Tissues –
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Types of tissues
 Epithelial
o Cover organs and lines body surfaces
o Made of tightly packed cells (lacks blood vessels, replaced frequently,
prominent nuclei)
o Simple—single layered, used for diffusion and filtration
o Stratified—two or more layers, best suited for protective materials because it
can loose layers of cells
 Keratin hardens and makes a protective shell, blocks chemicals and
microorganisms, keep liquids in
o Function in secretion, absorption, excretion
o Types:
 Squamous—tightly packed flattened cells
 Cuboidal—cubed shaped
 Columnar—elongated
 Pseudostratified ciliated columnar—appears to be stratified, but its
not (this is due to the nuclei), and has cilia
 Transitional—changes in response to pressure
 Glandular—made up of cells designed to secret substances into body
fluids
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Connective
o Binds, supports, protects, serves as frameworks, fill spaces, store fats,
produce blood cells, fight infection, repair tissue damage
o Have a matrixnonliving material surrounding the cells
o Fibers found are: collagenous, reticular fibers, and elastic fibers
o Cells types:
 Fibroblasts: produce fibers
 Macrophages: produced from white blood cells
 Most cells: release heparin (prevents blood clotting)
 Historine: promotes reaction
o Types:
 Loose fibrous connective—binds the skin to underlying organs and
fills space between muscles
 Dense connective tissue—found all over body, found in tendons,
ligaments, deep skin layer
 Cartilage—is a rigid connective tissue that provides a supportive
framework for various structures
o Most common type is the hyaline (found in ends of
bones, part of nose, respiratory passages)
o Elastic cartilage—very flexible (found in ear)
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Fibrocartilage—is the toughest of the three (found in
vertebrae of spinal chord, in knees)
Bone—cells and matrix for concentrically shaped
circles around a central canal
Blood—maintain stable internal environmental
conditions, transportation, exchanges of substances,
composed of formed elements and a liquid blood
plasma
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Muscle
o Function is to contractmoving body parts
o Skeletal muscle tissue
 Found attached to bones
 Cells appear striped and are striations
 Voluntary muscle contractions
 Long parallel fibers
o Smooth muscle
 Found in the walls of internal organs
 Shape of cells—spindle shaped
 One single central nuclei
 Involuntary
o Cardiac muscle
 Cells also appear striped or striated
 Branching cells
 Distinct plate-like structure between connecting cells
 Found in the heart and is branched
 It is involuntary
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Nerve
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Nerve cells sense certain types of changes
Carry impulse
Neurons – primarily elongated cells with long extensions or branches.
Support cells that care for the neurons.