Biopsychology Flashcards
What is the nervous system?
-a specialised communication system made up of a network of cells called neurons
-based on electrical and chemical signals
two main functions of the nervous system
-to collect process and respond to information in the environment
-to co-ordinate organs + cells in the body
What are the subsystems of the nervous system?
-the central nervous system
-the peripheral nervous system
the CNS
-made up of the brain and spinal cord
-the brain receives info from sensory receptors (eyes, ears, skin etc) about the environment
- brain then sends this information to the muscles and glands of the body through the spinal cord
The brain
-divided into 2 hemispheres
-responsible for all conscious awareness
-the cerebral cortex(outer layer of the brain) is responsible for higher-level processes including language, memory, emotion, intelligence, personality etc.
4 main areas of the brain
-cerebrum= the largest part of the brain + 4 lobes with different primary functions i.e the frontal lobe which is involved with thought and the production of speech
-cerebellum= controls motor skills + balance i.e coordinating muscle movement
-diencephalon= contains the thalamus which directs impulses to the relevant area of the brain and the hypothalamus which regulates body temp, release of hormones, hunger + thirst
-the brain stem= regulates automatic functions i.e breathing, motor and sensory neurones pass these impulses through CNS
The spinal cord
-role is to relay info between the brain and the rest of the body
-an extension of the brain
-connected to different parts of the body by pairs of spinal nerves, which connect with specific muscles and glands(PNS)
-contains neurons/nerve cells that enable us to perform simple reflexes i.e pulling your hand away from a hot plate
the PNS
-transmits messages, via millions of neurons(nerve cells), to and from the CNS
-divided into autonomic nervous system and the somatic nervous system
the ANS
-governs involuntary actions in vital organs and glands i.e breathing rate, digestion, stress responses
-divided into parasympathetic and sympathetic nervous systems
-only motor neurons are involved
-control centres are in the brain stem
the SNS
-controls skeletal muscle and movement
-carries commands from the motor cortex in your brain
-involved in reflex + voluntary actions
-both sensory AND motor neurons are involved
the syNS and the psNS
-regulate the same organs but have opposite effects due to the neurotransmitters in each division–} either excitatory(which increases activity) or inhibitory(calming effect)
-syNS prepares the body for flight or fight= sends messages to every organ and gland within the body, preparing for rapid action when the individual is under threat
-the PSNS relaxes the body once the emergency has passed
What is the endocrine system?
-instructs glands to release hormones in the bloodstream–} hormones are carried towards target organs with a specific receptor in the body
-acts slower than the nervous system but had widespread effects
Hypothalamus
-regulates internal body temp
-controls the pituitary gland + links the NS to the endocrine system
Pituitary gland
-‘master gland’–} control the release of hormones from other glands i.e oxytocin(love hormone)
Pineal gland
-produces the hormone melatonin, responsible for making you sleepy
Thyroid + Parathyroid gland
-secretes thyroxine to regulate metabolism
-affects metabolic rates therefore affecting growth
Thymus
-serves a vital role in the training and development of T-lymphocytes (type of white blood cell involved in the immune system)
Pancreas
-controls blood glucose levels with the release of insulin/glucagon
Adrenal glands
-regulates metabolism + maintains balance of salt and water in the body
-produces adrenaline, involved in the stress response
Ovary (in females)
-responsible for producing hormones in sexual development in females i.e oestrogen
Placenta (during pregnancy)
-provides O2 + nutrients to your growing baby + removes waste products from baby’s food
Testes (in males)
-responsible for providing hormones in sexual development in males i.e testosterone
Hormones
-secreted into the bloodstream and affect any cell in the body that have a receptor for that particular hormone
-i.e thyroid gland produces thyroxine–} increases heart rate + metabolic rates which affects growth rates
What is the fight or flight response?
-evolved as a survival mechanism= enabled humans and animals to react quickly
-upon sensing a threat, the amygdala becomes mobilised–} associates sensory signals with emotions i.e fear or anger
-this sends a distress signal to the hypothalamus which communicates to kickstart the response
Fight or flight response
-when a stressor is perceived, the hypothalamus activates the pituitary gland
-this triggers activity in the sympathetic branch of the ANS
-ANS changes from its normal resting state to the physiologically aroused sympathetic state
Adrenaline
-released by the adrenal medulla(part of the adrenal gland near the kidney) into the bloodstream
-triggers physiological changes in the body:
- increased heart rate
- slow digestion in the gut
- inhibits salivary production in salivary glands
- triggers release of blood glucose (to supply energy)
- inhibits urination by relaxing the bladder (takes up less energy)
- dilates pupils (take in more light to see)
- dilates bronchi in the lungs (more O2)
Immediate and automatic
-physiological changes are an acute and automatic response in the body
-i.e increased heart rate + breathing rate, dilated pupils
Parasympathetic action
-returns the body to its resting state
-works antagonistically to the sympathetic system
-i.e stimulates digestion + saliva production etc
-rest and digest response
Evaluating fight or flight:
Gender bias
-Taylor et al (2000) suggested that, for women, behavioural responses to stress are ‘tend and befriend’ rather than fight or flight–} protect themselves and their young through nurture and form protective alliances with other women
-different way of coming because their responses are based around being the primary caregiver of their offspring
-produce higher levels of oxytocin than men
-Lee and Harvey (2012) found that the SRY gene, found exclusively on the male Y chromosome, results in the fight or flight response
HOWEVER Von Dawans et al found that acute stress could lead to ‘tend and befriend’ for both men AND women i.e human connection during 9/11–} protective nature of human social relationships
Evaluating fight or flight:
weak application
-the physiological responses associated with fight or flight are not adapted to modern life
-repetitive stress response leads to a constant raised BP caused by the SyNS
-this can lead to physical damage in blood vessel + eventually heart disease
Evaluating fight or flight:
limited explanation
-Gray(1998)= the first phase of reacting to a threat is to avoid confrontation by FREEZING
-the adaptive advantage is that freezing focuses attention and allows you to look for new information in order to make the best response for that particular threat
What is a neuron?
-aka a nerve cell
- a specialised cell designed to transmit information to other neurons, muscle, or gland cells through electrical + chemical signals
- over 100 billion neurons in the body – of which 80% are located in the brain
3 main types of neurons
-sensory neurons= carry messages from the PNS to the CNS, have long dendrites and short axons
-relay neurons= connect the sensory and motor neurons, have short dendrites and axons
-motor neurons= connect the CNS to effectors i.e muscles + glands, have short dendrites and long axons
The structure of a neuron: cell body
-has a nucleus which carries the genetic material of the cell
-determines what type of cell it is
The structure of a neuron:
dendrite
-protrude from the cell body
-carry nerve impulses from neighbouring neurons towards the cell body
The structure of a neuron:
axon
-carries the impulses away from the cell body down the length of the entire neuron
The structure of a neuron:
myelin sheath
-fatty layer that covers the axon
-protects the axon and speeds the electrical transmission of the impulse
The structure of a neuron:
Nodes of Ranvier
-gaps that are segmented in the myelin sheath by speeding up the transmission of the impulse by forcing it to ‘jump’ across the gaps along the axon
The structure of a neuron:
axon terminal buttons
-communicates with the next neuron in the chain across a gap known as the synapse
Where are the neurons located?
-cell bodies of motor neurons may be in the CNS but the long axons form part of the PNS
-sensory neurons are located in the PNS, in clusters(ganglia)
-Relay neurons make up 97% of all neurons and most are found within the brain + visual system
Electrical transmission
-a neuron is negatively charged when in a resting state within a cell compared to the outside
-when a neuron is activated by a stimulus, the inside of the cell becomes positively charged–} causes action potential to occur
-creates an electrical impulse that travels down the axon towards the end of the neuron
How do neurons communicate with each other?
-neurons communicate with each other in groups called neural networks (not physically connected)
-signals WITHIN neurons are transmitted electrically but signals BETWEEN neurons are transmitted chemically across the synapse (gap between 2 dendrites)
Neurotransmitters
-chemical messengers in the NS that can trigger an electrical impulse–} do this by diffusing across the synapse to the next neuron in the chain
-around 30 different types in the brain
-own specific molecular structure that fits perfectly in a receptor site(lock and key)
-have specialist functions
-direction of travel is one way(pre to postsynaptic neuron)
Why are neurotransmitters needed?
-electrical impulses cannot pass from the axon terminal to the adjacent dendrite
-instead must pass via a chemical messenger
-chemical message is converted back into an electrical impulse once it reaches the postsynaptic receptor site
4 types of neurotransmitters
-adrenaline= produced in stressful situations, increases heart rate + blood flow to increase awareness(causes excitation)
-noradrenaline= affects attention and responding actions in the brain, contracts blood vessels
-dopamine= feelings of pleasure, addiction and motivation
-serotonin= contributes to well being and happiness, helps sleep cycle + digestive system regulation(causes inhibition)
Excitatory neurotransmitters
-when detected by the post-synaptic receptors, they make the electrical charge more positive(depolarisation)
-create an excitatory post synaptic potential(EPSPs)–} formation of a new action potential is more likely= ‘on switch’
Inhibitor neurotransmitters
-when detected by the post-synaptic receptors, they have a negative charge on the post-synaptic neuron(hyperpolarisation)
-results in an inhibitory post-synaptic potential(iPSPs)—} formation of a new action potential less likely= ‘off switch’
Summation
-net effects of all the excitatory + inhibitor neurotransmitter summed determines whether the postsynaptic cell is fired
-the net effect has to reached(excitatory input> inhibitory input)
-if the threshold is reached, then the new action potential is formed and then travels down the next axon
Synaptic transmission
-an action potential(electrical impulses) travels down the axon and triggers the synaptic vesicle to release neurotransmitters
-these chemically diffuse across the synapse cleft + bind to postsynaptic receptor sites of the dendrites on the next neuron
-neurotransmitters that don’t bind to the next receptor site are reabsorbed by the presynaptic neuron via a transport protein
-any left over neurotransmitters are broken down by enzymes
-synaptic vesicles are replenished with new + re-used neurotransmitters
Localisation vs holistic theory
-it was believed that all parts of the brain were involved in processing of thought and action before investigations in the 19th century
-Broca and Wernicke argued that separate parts of the brain perform different tasks in different parts of the body(cortical specialisation)
-i.e if a specific area of the brain becomes damaged, it may cause damage in the part of body it is associated with
What is lateralisation?
-the idea that the 2 hemispheres of the brain are functionally different and each control/dominate specific physical + psychological functions i.e the left is dominant for language
-the brain is also cross-wired= the left part is responsible for the right side of the body and vice versa
Cerebral cortex
-outer layer of both hemispheres
-divides into 4 lobes, each associated with different functions
Frontal lobe
-responsible for cognitive functions i.e attention, thinking, memory + learning
-also processes the autonomic and emotional processes
The motor cortex
-located in the frontal lobe in both hemispheres of the brain
-responsible for voluntary movement in the opposite side of the body
-damage to this may result in loss of control of fine movements
Broca’s area
-small area of the left frontal lobe
-critical for speech production
-when damaged, patients suffer with Broca’s aphasia
Temporal lobe
-processes auditory information
-helps in understanding of speech and written language and memorising symbolic sounds and words
The auditory cortex
-located in the temporal lobe in both hemispheres
-analyses speech based info
-sound waves are converted to nerve impulses in the cochlear
-travels to the brain stem for a basic decoding(i.e duration + intensity of sound), then the thalamus which acts as a relay station for processing then to the auditory cortex to be recognised + responded to
-damage may lead to partial/full hearing loss
Wernicke’s area
-back portion of the left temporal lobe
-involved in understanding language
-damage may lead to inability to understand + comprehend language
Parietal lobe
-mainly concerned with processing physical sensations + coordination with visual and auditory sensations
The somatosensory cortex
-located in the parietal lobe
-in both hemispheres
-detects sensory info from different parts of the body
-uses info from the skin to produce sensations of touch, pressure, pain + temp and localised this to specific areas
-the amount of somatosensory area in a part of the body relates to the amount of sensitivity in that area
Occipital lobe
-interprets visual impulses, memorises visual stimuli and helps in colour visual orientation
The visual cortex
-located in the occipital lobe of the brain
-in both hemispheres
-visual processing in the retina leads to nerve impulses being transmitted to the brain via the optic nerve
-each eye sends info from the right visual field to the left visual cortex and vice versa(cross-wired)
-damage to one side of the brain may lead to blindness in the opposite visual field