory and sleep alcohol and anti-anxiety increase Gaba activity
acetylcholine (ACh)
involved in muscle contraction, cortical arousal, selective attention, sleep and memory, nicotine increases, botox blocks it
noradrenaline (norepinephrine)
involved in cortical arousal and autonomic NS, meth increases it
dopamine
motor function, reward eg. food, sex, drugs, gambling, shizo= increased parkingsons= less
serotonin
cortical arousal, mood, sleeping, eating- used to treat depression by increasing, MDMA increasing serotonin
endorphins
involved in pain control, mood elevation, called endogenous opioids,
anadamine
associated with pain, control, eating behaviour, motivation, memory and sleep- endogenous cannaboid
agonist drugs
enhance the effect of a neurotransmitter either by amount released, or mimicking it and binding to receptors eg. morphine and prozac
antagonists
inhibits the effect of a given neurotransmitter by either reducing the amount and release or by blocking receptors eg. antipsycotics block dopamine receptors
peripheral NS
carries information to and from the CNS includes somatic and autonomic NS- sympathetic and parasympathetic NS
somatic NS
part of PNS- VOLUNTARY, transmits commends to skeletal muscles, conveys sensory info to CNS and sends motor msgs to muscles, receives information from muscles and skin
Autonomic NS
part of PNS- serves basic life functions such as beating heart and response to stress, sends and recieves info to and from the glands and organs of a body
CNS
directs psychological and basic life processes- responds to stimuli
nervous system
provides the biological basis or psychological experience
spinal cord
recieves sensory input, sends to brain, responds with motor output
brain
directs psychological activity, processes info, maintains life supports
parasympathetic NS
routine maintenance of energy resources (rest and digest) and decreasing arousal
steps in detecting a threat
activation of sympathetic NS,
steps in detecting a threat
- activation of sympathetic NS- stimulates peripheral organ and muscular response increase breathing and heart rate- digestion and salivation inhibited, pupil dilates, bowel relax
- response, threat is appropriately responded to flight vs fight or our perception chnages
- activation of the parasympathetic branch, decreases the activation state of the peripheral organs musculature, restoring normal levels of function
definition of the endocrine system
system of glands that control vital functions eg. growth, metabolism, cardiovascular, reproduction
what are hormones
chemicals released by the endocrine glands into the bloodstream- bind to cell recepor sites in organs of the body, similar actions and roles as neurotransmitters in the CNS
role of hypothalamus in the endocrine system
regulates both the ANS and endocrine system by activating the pituiarty gland
role of pituitary in the endocrine system
releases hormones which have a direct effect or which activate glands further down the chain
oxytocin
involved in birth contractions, milk production, maternal/romantic love, interpersonal trust
what is the HPA axis
works in conjunction with sympathetic system to respond to stress
hypothalamus, releasing factor, anterior pituitary, ACTH (through blood), adrenal cortex, cortisol
adrenal glands function
release adrenaline and cortisol triggering flight or fight or maintaining it- when chronically activated by HPA axis, can cause big problems
role of thyroid gland in the endocrine system
releases growth hormone, metabolises ones, hypothyroidism associated with fatigue and depreaaion
role of pancreas in the endocrine system
controls blood sugar levels- produces insulin
role of gonads in the endocrine system
releases sex hormones- oestrogen and testostrone
