BIO 201 TTK #2

Donaldson

Histology

the study of tissues

4 Types of Tissue

Epithelial, connective, muscle and nervous.

Epithelial Tissue

Covers and lines body surfaces and cavities. Cells are tightly packed together, have an apical and basal surface, are avascular, are innervated, and are highly regenerative.

Connective Tissues

connect structures, bind, support and protect other tissues and allow for transportation of substances throughout the body

Muscle Tissue

Allow for contraction

Nervous Tissues

generate, send, and receive messages

Extracellular matrix- (ECM)-

composed of substances in a liquid, thick gel, or solid that surround the cells of a tissue. Consists of ground substance and fibers.

Epithelial Tissues

have a free surface called the apical surface and a basal surface to which they are bound

Naming Epithelial Tissue

based on the number of cell layers and the shape of the cells. (for example, simple squamous would be one cell layer thick and the cells would be flattened.)

Simple Epithelia

One Cell layer thick

Stratified Epithelia

More than one cell layer thick

Squamous

Flat

Cuboidal

Cube shaped

Columnar

Tall and elongated

Goblet Cell

a specialized type of columnar cell that secretes mucous.

Simple Squamous Epithelium

once cell layer thick, flattened cells.
One location would be the alveoli (air sacs) of the lungs.

Stratified Squamous Epithelium

found in areas of abrasion/friction.
Keratinized _________ is found on the outside layer of the skin

Simple Columnar Epithelium

one cell layer thick of column shaped cells. One location would be the small intestine

Pseudostratified ciliated columnar epithelium-

Found in Tracheae

Transitional Epithelium

several layers of epithelial cells and the underlying basal lamina found in the organs of the urinary system; cells can change shape from dome shaped to squamous when the bladder is stretched.

Endocrine Glands

secrete their products (usually hormones) directly into the bloodstream

Exocrine Glands

secrete their products (ex: sweat) through an epithelium-lined duct.

Merocrine Secrection

products are packaged in secretory vesicles for release by exocytosis

Holocrine Secretion

product accumulates in cytosol and is released when cell ruptures and dies (ex:oil.)

Connective Tissue Proper

also known as general connective tissue. It is widely distributed in the body. Types include loose, dense, reticular and adipose. Cells found in this tissue include fibroblasts, adipocytes, mast cells and phagocytes.

Phagocytes

cells that ingest foreign cells, dead cells, and other cellular debris by phagocytosis

Adipose Tissue

fat tissue- consists of fat-storing adipocytes that are the major energy reserve in the body. This tissue also provides insulation, warmth, shock absorption, and protection.

Cartilage

the three types are hyaline cartilage, fibrocartilage and elastic cartilage. The embryonic skeleton is composed of hyaline cartilage, the vertebral discs are fibrocartilage, and the tissue found the external ear is elastic cartilage (very stretchy.)

Bone Tissue

provides protection and support. The extracellular matrix is inorganic calcium phosphate crystals, making bone one of the hardest substances in the body.

Erythrocytes

red blood cells- these cells transport oxygen through the body

Skeletal Muscle Tissue

found attached to the skeleton. It is voluntary muscle and allows for movement

Cardiac Muscle Tissue

is found only in the heart and is involuntary

Smooth Muscle Tissue

found in digestive organs, uterus, etc.
Involuntary, uninucleate, and non-striated

Neurons

cells capable of sending and receiving electrical messages.

Neuroglial Cells

support cells of the nervous tissue that are capable of mitosis (unlike the neurons.)

True Membranes

serous and synovial

Serous Membranes

fold over themselves giving the appearance of two layers; the outer parietal layer is in contact with the body wall, while the inner visceral layer covers the organ within the body cavity

Synovial membranes

line the cavities surrounding freely moveable joints such as the knee or shoulder

Membrane-like Structures

mucous and cutaneous membranes

Mucous Membranes-also called mucosae

line all body passages as components of the walls of hollow organs that open to the outside of the body

Cutaneous membrane

Refers to the skin

Stem Cells

immature cells capable of replacing worn epithelial cells of the skin and digestive tract

Gap Junctions

small pores formed by protein channels between adjacent cells that allow small substances to flow freely between each cell’s cytoplasm

Tight Junctions

also known as occluding junctions, hold cells closely together such that space between is impermeable to movement of macromolecules

Tissue Repair

process of wound healing; dead and damaged cells are removed and replaced with new cells or tissues

Membrane

thin sheets of one or more tissues that line a body surface or cavity.