biopsychology

what is the structure of the nervous system

what is the function of the central nervous system

central coordinator for all bodyily functions

function of the brain

cerebral cortex is the decision maker

function of the spinal cord

• reflex responses

• relays messages between peripheral nervous system and brain

function of peripheral nervous system

• neurons transmit messages to and from central NS

• collects info from internal and external environment and sends to central NS

function of somatic NS

carries sensory and motor infor to and from spinal cord

-responsible for deliberate, voluntary and conscious actions

function of autonomic NS

• responsible for unconscious, involuntary actions

• eg digestion, heart rate

function of sympathetic NS

• initiates fight or flight response before our conscious mind has recognised threat

• shuts down unnessecary functions eg digestion, immune system

function of parasympathetic NS

• shuts down fight or flight response

• works antagonistically with sympathetic NS

• restarts responses eg decreases heart rate, increase sailva production

what is the steps of the fight or flight response

1. hypothalamus identifies threat, instructs sympathetic NS to act

2. adrenaline released from adrenal glands into blood

3. adrenaline promts physical changes to prepare

4. parasympathetic activated to return body to its normal resting state. (occurs slower than sympathetic)

define hormone

chemicals secreted by the endocrine glands into the bloodstream which distributes it around the body

give 4 examples of endocrine glands

1. pituitary gland

2. thyroid gland

3. pineal gland

4. pancreas

what does the pituitary gland do

-controls growth, metabolism, blood pressure and reproduction

-secretes FSH

what does the thyroid gland do

• controls growth, energy use and body temp

• secretes thyroxine

what does the pineal gland do 

• controls sleep patterns and circadian rythm

• secretes melatonin

what does the pancreas do

• controls sugar levels within body

• secretes insulin

what is a neuron

• cells that conduct nerve impulses and make up the nervous system

function of the dendrite

receives the nerve impulse from other neurons

function of the axon

electrical impulse passes along

function of myelin sheath

insulates and protects the axon from external influences that might affect the transmission of the impulse

function of the nodes of ranvier

speed up the transmission by forcing it to jump

function of the axon terminals

send signals to adjacent cell

what are the three types of neurons

1. sensory

2. relay

3. motor

describe the sensory neuron

• carries messages from peripheral NS to central NS

• long dendrites and short axon

• unipolar

describe the relay neuron

• transfers messages from sensory neuron to motor neurons

• short dendrites and short axon

• multipolar

describe a motor neuron

• transfers messages from central NS to effectors eg muscles

• short dendrites and long axon

describe the process of the reflex arc

1. environmental stimuli detected by sensory neuron in peripheral NS 

2. message reaches relay neuron 

3. transfers message to motor neuron which carries message to an effector eg muscle

4. muscle contracts and pulls away from environmental stimuli

describe process of how neurons fire

1. neuron has a negative charge before receiving a signal

2. when a message is received, the charge of neuron changes to positive which creates an action potential

3. action potential allows electrical signal to travel down axon meaning neuron has fired

what is a neurotransmitter

chemicals that are released from a pre synaptic neuron into a synapse

describe process of synaptic transmission

1. electrical impulse travels along axon of the transmitting neuron called action potential

2. triggers nerve endings of pre synaptic neurons axon terminal to release from the vesicles

3. neurotransmitters diffuse across synapse and bind w specialised receptors on post synaptic neuron

4. receptors on post synaptic neuron bind to specific neurotransmitters which stimulates post synaptic neuron to transmit electrical impulses

5. remaining neurotransmitters left in synaptic cleft are reuptaken in vesicles of pre synaptic neuron and reused or broken down by enzymes

what is excitation

neurotransmitters can be excitatory meaning it is more likely the next neuron will fire

eg acetylcholine

what is inhibition

neurotransmitters can be inhibitory meaning it is less likely the next neuron will fire

eg serotonin

what is localisation of function in the brain

the theory that specific areas of the brain are associated w particular physical and physiological functions

what is lateralisation

dominance of one hemisphere of the brain for particular physical and physiological functions

what are the three layers of the brain

1. central core

2. limbic system

3. cerebrum

describe the central core layer of the brain

• regulates our autonomous behaviours eg breathing

• regulates eating and drinking

• regulates endocrine system to maintain homeostasis

describe the limbic system layer of the brain

• controls our emotions

• key roles in memory as contains structures like hippocampus

describe the cerebrum layer of the brain

• regulates our higher intellectual processes

• outermost layer is cerebral cortex which appears grey because of location of cell bodies

• made up of left and right hemisphere connected by corpus callosum which enables messages between left and right hemisphere

what are the 4 lobes

1. frontal

2. temporal

3. occipital

4. parietal

what is the frontal lobe responsible for

• for our awareness of what we are doing within our environment

what is the temporal lobe responsible for

• auditory info and memory acquisition

what is the parietal lobe responsible for

• sensory info and coordination

what is the occipital lobe responsible for

• visual info

what is the motor cortex

• responsible for voluntary motor movements

• located in the frontal lobe of both hemispheres

• different parts of cortex control different parts of the body

describe the process of processing sound in the auditory centres

1. sound waves converted to nerve impulses in cochlea

2. impulses travel to auditory cortex via auditory nerve

3. basic decoding occurs at brain stem eg duration

4. thalamus acts as a relay station which carries out further processing

5. sound is recognised and finally reaches auditory cortex

describe the somatosensory cortex

• detects sensory events from different regions of the body

• located in the parietal lobe

• processes sensory info related to touch

• uses sensory info from skin to produce sensations which are localised to specific body regions

describe the process of processing visual info in the visual centres

1. light enters retina and strikes receptors

2. nerve impulses from retina travel to areas of the brain via optic nerve

3. some travel to areas involved in circadian rhythms

4. most terminate in the thalamus which acts as relay station passing info to visual cortex

function of broca’s area

responsible for production of speech

function of wernickes area

responsible for comprehension of speech

describe broca’s research

• he treated patient who could only say 1 word

• treated 8 others with lesions on left frontal hemispheres who had similar language deficits

• patients with damage to right frontal lobe had no similar issues

• led to development of broca’s area

describe wernicke’s research

• patients w lesions on wernickes area could speak but couldnt understand language

• proposed that language has 2 regions - language and cognitive tasks

AO3 of localisation

1. supporting case studies. phineas gage injured in an accident where a tamping pole went through his pre frontal cortex. his personality switch from normal and kind to crude, vulgar and mean. this change supports the theory of localisation as it suggest injured area is responsible for personality.

2. brain scan evidence to support theory. study used brain scans to demonstrate how wernicke’s area was active during a listening track and broca’s area was active during a reading task suggesting different areas had different functions. highlt scientific and objective method for measuring brain activity

3. supporting neurological evidence. practices of surgically removing areas of the brain to control behaviour developed in the 1950s eg lobotomy. study had 44 OCD patients undergo neurosurgery. at post surgery check up 1/3 had met criteria for successful response. the success of these procedures suggest that behaviours associated w mental disorders  are localised

4. lashley’s research. he suggested that higher cognitive functions eg learning, are not localised but distributed in a more holistic way. he removed 10-50% of cortex in rats that were learning a maze. he found no area proved to be more important than any other area. shows the learning process requires every part of cortex rather than localised areas. learning is too complex to be localised and requires brain as a whole.