S1_L2: Neurons, Glia, Receptors, & Nerve Fibers Flashcards
Membrane-bound vesicles formed by the budding off of the Golgi apparatus that serves the cell by acting as intracellular scavengers. These contain hydrolytic enzymes and are involved in the process of intracellular digestion.
Lysosomes
Which 2 filamentous protein structures provide a stationary track that permits specific organelles to move by molecular motors
Microtubules and microfilaments
Source: Snell
Determine the corresponding descriptions of the connective tissue sheaths surrounding a peripheral nerve
- connective tissue sheath surrounding bundles of nerve fibers
- dense connective tissue sheath surrounding the nerve trunk
- loose, connective tissue between individual nerve fibers
A. Endoneurium
B. Perineurium
C. Epineurium
- B
- C
- A
Collective term for cranial and spinal nerves and each of these consists of parallel bundles of nerve fibers, which may be efferent or afferent axons, and may be myelinated or unmyelinated
Peripheral nerve
TRUE OR FALSE: The central nervous system does not have lymphatic capillaries
True
TRUE OR FALSE: Conduction velocity is positively affected by factors such as fiber diameter and myelination
True
Determine the corresponding descriptions of the fenestrated & non-fenestrated capillaries of CNS
- Located in specialized areas of brain that lack a blood-brain barrier
- Ubiquitous in white and gray matter
- Endothelial cells with tight junctions are surrounded by a continuous basement membrane & an outer investment of astrocytic foot process
- Consists of endothelial cells with fenestrations that permit free passage of blood-borne substances into extracellular spaces of CNS
- Endothelial cells & their tight junctions constitute the blood-brain barrier
A. Fenestrated
B. Non-fenestrated
- A
- B
- B
- A
- B
TRUE OR FALSE: The myelin sheath is not part of the neuron but is formed by supporting neuroglial cells
True
The plasma membrane of the neurolemma (Schwann’s sheath) that surrounds an axon. It transmits signals from Schwann cells to axons needed for the stability of myelinated axons.
Mesaxon
Circular truncated cone shape in the myelin internode and a specific feature of myelinated nerve fibers
Schmidt-Lanterman Incisures
A segmented, discontinuous layer interrupted at regular intervals by the Nodes of Ranvier. It serves as the insulator of the nerve fiber and consists of a spirally-wrapped plasma membrane.
Myelin sheath
Determine the corresponding descriptions of the myelination in the Peripheral and Central Nervous System
- Only 1 fiber is served by the cell
- Mesaxon is absent
- Cell responsible is the Schwann cell
- Cell responsible is the oligodendrocyte
- The cell can serve up to 60 nerve fibers
A. Peripheral Nerve
B. CNS Tract
- A
- B
- A
- B
- B
Determine the corresponding functions of the types of sensory axons
- Proprioception, Golgi Tendon Organs
- Touch, pressure, fast pain, and temperature
- Slow pain and temperature, unmyelinated fibers
- Proprioception, muscle spindles
- Touch, pressure, and vibration
A. Ia (Aα)
B. Ib (Aα)
C. II (Aβ)
D. III (Aδ)
E. IV (C)
- B
- D
- E
- A
- C
Which of these neurons is the largest and the smallest in diameter size?
Choices: Alpha (Aα), Gamma (Aγ), Preganglionic autonomic fibers (B), Postganglionic autonomic fibers (C)
Largest: Alpha (Aα)
Smallest: Postganglionic autonomic fibers (C)
Conduction velocity of Ia (Aα) & Ib (Aα) sensory axons
70-120 m/s
Conduction velocity of II (Aβ) sensory axons
30-70 m/s
Conduction velocity of III (Aδ) sensory axons
12-30 m/s
TRUE OR FALSE: Neuroglia are capable of mitotic cell division throughout adult life
True
TRUE OR FALSE: Microglia do not form tumors and tumors are derived from astrocytes, oligodendrocytes, and ependymocytes.
True
A phenomenon following nerve damage which gives the impression that the Nissl substance has disappeared
Chromatolysis
Aka neurilemmal cells. These are derivatives of the neural crest and function in regeneration and remyelination of severed axons in the PNS.
Schwann cells
Intercalated or internuncial neurons that interconnect motor or sensory neurons within the central nervous system (CNS)
Interneurons
Determine the corresponding functions of the main structures in a nerve cell body
- Role in formation and retraction of cell processes and in cell transport
- Form the main component of the cytoskeleton; determines the shape of the neuron; consists of spiral protein threads that play a role in developing and regenerating nerve fibers
- Cell transport of peptide vesicles and organelles; development and maintenance of cell shape
- Controls cell activity
- Adds carbohydrate to protein molecule to form glycoproteins; packages products for transport to nerve terminals; active in lysosome production and in the synthesis of cell membranes
A. Nucleus
B. Golgi complex
C. Neurofibrils / Neurofilaments
D. Microfilaments
E. Microtubules
- D
- C
- E
- A
- B
Determine the corresponding functions of the main structures in a nerve cell body
- Formation of the spindle during cell division; formation & maintenance of microtubules
- Related to formation of dopamine
- Form chemical energy, possess many enzymes which take part in the tricarboxylic acid cycle (Krebs or citric acid cycle) and the cytochrome chains of respiration
- Synthesizes protein
- Harmless metabolic byproduct as the result of lysosomal activity
A. Nissl substance
B. Mitochondria
C. Centrioles
D. Lipofuscin
E. Melanin / Neuromelanin
- C
- E
- B
- A
- D
Determine the corresponding appearance of the main structures in a nerve cell body
- Filaments 3-5 nm in diameter, composed of actin
- 10 nm in diameter, run parallel to each other through the cell body into the neurites
- Pale, chromatin widely scattered; single prominent nucleolus
- Run between neurofibrils, 25 nm in diameter
- Made up of smooth endoplasmic reticulum
A. Nucleus
B. Golgi complex
C. Neurofibrils / Neurofilaments
D. Microfilaments
E. Microtubules
- D
- C
- A
- E
- B
Determine the corresponding appearance of the main structures in a nerve cell body
- Wall made up of bundles of microtubules
- Double membrane with the inner membrane thrown into folds or cristae
- Yellowish brown-blackish pigment in the neurons of the substantia nigra and locus coeruleus
- Broad cisternae; ribosomes are basophilic
- Yellowish brown granules within the cytoplasm that accumulate with aging
A. Nissl substance
B. Mitochondria
C. Centrioles
D. Lipofuscin
E. Melanin / Neuromelanin
- C
- B
- E
- A
- D
Determine the corresponding shape of the main structures in a nerve cell body
- Irregular wavy threads; clusters of flattened cisternae and small vesicles
- Linear tubes
- Linear fibrils
- Large, rounded
A. Nucleus
B. Golgi complex
C. Neurofibrils / Neurofilaments
D. Microfilaments
E. Microtubules
F. Both C and D
- B
- E
- F
- A
Determine the corresponding shape of the main structures in a nerve cell body
- Lipochrome granules
- Small, paired hollow cylinders found in immature dividing nerve cells
- Granules of rough endoplasmic reticulum (RER) arranged in the form of broad cisternae stacked one on top of the other
- Granules
- Spherical, rod shaped
A. Nissl substance
B. Mitochondria
C. Centrioles
D. Lipofuscin
E. Melanin / Neuromelanin
- D
- C
- A
- E
- B