Exam 2 - Lecture 16 (Nervous Tissue) Flashcards
What does the CNS consist of?
Brain & spinal cord
What does the PNS consist of?
Cranial & spinal nerves
What are the 3 nervous systems?
- CNS
- PNS
- ANS
What are the 3 main parts of the brain?
- Cerebellum
- Cerebrum
- Brain stem
What is the meninges?
C.t. sheath (3 layers) that encloses the CNS.
What are the 3 layers of meninges?
- Dura mater (outer)
- Arachnoid (middle)
- Pia mater (inner)
What makes up the leptomeninges?
Pia mater + arachnoid
What is the subarachnoid space?
Space between arachnoid and pia mater
What circulates within the subarachnoid space?
CSF
What is CSF similar to?
intercellular fluid
What are the components of the CNS that project out of the white matter?
- Rootlets
- Dorsal root
- Dorsal root ganglion
- Ventral root
- Spinal nerve (paired)
Where is white vs. grey matter in the CNS (NOT brain)?
Grey matter = inside
White matter = outside
Where is white vs. grey matter in the brain (cerebrum)?
Grey matter = outside
White matter = inside
What are the “granules” in the CNS that stain purple?
Nissl substance in the cytoplasm of neurons (stained with Nissl stain)
What are the 2 functions of the CSF?
- Protection
2. Maintain chemical stability of the CNS
What color is CSF?
clear
What are two examples of problems that can be associated with the meninges?
- Meningitis
2. Meningioma
What is meningitis?
Inflammatory disease; can be caused by bacteria, visrus, mycosis, etc.
What are symptoms of meningitis?
Cervical pain and fever
What type of infection is meningitis?
Secondary infection to the CNS
Is meningitis contagious?
YES
What is meningioma?
Primary brain tumor
In what species are meningiomas common?
Dogs older than 10 yrs (40% of all canine primary brain tumors)
What cells are found in gray matter?
Neurons and neuroglia
What cells are found in white matter?
Neuroglia ONLY
Where are neurons found?
gray matter
When do neurons stop dividing?
3-4 months after birth
What type of cells are neurons and what do they generate?
excitable; generate APs
What are the 3 main parts of a neuron?
- Cell body
- Dendrites
- Axon
What 2 things are found in the cell body of a neuron?
- Nucleus (nucleolus)
2. Cytoplasm (Nissl substance)
What is Nissl substance made of?
RER and ribosomes
How many axons does each neuron have?
1
What are the 3 classifications of neurons?
- Multipolar
- Bipolar
- Unipolar
What are the functions of multipolar neurons?
sensory and motor
What is the function of bipolar neurons?
sensory
What is the function of unipolar neurons?
sensory
What is the structure of multipolar neurons?
One axon, multiple dendrites coming from cell body (multiple processes)
What is the structure of bipolar neurons?
Cell body with 1 dendrite at one end and one axon at the other (2 processes)
What is the structure of unipolar neurons?
Cell body with one axon from end to end (1 process)
Where are motor neurons found?
ventral horn
Where are sensory neurons found?
dorsal horn
What is the area between the ventral and dorsal horns called?
intermediate substance
Where is the dorsal root ganglion?
Dorsal horn just before it merges with the ventral horn
Where are the cell bodies of sensory neurons found?
In the dorsal root ganglion of the dorsal horn
What are perikaryon?
Neuronal cell bodies
What are dendrites?
Projection from the soma of the neuron
What are axons?
Long projection from the soma of the neuron that conducts APs away from the cell body
