Quiz 2

• What is the function of astrocytes?

  • Regulates vasoreactivity
  • Helps to form the Blood brain barrier
  • Provides energy
  • Envelopes synapses
• What is the function of oligodendrocytes?

  • Provides trophic support
  • Provides lactate
  • Produce neurotrophins
• What is the function of schwann cells?

  Insulate the electrical charge carried by ions, speeds up conduction
• What is the function of microglia?

  • Removes debris
  • Defense mechanism against pathogens
  • Involved in synaptic pruning
• What are the homeostatic functions of astrocytes?

  Cellular homeostasis

  • Synaptogenesis, synaptic stability, and plasticity
  • Neurogenesis, neuronal development, and guidance

  Metabolic homeostasis

  • Formation of NVU
  • Control over the BBB
  • Regulation of the CBF
  • Metabolic support

  Molecular homeostais

  • Homeostasis of ion and water
  • Regulation of pH
  • Neurotransmitters
• Can you name and distinguish between two myelinating cells?

  Oligodendrocytes: Found in the center nervous system

  Schwann cells: Found in the peripheral nervous system
• Can you explain two functiond of oligodendrocytes?

  • Provides lactate as a source of ATP production for a neuron
  • Produces neurotrophins that support neuronal growth and support
• Can you describe the composition of the plasma membrane?

  Phospholipid bi-layer, phosphate heads that are hydrophillic and a lipid tail that is hydrophobic
• Do you know the difference between hydrophobic and hydrophillic?

  Hydrophilic

  • Water loving
  • Attracts water molecule
  • Interacts and dissolves in water
  • Polar molecule

  Hydrophobic

  • Water-resistant
  • Repels water molecules
  • Does not interact or dissolve in water
  • Non-polar molecules
• Can you explain what makes water so unique?

  • Polar
  • Liquid at room temperature
  • Good solvent (Universal solvent)
• Can you describe an ion channel?

  • The function of an ion channel is to transport ions across the plasma membrane to regulare cell membrane potential
  • Ion pumps use active transport against a concentration gradient, whereas ion channels allow ions to passively flow down a concentration gradient
• Can you explain the basic structure of an amino acid, how many amino acids are there, and what makes them different?

  Basic Structure

  • Hydrogen atom
  • Amino group
  • Carboxyl group
  • R group

  # of amino acids? 20

  What makes amino acids different: R groups
• Do you know what a peptide bond is?

  When the carboxyl group of an amino acid attacks the amino group of another amino acid
• Can you explain the four structures of a protein?

  Primary structure

  • Linear structure of amino acids with a polypetide backbone

  Secondary structure

  • Regions stabilized by hydrogen bonds between the polypetide backbone
  • Alpha and beta formation

  Teritary structure

  • Interactions between R groups

  Quaternary structure

  • When the teritary structures come together and form a 3d structure
• Can you summarize what would happen if there was a hypothetical gene mutation a gene encoding for 1 subunit of a K+ channel?

  • Loss of function
  • Gain of function
  • Altered selectivity or gating
  • Dominant-negative effect
• Do you understand why ions can't freely pass through the plasma membrane?

  The plasma membrane id hydrophobic inside and there are strongly attached so its diffcult to pass between them for a hydrophillic molecule (Prevents passive diffusion of charged ions and polar molecules across the membrane)
• Do you know what diffusion is?

  Diffusion is the movement of particles from an area of high concentration to an area of low concentration
• Do you know what an electrical gradient is?

  The electrical gradient determines the direction which ions will flow through an open ion channel; opposite charges attracts and require ATP for active transport
• Can you explain how concentration and electrical charge influence the movement of ions?

  Ions diffuse down concentration gradients from regions of high concentration to low concentration. Ions also move toward regions of opposite charge
• If given an example of a solution with a semi-permeable membrane, could you explain the movement of ions?


  There will be a diffusion of water, it can reach equilibrium, there will be ion movement, and ionic equilibrium
• Can you define the resting membrane potential?

  Difference in charge between the inside and the outside of a cell

  Value: -70mV
• Do you understand why there is a charge difference across the membrane of a neuron?

  Charge difference is due to an unequal distribution of charged ions across the membrane
• Do you know whether the inside of the neuron is more negative or positive compared to the outside?

  The inside of a cell is more negative compared to the outside of the cell
• Do you know the major lobes of the cerebrum, their locations, their functions?

  1. Frontal lobe: voluntary movement, expressive language and higher-level executive function
  2. Parietal lobe: Receiving and processing sensory input such as touch, pressure, hearing, cold, and pain
  3. Occipital lobe: Visuospatil processing, distance and depth perception, color determination, object and face recognition, and memory formation
  4. Temporal lobe: Managing your emotions, processes information from your sense, stores and retrieving memories, and understanding language
• Can you distingush between a gyrus and a sulcus?

  Gyrus: folds and bumps on the brain

  Sulcus: indentations of grooves on the brain
• Can you identify and describe the location of the lateral sulcus (sylvian fissure) and longitudinal fissure?

  Lateral sulcus: Separates the temporal lobe and the frontal parietal lobes

  Longitudinal fissure: Divides the brain into 2 hemispheres
• Can you identify the location and describe the function of the hippocampus, hypothalamus, thalamus, and amygdala?

  Hippocampus: memory, learning, and emotions

  Hypothalamus: maintaining homeostasis

  Thalamus: relay motor and sensory signals

  Amygdala: regulates emotion and memory and associated with the award system and the fight-or-flight response
• Can you identify the function of the cranial nerves and explain what would happen if each were damaged?

  Olfactory: smell

  Oculomotor: eye movement and pupil reflex

  Trigeminal: facial sensation and chewing

  Facial: face movement and taste

  Glossopharyngeal: throat sensation, taste, and swallowing

  Accessory: neck movement

  Optic: vision

  Trochlear: eye movement

  Abducens: eye movement

  Vestibulocochlear: hearing and balance

  Vagus: movement, sensation, and abdominal organs

  Hypoglossal: movement, sensation, and abdominal organs
• Do you know which side of the membrane Na, K, Cl, and Ca ions are concentrated when a neuron is at rest?

  Na, Cl, and Ca are highly concentrated on the outside of the cell; K is highly concentrated on the inside of the cell
• Do you understand what forces influence ionic movement?

  Concentration (Ions move from a higher concentration to a lower concentration) and electrical gradient (opposite charges attract)
• If a channel for any of the ions open on a membrane when a nueron is at rest, do you know which way the ions would flow? Do you understand the effect that would have on the membrane potential?

  Sodium (Na+): depolarize the cell; bringing it closer to trigger an action potential

  Potassium (K+): hyperpolarize the cell; makes it harder to reach an action potential

  Chloride(Cl-): hyperpolarize the celll; makes it harder to reach an action potential

  Calcium (Ca2+): trigger intercellular processes
• Do you understand the concept of selective permeability?

  Some substances can pass through the membrane, while other cannot pass through
• Do you know that electrochemical equilibrium is?

  When the concentration of the electrochemical equilibrium across the membrane when its concentration gradient is exactly equal and opposite of its electrical gradient
• Do you understand how chemical and electrical forces influence the equilibrium potential of an ion?

  Chemical forces affect the equilibrium potentional by creating a perference for ions ot move from higher concentration to a lower concentration.

  Electrical forces influence the equilibrium potential by determining how strong ions are attracted or repelled by other ions
• Do you understand the concept and general principles of equilibrium potential?

  Balance of forces: pushing an ion in one direction by pulling another one in an opposite direction

  Ion-specific: Each ion has their own equilibrium potential

  Influence of membrane potential: Determines the resting membrane potential
• Do you know the equilibrium potential of the major ions at play?

  K: -80mV; Na: 62mV; Ca2+: positive and Cl-: negative
• Do you know what to use the Nernst equation to calculate? Do you understand what factors the equation takes into account?

  • Used to calculate the equilibriu, potential (in mV) for an ion
  • Takes into account: temperature, a charge of the ion, and the ratio of external and internal ion concentrations
• Do you know the major ions that contrinute to the RMP?

  Na+ (sodium) and K+ (potassium)

  Na+ on the outside of the cell & K+ on the inside of the cell
• Do you know which ion the neuronal membrane is most permable to?

  K+ (Potassium)
• Do you understand the difference between equilibrium potential and membrane potential?

  Membrane potential refers to the difference in electrical potential across the cell membrane; equilibrium potential refers to the electric potential having a new flow of 0