Anatomy and Physiology Chapter 6 Nervous System Anatomy and Physiology

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

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

Neurology 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

Divisions of the Nervous System 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

The Brain and Spinal Chord 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

Nerve Cell Structure and Function 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

Types of Nerves Sensory (afferent) nerves Motor 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

Nerves of the head, face and Neck Fifth Cranial Nerve Trifacial Trigeminal Chief sensory nerve of the face Largest cranial nerve

Infratrochlear Nerve – affects the membrane and skin of the nose – 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

Nerves of the Arm and Hand 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

Nerves of the Lower Leg and Foot 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