bio psych

• What is the nervous system (NS) ?

  A specialised and complex network of cells in the human body. It is our primary internal communication system.
• What are the 2 main functions of the NS?

  - Collecting, processing, and responding to information in the environment.

  
  

  - Coordinating the working of different organs and cells in the body.
• What are the 2 main subsystems of the NS?

  The Central Nervous System (CNS)

  The Peripheral Nervous System (PNS)
• What is the CNS made up of?

  brain and spinal cord
• The spinal cord


  extension of the brain, connected to the brain via the brain stem.
• What is the spinal cord responsible for?

  reflex actions such as pulling your hand away form a hot surface done by passing messages to and from the brain, linking it to the PNS.
• The brain


  source of conscious awareness and where the decision-making takes place. It is split into two near-symmetrical hemispheres which are connected by a group of structures.
• What is the main structure in the brain?

  Corpus Callosum
• How are the brains hemispheres split for processes?

  CONTRALATERAL PROCESSES:

  
  

  LEFT HEMISPHERE = activity on right side of the body

  RIGHT HEMISPHERE = activity on left side of the body
• What is the cerebral cortex?


  Highly developed part of human brains that distinguishes mental functioning from that of other animals. It is about 3mm thick and covers the inner parts of the brain.

  
  

  This is why various areas of the brain are often divided into cortical and subcortical.
• What is 'cortical'?


  Belonging to the cortex
• What is 'subcortical'?


  Below the cortex
• How many subcortical structures are there?

  5

  
  

  Thalamus, Hypothalamus, Limbic System, Cerebellum, Corpus Callosum.
• Thalamus?


  The brain's relay system

  
  

  It receives information from various senses and passes it on to the appropriate areas of the cerebral cortex for higher-level processing.

  
  

  Also carries out own initial processing, acting as a 'gate' or filter of information. It is thought to play a role in sleep, wakefulness and OCD.
• Hypothalamus?


  Below the thalamus. Controls motivational behaviours such as hunger, thirst and sex.

  
  

  Maintains balance in bodily functions such as homeostasis, as well as regulation of hormones in the endocrine system via its connection with the pituitary gland.
• Limbic System?


  Consists of several structures such as amygdala (plays role in regulating emotional responses).

  
  

  Has role in memory and learning.

  
  

  Highly interconnected with areas of the cortex, integrating cortical and subcortical parts of the brain.
• Cerebellum?


  Has 2 hemispheres.

  
  

  Primary role is to coordinate posture, balance and movement by receiving and regulating information from the spinal cord and other areas such as the motor cortex.

  
  

  10% of brains entire weight but contains almost 50% of its neuron's.
• Corpus Callosum?


  Dense collection of nerves physically connecting the two hemispheres below the cortex.

  
  

  Allows for communication between the hemispheres by passing signals back and forth.

  
  

  Critical given the brain's contralateral control, as it integrates activities of both sides of the body.
• What is Lateralisation?


  The two hemispheres of the brain perform different functions although they are structurally identical
• What is localisation?


  Within each hemisphere, certain areas perform certain functions and behaviours
• The Cerebral Cortex?


  Sub-divided into four lobes each named after bones - each lobe has a different function
• Frontal Lobe?


  - Located in the front of the brain

  
  

  - 40% of cerebral cortex in humans

  
  

  - Control high level functions such as thinking, planning, problem-solving, and decision-making.

  
  

  - Contain motor-cortex

  
  

  - Left frontal lob includes Brocha's area
• Motor Cortex?


  - A long strip of neurons that runs down alongside central sulcus of both hemispheres.

  
  

  - Each motor cortex control voluntary movements on the opposite side of the body (contralateral)
• Parietal Lobes?


  - Back of the brain

  
  

  - Directly alongside sulcus lies somatosensory cortex - processes sensory informations from the skin e.g., touch, temperature, pressure.
• Temporal Lobes?


  - Beneath lateral sulcus of each hemisphere

  
  

  - Each lobe contains auditory cortex which deals with sound information.

  
  

  - Processes location, volume of sound therefore understanding language

  
  

  - LEFT TEMPORAL LOPE = WERNICKE'S AREA
• Occipital Lobes?


  - Located at back of the brain

  
  

  - Each lobe contains primary visual cortex and several secondary areas.

  
  

  - Vision from the right is processed by left visual cortex. vice versa.
• What are the language areas of the brain?

  Broca's area

  Wernicke's area
• Broca's area?


  - Identified by Pierre Paul Broca in 1860s

  
  

  - In left frontal lobe

  
  

  - Responsible for speech production

  
  

  - Damage to this are is called BROCAS ASPHASIA (Main feature of this is slow, laborious speech lacking fluency
• Wernicke's area?


  - Identified by Karl Wernicke around same time as Broca

  
  

  - Describing patients who had difficulty understanding language, producing fluent but meaningless speech (Wernickes Asphasia)

  
  

  - Located main area of damage in left temporal lobe
• What is a neuron?

  a nerve cell - the basic unit of the nervous system
• What do neurons do?

  They allow the nervous system to fulfil its communication function by transmitting signals electrically and chemically
• Structure of the neuron?

  - Vary in size from less than a millimeter to up to a meter long

  
  

  - CELL BODY (or soma) - includes nucleus containing genetic material of the cell.

  
  

  - DENDRITES - carry impulses from neighbouring neurons towards cell body

  
  

  - AXON - carries impulses from cell body down the length of the neuron

  
  

  - MYELIN SHEATH - fatty layer covering axon formed from glial cells - increases speed of electrical transmission of the impulse

  
  

  - NODES OF RANVIER - gaps in myelin sheath - allows myelin sheath to increase speed of transmission by forcing impulses to 'jump' across gaps along length of axon

  
  

  - TERMINAL BUTTONS - involved in communication across synapse
• What are the 3 types of neuron?

  Sensory Neuron

  Motor Neuron

  Relay Neuron
• Sensory Neuron?


  - Carry messages from sensory receptors (e.g., touch and temperature-sensitive receptors) along nerves in peripheral nervous system to the nervous system.

  
  

  - Have long dendrites and short axons
• Motor Neuron?


  - Carry messages from CNS, along nerves of PNS, to effectors in the body (e.g., muscles and glands).

  
  

  - Short dendrites and long axons
• Relay Neuron?


  - Connect sensory and motor neurons together and connect other relay neurons.

  
  

  - Have short dendrites and short axons

  
  

  - Only found in CNS
• Synaptic Transmission?


  - Neurons communicate with each other within groups known as neural networks

  
  

  - Do not touch - separated by synaptic cleft

  
  

  - Signals in neuron transmitted electrically but signals across neurons across synapse are chemically transmitted

  
  

  - Synaptic transmission is a chemical process using neurotransmitters

  
  

  - When ACTION POTENTIAL reached end of the neuron it triggers release of neurotransmitter into synaptic vesicles
• What are neurotransmitters?


  Chemicals that diffuse across the synapse to the next neuron in the chain
• Neurotransmitters?


  - When the neurotransmitter molecules cross the gap, they fit into the matching receptor sites on the postsynaptic neuron.

  
  

  - There are different receptors for different neurotransmitters

  
  

  - The chemical signal carried by neurotransmitters is converted back into an electrical signal in postsynaptic neuron which may fire another ACTION POTENTIAL

  
  

  - Neurotransmitter molecules remaining in the synapse are absorbed into presynaptic neuron, usually being broken down first.

  
  

  - This process is called 're-uptake' and means the neurotransmitters can be used again
• Functions of neurotransmitters?


  - Each neurotransmitter has its own molecular structure, fitting into specific post-synaptic receptor

  
  

  - They have specific functions.

  
  

  - EXAMPLE = acetylcholine found where motor neurons meet muslce - causes muscle to contract when released