peripheral and visceral nervous system

Question 1

Parts of the PNS

Answer 1

• Sensory: sensory or motor nuclei
  
  • CN nuclei 3-12
  • equivalent to: dorsal horn
• Motor:
  
  • somatic motor: CN nuclei, 3, 4, 6, 11, 12
    
    • skeletal muscles
    • equivalent to: ventral horn
  • sympathetic: CN nuclei 5, 7, 9, 10
    
    • no equivalent
  • parasympathetic: CN nuclei 3, 7, 9, 10
    
    • equivalent to Sii-Siv
• Sensory ganglia
  
  • equivalent to dorsal root ganglion

Question 2

Cranial Nerves

Answer 2

• (1) olfactory nerve (s): cribriform plate, sense of smell
• (2) optic nerve (s): optic canal, pupil
• (3) occulomotor nerve (mv): s.o.f, extraocular ciliary sphincter pupil muscles
• (4) trochlear nerve (m): s.o.f, 1 pupil muscle
• (5) trigeminal nerve: s.o.f., r.f., o.f
  
  • ophthalmic (s): orbit, forehead, root of nose
  • maxillary division (s): skin of face, sinus, dura mater, palate
  • mandibular division (sm): floor of mouth, scalp on sides, muscle of mastication
• (6) abducens nerve (m): s.o.f., 1 extraocular muscle
• (7) facial nerve (smv): i.a.m, all glands except parotid, mixed nerve, parasympathetic nerve, taste and salivary glands
• (8) vestibularcochlear nerve (s): i.a.m, balance and hearing, 2 branches (vestibular and cochlear nerve)
• (9) glossopharyngeal nerve (smv): j.f, parotid salivary gland, carotid sinus and body, tongue and oropharynx
• (10) vagus nerve (smv): j.f, palatine pharyngeal laryngeal muscle, larynx and trachea, heart lungs and GI tract
• (11) accessory nerve (m): j.f, trapezius and sternocleidomastoid muscle
• (12) hypoglossal nerve (m): h.c, all tongue muscles except 1

Question 3

Spinal Nerves Info

Answer 3

• made up of dorsal and ventral horn
• horns split into ramus on each side
  
  • dorsal: at the back, thinner, overlined skin and deep back muscles
  • ventral: at the front, thicker, rest of skin
    
    • forms nerve plexus and intercostals
• leave vertebral canal in corresponding foramina
  
  • intervertebral foramina (T, L)
  • sacral foramina (S)
• caudal equina: bundle of roots after end of spinal cord (Lii- coccyx)

Question 4

Spinal Nerves Nomenclature

Answer 4

• Cervical (Ci - Cxiii)
  
  • Cervical Plexus (Ci - Civ)
  • Brachial Plexus (Cv - Cviii)
• Thoracic (Ti - Txii)
  
  • no plexus, called intercostal nerves (Ti - Txi)
• Lumbar (Li - Lvii)
  
  • Lumbar Plexus (Li - Liv)
• Sacral (Si - Sv)
  
  • Sacral Plexus (Liv - Siv)
• Coccygeal (Co)
  
  • (Siv - Sv)
• Nerve Plexus: intertwined network of nerve fibers
  
  • cannot exist in T because ribs prevent intertwined
  • somatic vs visceral
    
    • s: ventral rami to communicate and redistribute fibers
    • each branch carries fibers from several spinal nerves, and distribute via different branches
    • v: autonomic nerves

Question 5

Dermatome v Myatome

Answer 5

• Dermatome: patch of skinskin innervated by a single spinal nerves / segments
  
  • trunk: nipple (T4), xiphoid process (T5-6), belly button (T10)
  • upper limb: deltoid muscle (C5), tip of thumb, middle, pinky (C6-8), medial forearm (T1)
  • lower limb: inguinal groin (L1), medial thigh (L2), medial knee (L3), medial foot (L4), dorsal aspect of foot (L5), lateral foot (S1), back of knee (S2)
• Myatome: section of muscle innervated by a single spinal nerves / segments

Question 6

Cervical Plexus (Ci-Civ)

Answer 6

• cutaneous branches: for back of head, neck, motor to neck via ansa cervicalis
• phrenic nerve: keeps diaphragm alive (Ciii-Civ)

Question 7

Brachial Plexus (Cv-Ti)

Answer 7

• roots (join) U, M, L trunks (split into) A P cords (unite) L, P, M branches
• Musculocutaneous Nerve (L): anterior arm muscles, skin of lateral forearm, corachobrachialis muscle
• Axillary Nerve (P): covers deltoid muscle
  
  • surgical neck of humerus,
• Median Nerve(LM): anterior arm muscles, skin of lateral 3.5 fingers, thenar muscles, #1-2 lumbricals
  
  • behind medial epicondyle
• Radial Nerve (P): posterior arm and forearm, 2/3 of hand
  
  • behind shaft of humerus
  • thick, huge nerve
• Ulnar Nerve (M): 1.5 muscle of anterior forearm, skin of 1.5 fingers on medial hand. majority muscles of hand
  
  • through carpal tunnel

Question 8

Lumbar Plexus (Li - Liv)

Answer 8

• Lateral Femoral Cuteneous Nerve: lateral thigh
• Femoral Nerve: anterior thigh
  
  • branch: Saphenous Nerve - medial leg and foot
• Obturator Nerve: adductor compartment of thigh

Question 9

Sacral Plexus (Liv - Lv)

Answer 9

• Superior and Inferior Gluteal
• Sciatic: longest nerve
  
  • start at pelvis > thigh > tibial and common fibular nerve
  • tibial nerve: muscle of posterior leg
    
    • terminal branches: medial and lateral plantar nerve (muscles of sole of foot)
  • common fibular nerve: 2 branches
    
    • superficial fibular nerve: muscle of lateral leg
    • deep fibular nerve: muscle of anterior leg
• Pudendal: nerve of perineum, diamond-shaped at bottom of pelvis