Cells and tissues

classification of epithelium

Classification on the basis of arrangement (layers)

stratified epithelium

Stratified epithelia consist of two or more cell layers. considerably more durable than the simple epithelia these epithelia function primarily to protect (skin)

where are stratified squamous cells found?

Stratified squamous epithelium is found in sites that receive a good deal of abuse or friction, such as the esophagus, the mouth, and the outer portion of the skin

simple epithelia

concerned with absorption, secretion, and filtration. Because simple epithelia are usually very thin, protection is not one of their specialties. ex: in the gut; lumen of small intestine; alveoli of lung

support

connective

chlorine

in ionic form, a makor extracellular anion

potassium

in its ionic form, the major intracellular cation necessary for the conduction of nerve impulses and for muscles contraction

cells

the smallest structural and functional unit of an organism typically microscopic and consisting of cytoplasm and a nucleus enclosed in a membrane

pseudostratified columnar epithelium

All of the cells of pseudo stratified columnar epithelium rest on a basement membrane. However, some of its cells are shorter than others, and their nuclei appear at different heights above the basement membrane

glandular epithelium

Composed of cells that are specialized to produce and secrete substances.

epithelial absorption

Epithelium specialized to absorb substances lines some digestive system organs such as the stomach and small intestine, which absorb food nutrients into the body.

Special Characteristics of Epithelium

Except for glandular epithelium (described), epithelial cells fit closely together to form continuous sheets. Neighboring cells are bound together at many points by specialized cell junctions, including desmosomes and tight junctions. The membranes always have one free (unattached) surface or edge. This so-called apical surface is exposed to the body's exterior or to the cavity of an internal organ. The exposed surfaces of some epithelia are slick and smooth, but others exhibit cell surface modifications, such as microvilli or cilia. The lower surface of an epithelium rests on a basement membrane, a structureless material secreted by both the epithelial cells and the connective tissue cells that abut the epithelium. Epithelial tissues have no blood supply of their own (that is, they are avascular) and depend on diffusion from the capillaries in the underlying connective tissue for food and oxygen If well nourished, epithelial cells regenerate themselves easily

simple columnar

Forms the lining of the stomach and small intestine functions in absorption and secretion

Pseudostratified Columnar Epithelium

Like simple columnar epithelium, this variety mainly functions in absorption and secretion.

pseudostratified ciliated columnar

Lines much of the respiratory tract The mucus produced by the goblet cells in this epithelium traps dust and other debris, and the cilia propel the mucus upward and away from the lungs.

epithelial secretion

Secretion is a specialty of the glands, which produce such substances as perspiration, oil, digestive enzymes, and mucus.

fibroblast

The elongated shape of this cell lies along the cable-like fibers that it secretes

Fibroblasts

The elongated shape of this cell lies along the cable-like fibers that it secretes. It has an abundant rough ER and a large Golgi apparatus to make and secrete the protein building blocks of these fibers; a cell in connective tissue which produces collagen and other fibers.

epithelial filtration

The epithelium lining the respiratory tract has cilia, which sweep dust and other debris away from the lungs. In the kidneys, epithelium both absorbs and filters.

epthelial cells

The hexagonal shape of this cell is exactly like a "cell" in a honeycomb of a beehive. This shape allows epithelial cells to pack together in sheets. An epithelial cell has abundant intermediate filaments that resist tearing when the epithelium is rubbed or pulled. behaves like wallpaper that covers surfaces

skeletal muscle and smooth muscle cells

These cells are elongated and filled with abundant contractile filaments, so they can shorten forcefully and move the bones or change the size of internal organs

why is it called transitional epithelium?

This ability to slide past one another and change their shape (undergo "transitions") allows the ureter wall to stretch as a greater volume of urine flows through that tubelike organ. In the bladder, it allows more urine to be stored.

Erythrocyte (red blood cell)

This cell carries oxygen in the bloodstream. Its concave disk shape provides extra surface area for the uptake of oxygen and streamlines the cell so it flows easily through the bloodstream. So much oxygen-carrying pigment is packed in here than all other organelles have been shed to make room.

nerve cell (neuron)

This cell has long processes for receiving messages and transmitting them to other structures in the body. The processes are covered with an extensive plasma membrane, and a plentiful rough ER is present to synthesize membrane components

hydrogen

a component of most organic molecules; in ionic form, influences the pH of body fluids

nitrogen

a component of proteins and nucleic acids (genetic material)

sulfur

a component of proteins, particularly contractile proteins of muscle

iron

a component of the functional hemoglobin molecule (which transports oxygen within red blood cells) and some enzymes

transitional epithelium

a highly modified, stratified squamous epithelium that forms the lining of only a few organs—the urinary bladder, the ureters, and part of the urethra All these organs are part of the urinary system and are subject to considerable stretching Cells of the basal layer are cuboidal or columnar; those at the free surface vary in appearance When the organ is not stretched, the membrane is many-layered, and the superficial cells are rounded and domelike. When the organ is distended with urine, the epithelium thins, and the surface cells flatten and become squamous like

oxygen

a major component of both organic and inorganic molecules; as a gas, essential to the oxidation of glucose and other food fuels, during which cellular energy (ATP) is produced

Macrophages

a phagocytic cell This cell extends long pseudopods ("false feet") to crawl through tissue to reach infection sites The many lysosomes within the cell digest the infectious microorganisms it takes up

secretory portion of exocrine gland

acinar or tubular may be branched produce secretory product

parts of a cell

all cells have 3 main parts: nucleus, cytoplasm and plasma membrane

sodium

as an ion, the major extracellular cation important for water balance, conduction of nerve impulses and muscle contraction

conducting portion of exocrine gland

branched or unbranched modifies secretory product by absorption contributes to secretion in some glands

gland

consists of one or more cells that make and secrete a particular product, a secretion

which cell covers and lines body organs?

epithelial cells

covering

epithelium

the 4 primary tissue types MENC

epithelium connective tissue nervous tissue muscle all interweave to form the fabric of the body

epithelial protection

epithelium of the skin protects against bacterial and chemical damage

2 types of glandular epithelium

exocrine and endocrine

what cells store nutrients?

fat cells

oocyte

female The largest cell in the body this egg cell contains several copies of all organelles, for distribution to the daughter cells that arise when the fertilized egg divides to become an embryo

which cells connect body parts?

fibroblasts and erythrocytes

calcium

found as a salt in bones and teeth in ionic form, required for muscle contraction , neutral transmission and blood clotting

body tissues

groups of cells that are similar in structure and function

Function of fibroblasts

has an abundant rough ER and large golgi apparatus to make and secrete the protein building blocks of fibers a cell in connective tissue which produces collagen and other fibers

neutron

in the nucleus neutral charge mass 1 amu

proton

in the nucleus positive charge mass 1 amu

examples of pH

lemon juice; gastric juice= 2 saliva; milk= 6.5 distilled water= 7 human blood; semen= 7.4 household bleach= 12

endocrine

lose their connection to the surface (duct); thus they are often called ductless glands Their secretions (all hormones) diffuse directly into the blood vessels that weave through the glands

what cells that fight disease?

macrophages

sperm

male This cell is long and streamlined, built for swimming to the egg for fertilization. Its flagellum acts as a motile whip to propel the sperm.

movement

muscle

iodine

needed to make functional thyroid hormones

what cells gather info and control body functions?

nerve cell

control

nervous

what are the cells of reproduction?

oocyte and sperm

electron

orbitals outside the nucleus negative charge 1/1800 amu

common elements that make up the human body

oxygen (65%) carbon (18.5%) hydrogen (9.5%) nitrogen (3.2%) calcium (1.5%) phosphorus (1%) potassium (0.4%) sulfur (0.3%) sodium (0.2%) chlorine (0.2%) magnesium (0.1%) iodine (0.1%) iron (0.1%)

Phosphorus

present as a salt, in combination with calcium in bones and teeth also present in nucleic acids and many proteins; forms part of the high-energy compound ATP

magnesium

present in bone important cofactor for enzyme activity in metabolic reactions

epithelial functions (FAPS)

protection, absorption, filtration, and secretion

what are the subatomic particles?

protons, neutrons, electrons

Erythrocyte

red blood cell this cell carries oxygen in the bloodstream its concave disk shape provides extra surface area for the uptake of oxygen and streamlines the cell so it flows easily through the bloodstream

exocrine glands

retain their ducts, and their secretions empty through the ducts to the epithelial surface include the sweat and oil glands, liver, and pancreas, are both internal and external.

simple cuboidal

secretion and absorption

epithelium

simple stratified squamous cuboidal columnar

simple squamous epithelium

single layer of thin squamous cells resting on a basement membrane the cells fit closely together, like floor tiles ex: form part of the alveolar walls

which cells move organs and body parts?

skeletal muscle and smooth muscle cells

fat cells (adipocytes)

store nutrients The huge spherical shape of a fat cell is produced by a large lipid droplet in its cytoplasm.

epithelial tissue

the lining, covering, and glandular tissue of the body Glandular epithelium forms various glands in the body. Covering and lining epithelium covers all free body surfaces and contains versatile cells. One type forms the outer layer of the skin. Others dip into the body to line its cavities. Because epithelium forms the boundaries that separate us from the outside world, nearly all substances that the body gives off or receives must pass through epithelium

Stratified Squamous Epithelium

the most common stratified epithelium in the body It usually consists of several layers of cells. The cells at the free edge are squamous cells, whereas those close to the basement membrane are cuboidal or columnar

carbon

the primary elemental component of all organic molecules, including carbohydrates, lipids, proteins, and nucleic acids

what are examples of endocrine glands

thyroid, adrenals, and pituitary

secretion

typically contains protein molecules in an aqueous (water-based) fluid.

Stratified Cuboidal and Stratified Columnar Epithelia

typically has just two cell layers with (at least) the surface cells being cuboidal in shape The surface cells of stratified columnar epithelium are columnar cells, but its basal cells vary in size and shape Both of these epithelia are fairly rare in the body, found mainly in the ducts of large glands.