Compendium Review Unit 1 Topic 1: Cells

cutaway of human skin
A. melanocyte
B. muscle
C. sebaceous gland
D. hair shaft
E. epidermis
F. dermis
G. subcutaneous tissue
H. fat
I. artery
J. sweat gland
K. hair follicle


Our skin is made up of four different tissue types. The epithelial tissue, connective tissue, muscle tissue and nervous tissue.

Epithelial tissue covers the whole surface of the body. It's made up of cells closely packed and ranged in one or more layers. This tissue is specialised to form the covering or lining of all internal and external body surfaces. Epithelial tissue that occurs on surfaces on the interior of the body is known as endothelium. Epithelial cells are packed tightly together, with almost no intercellular spaces and only a small amount of intercellular substance. Epithelial tissue, regardless of the type, is usually separated from the underlying tissue by a thin sheet of connective tissue; basement membrane. The basement membrane provides structural support for the epithelium and also binds it to neighbouring structures. http://www.botany.uwc.ac.za/sci_ed/grade10/mammal/Epithelial.htm

Connective tissue is widespread in the body. It's main function is to bind and strenghten other organs and tissues. It also compartmentalizes and divides other tissue structure. Loose connective tissue is known as adipose tissue and is used for storing fat.

Muscle tissue a very specialized tissue that has both the ability to contract and the ability to conduct electrical impulses. Muscles are are classified both functionally as either voluntary or involuntary and structurally as either striated or smooth. From this, there emerges three types of muscles: smooth involuntary (smooth) muscle, striated voluntary (skeletal) muscle and striated involuntary (cardiac) muscle. http://www.uoguelph.ca/zoology/devobio/210labs/muscle1.ht

Nervous tissue is specialized to react to stimulation and to send out impulse message to certain organs in the body. When that happens the body then sends out a reaction. Nerve tissue is made up of special nerve cells called neurons. Neurons are easily stimulated and send out warning messages very quickly. The endoneurium, which consists of a thin layer of loose connective tissue, surrounds the individual nerve fibers. There are three main type of neurons each are classified by their function. They are sensory neurons, motor neurons and interneurons.