Parasympathetic Nervous System

Peripheral nervous system includes

cranial nerves, spinal nerves, and autonomic nervous system

Peripheral nervous system is divided into

somatic nervous system and autonomic system

Somatic nervous system

controls voluntary information such as skeletal muscles

Autonomic nervous system

controls involuntary information such as organs

How many cranial nerves?

12 cranial nerves represented as roman numerals

Cranial nerve I - Olfactory nerve

carries sense of smell

Cranial nerve II - Optic nerve

sense of vision

Cranial nerve III - Oculomotor nerve

eye movement

Cranial nerve IV - Trochlear

eye movement

Cranial nerve V - Trigeminal neve

carries sensation from face and motor info to chewing muscles (temporalis and masseter muscles)

Cranial nerve VI - Abducens

eye movement

Cranial nerve VII - Facial nerve

carries sensation info for taste from anterior 2/3 of tongue and motor info to muscles of facial expression

Cranial nerve VIII - Auditory pr Vestibulocochlear nerve

carries info for hearing, balance, and equilibrium

Cranial nerve IX - Glossopharyngeal nerve

carries sensory info for taste from posterior 1/3 of tongue and info to swallowing muscles

Cranial nerve X - Vagus nerve

carries sensory and motor info to and from organs

Cranial nerve XI - Spinal Accessory nerve

carries motor info to sternocleidomastoid and trapezius muscles (neck and upper back)

Cranial nerve XII - Hypoglossal nerve

carries motor info to tongue

Spinal nerves emerge from

spinal cord, 31 total

How many spinal cord nerves in each section?

8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal

What do spinal nerves do?

carry sensory and motor info

Dermatomes

body divided into sections, each representing specific area based on spinal nerves

Autonomic nervous system function

works to maintain homeostasis even when unconscious (sleeping); balance of fluids, electrolytes, blood pressure, nutrients, and blood gasses

How does ANS (aka visceral motor system) maintain homeostasis?

sends motor impulses to viscera, cardiac, and smooth muscle

ANS divided into

sympathetic division and parasympathetic division

Sympathetic division

fight or flight, located in thoracic and lumbar spines and sends fibers to organs

Parasympathetic division aka craniosacral

originates in the brain and sacral region but begins in cervical and lower lumber spines and sends fibers to the same organs as sympathetic

How do sympathetic and parasympathetic divisions work?

have opposite effect thus maintains balance based on body’s needs

Sympathetic nervous system function

increase heart rate, dilate air passages, increase activity of sweat glands, increase glucose levels in blood, dilate pupils, decrease unrinary activity and decrease digestive activity; increases blood sent to cardiac and skeletal system while decreasing blood to skin (flush pale)

Parasympathetic nervous system function

rest and digest; pupil constriction, decrease heart rate and breathing, increase digestion

What are nerves?

Bundles of fascicles that are composed of individual nerve fibers (axons)

Epineurium

dense connective tissue that surrounds and protects nerve; outer layer of nerves

Perineurium

sheath that surrounds each fascicle

Endoneurium

thin layer of connective tissue that surrounds each neuron

Layers of nerves

epineurium, bundles of fascicles surrounded by perineurium, bundles of neurons surrounded by endoneurium

Plexi

combined spinal nerves

Cervical plexus (c1-c4)

innervates posterior head and skin of neck

Phrenic nerve (c3-c5)

emerges from cervical and brachial plexi and runs through thorax to innervate diaphragm

Brachial plexi (c5-t1)

consists of ventral rami from spinal nerves c5-t1 and form axillary, radial, musculocutaneous, ulnar, and median nerves

Lumbrosacral plexus

lumbar plexus (L1-L4) and sacral plexi; obturator, femoral, and sciatic nerve