Where are the cell bodies of motor nerves located?
CNS - brainstem or spinal cord
Where are the cell bodies of sensory nerves located?
PNS = DRG
Cranial Nerves = Trigeminal, Geniculate Ganglia etc..
Where are the preganglionic sympathetic neurons located in the CNS?
Lateral Horn
T1-L2
Postganglionic sympathetic neurons of the PNS are located?
Paravertebral
Prevertebral
What is the name of the connective tissue that covers each nerve fibre?
Endoneurium
T or F
Epineurium covers fascicles
False
Perineurium = fascicle
What does the Epineurium cover?
Covers several fascicles
What is an aka for Schwann Cells?
Neurolemma
T or F
Nuclei = CNS Ganglia = PNS
True
T or F
The Schwann cells are only found in the CNS
False
PNS
What is the morphology typically of a sensory neuron?
Pseudounipolar
Relay neurons and interneurons have what morphological shape?
Bipolar
T or F
Unmyelinated axons do not have Schwann cells
False
EVERY axon has a Schwann cell associated with it but not every axon with Schwann cell is myelinated
Fascicle + fat + blood vessels = ?
Nerve
How many nerve fibres are found in each nerve rootlet
20-100
What morphology is associated with motor neurons?
Multipolar
T or F
There are no synapses in DRG only cell bodies.
True
What organelle forms Lysosomes?
Golgi Body
Are microtubules or microfibrils larger?
Tubules = largest Fibrils = smallest
What is the aka for Endoplasmic Reticulum
Nissle Body
T or F
Pseudounipolar is the most common neuron in the body.
False!
Multipolar
What morphology of neurons is associated with special senses?
Bipolar
What is the most common Neurotransmitter?
ACH
What are the two ways to move electrical signals?
Conductivity = continuous
Saltatory Conduction = leaping *nodes of ranvier
A typical lower motor neuron has what type of fibre?
Alpha
What fibres are responsible for sensing the degree of stretch of a muscle?
Gamma
T or F
Pain reflex is required to make it to the brain
False
Does not require brain interaction
On same spinal cord segment
Name the 5 things required in a reflex loop
- Stimulus to some receptor
- Afferent neuron
- Integrating centre
- Efferent neuron
- Effector = smooth, skeletal muscle or gland
What are some aka for Patellar reflex?
Stretch reflex
Deep tendon reflex
What is Wallerian Degeneration
When there is nerve injury and the axon is crushed or cut leading to changes distal to the lesion.
1a fibres = ?
Muscle spindle (annulospiral)
1b = ?
Golgi tendon organ
II fibres = ?
Encapsulated endings
III fibres = ?
pain temperature
What fibre types are considered to be the slowest, unmyelinated and responsible for pain, temperature, touch?
“C”
postganglionic autonomic
In this type of nerve damage, the cell body tried to survive by forming a halo around the cell body.
Chromatolysis
What are growth cones?
They help with regeneration of nerve and will poke and try to help axon grow & move to where it is supposed to go. Helps provide direction in healing.
in what zone are neural stem cells found?
Ventricular Zone (innermost)
- replication is taking place and increases in #
- cells are undetermined
This zone of a neuron contains blast cells (neuroblast or glialblast)
Intermediate Zone
- cells are determined = Neuron or Glial
T or F
The cells of the intermediate zone are mature
False
Only mature cells found in the marginal zone.
What are the most numerous Glia cells?
Astrocytes
What cells will form scar tissue in damaged brain tissue?
Astrocytes
These cells form the myelin sheath in CNS
Oligodendrocytes
T or F
Oligodendrocytes will only myelinated one cell at a time
False
These are described as being the immune system of the CNS
Microglia
Satellite cells aka ?
Schwann Cells
These cells are said to facilitate regrowth of axons
Schwann cells
T or F
Satellite cells are bipolar
False
Pseudounipolar
C5 dermatome = ?
Upper arm
C6 dermatome = ?
Thumb & lateral forearm
C7 dermatome = ?
middle finger
Fingers 4 & 5 = what dermatome?
C8
The nipple area is associated with which dermatome?
T4
L5 dermatome = ?
big toe
Umbilicus = what dermatome?
T10
Heel = what dermatome?
S1
T or F
Discriminative touch and kinesthetic stimuli are carried by what type of axons?
Myelinated type A
T or F
Phasic receptors will stop responding even when stimulus continues
True
T or F
Tonic receptors have a refractory period before responding again
False
No refractory period. Phasic do though!
Name the non encapsulated receptor types
Free-nerve endings
Follicular
Merkel Cell
Name all the slow adapting receptor types
Merkel Cell
Ruffini’s
What receptors detect shearing or drag
Ruffini’s
Which receptor type is closest to the surface
Meissner’s
T or F
Alpha motor fibres are extrafusal
True
Which type of motor neurons innervate intrafusal fibres?
Gamma
T or F
Flower spray endings will detect the rate of stretch of a muscle
False
Flower spray = degree of stretch
annulospiral endings = rate of stretch
Where are the golgi tendon organs located?
Found at the muscle-tendon junctions.
They measure the force of the contraction
What is an aka for the Flexor Reflex
Withdrawal reflex
Sensory info from joints, muscle, and skin are integrated in what lobe of the brain?
Parietal
Conus modularis is located at what spinal level
L2
Dural sac with arachnoid sac is at what spinal level?
L2-S2
Are pure fibres unipolar or multipolar?
Both!
T or F
The filum terminale is a thickened dura mater
False
Pia
T or F
A plexus is formed by dorsal rami
False
Ventral
What space in the spinal canal contains fat and a plexus of veins
Epidural
What meningeal layer contains trabeculae?
Arachnoid
What meningea layer is attached to spinal cord surface
Pia
What ligament is an extension of the dural sac?
Coccygeal Ligament
How many denticulate ligaments attach to dura from foramen magnum to below thoracic vertebrae
21
Cauda Equina is located at what spinal level
L1/L2