Biol 224 Theme 8

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Biol 224 Theme 8
2013-10-10 02:23:10
Biol 224

Theme 8
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  1. Control Systems in the Body
    • -nervous system-co-ordinates rapid responses
    • -endocrine system-co-ordinates duration responses
  2. Nervous System
    • -provides rapid regulation over great distances
    • -coordinate multiple organs
    • -enables rapid detection and response to threats or opportunities
    • -allows past even recall and ability to anticipate events
  3. Reflex Arc
    • -simplest sensory neuron that controls an effector cell directly 
    • -used to translate sensory information into action potentials
  4. Ganglia
    • -formed when information is transmitted through more than one synapse 
    • -mass of nerve cell bodies composed mainly of the body of the soma of cells and dendritic structures bundled and/or connected
    • -simplest form of CNS where multiple neuronal signals can be integrated
  5. Plexus
    • -interconnection of ganglia form a plexus
    • -provide relay points between different neurological structures, such as the CNS and PNS
  6. Rudimentary Brain
    • -highly specialized ganglion
    • -multiple synaptic connections allow for complex control of responses
    • -considered the highest integrator and regulatory centre that can modify the basic reflex response(can suppress, alter sensitivity etc)
    • -can activate areas in anticipation of an event, based on memory
  7. Centralization
    -evolution of longitudinal association of diffuse neuronal cell bodies into a distinct nerve cord
  8. Cephalization
    -concentrations of neurons in the head(leading part of body) that typically deals with more environmental inputs
  9. Central Nervous System (CNS)
    • -integrates neural information
    • -coordinates activity of all body parts 
    • -consists of brain and spinal cord
    • -brain protected by skull, spinal cord by vertebrae
    • -both encased in meninges(membranes)
  10. Spinal Cord
    • -long, thin tubular bundle of nervous tissue
    • -support cells that extend from brain via the medulla oblongata 
    • -transmit signals between brain and rest of body
    • -also independently contains neural reflex circuits
  11. Peripheral Nervous System (PNS)
    • -nerves and ganglia outside of the brain and spinal cord
    • -not protected by bones or blood-brain barrier
    • -divided into somatic nervous system(SNS- sensory systems) and autonomic nervous system (ANS)
    • -connects CNS to limbs and organs
    • -conducts motor information 
    • -conducts sensory information to CNS
    • -coordinates certain reflexes
  12. Cranial Nerves
    • -carry info in and out of brain
    • -smell, vision, eye, eye muscles, mouth, taste, ear, neck, shoulders and tongue
    • -one of three parts of somatic nervous system
  13. Spinal Nerves
    • -carry sensory info into the spinal cord and carries motor commands
    • -one of three parts of somatic nervous system
  14. Association Nerves
    • -integrates sensory input and motor output
    • -one of three parts of somatic nervous system
  15. Autonomic Nervous System (ANS)
    • -control systems below the level of consciousness 
    • -involuntary visceral functions: heart rate, digestion, respiration rate, salivation, perspiration, pupil diameter, urination and sexual arousal 
    • -some functions work in tandem with the conscious brain (breathing)
  16. Sympathetic Nervous System
    • -fight or flight, triggers increased heart rate, breathing and relaxed airways
    • -contains very short axons
    • -uses acetylcholine at presynaptic level
    • -norepinephrine as neurotransmitter to target 
    • -originate at thoracolumbar sympathetic nerves (vertebrae)
    • -part of ANS
  17. Parasympathetic Nervous System
    • -rest or digest:slows heart rate, promotes digestion
    • -very long axons, ganglia act close to targets 
    • -acetylcholine at presynaptic level and final neurotransmitter
    • -originates at craniosacral parasympathetic nerves (vertebrae)
  18. Adrenal Medulla
    • -works as endocrine gland when activated by acetylcholine as part of sympathetic nervous system
    • -secretes 80% epinephrine and 20% norepinephrine
    • -activated by cholinergic preganglionic sympathetic fibers 
    • -allows adrenal medulla to provide epinephrine and norepinephrine to blood supply that can act at α, β1, and β2 receptors
  19. Cholinergic Axons
    • -preganglionic sympathetic axons and
    • preganglionic parasympathetic axons are cholinergic axons
    • -neurotransmitter is acetylcholine
  20. Adrenergic Axons
    • -all postganglionic sympathetic axons are adrenergic axons
    • -neurotransmitter is norepinephrine 
    • -EXCEPT: sweat glands, piloerectile muscles of the body hairs, and skeletal muscle arterioles secret acetylcholine
  21. Catecholamines
    • -neurotransmitters of the sympathetic ANS
    • -biogenic amines derived from phenylalanine and tyrosine 
    • -epinephrine(adrenaline) stress hormone released from adrenal medulla (also present at low levels in the brain)
    • -norepinephrine(noradrenaline) involved in sleep and wake, fullness, attention and feeding behavior
    • -both secreted by sympathetic axons
  22. Fight or Flight or Freeze
    • -AKA hyperarousal or acute stress response
    • -stimulation of the sympathetic branch of ANS prepares body for fight or flight
    • -stimulates heartbeat, raises blood pressure, dilates pupils, dilates airways, stimulates glycogenlysis, diverts blood flow to muscle and brain, inhibits peristalsis, inhibits contraction of bladder and rectum
    • -release of adrenaline from the adrenal medulla ensures that all body cells are exposed to sympathetic stimulation even if not directly effected by postganglionic neurons