General Functions of the Nervous System

Central And Peripheral Nervous System

The nervous system is composed predominantly of neural tissue, but also includes some blood vessels and connective tissue. Neural tissue consists of two cell types nerve cells, or neurons nu'ronz , and neuroglia nu-rog'le-ah or glial cells. Neurons are specialized to react to physical and chemical changes in their surroundings. Small cellular processes called dendrites den'dritz receive the input, and a longer process called an axon ak'son or nerve fiber carries the information away from the...

Critical Thinking Questions

What acidic and alkaline substances do you encounter in your everyday life What foods do you eat regularly that are acidic What alkaline foods do you eat 2. Using the information on page 51 to distinguish between saturated and unsaturated fats, try to list all of the sources of saturated and unsaturated fats you have eaten during the past twenty-four hours. 3. How would you reassure a patient who is about to undergo CT scanning for evaluation of a tumor, and who fears becoming a radiation...

Structure of a Skeletal Muscle

Aponeuroses

A skeletal muscle is an organ of the muscular system. It is composed primarily of skeletal muscle tissue, nervous tissue, blood, and connective tissues. An individual skeletal muscle is separated from adjacent muscles and held in position by layers of dense connective tissue called fascia fash'e-ah . This connective tissue surrounds each muscle and may project beyond the end of its muscle fibers to form a cordlike tendon. Fibers in a tendon intertwine with those in the periosteum of a bone,...

Microscopic Structure

Electron Microscopy Bone

Recall from chapter 5 page 158 that bone cells called osteocytes os'te-o-sltz are located in tiny, bony chambers called lacunae, which form concentric circles around central canals Haversian canals . Osteocytes transport nutrients and wastes to and from nearby cells by means of cellular processes passing through canali-culi. The intercellular material of bone tissue is largely collagen and inorganic salts. Collagen gives bone its strength and resilience, and inorganic salts make it hard and...

Muscles that Move the Foot

Gastrocnemius

Movements of the foot include movements of the ankle and toes. A number of muscles that move the foot are located in the leg. They attach the femur, tibia, and fibula to bones of the foot and are responsible for moving the foot upward dorsiflexion or downward plantar flexion and turning the foot so the toes are inward inversion or outward eversion . These muscles are shown in figures 9.39, 9.40, 9.41, 9.42, in reference plates 68, 69, 70, and are listed in table 9.14. Muscles that move the foot...

Exercise For Sartorius Html

Biceps Femoris Long And Short Head

As its name implies, the biceps femoris bi'seps fem'or-is has two heads, one attached to the ischium and the other attached to the femur. This muscle passes along the back of the thigh on the lateral side and connects to the proximal ends of the fibula and tibia. The biceps femoris is one of the hamstring muscles, and its tendon hamstring a Muscles of the anterior right thigh. Isolated views of b the vastus intermedius, c-e adductors of the thigh, f-g flexors of the thigh. a Muscles of the...

Pictures Of A One Month Old Foetus

Six Month Old Fetus

Eporters gathered in Aries, France, on March 1, 1995, to R celebrate a very special birthday. Jeanne Calment, a woman with the distinction at the time of being listed in The Guinness Book of Records as oldest living human, was turning 120 years old. Although she was able to ride her bicycle daily up until her 100th birthday, after that Jeanne began to feel some physical effects of her many years. Her hearing diminished, and she lost her vision to cataracts. She hadn't been able to walk since...

Regeneration of Nerve Axons

Neurone Bout Distal Proximal

Injury to the cell body usually kills the neuron, and because mature neurons do not divide, it is not replaced. However, a damaged peripheral axon may regenerate. For example, if injury or disease separates an axon in a peripheral nerve from its cell body, the distal portion of the axon and its myelin sheath deteriorate within a few weeks. Macrophages remove the fragments of myelin and other cellular debris. The proximal end of the injured axon develops sprouts shortly after the injury....