Chapter 4 - Tissues

Tissue

a group or layer of cells that work together to perform a specific function

Epithelial tissue

also referred to as the “epithelium” the sheet of cells that cover exterior surfaces of the body and lines, internal cavities and passageways from certain glands

Connective tissue

binds the cells and organs of the body together and functions in protection, support, and integration of all parts of the body

Histology

the study of the microscopic structure of tissues

Pathologist

a medical doctor who specializes in pathology

Ectoderm

develops into nervous tissues, epidermis of skin and other structures

Mesoderm

gives rise to all connective tissues, most muscle tissues

Endoderm

gives rises to epithelial linings of GI & respiratory tracts

apical cell surface

lateral cell surface

Tight junctions

retard passage of substances through epithelial membranes

basal cell surface

Adherens junctions

makes it possible for epithelia to bend and fold

Desmosomes

anchor cells to neighboring cells

Hemidesmosomes

anchor cells to basement membrane

Gap junctions

connect cells and allow diffusion of ions in small molecules between those cells. It allows signals between sales to regular growth and cell differentiation.

Basement membrane (the blue line thinger)

a thin layer that anchors epithelial tissue to the connective tissue underneath it

Simple squamous epithelium

a single layer of flat thin cells that allows for easy diffusion and infiltration

location: air sacs of lungs, lining of blood vessels

Simple cuboidal epithelium

a single layer of cube shaped cells that functions in secretion and absorption

locations: kidney tubules, glands, ducts

Simple columnar epithelium

a single layer of tall column like cell specialized for absorption(microvilli) and secretion.

location: lining of the stomach, intestines and uterus

Stratified squamous epithelium

many layers of flat cells that protects against abrasion

ex: found in the skin (keratinized) and the mouth/esophagus (non-keratinized)

Transitional epithelium

layers of cells that stretch and chain shape; allows organs to expand

ex. Found in the bladder in the uterus.

Pseudostraitified columnar epithelium

looks like multiple layers, but it's just one; often has Celia and goblet cells for moving mucus

Exocrine glands

Glands that secrete substances onto a surface or into ducts.

ex. Sweat glands, salivary glands, and oil glands

Acinar glands

rounded or sac-like glands

ex. Sebaceous (oil) glands.

Tubular glands

tube-shaped glands

ex. Intestinal glands

Tubuloacinar glands

has both tubular and acinar parts

ex. Pancreas

Simple gland

the duct that doesnt have branches

Compound gland

the duct that DOES have branches

Merocrine glands

When the product is released by means of exocytosis

Apocrine glands

the apical part of the cell breaks off to become the secretion

Holocrine glands

an entire cell burst and becomes the secretion. The cell that is sloughed off will be replaced by a new cell.

Endocrine glands

glands that secrete hormone directly into the bloodstream (the hormones enter the intersitial fluid)

fibroblast

loose and dense connective tissue (CT)