Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Anatomy 6512 > Peripheral Nervous System and Spinal Cord > Flashcards

Peripheral Nervous System and Spinal Cord Flashcards

1
Q

What types of nerves come from the 3 horns of the spinal cord?

A

Anterior/Ventral: Motor
Intermediate/Lateral: Autonomics
Posterior/Dorsal: Sensory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which functional components are positioned more intermediate in the spinal cord? Visceral or Somatic?

A

Visceral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 3 meninges that wrap a peripheral nerve and their order of structure?

A

Endoneurium: surround individual fibers
Perineurium: surrounds fascicles, continuous with arachnoid and blood-nerve barrier
Epineurium: around nerve trunks, provides tensile strength and continuous with dura.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Blood supply of a nerve is between what 2 coverings?

A

Epineurium and Perineurium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Difference between a schwann cell that makes myelin and one that does not.

A

Those that make myelin can only invest on one segment of one fiber, but those that do not can invest on multiple nerve fibers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is myelin and its function?

A

It is a membrane of glial cells made of specialized lipids and proteins that insulates the axon membrane and increases conduction velocity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What cells produce myelin in the CNS? PNS?

A

CNS-oligodendrocytes

PNS-Schwann cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the name and function of the bare segments between myelin segments?

A

Nodes of Ranvier, they function to initiate another depolarization and continue move the signal along the neuron by means of saltatory conduction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

During saltatory conduction, where does depolarization occur, when is it renewed, and in what direction?

A

Depolarization occurs are the Nodes of Ranvier, is renewed at the next node, and can go in either direction. (The axon hillock is the site of the initial depolarization)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Difference between oligodendrocytes and schwann cells?

A

Oligodendrocytes can myelinate segments of multiple different axons while schwann cells can only myelinate one segment of one axon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where does the transition from Oligodendrocytes and schwann cells generally occur?

A

Just proximal to the foramen (varies greatly)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Result of losing a schwann cell?

A

Slower Action potential conduction velocity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What type of fibers are associated with pain, heat, and touch?

A

small, unmyelinated or poorly myelinated axons. (epsilon or C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of fibers are large and heavily myelinated?

A

Muscle spindle primary endings (1a), golgi tendon organs (1b), and lower motor neurons (alpha)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What type of fibers are intermediate in size and myelination?

A

Meissner and Pacinian corpuscles (Abeta) and axons to intrafusal fibers (gamma)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 5 main sensory receptor types and what do they detect?

A

Chemoreceptors: pH, taste, metabolites, etc.
Photoreceptors: light
Mechanoreceptors: movement, auditory, vesitublar (most diverse of all 5)
Nociceptors: pain
Thermoreceptors: temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Muscle spindles are also what type of specialized receptors?

A

Proprioceptors (awareness in space)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Main function of a receptor for a neuron?

A

To turn a physical stimulus into and electrical signal that the nervous system can understand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What do receptor potentials encode?

A

They encode the intensity and duration of a stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a receptive field?

A

They convey information about the location of a stimulus. In more sensitive areas like the tip of a finger, there are more receptors and smaller receptor fields but in less sensitive areas like the elbow, there is larger fields and less receptors.

21
Q

How do sensory receptors adapt and what is the exception?

A

They become less sensitive to the stimulus if it is maintained. The exception is nociceptors

22
Q

At what level does adaptation occur and give examples of slow and fast adapting receptors.

A

Adaptation occurs at the receptor level but CNS can also regulate receptor sensitivity.
Slowly adapting: muscle spindle (detect static position)
Rapidly adapting: Pacinian corpuscles and hair receptors

23
Q

What are the 2 types of encapsulated receptors in muscles?

A

Muscle spindles and golgi tendon organs

24
Q

What is the function of Muscle spindles?

A

They detect Muscle length. The ends of intrafusal fibers (in a capsule) are attached to extrafusal fibers, so when the muscle stretches, so do the intrafusal fibers.

25
Q

What is the function of Golgi tendon organs?

A

They detect muscle tension and are found in muscle-tendon junctions. Sensory fibers are branched among collagen fibers in a capsule. Muscle contraction distorts the capsule, firing sensory fibers

26
Q

Is the epidural space a real or potential space and why?

A

Yes, it is a real space because the dura mater of the spinal cord does not attach to the vertebrae.

27
Q

Describe the structure and organization of spinal nerves.

A

Dorsal and Ventral rootlets coalesce to form dorsal and ventral roots, which then coalesce to form the spinal nerves. (Each dorsal root has a dorsal root ganglion, containing cell bodies of sensory neurons)

28
Q

What is the exception to dermatomes and clinical significance?

A

Each spinal nerve innervates one dermatome except C1, which has a rudimentary dorsal root. Clinically, they allow diagnosis of the level of a cord lesion/sensory deficit

29
Q

What are spinal cord enlargements and where are they located?

A

They are areas with more motor neurons to supply the upper and lower extremities (larger anterior horn)
Cervical: C5-T1
Lumbar: L2-S3

30
Q

What is the conus medullar is and filum terminal?

A

Conus medullaris is the caudal end of the cord

Filum terminalis is the extension of pia that terminates in dura that is attached to the coccyx.

31
Q

Describe the transition of spinal cord structure as you descend in levels

A

White matter is greatest at Cervical levels but decreases as you go down. The overall shape changes from oblong at cervical levels to circular at lower levels. Posterior intermediate sulcus disappears around T6. Cauda equina begins to appear at the Lumbosaccral level.

32
Q

What travels through the anterior median fissure of the spinal cord?

A

Anterior spinal artery (br. of vertebral artery)

33
Q

The 2 sides of the spinal cord communicate through what?

A

Anterior white commisure, which is at the end of the anterior median fissure

34
Q

What are 2 significant structures in the posterior horn and their function?

A

Substantia gelatinosa (Laminae II): pain and temp.
Lissauer’s tract: finely myelinated and unmyelinated fibers (pain)
They are very large at lumbar levels

35
Q

Function of lower motor (alpha) neurons and location of their clusters in the anterior horn?

A

They function as the only means to move a muscle. Axial muscles are innervated by medial clusters, limb muscles are innervated by lateral clusters.

36
Q

What type of neurons innervate muscle spindles? Muscle fibers?

A

Spindles: Gamma-motor neurons

Fibers- Alpha motor neurons

37
Q

What are the 2 specialized columns in the anterior horn at cervical levels?

A 
Spinal accessory nucleus (caudal medulla-C5)
Phrenic nucleus (C3,4,5)
38
Q

Where are preganglionic sympathetic and parasympathetic neurons located in the spinal cord and how do they leave?

A

Sympathetic: T1-L3 (form distinct horn)
Parasympathetic: S2-S4 (no distinct horn)
*Both are located in the intermediate/lateral horn and exit via anterior/ventral roots

39
Q

Function and location of Clarke’s nucleus.

A

Collection of neurons on medial surface of intermediate gray matter from T1-L2. It is a relay nucleus for transmission of info to cerebellum, proprioceptive info from leg.

40
Q

Posterior intermediate sulcus separates what 2 structures?

A

Fasciculus cuneatus and gracilis (sensory fibers for proprioception and tactile info)

41
Q

What is the corticospinal tract?

A

Axons from upper motor neurons in cortex that tell lower motor neurons what to do (lateral funiculi)

42
Q

Describe positional changes of the spinal cord.

A

At 3 months pregnant, the cord extends the length of the embryo and nerves exit intervertebral foramen at level of origin. When they are born, the end of the cord moves upward and nerves run obliquely. Cauda equine travels from end of cord (L1/2) to end or dura at S2

43
Q

Where is a lumbar puncture performed at?

A

L4-5 (sometimes 2-3?) (caudal equine)

44
Q

What is the other meningeal anchor of spinal cord besides film terminal?

A

Denticulate ligaments, pia-arachnoid extensions. They prevent the cord from rotating and are located in the lateral aspect of cord.

45
Q

What do all reflexes involve?

A

A receptor, an afferent neuron (cell body in dorsal root ganglion), and an efferent neuron (cell body in CNS)

46
Q

What is the ONLY reflex that doesn’t involve interneurons?

A

The stretch reflex (tapping knee)

47
Q

Describe stretch reflex.

A

Monosynaptic, only 2 neurons and 1 synapse. Tapping patellar tendon stretches the spindles slightly, which goes into cord and excites alpha motor neuron to extend leg. (important in movements and maintaing posture)

48
Q

What can golgi tendon organs (1b) have the capability to do during reflexes?

A

They have inhibitory and stimulating interneurons between afferent/efferent neurons. Thought to contribute to fine adjustment of force in muscle contraction during activity.

49
Q

What do spinal arteries get help from in supplying the cord? Location of biggest one?

A

Radicular arteries, which are branches of intercostal arteries. The biggest one is the Artery of Adamkiewicz at level T12.

Anatomy 6512 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions