“Whoso neglects learning in his youth, loses the past and is dead for the future” -Euripides, Greek playwright
TISSUES
Atoms Molecules Cells TISSUES Organs Systems Organism (human)
Tissue- Similar cells with the same function
4 types of human tissue
I. EPITHELIAL TISSUE Function-cover or lining of organs A. Stratified squamous epithelium 1. Function- protect from injury a. cells on the bottom are round-they become flat near the top 2. Location- skin
B. Simple columnar epithelium 1. Shape- long rectangles, packed close together 2. Location- lining of digestive tract (stomach, intestines) 3. Function- to secrete chemicals and absorb nutrients
C. Ciliated Epithelium A. Similar to columnar epithelium, but with CILIA B. Location: trachea, oviducts (uterine tubes) C. Function: movement of mucus or egg by ciliary action FYI: There are other kinds of epithelium: simple squamous, cuboidal, transitional, etc.
II. CONNECTIVE TISSUE *Living cells in a nonliving MATRIX
Loose connective (areolar) Matrix- collagen and elastin (proteins), tissue fluid (water) Location: dermis of skin, subcutaneous layer, around nerves and blood vessels
B. Dense (Fibrous)Connective Tissue 1. Matrix- parallel collagen fibers (strength) 2. Location- ligaments and tendons
C. Blood 2. Nonliving MATRIX- plasma (mostly water) 1. Living cells- red blood cells, white blood cells, platelets 2. Nonliving MATRIX- plasma (mostly water)
D. Bone 1. Living cells- osteocytes 2. Matrix- calcium, phosphorous, collagen
E. Cartilage 1. 3 types of cartilage a. hyaline cartilage- connects ribs to sternum, covers ends of bones b. elastic cartilage- shape of outer ear, vocal cords c. fibrocartilage- between vertebrae
F. Adipose A. large cells found throughout the body B. Structure- vacuole with fat droplet C. Function - stored energy, food, padding , insulation
III. NERVOUS TISSUE A. Made of neurons (nerve cells) B. Function- send and receive messages, communicate C. Location- brain, spinal cord, nerves
IV. MUSCLE TISSUE A. Function: contract B. 3 types- smooth, cardiac and skeletal muscle (voluntary) 1. Skeletal muscles- striated (striped), multiple nuclei a. Location- in muscles that attach to bones
V. TISSUE REPAIR A. Regeneration- new cells are same type and normal function is restored B. Fibrosis- Replacement tissue develops (scar tissue)- some loss of function C. The type of repair depends upon: 1. How severe the injury is 2. What kind of tissue
VI. Tissues that Regenerate A. Epithelial tissues B. Loose and Dense connective tissue C. Bone
VII. Tissues that don’t regenerate A. Skeletal and cardiac muscle B. Nervous tissue
VIII. PATHOLOGY A. Cancer 1. Produced by cell mutation a. cancerous cells -reproduce quickly Take away function of tissues Can metastasize (spread) to all parts of the body 2. May produce tumors a. benign b. malignant- can metastasize (spread)