Chapter 6 Nervous System

 Exceptionally well-organized system  Responsible for coordinating all the many activates performed, both inside and outside, of the body

 Fine fibers all over every square inch of the body  100 billion nerve cells  Neurons

 Scientific of the structure, function and pathology of the nervous system  Understanding how nerves work  Proficient manner in administering massages or shampoos  Understand the effects treatments have on the body as a whole

 Central  Controls consciousness and many mental activities  Voluntary functions of the five (5) senses  Voluntary muscle action  Including all body movements  Facial expressions  Consists of:  Brain  Spinal cord  Nerves themselves

 Peripheral  Carry impulses, or messages, to and from the central nervous system  Connects outer parts of the body to the central nervous system  Sensory and motor nerve

 Autonomic  Controls involuntary muscles  Regulates action of smooth (non-striated) muscles, glands, blood vessels, and heart

 Brain  Largest and most complex nerve tissue in the body  Weighs less than 3 lbs.  Controls:  sensation, muscles, activity of glands  And the power to :  think, sense, and feel  12 pairs of cranial nerves

 Spinal Chord  Portion of the Central Nervous System originates in the brain & extends down the trunk  Protected by the spinal column  31 pairs of spinal nerves

 Neuron – nerve cell  Dendrites – tree-like branches of nerve fibers extending from the nerve cell that receive impulses from other neurons  Axon – axon terminal – send impulses away from the cell body to other neurons, glands, or muscles

 Nerves  Whitish cords  Made of bundles of nerve fibers  Held together by connective tissue  Impulses transmitted through the tissue

 Sensory (afferent) nerves  Carry impulses /messages from the sense organs to the brain  Nerve endings called - receptors  Motor nerves  Carry impulses from the brain to the muscles

 Reflex  Automatic response/reaction to a stimulus causing a reaction  Involves movement of an impulse from a sensory receptor along the sensory nerved to the spinal cord  Responsive impulse sent along a motor neuron to a muscle

 Fifth Cranial Nerve  Trifacial  Trigeminal  Chief sensory nerve of the face  Largest cranial nerve

 Auriculotemporal nerve – external ear and skin above temple, up to the top of the skull  Infraorbital Nerve – skin of the lower eyelid, side of nose, upper lip, and mouth  Infratrochlear Nerve – affects the membrane and skin of the nose –  inside corners of the eye  Mental Nerve – skin of lower lip and chin

 Nasal Nerve – point of the lower side of the nose  Zygomatic Nerve – muscles of the upper cheek  Seventh Cranial Nerve – Chief Motor Nerve of the face

 Posterior Auricular Nerve – muscles behind the ear at base of skull  Temporal nerve – muscle of the temple, side of the forehead, eyebrow eyelid, upper part of cheek  Buccal Nerve – muscle of the mouth

 Cervical nerve – side of neck and the platysma  Originate in the spinal cord  Branches supply muscles of the scalp at the back of the head and neck  Greater Occipital Nerve – back of head, affects the scalp up to the top of the head  Smaller Occipital Nerve – base of skull, affect scalp and muscle behind the ear

 Greater Auricular Nerve – side of neck, affects the face, ears, neck and parotid gland  Cervical Cutaneous Nerve – side of neck, affects the front and sides of neck as far down as the breastbone

 Digital nerve – fingers  Radial Nerve – thumb side of arm and back of hand  Median Nerve – supplies arm & hand  Ulnar Nerve – little finger side of arm and palm of hand

 Tibial Nerve –  Division of the sciatic nerve  Passes behind the knee  Muscles of the calf  Skin of leg  Sole, heel and underside of toes

 Sural nerve – outer side and back of the foot and leg  Dorsal Nerve – skin on top of the foot