A&P 1 test 4 (PNS and REFLEXES)

what are the plexus?

Cervical plexus (C1-C4), Brachial Plexus (C5-T1), Lumbar plexus (L1-L4), Sacral plexus (L4-S4),

What are the major nerves (Cervical plexus)?

Phrenic nerve, lesser occipital nerve, transverse cervical nerve

What are the major nerves (brachial plexus)?

Musculocutaneous nerve, axillary nerve, radial nerve

What are the major nerves (lumbar plexus)?

Femoral nerve, obturator nerve, lateral femoral cutaneous nerve

What are the major nerves (Sacral plexus)?

Sciatic nerve, tibial nerve, common fibular nerve.

which parts of the body is supplied by each plexus? (cervical plexus)

neck muscles, skin of the head, neck, and diaphragm

which parts of the body is supplied by each plexus? (brachial plexus)

upper limbs (skin and muscles)

which parts of the body is supplied by each plexus? (Lumbar plexus)

anterior and medial thigh (skin and muscles)

which parts of the body is supplied by each plexus? (sacral plexus)

Gluteal region, posterior thigh, most of the leg and foot

Are spinal nerves sensory, motor, or mixed?

mixed nerves

define dermatomes

an area of skin supplied by the sensory fibers of a single spinal nerve

what is the significance of dermatomes?

allows the mapping of skin sensation directly specific to spinal nerves and cords.

Olfactory (cranial nerve 1)

smell. only nerve that bypasses the thalamus.

Optic nerve (cranial nerve 2)

vision. Carries visual information from retina to brain.

Oculomotor (cranial nerve 3)

eye movement, pupil constriction, lens accommodation. Controls most eye movements.

Trochlear (cranial nerve 4)

motor to superior oblique muscles (eye depression + intorsion). Only cranial nerve that exits dorsally from the brainstem.

Trigeminal (Cranial nerve 5)

Sensory: face, scalp, cornea, nasal/oral cavities. Motor: muscles of mastification (chewing). Largest cranial nerve.

Abducens (Cranial nerve 6)

motor to lateral rectus (abducts eye). damage → eye pulled medially

Facial nerve (cranial nerve 7)

motor: facial expression, Sensory: taste from anterior 2/3 of tongue, Parasympathetic: lacrimal, submandibular, sublingual glands. Bell’s palsy affects this nerve

Vestibulocochlear (cranial nerve 8)

Hearing (cochlear), balance/equilibrium (vestibular). Damage → vertigo, hearing loss.

Glossopharyngeal (cranial nerve 9)

Taste posterior 1/3 of tongue, Sensation from pharynx. responsible for the afferent limb of the gag reflex.

Vagus (cranial nerve 10)

Motor to pharynx/larynx (speech, swallowing), parasympathetic to heart, lungs, GI tract, sensory from thoracic/ abdominal organs. Most extensive parasympathetic nerve.

Accessory (cranial nerve 11)

motor to sternocleidomastoid and trapezius. turns the head and elevates shoulders

Hypoglossal (cranial nerve 12)

Motor to tongue muscles. tongue deviates toward the side of a lesion.

what is the difference between an interoceptor and an exteroceptor?

interoceptors monitor the internal environment while exteroceptors monitor the external environment.

what is a proprioceptor?

a sensory receptor that lets your brain know where your body is and how it’s moving.

name three proprioceptors

Muscle spindles, Golgi tendon organs, joint kinesthetic receptors.

what is the location and function of the Meissner corpuscle

location: superficial dermis. Function: light touch, low-frequency vibration, changes in texture.

What is the location and function of the Merkel discs?

Location: deep epidermis (stratum Basale). Function: detects light touch, pressure, form and texture

What is the location and function of the Pacinian corpuscle?

Location: deep in the dermis. Function: Deep pressure, high-frequency vibration, rapid changes in mechanical stimuli

What is a nociceptor? 

a sensory receptor that detects pain

What stimulates these receptors? (Nociceptor)

anything that is potentially damaging to tissues.

What is the definition of referred pain?

pain that is felt in a location different from the actual site of the stimulus or injury.

what is the definition of Phantom pai?

pain or sensation felt in a limb or body part that has been amputated.

what is the definition of adaptiation?

a decrease in the sensitivity of a receptor during a constant, unchanging stimulus.

What is the definition of Punctate distribution?

the concept that sensory receptors are not evenly distributed across the skin.

where would you find chemoreceptors?

found in the nose, tongue, blood vessels.

Where would you find photoreceptors?

found only in the retina

where would you find mechanoreceptors?

found in the skin, ear, muscles, tendons, and organs.

How are chemoreceptors stimulated?

stimulated by chemicals, respond when specific molecules bind to them.

How are photoreceptors stimulated?

stimulated by light. respond when photons of light hit them.

How are mechanoreceptors stimulated?

respond when they are physically deformed by pressure, stretch, vibration, or movement.

is Cranial nerve 1 (olfactory) sensory or motor?

Sensory

Is cranial nerve 2 (optic) sensory or motor?

sensory

Is cranial nerve 3 (oculomotor) motor or sensory?

motor

Is cranial nerve 4 (Trochlear)

motor

Is cranial nerve 6 (abducens) motor or sensory

motor

Is cranial nerve 11 (accessory) sensory or motor?

motor

is cranial nerve 12 (hypoglossal) motor or sensory?

Motor

Is cranial nerve 8 (vestibulocochlear) sensory or motor?

sensory

IS cranial nerve 5 (trigeminal) sensory or motor?

mixed

Is cranial nerve 7 (facial) sensory or motor?

Mixed

IS cranial nerve 9 (glossopharyngeal) sensory or motor?

mixed

IS cranial nerve 10 (vagus) sensory or motor?

mixed

What are the components of the reflex arc?

Receptor, Sensory (afferent) neuron, integration center, motor (efferent) neuron, effector.

What information does the DRG carry?

Sensory (afferent) only.

What is located in the dorsal root?

axons, fibers whose cell bodies live in the dorsal root ganglion

What kind of information does the dorsal root carry?

Sensory only.

what information does the ventral root carry?

axons (motor)

what does the spinal nerve contain?

Motor and sensory fibers

What information does the spinal nerve carry?

sensory and motor.