Flashcards in Biopsychology Deck (52):
How can the nervous system be divided?
Central nervous system (CNS) and peripheral nervous system (PNS)
What is the endocrine system?
hormone system; is much slower to communicate but much longer lasting than the nervous system
What is the nervous system?
The body's fast and short lived system of communication
What does the peripheral nervous system consist of?
Somatic nervous system (controls voluntary movements)
Automatic/Autonomic nervous system (controls involuntary responses/actions)
How can the Automatic nervous system be divided?
Sympathetic division: fight or flight
Parasympathetic division: rest or digest
What are the key sections of the brain (general)?
Frontal lobe (problem solving), Parietal lobe (sensory processing), temporal lobe (language and auditory processing), occipital lobe (visual processing), cerebellum (fine motor movements)
What are the key sections of the inner brain?
Hypothalamus (regulating endocrine system), Limbic system (animal instincts), thalamus (processing sensory info), hippocampus (memory), pituatary gland (master gland in endocrine system), cerebellum
What is a neuron?
neurons are cells that process and transmit messages through electrical and chemical signals
What are the parts of the neuron?
Cell body, dendrites, axon, myelin sheath, nodes of Ranvier, terminal buttons
What is the cell body?
Includes nucleus, containing the genetic material of the cell
What are the dendrites and terminal buttons?
Dendrites- protrude from cell body. carry nerve impulses from neighbouring neurons towards the cell body
Terminal buttons: communicate with the dendrites of the next neuron
What is the axon and myelin sheath?
Axon- carries impulses away from cell body
Myelin sheath- protects axon and speeds up electrical transmission
What are the nodes of Ranvier?
They are segmented gaps in the myelin sheath that speed up the impulse by forcing it to 'jump' across gaps down the axon
What are sensory neurons?
Internal and external receptor cells around the body take in information from the 5 senses. Information is then carried from the PNS to the CNS (brain)
Unipolar- one protrusion from cell body, Long dendrites
What are relay neurons?
Carry messages from one part of the CNS to another
Connect sensory and motor neurons or between relay neurons
What are motor neurons?
Carry messages from CNS
Connect the CNS to 'effectors' (such as muscles, organs and glands)
Short dendrites, long axons
What is a synapse?
Neurons do not touch, between each is a tiny gap called a synapse or synaptic gap
How are signals within neurons transmitted?
How do signals travel across synapses?
What is the first stage of synaptic transmission?
Electrical impulse reaches the pre-synaptic nerve terminal and triggers synaptic vesicles to move to the pre-synaptic cell membrane
What is the second stage of synaptic transition?
Synaptic vesicles fuse with the pre-synaptic cell membrane and release neuro-transmitters into the synaptic gap
What is the third stage of synaptic transition?
These neuro-transmitters enter the synaptic fluid and diffuses across the synaptic gap. If the neuro-transmitter fits the receptor sites of the post-synaptic neuron, it is taken up
What is the final stage of synaptic transmission?
Once enough receptors have neuro-transmitters bound to them, the chemical message is converted back into an electrical impulse
What is the lock and key mechanism?
when the right neurotransmitter (key) meets the right receptor (lock) a specific ion channel in the membrane is opened up
ions flow through the membrane into the neuron along their pathway. The flooding of ions cause a potential in the dendrites
What are the two actions of neuro-transmitters?
Excitatory and inhibitory
What do excitatory neuro-transmitters do?
(E.g. Adrenaline) are 'on' switches, these make it more likely that the next neuron will fire
What do inhibitory neurotransmitters do?
(e.g. GABA) are 'off' switches, these make it less likely that the next neuron will fire
How does the next neuron 'assess' whether or not to fire?
Post-synaptic neuron 'sums up' the total of excitatory and inhibitory signals (summations) and whichever signal the neuron receive most of will determine whether the neuron fires or not
What is temporal summation?
A large number of EPSPs at the same synapse by a series of high frequency action potentials on the pre-synaptic neuron. The rate at which a particular cell fires is determined by what goes on in the synapses (so if IPSPs are higher frequency the signal will fire at a slower rate)
What is special summation?
A large no. of EPSPs are generated at many different synapses on the same post-synaptic neuron, so it will fire at a faster rate (lower if large no. of IPSPs)
What are the key endocrine glands?
Hypothalamus, pituitary, thyroid, parathyroid, adrenal glands, pancreas, testes (male)/ovaries (female)
What does the adrenal gland do?
location: above kidneys (back), secretes: adrenaline, function: to initiate fight or flight
What does the testes gland do?
secretes: testosterone, function: linked to agression
What do the ovaries do?
location: pelvis, secretes: progesterone and oestrogen, function: regulates female menstrual cycle
What does the Hypothalamus do?
Location: in limbic system, secretes: various, function: acts as a thermostat- measuring hormone levels
What does the pituitary gland do?
Location: in limbic system, secretes: various, function: "master gland" - tells other glands what to release
What is the endocrine system?
Acts much slower than nervous system (but more widespread effects), made up of multiple glands around the body. Each gland releases different hormones into the blood which regulate activity of various organs/tissues
What happens as hormones travel around the body?
As hormones travel in the blood, they contact most cells, but they only affect a smaller no. of target cells with the right receptors for that hormone (cell can't be affected if no receptor for that hormone)
What happens after hormones contact target cells?
When enough receptor sites on the organ are stimulated by the hormone there is a physiological reaction in the target cell
How are hormone levels regulated?
Hypothalamus sends message to pituitary gland in form of a releasing hormone; pituitary gland releases hormone into the blood. This stimulating hormone targets a specific gland to release melatonin
How does the release of melatonin regulate hormone levels?
Levels of melatonin in blood rise, when they reach a certain level the hypothalamus shuts down secretion of the releasing hormone and pituitary gland stops releasing stimulating hormone. This slows down secretion of target gland's hormone production = stable concentrations in the bloodstream
What triggers the fight or flight response?
In stressful/threatening situation body reacts biologically- preparing you to fight the threat or run away
What systems are involved in the fight or flight response?
Both the endocrine and nervous system are involved
What is the fight or flight response?
Started by the autonomic nervous system (specifically the sympathetic branch) as an unconscious reflex response. However this response also requires the secretion of hormones
Why do we have the fight or flight response?
Evolved survival mechanism to allow people to act in life threatening situations but can be activated in no-useful situations
What biologically starts the fight or flight response?
Sympathomedullary pathway: the fight or flight response
Our amygdala associates sensory signals with emotions such as fear/anger.
When we're faced with a threat our amygdala identifies this and sends a distress call to our hypothalamus
What occurs in the hypothalamus during the fight or flight response?
When hypothalamus identifies a stressor it activates the sympathetic nervous system (via the brain stem)
The SNS sends a signal to adrenal medulla causing release of adrenaline and noradrenaline into the blood
What happens in fight or flight response when adrenaline is released into the blood?
As adrenaline circulates it causes physiological changes
heart rate rises, digestion slows down, pupils dilate
What happens during fight or flight when the threat has passed?
The parasympathetic branch of the autonomic nervous system is activated. This returns the body to its normal resting state.
What happens during fight or flight if stressful situation continues?
HPA axis (pituitary-adrenal system) is activated as initial adrenaline subsides, release of cortisol, emphasis on energy production and stamina (long term response)
How do reactions of females differ from males? (evaluation point)
Tend and Befriend- it isn't advantageous to run away and leave children behind so they befriend competitors