Topic 4- Tissue Level of Organization Vocabulary

Flashcards covering the key vocabulary and definitions from Chapter 4 lecture notes on the Tissue Level of Organization.

Tissues

Groups of cells that are similar to each other in structure and function.

Histology

Study of tissues.

Matrix

Fluid material between the cells of a tissue.

Collagen

Gives the tissue flexible strength.

Elastin

Gives the tissue the ability to stretch and rebound.

Cell Junctions

Contact points between the cell membranes of tissue cells.

Tight Junctions

Fuse membranes together.

Adhering Junctions

Circle around cells like a belt.

Desmosomes

Creates stability between cells so they do not separate.

Hemidesmosomes

Anchor cells to basement membrane and not other cells.

Gap Junctions

Not actually connecting but allow for muscle and nerve impulses to spread.

Epithelial Tissue

Covers and lines body cavities, bottom attaches to underlying structure, top is exposed.

Squamous Cells

Cells are flat and scale-like.

Cuboidal Cells

Cells are as tall as they are wide like a cube.

Columnar Cells

Cells are taller than they are wide (like a column).

Simple

Single layer of cells of the same shape.

Stratified

Many layers of cells, named for the shape of the cells in the outer layer.

Simple Squamous Epithelium

Single layer of flat cells, thinnest of all epithelium; functions in gas exchange in lungs and blood filtration in kidney.

Simple Cuboidal Epithelium

Cubed (looks like dice) single layer; found in glands and kidney tubules; functions to absorbs water and electrolytes, secretes enzymes and hormones.

Simple Columnar Epithelium

Single layer of column shaped cells; found primarily in the lining of the digestive tract; functions in protection, absorption, secretion.

Pseudostratified Columnar Epithelium

Single layer of column shaped cells but appear to have multiple layers; found in respiratory tract; functions in secretion.

Stratified Squamous Epithelium

Several layers under a single layer of flat squamous; location is superficial layer of the skin; protects from sunlight and bacteria.

Exocrine Glands

Have ducts that lead to the outside of the body (sweat, mucous, and saliva).

Endocrine Glands

Have no ducts that lead outside the body (hormones).

Connective Tissue

Most abundant of all 4 types of tissue; found in skin, membranes, muscles, bones, nerves and all internal organs, contains an extracellular matrix which will determine how strong and flexible tissue is.

Collagen Fibers

Resists pulling and stretching, allows for flexibility without breaking.

Elastin Fibers

Adds strength and stability, helps tissue return to original shape after being stretched (elasticity).

Reticular Fibers

Support and strength.

Loose Fibrous Connective Tissue

Most widely distributed, contains collagen and elastin.

Adipose Tissue

Subcutaneous layer (under the skin) fat tissue, insulates the body from heat loss, provides protective cushion, and allows for energy storage.

Dense Fibrous Connective Tissue

Thick bundles of collagen fibers packed closely together; locations: tendons, ligaments, capsules, and fascia.

Elastic Tissue

Walls of vessels arteries or bronchial tubes; allow for stretching and recoil to original shape.

Cartilage

No blood supply; matrix is not as hard as bone; formed by chondrocytes; 3 types: hyaline, elastic, fibrous.

Hyaline Cartilage

Large amounts of collagen; found where strong support and some flexibility are needed; forms most of skeleton before it is replaced by bone.

Elastic Cartilage

Large amounts of elastic cartilage; found in the external ear.

Fibrocartilage

More collagen than hyaline, put in thicker bundles; absorbs shock well; found in areas where a great deal of pressure is applied (knees, jaw, spinal column).

Bone

Hardest of all connective tissue; formed by osteocytes.

Membranes

Thin, sheet-like structures that protect body surfaces, line body cavities, cover the inner surfaces of organs, reduce friction during organ movements, and reduce friction between bones and joints.

Epithelial Membranes

Epithelial tissue with an underlying of fibrous connective tissue (cutaneous, serous, mucous).

Connective Tissue Membranes

Composed of various types of connective tissue with no epithelial cells (synovial).

Serous Membrane

Lines cavities that do not open to the outside and covers the surface of the organs in that cavity.

Mucous membrane

Lines cavities that are open to the outside of the body, keeps the membrane moist and soft.

Muscle Tissue

Cells are long and slender, therefore, referred to as fibers with a high degree of contractility (skeletal, smooth, cardiac).

Skeletal Muscle Tissue

Voluntary control; attach to bones; have a striated appearance (lines) due to the arrangements of proteins in the muscle fiber.

Smooth Muscle Tissue

Involuntary control; found in walls of viscera, walls of blood vessels; have a non-striated appearance.

Cardiac Muscle Tissue

Found in heart only; have a striated appearance but are involuntary; intercalated discs give the striated appearance and form tight junctions that promote rapid conduction of electrical signals throughout the heart.

Nervous Tissue

Found in peripheral nerves, brain and spinal cord; consists of two types of cells: neuron and neuroglia.

Neurons

Transmit electrical signals between brain and spinal cord.

Neuroglia

Support and take care of the neurons.