Chapter 13 Packet Review Flashcards
Spinal cord ends between?
L1 and L2
Dorsal Root Ganglia
Cell bodies of sensory neurons outside the spinal cord
Ventral roots contain?
the axons of motor neurons
A spinal nerve is formed when?
the dorsal and ventral roots merge and are bound together
Spinal nerves are___nerves; they contain both___&___fibers within a sheath
mixed
sensory and motor
How many pairs of spinal nerves?
31
A thoracic spinal nerves name reflects the vertebrae just ___it?
Above (I.E. the T1 nerve is just below the T1 vertebrae)
A cervical spinal nerve reflects the vertebrae type right____it?
Below (I.E. the C3 nerve is just above the C3 vertebrae)
There are___ cervical vertebrae, but ___ cervical nerves
7, 8
Lengthening of the spinal cord ends at what age?
4
Spinal Meninges
provide physical stability & shock absorption, oxygen and nutrients to the spinal cord tissue
Dura Mater
“Tough Mother” outermost layer made of fibrous connective tissue
Arachnoid Mater
“Spider” middle spinal membrane
Arachnoid Trabeculae
network of collagen and elastin fibers
Subarachnoid Space
between arachnoid membrane and the pia mater. Contains cerebral spinal fluid
CSF, Cerebral Spinal Fluid
absorbs shock, acts as diffusion for gases and nutrients
Pia Mater
“delicate mother” innermost layer, very thin
Grey Matter
deep to white matter. make up the horns of the spinal cord. consists of: cell bodies, neuroglia, and unmyelinated axons
Nuclei
masses of grey matter within the CNS
Dorsal horn______nuclei?
Ventral horn______nuclei?
sensory
Motor
White matter
superficial tissue of the spinal cord that contains myelinated and unmyelinated axons
3 region of ______ in the spinal cord?
white matter
Anterior white commissure
regions where axons cross from one side of the spinal cord to the other
Tract
bundle of axons in CNS with similar structure and function
short tracts send sensory or motor info within spinal cord
Longer tracts connect the spinal cord with the brain
Nerves
a group of axons from many neurons with vascularization throughout three connective tissue layers
Epineurium
outermost layer
Perineurium
Middle layer, compartmentalize bundles of axons
Endoonerurium
innermost layer surrounds individual axons
4 steps of peripheral distribution of spinal nerves: Step 1?
!. sympathetic nerve, dorsal ramus and ventral ramus carry senory info through the dorsal root to the somatic and visceral nuclei
Step 2 of distribution of spinal nerves?
- spinal cord interprets info
Step 3 of distribution spinal nerves?
- response info is sent to visceral somatic motor nuclei in the ventral horn
Step 4 of distribution of spinal nerves
- info then travels through ventral root and separated into dorsal, ventral or sympathetic rami
Rami Communicantes
white and grey rami together in motor pathway
White rami gets its name from?
first branch from the spinal nerve carrying visceral motor fibers to a sympathetic ganglion; mylination gives it a light color
Gray rami gets its name from?
unmyelinated, postganglionic fibers that innervate glands and smooth muscles in the body and wall and limbs
Dermatome
a map of the body where a region of skin surface is monitered by a single pair of spinal nerves
Nerve Plexus
ventral rami of adjacent spinal nerves that lend their fibers and produce a series of compund nerve trunks
4 main plexuses?
- cervical
- brachial
- lumbar
- sacral
Name the location and what the Cervical plexus innervates?
Phrenic nerve?
- C1 - C5
- innervates muscles of the neck and diaphragm
* phrenic nerve provides nerve supply to the ENTIRE diaphragm
Name the location and what the lumbar plexus innervates?
- T12 - L4
2. innervates the lower limbs and pelvic girdle
Name the location and what the sacral plexus innervates
- L4 - S4
2. innervates the lower limbs
2 nerves the sciatic nerve branches into?
fibular and tibial
Neuronal Pools
functional groups of interconnected neurons; scattered or localized with a limited number of input sources and output destination
The human body has:
? sensory neurons
? motor neurons
? interneurons
10 million sensory
1/2 million motor
20 billion inter
Divergence
spread of info from one neuron to several
Convergence
many neurons synapse on 1 post synaptic neuron
Serial Processing
Sequential process w/info moving from one neuron to another
Parallel Processing
Divergence happens first then several neurons can process the some info SIMULTANEOUSLY
Reverberation
Causes a pos. feedback loop by further stimulating the presynaptic neuron
Reflex
involuntary responses to a stimulis
Spinal cord refles
reflex that does not depend on the brain
Reflex Arc
the pathway nerve impulses travel when a reflex is elicited; exhibits negative feedback
Part 1 of Reflex Arc?
Receptor-detect stimulus and generate impulses (foot on tac)
Part 2 of Reflex Arc?
Sensory neurons-transmit a graded potential that leads to an action potential that travels along the dorsal root
Part 3 of Reflex Arc?
CNS-contains one or more synapses
Part 4 of Reflex Arc?
Motor neurons-transmit impulses from the CNS to the effector through the vental root
Part 5 of Reflex Arc?
Effector-performs its characteristic action (pulling foot away from pain)
Innate reflex
form during development (chewing, suckling)
Acquired Reflexes
learned motor patterns enhanced by repetition (driving a car)
Stretch Reflexes
muscle that is stretched will automatically contract. Always monosynaptic
4 Steps of Stretch Reflex?
- muscle spindles are stretched
- sensory neurons get excited
- motor neurons are stimulated
- rapid muscle contraction to return muscle spindle to resting state
Tendon Reflexes
Polysynaptic; monitors tension on tendon
Withdrawal Reflexes
Polysynaptic; move effected body parts away from stimulus. It is triggered by pain
Flexor Reflex
Polysynaptic; painful stimulus will automatically cause the effected part to recoil
Crossed Extensor Reflexes
Polysynaptic; the motor response occurs on the side opposite the stimulus
