Tissues: Epithelium and Connective Tissue Essay

Submitted By Francesca-Castro
Words: 2048
Pages: 9

1. Muscle Ca+ ions controls muscle contractions of all muscle types
2. Nervous
3. Epithelial  function: gas exchange, reabsorption, cleaning of the respiratory system
4. Connective Tissues

Muscle Tissue:
 a contractile tissue of the body and is derived from the MESODERMAL layer of embryonic germ cells. It is classified as skeletal, cardiac, or smooth muscle, and its function is to produce force and cause motion, either locomotion or movement within internal organs
Skeletal muscle: is a type of striated muscle, usually attached to the skeleton. Skeletal muscles are used to create movement, by applying force to bones and joints; via contraction
Smooth muscle: found within he walls of organs and structures, such as the esophagus, stomach, intestines, bronchi, uterus, urethra, bladder, and blood vessels. (lumen of GI tract, respiratory, blood vessels) Smooth muscle unlike skeletal is NOT under conscious control. Smooth muscle is controlled by autonomic nervous system
Cardiac muscle: involuntary muscle but is specialized kind of muscle found only within heart. Myocardia requires MORE ATP for muscular contraction and movement of blood. Ergo lots of mitochondria which is required to pump large amounts of blood into the aorta, then body. (Controlled by ANS)
Clinical Point: If the patient has hypocalcaemia the muscle will not contract.
Hypocalcaemia affects blood pressure by keeping the heart muscle in perpetual contraction.

Nervous Tissue:
 Nervous tissue is specialized to react to stimuli and to conduct impulses to various organs in the body which bring about a response to the stimulus.
 Nerve tissue ( as in the brain, spinal cord and peripheral nerves that branch throughout the body) are all made up of specialized nerve cells called neurons.
 Neurons are easily stimulated and transmit impulses very rapidly
 axon carries the neurotransmitter which is produced by the cell body. They can either be stimulators or inhibitors. Synapse can occur between a neuron and muscle cell or another neuron.
 A nerve is made up of many nerve cell fibers (neurons) bound together by connective tissue. A sheath of dense connective tissue, the epineurium surrounds the nerve. This sheath penetrates the nerve to form the perineurium which surrounds bundles of nerve fibers. Blood vessels of various sizes can be seen in the epineurium.
 The endoneurium which consists of a thin layer of loose connective tissue surrounds the individual nerve fibers.

Epithelial Tissue:
1. Protection: epithelial cells from the SKIN protect underlying tissue from mechanical injury, harmful chemicals, invading bacteria and from excessive water.
2. Sensation Sensory stimuli: penetrate specialized epithelial cells. Specialized epithelial tissue containing sensory nerve endings is found in the skin, eyes, ears, nose and on the tongue.
3. Secretion in glands: epithelial tissue is specialized to secrete specific chemical substances such as enzymes, hormones.
4. Absorption: certain epithelial cells lining the small intestine ABSORB nutrients from the digestion of food
5. Excretion: epithelial tissues in the kidney excrete waste products from the body and reabsorb needed materials from the urine. Sweat is also excreted from the body by epithelial cells in the sweat glands.
6. Diffusion: simple epithelium promotes the diffusion of gases, liquids and nutrients. Because they form such a thin lining, they are ideal for diffusion of gases (eg. Walls of capillaries and lungs)
7. Cleaning: ciliated epithelium assists in removing dust particles and foreign bodies which have entered the air passages
8. Reduces friction: The smooth, tightly-interlocking, epithelial cells that line the entire circulatory system reduce friction between the blood and the walls of the blood vessels.
 Epithelia are sheets of cells that cover body surfaces and cavities. Their function is to protect the body (such as skin) or sensory reception such as olfactory epithelial