Final Exam Flashcards
What is the difference between nerve cells and glial cells?
-Nerve cells (neurons): Conduct electrical impulses/Long processes
-Glial cells (neurological cells): Supporting cells (“glue like”)/Short processes
Nerve Cells and Glial Cells are both found in the CNS/PNS (True/False)
True
The cell body is sometimes also called ____________ (2)
Soma or Perikaryon
What kind of nucleus does a cell body have?
Leptochromatic (increased euchromatin)
What are some differences between axons and dendrites?
- Length: Axon (Long)/Dendrite (Short)
- Function: Axon (Efferent)/Dendrite (Afferent)
- Origin: Axon (Axon Hillock)/Dendrite (Cell Body)
What is a neurophil?
Substances found between neuroglial cells including nerve cells and glial cell processes
Cell bodies of all neurons are located in the CNS, except _________
Ganglia (found in the PNS)
What are the four classifications of neurons?
-Multipolar
-Bipolar
-Pseudounipolar
-Anaxonic
What are the differences between four types of neurons?
- Multipolar: An axon and 2+ dendrites (Most common type)
- Bipolar: 1 major axon and 1 major dendrite
-Found in the eye, inner ear, olfactory, epithelium (sensory neurons) - Pseudounipolar: Starts as one but splits into two
- Axonic: No axon (does not produce an action potential)
-Numerous dendrites
How do Ligand-Gated Channel and Leaky Channels work?
-Ligand-Gated: Gates open when bound to a ligand
-Leaky Channel: Diffusion gradient
(Aid in maintaining equilibrium after hyperpolarization)
How does charge and concentrations of Na+ and K+ inside and outside of a Na-K Pump?
-Outside of Cell: More Positive/Less Negative (More Na+/Less K+)
-Inside of Cell: Less Positive/More Negative (More K+/Less Na+)
What is the typical movement of Na+ and K+ Ions within a Na-K Pump?
-3 Na+ In/2 K+ Out
What is the resting membrane potential?
-70mV
What are the membrane potentials needed for a K+ and Na+ channels
K+: -55mV
Na+: +40mV
What is the difference between depolarization and hyperpolarization?
-Depolarization: Influx of positive ions
( More EPSPs than IPSPs)
-Hyperpolarization: Influx of anions/out flux of positive ions (More IPSPs than EPSPs)
What causes depolarization and hyperpolarization?
Depolarization
-Excitatory Post Synaptic Potential (EPSP)
-Ligand-gated Na+ channels
Hyperpolarization
-Inhibitory Post Synaptic Potential (IPSP)
-Caused by Ca+ ions
-Voltage-relegated Ca+ channels open causing exocytosis of neurotransmitter-filled vesicles to synaptic cleft
EPSPs and IPSPs are __________ potentials
Graded
What happens at the axon hillock when the membrane potential reaches -55mV?
Causes the voltage gated/Na+ dependent channels to open
-Move down the axolemma
All action potentials will decay over time (True/False)
False
-Action potentials at +40mV (K+ channels) do not decay
Three common morphological types of synapses
-Axosomatic synapses: Axon to cell bodies (soma)
(Most Common)
-Axodentritic Synapse: Axon to dendrite
-Axoaxonic Synapses: Axons with other axons
Name the different glial cells in the CNS and PNS
-CNS glial cells: Oligodendrocytes, Astrocytes, Ependymal Cells, Microglia
-PNS Glial Cells: Schwann Cells, Satellite Cells
What are Oligodendrocytes?
-Small cells with many processes (“little arms”)
-Rounded Nucleus
-Function: electrical insulation/myelin production in CNS axons
(Looks like “fried egg”-nucleus (dark) and cytoplasm (white)
What is the predominant cell type in white matter?
Oligodendrocytes
What is the most abundant and largest glial cell?
Astrocytes
What are the main functions in Astrocytes?
-Structural and metabolic support of neurons (especially synapses)
-Repair processes
Ependymal cells can be either _______ or _________-shaped. What is the difference between the two?
-Columnar: Actively secreting cells
-Cuboidal
Where are Ependymal cells found?
Cerebrum ventricles and central canal (CNS)
Ependymal cells have _______ and ________ that extend into the ventricle cavity
-Cilia: Movement of cells for circulation
-Microvilli: Increased surface area
What is the function of Ependymal cells?
Production and movement of Cerebrospinal Fluid (CSF)
Where do Microglial cells originate and who are “brothers” to them
-Originate from monocytes
-“Brothers” to macrophages (similar characteristics)
What function to microglial cells have?
-Defense and immune related activities
-More specifically, they move and scan the neutropil for damaged components
-Phagocytotic: Important for immune defence in CNS
What are the major functions of schwann cells?
-Myelin production (form myelin sheaths around axon of PNS), insulate cells
What are the main functions of satellite cells?
-Structural and metabolic support for neuronal cell bodies (also insulation/nourish)
Which glial cells originate in the neural tube?
Oligodendrocytes, astrocytes, and Ependymal cell
Which glial cell originates in bone marrow (monocytes)?
Microglia
Which cells originate at neutral crest?
Schwann cells and satellite cells
Where are Schwann cells located?
Peripheral nerves
Where are Satellite cells found?
Peripheral ganglia
Where are pyramidal neurons found?
Cerebral cortex
How are pyramidal neurons arranged?
-Vertically
-Often Connected to a glial cell like an astrocyte
-Give out long vertical dendrites that radiate towards surface
What are some identifying characteristics of the cerebellum?
-“Wrinkled” appearance
-Highly folded (folia)
-Branching central medulla of white matter
What are the three layers of the cortex and what do they contain?
-Molecular layer: Outer layer; Few neurons and large numbers of unmyelinated fibers
-Purkinje Cells layer: Between ML and GL, huge neuron cells
-Granular layer: Inner layer; Majority of cell bodies
What are Purkinje Cells?
-Very large cell bodies
-A relatively fine axon extends down through GL
-An extensively branching dendritic system into the outer molecular layer
What are the three meninges?
-Dura Mater: Outer, tough layer
-Arachnoid Mater: Middle, “spider-like”
-Pia Mater: Inner
What is the dura mater?
-Dense, irregular connective tissue
-Separated from the arachnoid by a subdural space
What is the arachnoid mater?
-Consists of two layers: A CT layer and a trabeculae layer
-Contains CSF (between trabeculae spaces)
What is the pia mater?
-Flat cells: Closely associated with the nerve tissue
-Surrounds blood vessels and protects nervous tissue
What is the blood brain barrier made up of?
-Capillary endothelium
-Basement membrane (of the endothelial cells)
-Astrocyte processes (feet)
What is the Choroid Plexus?
-“Finger-like” projections covered in epidymal cells
-Found in the cavities of the brain (majority 3rd and 4th ventricle)
-Little protein content
-Has: lymphocytes, Na, K, and Cl-
What is the function of the choroid plexus?
Remove water from blood and release it as the CSF
What is each villus of the choroid plexus made of?
-Capillary endothelial cells
-Layer of pia mater
-Ependymal cells (line the ventricle cavities)
(NO astrocyte layer)
Nerve fibers in the PNS are made of axons that are covered with _______________
Schwann cells
Schwann cells form _____________ around axons with wide diameter forming __________________
Myelin sheath; myelinated nerve fibers
Small diameter axons are covered by Schwann cells but do not have a myelin sheath (True/False)
True
Explain the process of a myelinated axon
- Schwann cell wraps cytoplasmic process around axon
- Axon is completely enclosed (Mesaxon)
- Wrapping becomes more compact/Cytoplasm leaves
- Mature sheath has up to 100 Lamellae with most cytoplasm in the outermost layer
In a ____________ axon the nucleus stays in the periphery
Myelinated
___________ axons have smaller, thinner axons
Unmyelinated
Explain the process of unmyelinated axons
- Schwann cell envelops multiple axons
- Axons are enveloped by schwann cells, but have no myelinated sheath around each one
________ axons have a central nucleus
Unmyelinated
Name the different levels of nerve organization from outermost to innermost?
-Epineurium: Wraps around the entire nerve
-Perineurium: Wraps around each fascicle
-Endoneurium: Wraps around myelinated/myelinated Fibers and axons
Astrocytes participate in forming the blood brain barrier (True/False)
True
Influx of Na+ ions into the cell causes cell membrane depolarization (True/False)
True
Nissl bodies are made of Golgi bodies and neurotransmitters (True/False)
False
(They consist of granular endoplasmic reticulum and ribosomes)
Unmyelinated neurons do not have Schwann cells (True/False)
False
Since grey matter contains most of the cell bodies with dendrites, this is where most synapses occur (True/False)
True
During Saltatory conduction, action potential gets weaker at the nodes of Ranvier (True/False)
False
(Nodes of Ranvier allow the generation of a fast electrical impulse along the axon)
CSF has all the components of the blood (True/False)
False
(Contains no red blood cells)
Purkinje Cells contribute to the regulation and coordination of the motor functions (True/False)
True
The pyramidal neurons are found in the cerebellum (True/False)
False
(Found in cerebral cortex, hippocampus and the amygdala)
Na-K Pump carries out active transport by utilizing ATP (True/False)
True
Resting membrane potential is +40mv
False
(-70mV)
Multipolar neurons are few and rare
False
(They are the most common)
Mg+ stimulates the exocytosis of neurotransmitter filled vesicles in the axon terminal into the synapse
False
(Ca+)
Oligodendrocytes myelinated the axons in the CNS
True
Voltage-gated channels are found in the axon hillock and axolemma. Not in the dendrites.
True
EPSP and IPSP, both are subthreshold potentials. Individually, they are not sufficient to generate an action potential
True
Bipolar neurons are generally found in sensory epithelia of the body
True
A synapse between an axon and a perikaryon is called as Axosomatic synapse
True
(Soma = Perikaryon=Cell Body)
Efferent neurons transmit impulses to the CNS
False
(Afferent)
Inhibitory post synaptic potentials can cause membrane hyperpolarization
True
Dendrites are sensory in nature
True
Glial cells are found in the CNS and PNS both
True