A&p 2, Exam 2: The Spinal Cord

Front 1

1. At what age does the spinal cord stop growing but the vertebral column continues to grow?
2. What does cause to happen structurally in terms the lengths of certain spinal nerves?
3. What name is given to the organizational pattern of nerves you talked about in the above question?

Back 1

1. 4 years old
2. Vertebral column continues to elongate, but the spinal cord does not, forcing the dorsal and ventral roots to elongate, as opposed to entering the intervertebral foramen immediately adjacent to their respective spinal segments.
3. Cauda equina

Front 2

Where in the vertebral column does the spinal cord “end” and what is this called?

Back 2

Conus Medullaris: Termination of the spinal cord, it ends between L1 and L2

Front 3

Identify the location of the dorsal root, dorsal root ganglion, ventral roots & spinal nerves. What functional type of nerve is associated with each?

Back 3

1. Dorsal root: Connects to spinal cord bilaterally, on the posterior side. Sensory.
2. Dorsal root ganglion: “Blob” in the middle of the dorsal root. Sensory.
3. Ventral roots: Connects to spinal cord bilaterally, on anterior side. Motor.
4. Spinal nerves: Divides into dorsal and ventral roots. Sensory and motor.

Front 4

How are spinal nerves named (numbered) in comparison to the location of vertebrae?

Back 4

1. Each cervical nerve is names after the inferior vertebrae
2. Transition between naming schemes occurs at “C8”
3. Each thoracic nerve is named for the vertebrae superior to it

Front 5

Compare the meninges of the spinal cord to the brain - how are they the same / different?

Back 5

1. Spinal meninges are continuous with cranial meninges (prevents longitudinal movement)
2. Surrounded by adipose tissue
3. No subdural space
4. No division of dura matter into two layers

Front 6

Identify the location & functions of the different regions of grey & white mater of the spinal cord.

Back 6

1. White Matter
___Posterior white columns: Between the posterior gray horns and the posterior median sulcus
___Anterior white columns: Between the anterior gray horns and the anterior median fissure
___Lateral white column: Makes up the white matter between the anterior and posterior columns on each side.
___Anterior white commissure: At the tip of the Anterior Median Fissure

2. Grey Matter
___Posterior gray horns: Contain somatic and visceral sensory nuclei
___Anterior gray horns: Contain somatic motor nuclei only
___Lateral gray horns: Located only in the thoracic and lumbar segments contain visceral motor nuclei
___Gray commissure: Posterior to and anterior to the central canal contain axons that cross from one side of the cord to the other before they reach an area in the gray matter

Front 7

What is a nerve made up of (composed of)?

Back 7

Epineureum (covers nerve)
___a. Blood Vessels
___b. Perineureum (covers Fascicles)
___c. Fascicles
______i. Endoneureum (covers Axons)
______ii. Axons
______iii. Schwann Cells

Front 8

What are the names of the different layers of connective tissue found with a nerve (3)?

Back 8

1. Epineureum
2. Perineureum
3. Endoneureum

Front 9

What is a nerve plexus and name the nerves associated with each plexus?

Back 9

1. Nerve Plexus: Complex, interwoven network of nerves
2. Cervical Plexus:
___Innervate muscles of the neck
___Diaphragmatic muscles
______Phrenic nerve
3. Brachial Plexus:
___Axillary, median , ulnar, and radial nerves
4. Lumbar Plexus:
___Femoral nerves
5. Sacral Plexus:
___Sciatic, tibial and fibular nerves

Front 10

What are dermatomes?

Back 10

Bilateral region of skin monitored by specific pairs of spinal nerves.

Front 11

Define a reflex, monosynaptic, polysynaptic, ipsilateral and contralateral reflex.

Back 11

1. Reflex: Maintain homeostasis through rapid response
2. Monosynaptic: Sensory neuron innervates directly with a motor neuron
3. Polysynaptic: One or more interneuron involved in innervation
4. Ipsilateral: Sensory stimulus and motor neuron response occur on the same side of the body
5. Contralateral: Motor response occures on side opposite the stimulus

Front 12

A patellar and withdraw reflexes are examples of what types of reflexes?

Back 12

1. Patellar: Monosynaptic
2. Withdraw: Ipsilateral Polysynaptic

Front 13

What does a Monosynaptic reflex look like?

Back 13

Front 14

What does a Ipsilateral Polysynaptic reflex look like?

Back 14

Front 15

What does a Contralateral Polysynaptic look like?

Back 15

Front 16

How is the reflex of pulling your hand away from a hot surface different from the reflex involved when you step on a sharp tack?

Back 16

Ipsilateral (hot surface) v. Contralateral (tack)

Front 17

1. How is the BABINSKI(!) reflex different between adults and babies?
2. What is the clinical significance for each?

Back 17

1. Adults v Babies
___Babies: (Positive Babinski) Toes will curl outward in a dorsal flexion
___Adults: (Negative Babinski) Toes will curl inward in a plantar reflex
2. Can indicate damage to higher nervous centers or descending tracks

Front 18

Describe the types of neurons associated with any one particular tract in the spinal cord.

Back 18

1. Ascending Tracts: Sensory neurons
2. Descending Tracts: Motor neurons

Front 19

How many sensory neurons are involved in a typical sensory pathway?

Back 19

3

Front 20

How are first, second and third order neurons different?

Back 20

First: Has it’s cell body in the dorsal root ganglia
Second: Connect to the thalamus (usually an interneuron)
Third: Comes from thalamus and goes to primary sensory cortex

Front 21

How are the sensory pathways of the posterior column pathway, anterolateral (spinothalmic) pathway and spinocerebellar pathaways the similar and different?

Back 21

1. Posterior Column Pathway:
___a. Number of neurons: 3
___b. Location of cross-over: Medulla Oblongata
___c. End of path: Primary Somatosensory Cortex
2. Anterolateral (Spinothalmic) Pathway:
___a. Number of neurons: 6
___b. Location of cross-over: Spinal Cord
___c. End of path: Primary Somatosensory Cortex
3. Spinocerebellar Pathway:
___a. Number of neurons: 4
___b. Location of cross-over: Spinal Cord
___c. End of path: Cerebellum

Front 22

How are upper and lower motor neurons different?

Back 22

1. Upper:
___Cell bodies located in cerebral cortex and brain stem
___Alter activity of lower motor neurons (excitatory or inhibitory)
___Only the upper neurons can prevent a muscle contraction
2. Lower:
___Cell bodies in spinal cord (ant. horn), post. horn is sensory
___Only neurons to leave the CNS
___Damage prevents muscle associated from working
___Excite muscle cells (only role is to tell muscles to contract)

Front 23

1. What are the different tracts associated with the corticospinal pathway.
2. Of these different tracts how is the location of cross over different?
3. Which tract contains the largest grouping of motor neurons?

Back 23

1.
___a. Lateral Corticospinal Tract
___b. Anterior Corticospinal Tract
2.
___a. Anterior crossovers at the level of the spinal cord that they leave the spinal cord with
___b. Lateral crossover at the decussations
3. Lateral Corticospinal Tract

Front 24

What does the name of a pathway automatically tell you?

Back 24

1. Where it’s from
2. The route it takes
3. Where it’s going

Front 25

What does the sympathetic nervous system cause to happen in a fight or flight response?

Back 25

1. Increased heart rate
2. Pupil dilation
3. Increased respiration
___Increased bronchiole dilation (smaller tube=more resistance, larger tube=less resistance)
___Easier for air to move through
4. Decreased peripheral circulation

Front 26

1. How is the sympathetic nervous system involved in maintaining blood pressure?
2. How can alpha or beta blockers help to reduce hypertension?

Back 26

1. Norepinephrine binds to adrenergenic receptors, which constricts smooth muscle, leading to an increase in blood pressure.
2. Alpha blockers reduce signals from the sympathetic nervous system by preventing norep from binding to the muscle in the first place.

Front 27

What structures are only innervated by the symp. nerv. system and are not by the parasympathetic?

Back 27

Innervates blood vessels, sweat glands, adrenal glands and arrector pilli muscles. Parasympathetic doesn’t cause these things to relax, the sympathetic nervous system just ceases to send signals.

Front 28

Describe how the sympathetic and parasympathetic systems leave from different regions of the CNS or spinal cord to reach the peripheral areas (limbs and organs).

Back 28

1. Sympathetic: Leaves from thoracic and lumbar regions
2. Parasympathetic: Leaves from brain stem and sacral regions

Front 29

Describe how the parasympathetic and sympathetic NS are similar and different in terms of length of pre and post ganglionic fibers and myelination.

Back 29

1. Sympathetic: Long post-synaptically
2. Parasympathetic: Long pre-synaptically

Front 30

How are the sympathetic and parasympathetic systems similar and different in regards to the neurotransmitters and receptors involved in presynaptic and postsynaptic fibers?

Back 30

1. Pre-Synaptic: ACh for both
2. Post-Synaptic: Norep for sym., ACh for para.

Front 31

What are cholinergic and adrenergic fibers?

Back 31

1. Cholinergic: Associated with ACh (Sym. pre-synaptic, Para. pre and post-synaptic)
2. Adrenergic: Associated with Norep, Epi (Sym. post-synaptic)

Front 32

What receptors are associated with acetylcholine and norepinephrine and epinephrine?

Back 32

1. ACh: Cholinergic
2. Norep: Adrenergic
3. Epi: Adrenergic

Front 33

What are cholinergic and adrenergic receptors?

Back 33

1. Cholinergic: Associated with ACh (Sym. pre-synaptic, Para. pre and post-synaptic)
2. Adrenergic: Associated with Norep, Epi (Sym. post-synaptic)