Histology Anatomy Chapter 4

glands with ducts are

exocrine glands

Microvilli and Cilia

Apical Surface Features

A centriole that has left the centrosome

Basal body

Basal lamina + proteins and reticular layers of the underlying connective tissue deep to it.

Basement Membrane

They lock together Anchored by intermediate filaments In place so that the tissue doesn't tear apart

Cadherins

Whip-like, highly motile extensions of apical surface membranes Contains a core of nine pair of microtubules encircling one middle pair, microtubules originate from basal body.

Cilia

Based on # of cell layers either simple or stratified. Then based on shape of cells: Squamous Stratified Columnar

Classification of Epithelia

The supportive tissue

Connective tissue

Two disc-like plaques connected across intercellular space. Plaques are joined by proteins called cadherins, the proteins interdigitate into extracellular space

Desmosome

covers and protects surfaces, both outside and inside the body

Epithelial Tissue

The covering or lining of an organ

Epithelial tissue

Absorption Secretion of mucus, enzymes, and other substances Ciliated type propels mucus or reproductive cells. Use cilia to propel mucus.

Function of Simple Columnar Epithelium

Stretches and permits distension of urinary bladder

Function of Transitional Epithelium

Protection Absorption, secretion, and ion transport Diffusion Filtration Enzymes secrete a substance that forms slippery surfaces ie lubrication (reducing friction)

Functions of Epithelial Tissue

Maximize surface area across which small molecules enter or leave. Act as stiff knobs that resist abrasion

Functions of Microvilli

Secretion and Absorption

Functions of Simple Cuboidal Epithelium

Protection and secretion

Functions of Stratified Columnar Epithelium

Protection

Functions of Stratified Cuboidal Epithelium

Protects underlying tissues in areas subject to abrasion

Functions of Stratified Squamous Epithelium

Movement in coordinated waves Propulsion of substance in one direction. Has propulsion and recovery phase.

Functions of the Cilia

Anchor adjacent cells together Use intermediate filaments to resist pulling forces. For example cardiac muscle and epithelial tissue.

Functions of the desmosome

small,specialized contact region between cells containing protein channels that aid intercellular communication,allows ions and molecules to pass from one cell to another

Gap Junctions

Unicellular glands responsible for the production of mucus.

Goblet cell

Epidermis (skin)

Location of Keratinized Stratified Squamous Epithelium

Kidney Tubules Secretory portions of small glands Ovaries

Location of Simple Cuboidal Epithelium

Found in male urethra and large ducts of some glands. Fairly Rare

Location of Stratified Columnar Epithelium

Ureters, urinary bladder and part of urethra

Location of Transitional Epithelium

Small bronchi Uterine tubes and uterus (Where we need to secrete mucus and propel it out)

Location of ciliated simple columnar epithelium

Lining of esophagus, mouth and vagina. Think of it as a continuation of your skin

Location of non-keratinized Stratified Squamous Epithelium

Trachea and most of upper respiratory tract

Locations of Ciliated Pseudostratified Columnar Epithelium

Renal corpuscles Alveoli of lungs Lining of heart, blood and lymphatic vessels Lining of ventral body cavity

Locations of Simple Squamous Epithelium

Largest ducts of sweat glands Ducts of mammary glands and salivary glands

Locations of Stratified Cuboidal Epithelium

Cuts of male reproductive tubes like the vas deferens Ducts of large glands

Locations of non-ciliated Pseudostratified Columnar Epithelium

Finger-like extensions of plasma membrane Abundant in epithelia of small intestine and kidneys Reinforced by actin filaments, the actin filaments are connected to microfilaments

Microvilli

Tissue that allows for movement due to actin and myosin

Muscle tissue

The tissue responsible for control through electrical communication

Nervous Tissue

Digestive tract (stomach to anus) Gallbladder Ducts of some glands

Non-ciliated Simple columnar epithelium location

Very easy to see goblet cells with cilia

Picture of Pseudostratified Columnar Epithelium

Looks like a big oval surround by cuboidal cells.

Picture of Stratified Cuboidal Epithelium

Numerous layers of cells on top of each other, can tell whether it's keratinized or not based on whether there are strings of purple present in the top layers of cells.

Picture of Stratified Squamous Epithelium

All cells originate at basement membrane Only tall cells reach the apical surface May contain goblet cells and cilia Nuclei lie at varying heights within cells, giving the false impression of stratification Bottom line: Only one layer with varying heights of cells

Pseudostratified Columnar Epithelium

Secretion of mucus Propulsion of mucus by cilia

Pseudostratified Columnar Epithelium function

Single layer of column-shaped (rectangular) cells with oval nuclei Some have cilia at the apical surface If they have goblet cells they will have cilia and vice versa.

Simple Columnar Epithelium

Single Layer of cube-like cells with large, spherical central nuclei.

Simple Cuboidal Epithelium

Figure 4.3a Not a nucleus in every cell because of the cut. Looks like a tiled floor.

Simple Squamous Epithelium

Single layer of flat cells with disc-shaped nuclei Thin layer means it doesn't have very many organelles so it can't do very much

Simple Squamous Epithelium

Passage of materials by passive diffusion and filtration Secretes lubricating substance in serosae (Serosae lines our body cavities)

Simple Squamous Epithelium Functions

Looks like a mixture of ovals and cubes with lots of spherical nuclei. Figure 4.3b

Simple cuboidal epithelium picture

Very high cell content, very low matrix content. Matrix is just integral proteins not a lot of fluid Has specialized contacts specifically cell junctions Polarity Supported by connective tissue. (Does not have its own blood supply, all of its blood comes from capillaries in connective tissue) Avascular and innervated (contains nerves) Can regenerate at a very high rate

Special characteristics of Epithelia

Several layers of columnar cells. Basal cells usually cuboidal Superficial cells are elongated

Stratified Columnar Epithelium

Generally two layers of cube-shaped cells. Fairly rare.

Stratified Cuboidal Epithelium

Contains two or more layers of cells Regenerate from below Major role is protection Are named according to the shape of cells at apical layer

Stratified Epithelia

Many layers of squamous cells Deeper layers fo cells appear cuboidal or columnar Thickest epithelial tissue, is adapted for protection.

Stratified Squamous Epithelium

What layer allows for diffusion and filtration?

Thin layer of Epithelial Tissue

A group of closely associated cells that: Perform related functions Are similar in structure Are comprised of cells and extracellular matrix

Tissues

Her favorite and "special" Basal cells usually cuboidal or columnar Superficial cells are dome-shaped and squamous

Transitional Epithelium

Keratinized: contains the protective protein keratin (surface cells are dead and full of keratin) Non-keratinized: Forms moist lining of body openings (where less protection is needed)

Types of Stratified Squamous Epithelium

glycoproteins found just below the tight junction, act as a weak glue that holds cells together

adhesion belt

cells that persist in connective tissue are

adult stem cells

secretory products are released as fragments(pieces) of the gland cells

apocrine gland

the basal surface of most epithelial tissues is attached to a

basement membrane

pseudostratified (modification of simple epithelium)

columnar

tall and thin, similar to a column, taller thatn they are wide

columnar

mostly composed of cells,covers body surfaces and forms glands,distinct cell surfaces,cell and matrix connections,nonvascular,capable of regeneration

common epithelial tissue characteristics

cells are cube/square shaped, wide as they are tall

cuboidal

disk shaped structures with adhesive glycoproteins that bind cells to one another

desmosomes

consist of a protein called elastin and has the ability to return to its original shape

elastic fibers

glands with no ducts are

endocrine glands

not attached to other cells

free or apical surface

protecting underlying structures,acting as a barrier,permitting the passage of substances,secreting substances,and absorbing substances is

functions of epithelial tissues

similar to one half of a desmosome, attach epithelial cells to the basement membrane

hemidesmosomes

entire cells are shed by the gland and become part of the secretion

holocrine gland

attached to other epithelial cells

lateral surface

products are released, but no actual cellular material is lost

merocrine gland

this epithelium appears to be stratified but is not

pseudostratified columnar epithelium

very fine collagen fibers

reticular fibers

transitional (modification of stratified epithelium)

roughly cuboidal to columnar when not stretched and squamouslike when stretched

single layer of cells, with each cell extending from the basement membrane to the free surface is the

simple epithelium

single layer of cells

simple::: squamous,cuboidal,columnar

cells are flat or scale-like

squamous

consists of more than one layer of cells,only the basal layer attaches the deepest layer to the basement membrane is the

stratified epithelium

more than one layer of cells

stratified::: squamous-nonkeratinized (moist),keratinized,cuboidal(very rare),columnar(very rare)