Immersion Exam I: Back - PNS Lecture

Question 1

Sensory/Afferent Nerve

Answer 1

(pseudo-) unipolar neurons conducting impulses
from sensory organs to the CNS

Paresthesia: disruption of sensory/afferent nerves

Question 2

Motor/Efferent Nerve

Answer 2

multipolar neurons conducting impulses
from the CNS to effector organs (muscles & glands)

Paralysis: disruption of motor/efferent nerves

Question 3

Somatic System

Answer 3

“body wall:” somatic (parietal) mesoderm (dermatome, myotome)
dermis of skin, skeletal muscles, connective tissues
conscious, voluntary

Somatic sensations
• touch, pain, temperature, pressure
• proprioception: joints, muscles

Somatic motor activity: innervate skeletal muscles

Question 4

Visceral System

Answer 4

“organs:” splanchnic (visceral) mesoderm, endoderm
glands, cardiac muscle, smooth muscle
unconscious, involuntary

Question 5

Upper Brachial Plexus Injuries

Answer 5

• Increase in angle between neck & shoulder
• Traction (stretching or avulsion) of upper rootlets (e.g., C5,C6)
• Produces Erb’s Palsy

Question 6

Lower Brachial Plexus Injuries

Answer 6

• Excessive upward pull of limb
• Traction (stretching or avulsion) of lower rootlets (e.g., C8, T1)
• Produces Klumpke’s Palsy

Question 7

“Obstetrical” or “Birth palsy”

Answer 7

• Becoming increasingly rare
• Categorized on basis of damage
   • Type I: Upper (C5,6), Erb’s
   • Type II: All (C5-T1), both palsies
   • Type III: Lower (C8, T1),
       Klumpke’s Palsy

Question 8

Ventral vs. Dorsal Regions of the Body

Answer 8

Dorsal: covers the back, back of head, and gluteal regions

Limbs, and everything else = ventral rami

Face = cranial nerves

Question 9

Dermatome vs. Myotome

Answer 9

Dermatome: cutaneous (skin) sensory territory of a single spinal nerve

Myotome: mass of muscle innervated by a single spinal nerve