nervous (PNS) Flashcards
(38 cards)
Peripheral Nervous System contains:
- Cranial Nerves
- Spinal Nerves
- Autonomic Nervous system
There are 12 pairs of _____________, arranged symmetrically and attached to the brain, with the following origins:
- Midbrain
- Pons
- Medulla Oblongata
Cranial Nerves
III (Oculomotor), IV (Trochlear)
Midbrain
V (Trigeminal), VI (Abducens), VII (Facial), VIII
(Vestibulocochlear)
Pons
IX (Glossopharyngeal), X (Vagus), XI (Accessory), XII (Hypoglossal)
Medulla Oblongata
Each nerve may be classified as?
sensory (S)
motor (M)
mixed (Mx)
parasympathetic (PS).
Types of Cranial Nerves
Olfactory (I)
Optic (II)
Oculomotor (III)
Trochlear (IV)
Trigeminal (V)
Abducens (VI)
Facial (VII)
Vestibulocochlear (VIII)
Glossopharyngeal (IX)
Vagus (X)
Accessory (XI)
Hypoglossal (XII)
➢ Smell; passes through the cribriform plate to the olfactory bulb.
➢ Disorder: Anosmia (loss of smell).
Olfactory (I) - (S):
➢ Vision; crosses at the optic chiasm.
➢ Disorder: Anopsia (blindness).
Optic (II) - (S):
➢ Controls most eye movements, except for the lateral rectus and superior oblique muscles.
➢ Parasympathetic to the iris.
Oculomotor (III) - (M, PS):
➢ Thinnest nerve, innervates the superior oblique muscle.
Trochlear (IV) - (M):
➢ Three branches (ophthalmic, maxillary, mandibular); sensory to face, motor to mastication muscles.
➢ Sensory (anterior 2/3 of the tongue) and motor functions.
Trigeminal (V) - (Mx):
➢ Controls the lateral rectus muscle (LR6) for eye movement.
Abducens (VI) – (M):
➢ Taste (anterior 2/3 of tongue), facial expression muscles, parasympathetic to lacrimal and salivary glands (except parotid).
Facial (VII) - (Mx, PS):
➢ Hearing and balance.
Vestibulocochlear (VIII) - (S):
➢ Taste (posterior 1/3 of tongue), motor to pharynx muscles, parasympathetic to the parotid gland.
Glossopharyngeal (IX) - (Mx, PS):
➢ Longest nerve; sensory to internal organs, motor to laryngeal and pharyngeal muscles, parasympathetic to smooth muscles in organs.
Vagus (X) - (Mx, PS):
➢ Innervates the sternocleidomastoid and trapezius muscles.
Accessory (XI) - (M):
➢ Controls tongue muscles, excluding the palatoglossus.
Hypoglossal (XII) - (M):
Classification of Cranial Nerves
- Sensory Nerves (Afferent): I, II, VIII
- Motor Nerves (Efferent): III, IV, VI, XI, XII
- Mixed Nerves (Sensory & Motor): V, VII, IX, X
- The spinal cord gives rise to 31 pairs of spinal nerves that emerge from the vertebral canal through intervertebral foramina. These mixed nerves (sensory and motor) are formed by the union of:
o Dorsal Root:
o Ventral Root:
Spinal Nerves
Contains sensory neuron fibers.
Dorsal Root:
Contains motor neuron fibers.
Ventral Root
Spinal Nerve Distribution:
cervical pairs = ?
thoracic pairs =?
lumbar pairs = ?
sacral pairs = ?
coccygeal pair =?
- 8
- 12
- 5
- 5
- 1