biopsychology

• nervous system

  specialised network of cells, primary mode of communication via electrical impulses to collect, process and respond to stimuli and to co-ordinate the working of different organs
• central nervous system

  consists of the brain and spinal cord

  brain - centre of conscious awareness

  spinal cord - responsible for reflex actions, passes messages to and from the brain and connects the nerves to the pns
• peripheral nervous system

  transmits messages through neurones to and from the cns, sends information to outside world from cns to effector muscles / glands in the body

  • the pns is divided into the autonomic and somatic nervous system
• autonomic nervous system

  controls breathing, heart rate, digestion, stress response and sexual arousal - involuntary

  • the ans is divided into the sympathetic and parasympathetic nervous system
• somatic nervous system

  controls conscious / voluntary muscle movement

  responsible for receiving info from senses and sending to cns + transmitting info from cns to effector organs
• parasympathetic nervous system

  rest and digest state, controls heart rate, breathing, promotes digestion and constricts pupils etc
• sympathetic nervous system

  prepares body for fight or flight, increases heart rate, breathing state, stops digestion and dilates pupils

  • the two systems are antagonistic, can only happen one at a time
• endocrine system

  controls vital functions alongside the nervous system

  • instructs glands to release hormones into the bloodstream
• endocrine system vs nervous system

  endocrine - uses chemical messengers that are slow acting but more widespread and longer lasting

  nervous - uses electrical impulses that are fast acting
• glands

  organs that produce hormones
• hormones

  chemical messengers that circulate in the bloodstream to affect target organs

  each hormone has a specialised function
• pituitary gland

  'master gland' that controls release of hormones from other endocrine glands
• adrenal gland

  releases adrenaline + noradrenaline, responsible for activating fight or flight
• ovaries

  release oestrogen which regulates the menstrual cycle
• fight or flight

  a response when stressed through the physiological arousal of the body to prepare to fight or flee an aggressor
• fight or flight process

  hypothalamus activates sympathetic ns, which sends a message to adrenal glands which release adrenaline and noradrenaline, causing the body to respond (fight, flight or freeze)
• neurones

  cells that make up the ns, they are the ns's primary method of communication and process + transmit messages through chemical and electrical signals

  types of neurones - sensory, motor and relay
• sensory neurone

  registers input from the pns + and transports to cns
• relay neurone

  decides what to do and passes on the message on within the brain

  connects sensory to motor neurone or another relay neurone
• motor neurone

  tells muscles to move by connecting cns to effectors
• synaptic transmission

  neighbouring cells communicate across the synaptic gap that separates them through chemical messengers in order to pass on the electrical signal to the neighbouring neurone
• neurotransmitters

  brain chemicals that send signals from one neurone to the next through diffusing across the synapses (excitatory or inhibitory)
• synaptic transmission

  electrical impulses reach the presynaptic ending and trigger the release of neurotransmitters from vesicles across the synapse

  neurotransmitters bind with receptors on the postsynaptic membrane

  stimulation of postsynaptic receptors of neurotransmitters result in either excitation or inhibition of the postsynaptic membrane
• excitation

  when a neurotransmitter increases the positive charge of the postsynaptic neurone, increasing the likelihood that the neurone will fire and pass on the electrical impulse
• inhibition

  when a neurotransmitter increases the negative charge of the postsynaptic neurone, decreasing the likelihood that the neurone will fire and pass on the electrical impulse
• excitation and inhibition

  excitatory and inhibitory influences are summed (summation), if the net effect on the post synaptic neurone is inhibitory, the neurone will be less likely to fire and pass on the signal, and if the effect is excitatory, the neurone will be more likely to fire

  • action potential of the post synaptic neurone is only triggered if the sum of the excitatory and inhibitory signals at one time reach the threshold