Biopsychology

• The nervous system

  Neurons are the building blocks

  Of the nervous system.

  Made up of the central nervous system and peripheral nervous system.
• Function of the nervous system

  It controls the body by taking information from the environment using sensory receptors,then sends signals using sensory neurons to relay neurons in the CNS which encode this info into the CNS.

  Here the info is processed to wore out an appropriate response. Output signals are sent to muscles or glands using motor neurons.
• The Spinal Chord

  Relay's info between brain and rest of body which allows the brain to monitor and regulate bodily processes like digestion and breathing and also coordinate body movements.

  It is connected to parts of the body via spinal nerves which connect specific muscles and glands.

  Contains circuits of spinal nerves allowing us to perform simple reflexes without direct involvement of the brain.

  If damaged areas supplied by spinal nerves will be cut off.
• Brain - is made up of 4 main areas: Cerebrum,Cerebellum,Diencephalon,Brain Stem
• Cerebrum

  largest part of brain, further divided

  into 4 lobes. eg frontal lobe → thought and production

  of speech, occipital lobe → processing visual images cerebrum split into 2 halves, cerebral hemispheres, each specialised for particular behaviours. and communicate w each other through the corpus callosum
• Cerebellum

  sits beneath back of cerebrum, involved in controlling motor skills and balance, coordinating muslces for precise movements. Abnormalities in this area can cause speech and motor problems also epilepsy.
• Diencephalon

  lies beneath cerebrum on top of

  brain stem. in this area there are 2 important structures. thalamus → acts as a relay station for nerve impulses coming from senses and routing them to the appropriate part of the brain.

  Hypothalamus → regulates body temp,hunger,thirst acts as a link between endocrine system and nervous system
• Brain stem

  responsible for regulating automatic functions that are essential for life e.g breathing,swallowing motor and sensory neurons travel through allowing impulses to pass between brain and spinal cord.
• Peripheral Nervous System

  sends information to and from the central nervous system
• Somatic Nervous System

  transmits info to and from the senses and to and from CNS

  This is all under conscious control.

  The SNS uses sensory neurons

  to take info to CNS

  Also uses motor neurons to act on decisions of the CNS.
• Autonomic Nervous System

  Transmits information to and from internal organs to sustain life.

  •This part of the nervous system is automatic – NO conscious control.

  •Involved in homeostasis - The tendency of an organism to maintain an internal equilibrium, by adjusting physiological processes e.g. hunger, body temperature.

  •Made up of Sympathetic Nervous System and Parasympathetic Nervous System
• Sympathetic

  involved in responses that help us deal with emergencies such as increasing heart rare and blood pressure. Neurons travel to virtually every organ ana gland, preparing body for rapid action when necessary. slows body processes that are less important in emergencies such as digestion.
• Parasympathetic

  Relaxes the body again when the emergency nas

  Passed.

  slows heartbeat down and reduces blood pressure,digestion begins again
• Sensory Neurons

  carry nerve impulses from sensory receptors to spinal cord and brain. Sensory receptors are found in many places:eyes,ears,tounge and skin. Convert from these receptors

  into neutral impulses. when impulses reach brain they're translated into sensations eg heat, pain so the organism can react appropriately. Not all sensory info travels as far as brain,some neurons terminate in spinal cord,allows reflex actions to occur quickly.
• Relay Neuron

  allow sensory and motor neurons to communicate with eachother. The relay neurons lie wholy in the brain and spinal cord.
• Motor Neurons

  form synapses with muscies to control their contractions.

  They have long axons that form part of the PNS. They release neurotransmiters that bind to receptors on the muscles. Triggers muscle movement. Strengtn of muscre contraction depends on strength of axon.
• Neurotransmitters

  are chemicals that are released from a synaptic vesicle into the synapse by neurons

  They affect the transfer of an impulse to another nerve or muscle

  These neurotransmitters are "taken back up" into the terminal buttons of neurons through the process of reuptake. or they're broken down by an enzyme.
• Action Potential

  occurs when a neuron sends information down an axon. This action potential is an explosion of electrical activity. This means that some event (a stimulus) causes the resting potential to move forward when the action potential reaches synaptic vesicles,it causes them to release their contents (neurotransmitters)
• Synaptic transmission

  An electrical impulse travels along the axon of the transmitting synapse.

  • This triggers the nerve-ending of the pre-synaptic neuron to release chemical messengers called neurotransmitters.

  • These chemicals diffuse across the synaptic cleft (the gap) and bind with receptor molecules on the surface of the next neuron.

  • The receptor molecules on the second neuron bind only to the specific chemicals released from the first neuron. This stimulates the second neuron to transmit the synaptic impulse.
• • Reuptake: the neurotransmitter is reabsorbed in the vesicle of the pre-synaptic neuron after it has performed its function of transmitting a neutral impulse
• Synaptic transmission

  
• Synaptic transmission

  1. Action potential (instigation of brain activity)
  2. Chemical Messengers called neurotransmitters travel down pre synaptic neuron
  3. Vesicles containing NT's explode

  4. NT's released into synaptic gap

  5. Post synaptic receptors receive NT's and they diffuse into the post synaptic neuron
• Two types of NT:

  EXCITATORY: make it more likely that the Post-synaptic neuron will fire, increasing brain activity (eg dopamine)

  INHIBITORY: makes it less likely the Post-synaptic neuron will fire, reducing brain activity e.g GABA
• Brain → voluntary action

  Spinal cord → involuntary action
• Hot Plate how do 3 neurons work together to respond

  Stimulus(hot plate)

  sensory neurons in hands receive this info

  Pass that info (of heat) via relay neurons to the CNS

  CNS instructs motor neurons to send a movement message

  release the plate
• The Endocrine system

  This is a network of glands throughout the body that manufacture and secrete chemical messengers known as hormones. The endocrine and nervous systems work together very closely to regulate the physiological processes of the human body. The endocrine system uses blood vessels to deliver hormones to their target sites in the body.
• Endocrine Glands

  Regulate the activity of cells and organs in the body by secreting hormones and chemical substances into the bloodstream for the appropriate area.

  It is regulated by feedback from the Body.
• Hormones

  Chemicals that circulate in the bloodstream.

  Comes from the Greek word to excite.

  Hormones affect target cells.

  Too much or too little can have a bad effect on the body.

  Therefore it is essential that the body regulates hormone levels.
• Pituitary Gland

  The role of the pituitary gland is to produce hormones which influence the release of hormones from other glands and in doing so regulate many of the body’s functions. The Pituitary Gland is controlled by the hypothalamus which receives information from many sources about the basic functions of the body,then uses this information to regulate these functions.
• The hormones produced by the pituitary gland either directly cause change or stimulate other glands to produce hormones. High levels of hormones produced in other endocrine glands can stop the pituitary and hypothalamus releasing their own this is called negative feedback and stops levels from rising too high.
• The Pituitary gland has 2 main parts anterior (front) pituitary and posterior (back) pituitary.

  Anterior Pituitary produces two hormones important in the control of reproductive functioning,luteinising hormone (LH) and follicle-stimulating hormone (FSH),in females these hormones stimulate the ovaries to produce oestrogen and progesterone and in males they stimulate the testes to produce testosterone and sperm.

  Posterior Pituitary releases oxytocin which stimulates contraction of the uterus during childbirth.
• The roles of the ovaries and Testes

  Ovaries are responsible for the production of eggs and for the hormones oestrogen and progesterone. The testes produce the hormone testosterone. Testosterone causes the development of male characteristics such as growth of facial hair and voice deepening. Production is controlled by the hypothalamus and pituitary gland. Women also have testosterone but in smaller amounts.
• Adrenal Glands

  The two adrenal glands sit on top of the kidneys,each made up of 2 distinct parts,the outer part is called the adrenal cortex the inner region is known as the adrenal medulla.One of the main distinctions between the 2 is the hormone released by the cortex are essential for life those released by the medulla are not.
• Adrenal Cortex produces cortisol,which regulates or supports a variety of important bodily functions including cardiovascular. Cortisol production is increased in response to stress,if it is low the individual has low blood pressure and poor immune function also an inability to deal with stress. The adrenal cortex also produces aldosterone,which is responsible for maintaining blood volume and blood pressure.
• Adrenal Medulla releases adrenaline and noradrenaline,hormones that prepare the body for fight or flight. Adrenaline helps the body respond to a stressful situation for example increasing heart rate and blood flow to provide energy. Noradrenaline constricts blood vessels causing blood pressure to increase.
• Homeostasis

  The tendency of an organism to maintain an internal equilibrium, by adjusting physiological processes to meet external requirements. E.g. hunger – when we’re hungry, our stomach grumbles, indicating we need to eat (preservation of life)
• Sympathetic Nervous System

  Prepares you for fight or flight.

  What are some of the physiological effects of being in fight or flight mode?

  Increased heart rate, reduced activity in the stomach, inhibits saliva production, pupils dilate, relaxes bronchi in lungs, releases glucose
• Parasympathetic Nervous System

  Brings you back down from fight or flight mode once threat has passed.

  What are some of the physiological effects of being in fight or flight mode?

  Decreased heart rate, increased activity in the stomach, resume saliva production, pupils constrict, constricts bronchi in lungs,decreases glucose
• Fight or Flight

  Cannon first described the fight or flight response to stress.

  When someone enters a potentially stressful situation, the amygdala (part of the limbic system in the brain) is activated.

  The amygdala responds to sensory input (what we see, hear,smell, etc.) and connects sensory input with emotions associated with the fight or flight response (e.g. fear and

  anger).
• Fight or Flight

  If the situation is deemed as stressful/dangerous, the amygdala sends a distress signal to the hypothalamus, which communicates with the body through the sympathetic branch of the autonomic nervous system.

  Fight/Flight: in a scary situation, the sympathetic branch of the autonomic nervous system prepares you to stay and attack (fight) or run away (flight).