T1: Stimulated Excitable Cells Flashcards
Is it possible to get an action potential while in the relative phase? Why or why not? (MG)
Yes because some of the Na+ channels have already reset. Howver you cannot get an AP in the absolute phase as virtually every Na+ channel is inactivated.
Impulses propagate rapidly in... (MG) A. High capacitance axons B. Diameter does not play a factor in propagation speed C. small-diameter myelinated axons D. large-diameter myelinated axons
D. large-diameter myelinated axons
Myelination can decrease the capacitance meaning that less charge needs to be stored up before the impulse can propagate.
A greater length constant indicates…. (MG)
A. Lesser decrement of a graded electrical potential
B. Greater decrement of a graded electrical potential
C. Greater intracellular resistance
D. Lower membrane resistance
A. Lesser decrement of a graded electrical potential
Greater length constant = lesser decrement, lower intracellular resistance, greater membrane resistance
Radial Glia function and name in the cerebellum? (mm)
They are a scaffold for neuronal migration. they are named Bergman glia in the cerebellum and Müller cells in the retina.
What type of glia is a Tanycyte and what is its function? (mm)
It is a central glia derived from radial glia. It is the functional interface between blood and CSF. found near circumventricular organs. They also transport hormones
How does lidocaine suppress action potentials? (mm)
It surpasses action potential by blocking the voltage gated Na channels. This leads to a graded potential being present but no action potential forming.
Lysosomes use which kinda of transport? A.Kinesin Driven B. Dynein Driven C. Tau driven E. They don't move
RFA
B. Dynein- they use - retrograde transport
Kinsensin is + anterograde and is used by mitochondria and vesicles
A patient comes into your clinic with ALS. What is true of the damage neurons?
A. Bipolar
B. Unipolar
C. Golgi Type I
D. Golgi Type II
RFA
C. Golgi Type I- Motor neurons are what is damaged in ALS they are Multipolar and are classified as Golgi Type I (Long Axons)
Bipolar is characteristic of the neurons in the Retina, can be Golgi I or II
Unipolar is typically for transducing some type of physical stimulus (light, sound, temperature, etc.) into electrical activity, no dendrites, and a single axon that conveys the resulting signals into the spinal cord or brain.
Golgi Type II (Short Axon) is found in local interneurons
A patient comes into your clinic with headaches when upright which is relieved when lying down along with episodes of vomiting and double vision. A MRI T2 is done and lateral ventricles are dimmer than expected. After testing is done it is believed that inadequate production or activity of a glia cell is to blame for the symptoms which of the below cell types is most likely.
A. Tancytes B. Schwann Cells C. Oligodendrocytes D. Astrocytes E. Ependymal Cells F. Satellite Glia G. Microglia
RFA
E. Ependymal Cell
The issue is intracranial hypotension due to low CSF production. Ependymal Cells secrete CSF.
Tancytes- function between BBB and CST and transport hormones
Schwann Cells- responsible for myelination in PNS
Oligodendrocytes- responsible for myelination in CNS
Astrocytes- support cells of CNS, BBB support, K buffering
Satellite Glial- Support cells of PNS
Microglia- phagocytic cells of CNS
Which subunit of voltage gated channels is sensitive to voltage?
A) I B) II C) III D) IV E) V
FA
D) subunit IV is the voltage sesnor of the receptors
Length constant is the distance over which a graded electrical potential _____ in a cable-like conductor to ____ of its maximal amplitude.
A) amplified, 110% B) amplified, 137% C) decays, 10% D) decays, 37% E) Bob Saget
D) decays, 37%
Greater the length constant, indicates lesser decrement. Which translates to lower intracellular resistance and greater membrane resistance.
