biopsychology Flashcards
What does the CNS consist of?
brain and spinal cord
What are the two main functions of the CNS?
- control of behaviour
- regulation of the body’s physiological processes
how does the CNS carry out its functions?
- the brain receives information from the sensory receptors
- brain sends messages to the muscles and glands of the body in response
what are the four areas of the brain?
cerebrum
cerebellum
diencephalon
brain stem
what is the cerebrum?
- largest part of the brain
- has four lobes
- is split into two halves called hemispheres
what is the functional the cerebellum
- responsible for motor skills
- balance and coordinating muscles to allow precise movements
what does the diencephalon contain?
thalamus
hypothalamus
what does the thalamus do
regulates consciousness, sleep and alertness
what does the hypothalamus do
regulates body temperature, stress response and hunger and thirst
what is the main function of the spinal cord
- relays information between the brain and the rest of the body.
- allows the brain to monitor and regulate bodily processes (digestion, breathing, voluntary movement)
what does the PNS consist of
the nervous system throughout the rest of the body (not the brain or spinal cord)
how does the PNS work
transmits messages via neutrons (nerve cells) to and from the CNS
what are the two divisions of the PNS
somatic nervous system
autonomic nervous system
what is the function of the somatic nervous system
- controls voluntary movements and is under conscious control.
- connects the senses with the CNS
- has sensory AND motor pathways
- controls skeletal muscles
- CONTROLLED BY the motor cortex
what is the function of the autonomic nervous system
- involuntary control
- ONLY has motor pathways
- it controls smooth muscles and the internal organs and glands of the body
- CONTROLLED BY the brain stem
what are the two divisions of the autonomic nervous system
sympathetic nervous system
parasympathetic nervous system
when is the sympathies nervous system activated and what happens
- activated when a person is stressed
- heart rate, breathing increase. digestion stops
- salivation reduces, pupils dilate
- blood is diverted from the surface on the skin (fight or flight)
when is the parasympathetic nervous system activated and what happens
- activated when the body is relaxing and conserving energy
- heart rate, breathing reduce. digestion starts
- salivation increases, pupils constrict
what are neurons
specialised nerves cells that move electrical impulses to and from the CNS
what is the cell body
control centre of the neuron
what is the nucleus
contains genetic material
what do dendrites do
received an electrical impulse (action potential) from other neurons or sensory receptors
what is the axon
long fibre that carries the electrical impulse from the cell body to the axon terminal
what is the myelin sheath
insulating layer that protects the axon and speeds up the transmission of the electrical impulse
what are schwann cells
make up the myelin sheath
what are the nodes of ranvier
gaps in the myelin sheath. they speed up the electrical impulse along the axon
how do neurons differ?
structure
location
function
where are sensory neurons found
sensory receptors (eyes, ears, skin etc)
how do sensory neurons work
- sensory neurons convert information from sensory receptors into electrical impulses
- carry electrical impulses from the sensory receptors to the CNS via PNS
- when impulses reach the brain they are converted to sensations (heat/pain) so that body can react appropriately
- some sensory impulses terminate at the spinal cord
what do sensory neurons allow us to do
allows reflexes to occur quickly without the delay of sending impulses to begin
where are motor neurons located
in the CNS
but project their axons outside of the CNS
how do motor neurons work
- send electrical impulses via long axons to the glands and muscles
- so they can affect function
- when motor neurons are stimulated they release neurotransmitters that bind to the receptors on muscles
- this triggers a response and leads to movement
what are effectors
glands and muscles
where are relay neurons found
CNS
what do relay neurons do
- connect sensory neurons to motor neurons so that they can communicate with one another
- during a reflex arc the relay neurons in the spinal cord are involved in an analysis of the sensation and decide how to respond without waiting for the brain to profess the pain
what are action potentials
electrical impulses
how do neurons work
they transmit electrical impulses (action potentials) between the pre synaptic neuron and the post synaptic neuron
what is the pre-synaptic neuron
the neuron transferring action potential
what is the post synaptic neuron
the neuron receiving the action potential
what happens once the action potential reaches the pre synaptic terminal
- triggers the release of neurotransmitters from sacs on the vesicles in a process called exocytosis
- released neurotransmitter diffuses across the synaptic cleft where it binds to specialised post-synaptic receptor sites
what are vesicles
sacs on the pre synaptic membrane
what is the synaptic cleft
physical gap between the pre synaptic membrane and post synaptic membrane
how long does synaptic transmission take and how is it terminated?
- takes only a fraction of a second
- effects are terminated by a process called re-uptake
what happens after reuptake?
- the neurotransmitter is taken back by the vesicles on the pre-synaptic neuron where they are stored for later release
- the quicker the neurotransmitter is taken back the shorter the effects
information can only travel in ONE direction at a synapse….
- The vesicles containing neurotransmitters are ONLY present on the pre-synaptic membrane.
- The receptors for the neurotransmitters are ONLY present on the post- synaptic membrane.
- It is the binding of the neurotransmitter to the receptor which enables the information to be transmitted to the next neuron.
what does diffusion of the neurotransmitters mean
- can only go from high to low concentration
- can only travel from the pre synaptic to the post synaptic membrane
what are psychoactive drugs and how do they work
- medication that affects brain function to alter perception, mood or behaviour
- (SSRIs) affects (increases or inhibits) the transmission of neurotransmitters across the synapse
what type of neurotransmitter is GABA
inhibitory
what do excitatory neurotransmitters do
- cause an electrical charge in the membrane of the post synaptic neuron
- results in an excitatory post synaptic potential
- means that the post synaptic cell is more likely to fire an impulse
what do inhibitory neurotransmitters do
- cause an inhibitory post synaptic potential
- makes less likely that the neuron will fire an impulse
what can a neuron receive
both EPSPs and IPSPs at the same time
what is the likelihood that the cell will fire an impulse dependent on?
-determined by adding up the excitatory and the inhibitory synaptic input
what is summation and what does it determine
- net result of excitatory and inhibitory synaptic input
- determines whether or not the cell will fire an impulse
when will the neuron fire and not fire
- fires if the net effect is excitatory
- doesn’t fire if the net effect is inhibitory
what does the endocrine system provide
a chemical system of communication in the body via the blood stream
what do endocrine glands do
produce an secrete hormones into the bloodstream which are required to regulate many bodily functions
what are the major glands of the endocrine system
pituitary gland and the adrenal glands
what are target cells
(limited number of) cells that are affected by hormones
why do target cells respond to a particular hormone
- they have receptors for that hormone
- when enough receptor sites are stimulated by thar hormone there is a physiological reaction
where is the pituitary gland located and what does it do
- located in brain
- produces hormones whose primary function is to influence the release of other hormones from other glands in body
what is the pituitary gland controlled by
hypothalamus
how does the pituitary gland work
- hypothalamus receives information from many sources
- it sends signal to the pituitary gland in the form of a releasing hormone
- causes the pituitary gland to send a stimulating hormone into the bloodstream to tell the target gland to release its hormone
as levels of stimulating hormone rise in the bloodstream…
- hypothalamus shuts down production of the releasing hormone
- pituitary gland shuts down secretion of the stimulating hormone
what are the two divisions of the pituitary gland
- anterior pituitary gland
- posterior pituitary gland
what does the anterior pituitary gland do
releases the hormone called ACTH which regulates level of the hormone cortisol
what does the posterior pituitary gland do
releases the hormone oxytocin which is crucial for infant/mother bonding
what are the two parts of the adrenal glands
adrenal cortex and adrenal medulla
what is the adrenal cortex and what does it do
- outer section of the adrenal gland
- produces the hormone cortisol
- is produced in high amounts when someone is experiencing chronic stress
what is cortisol responsible for
- the cardiovascular system
- increases blood pressure and causes blood vessels to constrict
what is the adrenal medulla
inner section of the adrenal gland
what does the adrenal medulla do
- produces adrenaline
- produced when someone is suddenly stressed and needs it for fight or flight response
what does adrenaline do
- increases heart rate
- dilates pupils
- stops digestion
how does the sympathomedullary pathway work
- triggered by the hypothalamus
- hypothalamus sends signal to adrenal medulla which responds by releasing the hormone adrenaline into the bloodstream
what does adrenaline do
- increases heart rate
- construct blood vessels
- increase rate of blood flow
- raise blood pressure
- divert blood away from skin, kidneys and digestive system
- increase blood supply to brain and skeletal muscles
- increase respiration and swearing
how is adrenaline used to prepare for fight or flight
- increases blood supply and therefore oxygen
- to skeletal muscles for physical action
- increasing oxygen to brain for rapid response planning
how does the parasympathetic nervous system work
- when threat has passed the paraNS dampens down the stress response.
- slows down heartbeat and reduces blood pressure
- digestion restarts
strengths of fight or flight response
+ makes sense from evolutionary psychology bc it would have helped person to survive
+ studies support claim that adrenaline is essential in preparing body for stress.
+people who have malfunctioning adrenal glands do not have a normal fight or flight response to stress
limitations of fight or flight response
—taylor found that females tend and befriend in times of stress. they protect offspring and seek social groups for mutual defence. women have the hormone oxytocin, which means they are more likely to stay and protect their offspring
-von dawans has found that even males tend and befriend. during 9/11 attacks males and females showed tend and befriend as they tried to contact loved ones and help each other.
