neuro 3

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neuro 3
2013-04-10 16:38:49
neuro bio ib

neuro bio ib
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  1. Explain the effects of THC and cocaine in terms of their action at synapses in the brain.
    incl MOOD And behaviour
    • blocks reabsorption o dopamine and noradrenalin at synapses in brain
    • = increased energy alertness, talkativeness
    • Cocaine causes continuous transmission at these synapses, resulting in feelings confidence intense euphoria not related to any activity
    • May cause fear, jitters, and feelings o aversion
    • Addiction may be caused by artificially high lvls o dopamine, neurons may even create new receptors for dopamine
    • Increased sensitivity produces depression and cravings if cocaine lvls drop and dopamine lvls return to normal
    • Body may also adapt to cocaine use by reducing secretion o dopamine;= cocaine induced depression
  2. THC / cannabis
    • chemical THC binds to cannaboid receptors in various parts brain blocks synaptic transmission
    • Impairs synaptic transmission by reducing amount o excitatory neurotransmitters released;
    • THC is inhibitory psychoactive drug
    • Users claim increase intensity sensory perception, gives feeling emotional well being + allows clear thinking about complex ideas (no evidence)·
    • Evidence indicates actually impairs ability concentrate, control muscle contractions and judge times and distances (not safe to drive)
    • Short term effects include memory impairment, intoxication and appetite simulation
    • Long term uses may show attention deficits, memory loss and impaired learning ability
  3. addiction
    • Psychoactive drugs are often associated with ‘addictive behaviour’.
    • Addiction includes habitual behaviourCraves the use of the drug
    • Cannot exercise self control in limiting the taking of the drug
    • Habituation means that increasing quantities must be taken to achieve the same mental conditions
    • Show side effects of talking the drug and withdrawal behaviour if unable to satisfy the craving.
  4. Discuss the causes of addiction, including genetic predisposition, social factors and dopamine secretion (3)
    • some genes make it easier family addicted,        
    • dependent on the feelings that dopamine promotes.
  5. label Diagram of the human brain
  6. Functions of brain regions (5)
    • Medulla oblongata: Controls automatic and homeostatic activities, such as swallowing, digestion and vomiting, breathing and heart activity
    • Cerebellum: Coordinates unconscious functions, such as movement and balance, including hand eye coordination
    • Hypothalamus: Maintains homeostasis, coordinating nervous and endocrine systems, producing hormones tt are secreted by posterior pituitary gland; sends releasing factors to stimulate hormone  secretion by anterior pituitary gland
    • Pituitary gland: Posterior lobe stores and releases hormones produced by hypothalamus, anterior lobe produces and secretes hormones regulating many body functions
    • Cerebral hemispheres: Receives impulses fr eye, ear, nose and tongue, act as integrating centre for higher complex functions such as learning, memory and emotions
  7. waggle dance
    • workers communic by performing round (nearby food) or waggle dance (far food)
    • workers interpret dance 
    • angle indicates angle food fr horizontal direc o sun and number times waggle = dist o food src
    • may also regurgitate some nectar
  8. explain How brain lesions, animal experiments, and fMRI explain the function of specific brain regions (1 ex of each)
    • fMRI (functional magnetic resonance imaging) shows areas of the brain which have increased blood flow.
    • strong magnet measures number hydrogen atoms absorb then emit EM energy, diff types of tissue send diff signals
    • Increased red blood cell oygenation = (BOLD) contrast, is associated with increased neurone activity
    • trans into 3d images tt record regions o brain most active
    • presented with a stimulus the fMRI is taken and the region of the brain with increased blood flow is linked to with the processing
    • e.g. language thinking, find parts assoc with 
  9. lesions
    • lesions = damaged areas o brain
    • brain damaged patients show certain symp/functional disabilities
    • post mortem autopsies on stroke victims can associate particul brain area with symptoms
    • e.g. role of sight in visual cortex, rear o cerebral hemisphere = soldiers surviving bullet wounds in rear o skull
  10. animal experiments
    • removal of parts in healthy brain
    • resulting behaviour ->
    • e.g. severing fibres tt cross = clues interaction left and right halves
    • destroying pons in the brain of cats, died from sleep deprivation, linked with being able to fall asleep
  11. explain Sympathetic and Parasympathetic Nervous control o heart rate, movements iris, blood flow to gut
    • ANS part o peripheral nervous system tt used to control internal organs unconsciously
    • two parts, which have roles tt are largely antagonistic (opposing) 
    • Parasympathetic motor neurons: keep organs in suitable state for non-threatening situations; normal relaxed state
    • Sympathetic motor neurons: prepares organs for vigorous physical activity in response to threats or opportunities; “fight or flight” (Effects are similar to adrenaline)
  12. heart
    • para: Heart rate is slowed as the body is relaxed and less blood flow is needed. 
    • symp: Heart rate speeds up so that more blood can be pumped to the muscles.
  13. Blood flow to gut
    • para: Blood vessels are dilated, increasing blood flow in gut
    • symp: Blood vessels are constricted, decreasing blood flow to gut
  14. Iris of the eye
    • para: Circular muscle fibres contract, so pupil constricts to protect retina
    • symp: Radial muscles contract, dilating the pupil to give a better image
  15. explain The pupil reflex
    • ANS function illust by cntrl iris diaphragm reflex
    • controlling amnt light = import, if too little, cones not stimul for effective sight, if too much = damage overstimul/ loss sight
    • muscles iris reg pupil size
    • circular muscle fibres innervated by para syst, contracted, radial relaxed, small pupil and amnt light
    • radial muscle fibres innervated by symp, contrated, big pupil, circle relaxed
  16. discuss concept Death and the pupil reflex in testing for
    • death on a biological lvl
    • determine if the brain is still functional stimuli are presented such as shining light into the eye and looking for the associated pupil reflex
    • if yes, indicate some function at the basic brain level of the medulla oblongata
    • event of death cardiac output and ventilation can be maintained artificially, could use body for organ donation but must clarify brain death 
    • Absence of the pupil reflex indicates no basic brain function and allow surgeons to progress towards harvesting organs
    • depends on ones definition of 'living' and on local and national laws.
  17. outline Pain perception and the role of endorphins
    • pain recep located in skin + other organs, nerve endings perceive stimuli sent to sensory areas o cerebral cortex = feeling o pain
    • feelings nec to know when body damaged, avoid action, pain withdrawal
    • however, sometimes excessive + hinders important survival
    • pituit gland released endorphins, carried in blood to brain, bind to receptors in membr neurons tt send pain impulse + block release neurotrans
    • stressful times, after injury or running