Nervous system: PNS 12 cranial nerves and 31 spinal nerves

Peripheral nervous system (PNS)

- 12 pairs of cranial nerves - 31 pairs of spinals nerves

Reflexes

- Purpose: protective response - short cut taken by impulse - sensory (afferent) neurons transmit the impulse to the spinal cord - motor (efferent) neurons transmit from the spinal cords to the muscle or gland without processing from the brain

Parasympathetic (autonomic)

- counteracts the actions of the sympathetic response - rest and digest - dec heart rate - dec respiratory rate - dec blood pressure - in digestive tract

Sciatic nerve

- longest and largest nerve in the body - runs from lower back and all the way down each of your legs

Autonomic PNS

- maintains balance in the involuntary systems of the body and allows the body to react in times of emergency - sensory information from visceral organs to CNS - motor impulses from the CNS to smooth muscles, cardiac muscles, and glands

Hypoglossal XII

- sensory: propiception - motor: movement of tongue during speech and swallowing - innervates the muscles of the tongue

Oculi motor nerve III

- sensory: propioception - motor: movement of the eyelid, eyeball, and pupil dilation/constriction - innervates extrinsic muscles of the eyeball - mixed nerve

Trochlear IV

- sensory: proprioception - motor: eye movements - innervates: superior oblique muscle of the eye - mixed nerve

Abducens VI

- sensory: proprioception - motor: lateral movement of the eyes - innervates the lateral rectus muscles of the eye - mixed nerves

Accessory XI

- sensory: proprioception - motor: movements of the shoulders, head, and in the production of sound - innervates the larynx, neck, and shoulder - mixed nerve

Facial VII

- sensory: taste on anterior 2/3 of the tongue (somatosensory from the ear) -motor: controls muscles used in facial expressions - innervates the taste buds and facial muscles - mixed nerve

Glossopharyngeal IX

- sensory: taste on posterior 1/3 of tongue (somatosensory from the tongues and pharynx) - motor: swallowing muscles and secretion of saliva - innervates the tongue, pharynx, and parotid gland -mixed nerve

Spinal nerves

-31 pairs - named for where they exit the spinal column 0 all spinal nerves are mixed (sensory and motor)

Vagus X

-Sensory and motor: pharynx, larynx, respiratory passageways, hearts, esophagus, stomach, small intestines, most of large intestine, and gallbladder - innervates same structures - mixed nerve

Vestibulocochlear VIII

-Sensory: hearing the equilibrium (balance) - 2 branches: cochlear (hearing), vestibular (balance) - innervates the cochlea of the inner ear

Sympathetic (autonomic)

-allows body to react in times of emergency - fight or flight - inc heart rate - inc respiratory rate - inc blood pressure - dec digestive tract

Somatic PNS

-sensory infomation from skin, skeletal muscles and joints to CNS - motor impulses from CNS to skeletal muscle - controls voluntary muscle movements

Trigeminal V

-sensory: somatosensory (ability to distinguish touch, pain, and temperature) - 3 sensory branches: opthalmic, nacillary, mandibular - motor: muscles for chewing - innervates for forehead, upper and lower jaw - mixed nerves

Spinal reflex arc

1. sensory receptor 2. afferent pathway 3. integration center in the spinal cord 4. efferent pathway 5. effector response (muscle or gland)

Assessing reflexes

1. speed of contraction 2. intensity of contraction 3. duration of contraction 4. rapidity of relaxation 5. symmetry of response

Olfactory Nerve I

Sensory nerve- smell Innervates the mucous membrane of the nose

Optic nerve II

Sensory nerve- vision Innervates the retina of the eye

Proprioception

sense of the position of ones body part relative to another. receptors used to decide what muscles need to contract to maintain stability