the study of microscopic anatomy of cells and tissues

-each cell type has features particular to its function

tissues are formed by grouping cells together using a variety of intercellular junctions.

-connect adjacent cells mechanically at the cell membranes or through cytoskeletal elements within and between cells

-tight junctions

-adherens junctions

-desmosome

-hemidesmesome

-gap junction

found where a leakproof seal is needed between cells.

-they keep materials from leaking out of organs

-found in stomach, intestines, bladder

make an adhesion belt(like the belt on your pants) that keep tissues from seperating as they stretch and contract.

-the adhesion belt is formed by a group of glycoproteins called CADHERINS

-cadherins attach to microfilaments in the cytoplasm

act as "spot welds"

-they also use cadherins glycoproteins

-attach to intermediate filaments in the cytoplasm

-found in epidermis and cardiac muscle

pores(connexons) that allow small substances like ions to pass between cells.

-if one of the cells gets sick or dies, these seal like a hatch to prevent damage to other cells

-found in cardiac and smooth muscle, cornea, and lens of eye

endoderm, mesoderm, and ectoderm

1. epithelial tissues from all three germ layers

2. ct and muscle are derived from mesoderm

3. nervous tissue develops from ectoderm

1. epithelial tissues

2. connective tissues

3. muscle tissues

4. nervous tissues

used to line surfaces and form protective barriers.

-good at forming glands and lining hollow organs, body cavities, and ducts.

-secretes things like mucous, hormones, and other substances.

-all epithelia have a free apical surface and an attached basal surface

single layer of flat cells

found in air sacs of lungs, lining of blood vessels, the heart, and lymphatic vessels, in all capillaries.

is composed of a single layer of shaped cells.

-often found lining the tubules of the kidneys and many other glands.

forms a single layer of column like cells, might have cilia, microvilli, mucous.

-goblet cells are simple columnar cells that have differntiated to aquire the ability to secrete mucous

change shape depending on the state of stretch in the tissue

-apical "dome cells" of the top layer(seen here in relaxation) are an identifiable feature and signify an empty bladder. In a full bladder, the cells are flattened

appears to have layers, due to nuclei which are at various depths. in reality, all cells are attached to the basement membrane in a single layer, but some do not extend to the apical surface.

ciliated tissue has goblet cells that secrete mucous

protect, support, and bind organs. 

-fat is a type of CT that stores energy

-red blood cells, white blood cells, and platelets are all CT

macrophages: "big eaters" that swallow and destroy invaders or debris. they can be fixed or wandering.

neutrophils are also macrophages ("small eaters") that are numerous in the blood. mast cells and Eosinophils play an important role in inflammation

most widely distributed in the body, contains several types of cells and three fiber types. 

-used to attach skin and underlying tissues, and as a packing between glands, muscles, and nerves

is located in the subcutaneous layer deep to the skin and around organs and joints.

-it reduces heat loss and serves as padding and as an energy

consists predominantly of fibroblasts and collagen fibers randomly arranged.

-it provides strength when forces are pulling from many different directions

generate the physical force needed to make body structures move. they also generate heat used by the body.

smooth muscle

cardiac muscle

skeletal muscle

exhibit electrical excitability, the ability to respond to stimuli by producing electrical signals such as action potentials. 

ex: neurons and muscle fibers

-action potentials can propagate (travel) along the plasma membrane of a neuron or muscle fiber due to the presence of specific voltage-gated ion channels

line "interior" body surfaces open to the outside:

-digestive tract

-respiratory tract

-reproductive tract

parietal layer next to body wall

-serous fluid between layers

-visceral layer next to organ

lung cavity=pleura

heart cavity=pericardium

abdominal cavity=peritoneum

-parietal layer: outer layer that lines outer body walls.

-serous cavity: middle fluid filled cavity

-visceral layer: inner layer that covers organs

-epithelium=mesothelium=simple squamous EP

-connective tissue:thin layer of aerolar CT

enclose freely moveable joints and are made of connective tissues only.

-connective tissue cells secrete synovial fluid for lubrication

-synovial membranes also line bursas and tendon sheaths