neurophysiology review

• White matter consists primarily of myelinated axons of many neurons. Gray matter consists of neuron cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglia.

  
• 1.Identify the grey and white matter of brain and spinal cord (indicated by numbers).

  A) grey matter

  B) white matter

  
• Central Nervous System

  A) Motor cortex

  B) frontal lobe

  C) sensory cortex

  D) parietal lobe

  E) occipital lobe

  F) visual cortex

  G) cerebellum

  H) spinal cord

  I) temporal lobe

  J) auditory cortex

  
• Neuronal axons contain arrays of microtubules used for transport. What are the two transport modes and molecular motors involved?

  A) kinesin

  B) anterograde

  C) dynein

  D) dynactin

  E) retrograde

  
• Identify the various features (indicated by numbers) of a neuron of PNS.

  A) dendrites

  B) axon hillock

  C) axon terminalis

  D) schwann cell

  E) node of ranvier

  F) mylein sheath

  
• Functional Anatomy of Neurons

  •The electrical signals transmitted by neurons are called action potentials.

  •The input zone (dendrites and soma) receives input from other neurons

  •The summation zone (axon hillock) serves as the site where the nerve impulses combine and possibly trigger an impulse or action potential. Which will be conducted along the axon via the conduction zone.

  •The output zone (distal end of the axon) is where the nerve impulse is transmitted to the other neuron via the release of neurotransmitters.

  
• Identify the neurons classified by its function (indicated by numbers)

  A) afferent

  B) interneurone

  C) efferent

  
• •Estimates of ratio glia:neurones range from ~10:1 (older) to ~1:1 (newer)Varies by region: cerebral cortex ~4:1
• •Astrocytes: Structural & metabolic support - Assist with neuronal signalling - Brain-vascular interaction - Astrocytes are vital for maintaining the blood-brain barrier (BBB), which protects the brain from harmful substances in the blood.
• CNS: oligodendrocytes Myelinate multiple axons PNS: Schwann cells Myelinate single axon
• •CNS immune cells - Activated into phagocytic form
• •Form epithelial layer around ventricles and spine - Have cilia to move cerebrospinal fluid(CSF) around - Specialised form of ependymal cells in choroid plexus (production of CSF).
• Neuroglia or Glial cells

  A) capillary

  B) astrocyte

  C) Ependymal Cells

  D) Oligodendrocytes

  E) Microglia

  
• Identify the Neuroglia or Glial cells of PNS and their functions (indicated by numbers)

  A) schwann cell

  B) axon

  C) neuron cell body

  D) satellite cells

  
• What cell is responsible for myelination in the peripheral nerves?

  Schwann Cell - Myelination

  
• Which cells supply nutrients to the surrounding neurons and act as protective, cushioning cells?

  Satellite cells supply nutrients to the surrounding neurons and act as protective, cushioning cells

  
• Schwann cells are the equivalent of oligodendrocytes(CNS) in the peripheral nervous system. Unlike oligodendrocytes, each Schwann cell is only capable of myelinating a single axon.
• What cell is responsible for myelination in the CNS neurons?

  oligodendroglial cells
• What cell is responsible for myelination in the PNS neurons?

  Schwann cells
• An action potential is defined as a sudden, fast, transitory, self-propagated physio-chemical change in the resting membrane potential when gets stimulated.

  It consists of a wave of depolarisation, and repolarisation, can’t be summated and obeys all-or-none law.

  
• What is the resting membrane potential of a neuron?

  A neuron at rest is negatively charged: the inside of a cell is more negative than the outside: −70 mV

  
• Identify the ionic basis of nerve depolarization, repolarization and restoration of RMP (indicated by numbers)?

  Voltage gated Na channel, Voltage gated K channel and Na-K-ATPase

  
• What is a refractory period in a neuron?

  The refractory period is a state of recovery that occurs after a neuron has fired an action potential. During this period, another action potential cannot be easily produced.

  
• Nerve Action Potential

  A) depolarisation

  B) repolarisation

  C) refractory period

  
• Identify the structures (indicated by numbers)

  Unmyelinated and Myelinated neurons

  
• Which neurons have faster conduction velocity?

  Myelinated axons can conduct at velocities up to 150 m/s, whereas unmyelinated axon conduction velocities range from about 0.5 to 10 m/s

  
• What are the factors affecting conduction velocity in neurons?

  Conduction velocity in neurons is influenced by myelin sheath, thickness (axon diameter) and internode distance.

  
• What is a saltatory conduction?

  Saltatory conduction is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node.

  
• Saltatory conduction

  
• Synapse and Synaptic Transmission

  A) synaptic vesicles

  B) NT

  C) Synaptic cleft

  D) VG Ca2++ channel

  
• Synapse and Synaptic Transmission

  1. An action potential depolarizes the axon terminal.
  2. The depolarization opens voltage-gated Ca2+ channels, and Ca2+ enters the cell.
  3. Calcium entry triggers exocytosis of synaptic vesicle contents.
  4. Neurotransmitter diffuses across the synaptic cleft and binds with receptors on the postsynaptic cell.
  5. Neurotransmitter binding initiates a response in the postsynaptic cell.
  6. Degradation by enzymes
  7. Recycling
  8. Diffusion – out of the cleft

  
• Neurotransmitters -

  
• Ester (Choline derivative) - Acetylcholine
• Amino acids -

  Glycine

  Gamma amino butyric acid (GABA)

  Glutamate

  Aspartate
• Amines -Catecholamines

  Epinephrine (Adrenaline)

  Dopamine

  Norepinephrine (Noradrenaline)
• Amines - Indolamines

  Serotonin

  Histamine

  Taurine
• Peptides

  Endorphins, enkephalins, substance P, cholecystokinin
• Neurotransmitters -Others

  ATP, NO, CO
• Homeostasis & Autonomic Nervous System

  A) variable

  B) sensor

  C) integrator

  D) effector

  
• Homeostasis & Autonomic Nervous System

  A) temperature

  B) glucose

  C) lipids

  D) PO2

  E) PCO2

  F) PH

  G) Blood pressure

  H) pH

  I) Electrolyte's

  J) osmolality

  K) H2O