biopsychology Flashcards
what are the 2 major psychological systems that regulate behaviour in response to the environment in the body?
The nervous system and the endocrine system
what is the nervous system?
a network of cells in our body. it is the primary internal communication system
functions of the nervous system
to collect, process and respond to info in the environment
to coordinate the working of different organs & cells in the body
what is the nervous system made up of?
The central nervous system and peripheral nervous system
what is the peripheral nervous system made up of?
somatic and autonomic nervous systems
the autonomic nervous system is split into the sympathetic and parasympathetic branches
what is the central nervous system?
The CNS is made up of the brain & the spinal cord.
the CNS passes messages to & from the brain & connects nerves to the PNS; it’s the origin of all complex commands and decisions.
brain
the brain is the centre of all conscious awareness. the brain’s outer layer, the cerebral cortex, is highly developed in humans and is what distinguishes our higher mental functions from those of animals. only a few living creatures don’t have a brain. the brain is divided into 2 hemispheres.
spinal cord
(Made up of lots of axons and covered by the spinal column.) the spinal cord is an extension of the brain.The role of the spinal cord is to transfer messages to and from the brain, and the rest of the body
it is responsible for reflex actions such as pulling your hand away from a hot plate.
what is the peripheral nervous system?
the PNS transmits messages, via millions of neurons (nerve cells) to and from the CNS. the PNS is further sub-divided into the autonomic & somatic NS.
the PNS sends info to the CNS from the outside world, and transmits messages from the CNS to muscles & glands in the body.
autonomic nervous system (ANS)
transmits info to & from internal bodily organs. it is ‘autonomic’ as the system operates involuntarily (automatic). it has 2 main divisions - the sympathetic & parasympathetic NS. the ANS governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal & stress responses.
Somatic nervous system (SNS)
transmits info from receptor cells in the sense organs to the CNS. it also receives info from the CNS that directs muscles to act. the SNS controls muscle movement & receives info from sensory receptors.
what is the endocrine system?
controls vital functions in the body. acts much more slowly than the NS but has very widespread & powerful effects. it’s made up of a series of glands throughout your body which release chemicals known as hormones.
hormones are secreted into the bloodstream & affect any cell in the body that has a receptor for that particular hormone
pituitary gland
the ‘master gland’. controls the release of hormones from all the other endocrine glands in the body.
thyroid gland
produces thyroxine. affects cells in the heart to increase heart rate. also affects cells throughout the body increasing metabolic rates. this in turn affects growth rates.
adrenal gland
a pair of endocrine glands that sit just above the kidneys and secrete adrenaline and cortisol. regulates fight or flight response.
Consists of adrenal medulla (in middle) which secretes adrenaline in fast response to threat - eg immediate, life-threatening danger. Fight or flight mode
also consists of adrenal cortex which is the outer layer - secretes cortisol in slow response to stress - eg hours long exam.
pancreas
produces insulin & glucagon - involved in regulating blood glucose levels
ovaries
produces oestrogen. involved in the development of female sex organs
fight or flight response
this response is due to the ES (endocrine system) and autonomic NS working together. it’s a reflex response - designed to help the individual cope physically under any threat - activated under times of stress. it helps the individual to react quicker than normal
testes
produces testosterone Involved in puberty/ development of male.
process of the fight or flight response
1) when an environmental stressor is perceived (e.g. your friend jumps out to frighten you) the first thing that happens is the hypothalamus activates.
2) this triggers activity in the sympathetic branch of the autonomic NS (the ANS changes from resting state, parasympathetic branch, to sympathetic state).
3) at the same time, the adrenal gland releases adrenaline into the bloodstream.
4) this causes a series of changes in our body allowing us to fight/flight.
5) finally, once the threat/stressor has passed, your body returns to the parasympathetic NS and the physiological changes revert - its actions are antagonistic to the sympathetic system.
what body changes occur when the sympathetic branch is activated?
heart rate increases - speeds up blood flow to vital organs so adrenaline travels faster
breathing rate increases - more oxygen to brain for quick decisions
muscle tension - improves speed
pupils dilate - improves vision
digestion stops - conserves energy
saliva production stops - useless
sweating - regulates body temp
neurons
nerve cells - there are 100 bill neurons in the human NS, 80% of which are located in the brain.
by transmitting signals electrically and chemically, these neurons provide the NS with its primary means of communication
they vary in size from less than a mm to over a m long
they transmit info from 1-268 mph
sensory neurons
neurons that carry messages from the PNS to the CNS
they have long dendrites and short axons and have a myelin sheath over axon. Cell body is outside of dendrites.
convert external stimuli from the organisms environment into internal electrical impulses
relay neurons
connect the sensory neurons to the motor or other relay neurons
they have short dendrites and short axons. No myelin sheath.
motor neurons
neurons that carry signals from the CNS to the effectors such as muscles and glands
they have short dendrites and long axons
structure of a neuron
cell body, nucleus, dendrites, axon, myelin sheath, node of ranvier, axon terminal
cell body
contains the nucleus
nucleus
contains the genetic material of the cell
dendrites
branding extensions which carry nerve impulses from neighbouring neurons towards the cell body
axon
carries electrical impulses away from the neurons cell body towards the axon terminal
myelin sheath
protects/insulates the axon. speeds up electrical transmission of the impulse
node of ranvier
a gap between successive segments of the myelin sheath. these gaps speed up the transmission of the impulse by forcing it to ‘jump’ across the gaps along the axon
axon terminal
end of axon. communicate with the next neuron in the chain across a gap known as the synapse
process of synaptic transmission
electrical impulse will travel down pre-synaptic neuron reaching axon terminals. this will activate vesicles stored here which all contain neurotransmitters. neurotransmitters are chemicals which allow 2 neurons to communicate.
now, the message is chemical. the NT diffuse across the synapse and bind to the receptor sites in the post-synaptic neuron (dendrites) - certain NT’s will only bind to certain receptor sites, like a lock and key.
when the NT’s bind, they will either be excitatory or inhibitory. if they are excitatory the post-synaptic neuron is more likely to fire the electrical charge. inhibitory - less likely to fire.
summation - as both E & I NT fire, what happens for the next neuron is which ever NT is in majority.
what is the synapse/ synaptic cleft?
the small gap between two adjacent neurons
holistic vs localisation of function of the brain
holistic idea = all parts of the brain are involved in the processing of thought & action - whenever we do a behaviour it requires our whole brain.
localisation of function = each part of the brain has its own unique function - they perform different tasks and are involved with diff parts of the body i.e. skills, behaviour etc. are all localised. if a certain part of the brain becomes damaged through illness or injury, the function associated with that area will also be affected/lost.
structure of the brain
both hemispheres contain: frontal lobe, motor cortex, somasensatory cortex, parietal lobe, temporal lobe, occipital lobe
only the left hemisphere contains Broca’s area and Wernicke’s area
left and right hemispheres of brain
brain is divided into two halves. connected by a bundle of nerves called the corpus callosum.
your left hemisphere controls the right side of your body.
your right hemisphere controls the left side of your body.
the cerebral cortex is the outer layer of both hemispheres - about 3mm thick. separates us from animals because the human cortex is much more developed. often called ‘grey matter’ due to the look of all the cells.
each hemisphere is divided up into 4 lobes - frontal, parietal, temporal, occipital
frontal lobe
contains the motor area which controls voluntary movement in the opposite side of the body. damage to this area of the brain may result in a loss of control over fine movements (voluntary movements in app side of body)
parietal lobe
contains the somasensatory area. separated from the motor cortex by a ‘valley’ called the central sulcus. this area is where sensory info from the skin (e.g. heat, touch, pressure etc.) is perceived. receptors for our face & hands occupy over half the area
occipital lobe
the visual area - where all your sight is processed. the left eye goes to the right occipital lobe and the right eye goes to the left occipital lobe. damage to the occipital lobe can result in blindness.