BIOL10002 Lecture Notes - Lecture 48: Resting Potential, Acetylcholinesterase, Membrane Potential
31 May 2018
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Wednesday, 29 March 2017
Nervous System
Why have a Nervous system?
-Survival (competitive advantage)
-Experience the world (interpretation based on memory, learning, emotion & beliefs)
-Two categories of cells: Neurons and Gila (or glial cells- support, nourish and insulate)
Neurons
Nerve is a bunch of neurons
Neurons have 4 parts;
-Dendrites: receive info
-Cell Body: contains nucleus and most organelles
-Axon: conduct action potential away from cell body
-Axon Hillock:stimulates action potential
-Axon terminals: Synapse with target cell (releases neurotransmitters)
Glia
Outnumber neurons
Don’t transmit electrical signals but release transmitters
Support during development, supply nutrients, maintain interstitial environment
Others insulate axons, consume debris, and provide immune functions
Can assist in neuronal repair
Types that insulate;
Myelin producing Schwann cells (PNS)/Oligodendrocytes (CNS)- wrapped around,
mostly lipid (white matter): insulate and increase speed of communication
CNS v PNS
Central Nervous System
Peripheral Nervous System
Brain and Spinal cord
All other areas
!1
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Wednesday, 29 March 2017
Afferent- Sensory info to the CNS
-Dendrites in skin, muscle or organ
-Terminals end in spinal cord
-Synapse with interneurons
Efferent- Motor info from the CNS to muscles and organs
-Dendrites in the spinal cord
-Terminals in muscles or organs
Interneurons- communication between afferent, efferent and CNS
Autonomic NS- Involuntary
Sympathetic and Parasympathetic
Sensory neurons
Input via specialised receptors (modified cell connected to neuron or neuron itself)
Sensory systems transduce external and internal environmental stimuli into action
potentials- communicate via action potentials
Communication
-Within neurone electrical (action potential)
-Between neurones chemical- Synapse
SYNAPSE
Presynaptic - sends
Postsynaptic- receives
-neurotransmitters tell tissue what to do
Autonomic NS (involuntary)
Sensory-Somatic NS (Voluntary)
Afferent
Efferent
Central Nervous System
Peripheral Nervous System
!2
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Document Summary
Experience the world (interpretation based on memory, learning, emotion & beliefs) Two categories of cells: neurons and gila (or glial cells- support, nourish and insulate) Cell body: contains nucleus and most organelles. Axon: conduct action potential away from cell body. Axon terminals: synapse with target cell (releases neurotransmitters) Support during development, supply nutrients, maintain interstitial environment. Others insulate axons, consume debris, and provide immune functions. Myelin producing schwann cells (pns)/oligodendrocytes (cns)- wrapped around, mostly lipid (white matter): insulate and increase speed of communication. Efferent- motor info from the cns to muscles and organs. Input via specialised receptors (modi ed cell connected to neuron or neuron itself) Sensory systems transduce external and internal environmental stimuli into action potentials- communicate via action potentials. Ach binds to ach receptor on post-synaptic cell. Na+ moves into cell and depolarises it. Leading to action potential or contraction in muscle cells. Acetylcholinesterase is an enzyme which degrades ach (switched off signal)
