Peripheral and Autonomic Nervous Systems & Spinal Cord

Question 1

Motor function for vessels arises from what functional component?

Answer 1

Visceral efferent

Question 2

Motor function for muscles arises from what functional component?

Answer 2

Somatic efferent

Question 3

Sensory function for skin and muscles arises from what functional component?

Answer 3

Somatic afferent

Question 4

Stimuli for chemoreceptors

Answer 4

Taste, smell, pH, metabolite concentrations

Question 5

Stimuli for photoreceptors

Answer 5

Retinal visual receptors

Question 6

Stimuli for thermoreceptors

Answer 6

Temperature

Question 7

Stimuli for mechanoreceptors

Answer 7

Physical deformation, touch, muscle length and tension, auditory, vestibular receptors

Question 8

Stimulus for nociceptors

Answer 8

Pain

Question 9

Outline the two main areas of a PNS receptor

Answer 9

Receptive area - area in tissue where stimulus is received

Synaptic area - nerve that stimulus travels on to take to CNS

Question 10

“wiring patterns,” associated with what pathway, preserve location and nature information from a receptive field?

Answer 10

Ascending sensory

Question 11

Name and outline the function of the two encapsulated receptors in muscles

Answer 11

Muscle spindles - detect muscle length

Golgi tendon organs - detect muscle tension

Question 12

The caudal end of the spinal cord is known as:

Answer 12

Conus medullaris

Question 13

Outline the segments of the spinal cord according to nerve roots

Answer 13

8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

Question 14

Through what structures do dorsal rootlets and ventral rootlets enter and exit the cord respectively?

Answer 14

Dorsal rootlets enter cord via posterolateral sulcus. Ventral rootlets exit via anterolateral sulcus.

Question 15

What kinds of neurons are housed in dorsal root ganglia?

Answer 15

Cell bodies of sensory neurons

Question 16

Which spinal nerve has a rudimentary dorsal root, and consequently does not innervate a dermatome?

Answer 16

C1

Question 17

Are afferent fibers sensory or motor? Through what roots do they enter the cord? Where are two places they may terminate thereafter?

Answer 17

Sensory. Dorsal roots. May terminate in posterior horn or ascend to medulla.

Question 18

Motor neurons begin in what spinal horn? Through which roots do they leave?

Answer 18

Anterior, ventral

Question 19

What structure in a spinal cord cross section extends toward the cord center, leaving an indentation? What travels through this structure?

Answer 19

Anterior median fissure - anterior spinal a.

Question 20

What structure is located at the end of the anterior median fissure and allows for contralateral communication within the cord?

Answer 20

Anterior white commissure

Question 21

In a spinal cord cross section, the gray matter forms what shape? What white matter structures surround it?

Answer 21

H-shaped. Surrounded by white matter funiculi (PF, AF, LF)

Question 22

In a spinal cord cross section, longitudinal grooves reflect what?

Answer 22

Boundaries of funiculi or nerve fiber bundles.

Question 23

Where is the posterior intermediate sulcus found? What function does it perform?

Answer 23

Found only above T6. Separates bundles of sensory fibers arising from FG and FC

Question 24

Sensory fibers that arise from the leg are associated with what thoracic-level spinal cord structure?

Answer 24

Fasciculus gracilis

Question 25

Sensory fibers that arise from the arm are associated with what thoracic-level spinal cord structure?

Answer 25

Fasciculus cuneatus

Question 26

The posterior horn of spinal cord gray matter consists mostly of what kind of neurons?

Answer 26

Interneurons

Question 27

With what spinal cord structure is substantia gelatinosa associated with? What function does it serve?

Answer 27

Substantia gelatinosa is associated with posterior horn gray matter. It is involved in pain and temperature sensory

Question 28

Where is Lissauer's tract found? What's it composed of?

Answer 28

Found in posterior horn gray matter. It's composed of myelinated and unmyelinated fibers.

Question 29

Spinal cord laminae (Cytoarchitechtonic cell groups of Rexed) are found in what spinal cord structure?

Answer 29

Posterior horn gray matter

Question 30

Discuss spinal cord lamina I, II and V. What are their functions and relative locations to one another?

Answer 30

Spinal cord laminae are numberd I-V, and are placed in sequential order from the distal portion of the posterior horn to the proximal. Lamina I & V - relay sensory signals. Lamina II - Substantia gelatinosa (pain reception)

Question 31

What spinal cord structure contains motor neurons that control skeletal muscle?

Answer 31

Anterior horn

Question 32

What kinds of motor neurons cluster into groups? From where do they arise, and what do they innervate? What is the difference in function for medial and lateral clusters?

Answer 32

Alpha motor neurons in the anterior horn. Each innervates an individual muscle. Medial clusters innervate axial muscles and lateral clusters innervate limb muscles.

Question 33

Structurally, what is Clarke's nucleus? | Where is it found?

Answer 33

Collection of neurons found on the medial surface of intermediate gray matter from T1-L2.

Question 34

What is the function of Clarke's nucleus? Why is it sometimes considered part of the posterior horn?

Answer 34

Relays proprioceptive info from leg to cerebellum. It's sometimes considered part of the posterior horn because it's sensory.

Question 35

What are denticulate ligaments? What do they do?

Answer 35

Pia-arachnoid extensions. They suspend the cord.

Question 36

What is the function of filum terminale?

Answer 36

Anchors conus medullaris to end of the dural sheath and then to the coccyx

Question 37

Which reflex does not involve interneurons?

Answer 37

Stretch reflex

Question 38

What three components are involved in all reflexes?

Answer 38

- Receptor - associated afferent neuron (cell body in DRG) - efferent neuron (cell body in CNS)

Question 39

What does it mean for a reflex to be polysynaptic?

Answer 39

Has interneurons

Question 40

What components are involved in a monosynaptic stretch reflex?

Answer 40

Two neurons with a synapse between them

Question 41

Stretch reflexes also go by what name?

Answer 41

Deep tendon reflexes (DTRs)

Question 42

The posterior spinal artery is a branch of what cranial artery? Where in the spinal cord does it run?

Answer 42

The posterior spinal artery is a branch of either the vertebral or posterior inferior cerebellar artery (PICA). It runs in the posterolateral sulcus along dorsal rootlets

Question 43

What supplements spinal arteries at lower levels? Why is this necessary?

Answer 43

Spinal arteries are too small to supply more inferior areas, so they're supplemented by radicular arteries.

Question 44

What is a notable radicular artery? From where does it branch, what does it supply, and where is it located?

Answer 44

The great radicular artery branches from the left posterior intercostal artery to supply the entire lumosacral cord. It's found at T12.

Question 45

What structures are supplied by the anterior spinal artery?

Answer 45

Anterior horns and lateral funiculi

Question 46

What structures are supplied by the posterior spinal artery?

Answer 46

Posterior horns and dorsal columns

Question 47

What sorts of myelination patters are displayed in preganglionic and postganglionic fibers?

Answer 47

Preganglionic - thin myelin Postganglionic - unmyelinated

Question 48

What neurotransmitters are associated with 1st and 2nd synapse in Sympathetics and Parasympathetics respectively?

Answer 48

Ach, NE Ach, Ach

Question 49

In the sympathetic system, preganglionic fibers arise from what spinal segments?

Answer 49

T1-L2/3

Question 50

Parasympathetic outflow goes to what regions?

Answer 50

Thoracic, abdominal and pelvic viscera - none to limbs.

Question 51

What ganglia and structure are associated with CN III?

Answer 51

Ciliary ganglion to eye

Question 52

What ganglia and structure are associated with CN VII?

Answer 52

Pterygopalatine ganglion (to lacrimal/nasal glands) Submandibular ganglion (to submandibular and sublingual glands)

Question 53

What ganglia and structure are associated with CN IX?

Answer 53

Otic ganglion (to parotid glands)

Question 54

Only spinal levels with white communicating rami?

Answer 54

T1-L2/3

Question 55

Through what two conduits can postganglionic sympathetic fibers reach the head?

Answer 55

Cervical ganglia and carotic plexus