Biopsychology

• The nervous system contains nerve cells that
• What is the CNS divided into?


  the brain and the spinal chord
• The cns involves complex processing of outside information and is responsible for coordinating the activities of the body
• The spinal chord receives and transmits information from the brain to the body including reflex processing
• what is the peripheral nervous system divided into?


  the autonomic ns and somatic ns
• the ans is not under conscious control , is involuntary and controls actions of internal glands
• the sns is under conscious control, is voluntary and controls skeletal muscles
• what is the ans divided into?


  the sympathetic system and parasympathetic system
• the sympathetic nervous system increase bodily activities, prepares for fight or flight by releasing adrenaline and increases breathing rate, sweating and dilates pupils
• the parasympathetic nervous system is responsible for rest and digest by decreasing bodily activity, decreases breathing and heart rate, constricts pupils and decreases sweating
• What is the endocrine system?


  collection of glands in the body that regulate bodily functions by releasing chemical messengers called hormones into the bloodstream
• the pituitary gland releases the hormone ACTH which controls the release of hormones from other glands
• the hypothalamus releases the hormone CRH and links the nervous system to the endocrine system
• the pineal gland releases hormone melatonin which regulate sleep pattern and keeps body to a rhythm
• the thyroid gland produces hormone thyroxine which regulates metabolism
• the pancreas releases hormone insulin which regulates blood sugar levels
• the adrenal gland releases hormone adrenaline and regulates fight or flight
• the ovaries release the hormone oestrogen which is responsible for development of secondary sexual characteristics in females
• testes release hormone testosterone which is responsible for development of secondary sexual characteristics in males
• what are the three types of neurons?


  relay, sensory and motor
• sensory neurons detect sensations like pain at the sensory receptors, then an action potential travels across the nerve passing along the myelinated axon and this electrical signal is converted into a chemical signal via synaptic transmission in order to cross the synaptic gap
• relay neurons tend to be in the spine and send signals to the cns after a new action potential forms in the dendrites, immediately sending a signal along its axon to the motor neuron (relays pain sensation)
• motor neurons detect the signal from the relay neuron via synaptic transmission, and passes the signal along its own myelinated axon to stimulate an effector (eg a muscle to move the body or body part away from the pain)
• neurotransmitters are chemical messengers released by neurons have have two types
• what are two types of neurotransmitters?


  excitatory and inhibitory
• synaptic transmission is where the synapse allows the neurons to communicate by passing on chemical signals
• what do excitatory neurons do?


  increase the likelihood of a postsynaptic neuron firing
• what do inhibitory neurons do?


  make a neuron less likely to be fired
• Synaptic transmission involves an action potential traveling down the axon of a presynaptic neuron, which forces vesicles that contain neurotransmitters to merge with the cell membrane and release the neurotransmitter into the synaptic cleft.
• Receptors on the post synaptic neurons dendrite membrane detect the presence of neurotransmitter, changing the chemistry within the post synaptic neuron.
• If the charge in the post synaptic neuron surpasses a threshold, a new action potential is formed and the message is passed on, then the neurotransmitters detach from receptors and return to the presynaptic cell via transport proteins, a process known as reuptake.
• what is excitation?


  depolarisation ;- which is when electrical charge becomes positive and more likely to fire when detected by receptors
• what is inhibition?


  hyperpolarisation- when detected by receptors, charge becomes negative and less likely to fire
• Summation is the combined effect of all inhibitory and excitatory influences; resulting in an action potential forming or not
• psychological affects of adrenaline?


  increased anxiety, attention and alertness
• physical affects of adrenaline?

  Increased heart rate, elevated blood pressure, increased energy, dilated pupils, decreased blood flow to skin and digestive and immune systems
• what is the fight or flight response?


  evolutionary survival mechanism in response to a threat; primes body and mind for extreme action which is either fighting the threat or escaping it
• how does fight or flight work?

  the stressor is first detected by the hypothalamus, HPA is activated and pituitary gland releases hormone ACTH, this is then detected by adrenal cortex which releases cortisol. The hypothalamus also activates sympathetic system which triggers the adrenal medulla which in turn releases hormone adrenaline
• In short term, fight or flight results in acute stress; small amounts give focus and energy but exhausting if maintained
• in long term fight or flight results in chronic stress; stress related illnesses which can affect the immune and circulatory systems