Lab 1: Histology & Integumentary System (Bolded Terms) Flashcards
Histology
The study of tissues (a group of similarly structured cells that work together to accomplish a specific function).
4 Major Tissue Categories
epithelial, connective, muscle, and nervous
Epithelial tissue does what?
lines and covers organs (as well as their internal passageways), create boundaries between different environments, and forms glands
Epithelial tissue is made up of…
sheets of cells, with the cells in a given sheet tightly joined together via strong intercellular connections formed by tight junctions and desmosomes
Epithelia functions:
filtration, absorption, protection, secretion, excretion, and sensory reception
free or apical surface
an epithelium always has one surface where the cells are exposed to either the external environment or to an internal passageway or cavity
basal lamina functions…
as a filter at the base of the epithelium and can form a scaffold for wound repair
basal lamina
located between the epithelium and its connective tissue layer, is not cellular and is formed by glycoprotein secretions from the epithelial cells plus collagen fibers
simple epithelia
has only one layer
simple epithelia functions:
diffusion, absorption, filtration, and secretion
To protect epithelia at the free surface, cells called _______ secrete mucus that coats the cells
goblet cells
stratified epithelia are composed of
more than one layer
stratified epithelia can be found in…
areas exposed to abrasion and friction, such as the body surface and upper digestive tract
stratified epithelia functions:
protection
Name the different types of epithelia cells
squamous-shaped cell, cuboidal-shaped cell, and columnar-shaped cell
squamous-shaped cell
its nucleus is flattened, “squished”
cuboidal-shaped cell
its nucleus is round
columnar-shaped cell
its nucleus is oblong-shaped, but you will find the nuclei of this cell to be round as well
______ epithelia regenerate from basal cells that divide and then move out to replace older cells near the apical border
Stratified
Most common stratified epithelium
stratified squamous
Supported by connective tissue
the cells are attached to and supported by an adhesive basement membrane, which is an amorphous material secreted partly by the epithelial cells (basal lamina) and connective tissue cells (reticular lamina) that lie adjacent to each other w/ the reticular lamina deeper to the basal lamina
Avascularity
lining epithelial tissues have no blood supply of their own (avascular), but instead depend on diffusion of nutrients from the underlying connective tissue
Regeneration
If well nourished, epithelial cells can easily regenerate themselves
There are several characteristics that distinguish epithelial tissues from other tissue types:
- Regeneration 2. Polarity 3. Cellularity and specialized contacts 4. Supported by connective tissue 5. Avascularity 6. Innervated
Polarity
The membranes always have one free surface (apical surface), and typically that surface is significantly different from the basal surface
Cellularity and specialized contacts
cells fit closely together to form membranes (sheets of cells) and are bound together by specialized junctions
Innervated
meaning supplied by nerve fibers for regulation
epithelial cells or aka
basal lamina
connective tissue cells or aka
reticular lamina
basal surface
the surface opposite the apical surface, and also describes the deepest cell layer in epithelia with multiple cell layers.
avascular definition
having few or no blood vessels
thin and often permeable, flattened cells found where filtration, or the exchange of substances by rapid diffusion, is a priority
simple squamous epithelium
Description of simple squamous epithelium:
single layer of flattened cells w/ disc-shaped central nuclei and sparse cytoplasm; the simplest of the epithelia
Function of simple squamous epithelium:
allows passage of materials by diffusion and filtration in sites where protection is not important; secretes lubricating substances in serosae (tissue lining of a body cavity or outer lining of an organ)
Location of simple squamous epithelium:
kidney glomeruli; air sacs of lungs; lining of heart, blood vessels and lymphatic vessels; lining of ventral body cavity
consists of a single layer of cells as tall as they are wide and a spherical nucleus
Simple cuboidal epithelium
Description of simple cuboidal epithelium
single layer of cube-like cells w/ large, spherical central nuclei
Location of simple cuboidal epithelium
kidney tubules; ducts and secretory portions of small glands; ovary surface
Function of simple cuboidal epithelium:
secretion and absorption
Two simple squamous epithelia in the body have special names that reflect their location which are…
Endothelium and Mesothelium
single layer of tall, closely packed cells lining most of the digestive tract, the uterine tubes and the renal collecting ducts
simple columnar epithelium
Endothelium
provides a slick, friction-reducing lining in hollow organs that transmit body fluids (e.g., lymph, blood)
Mesothelium
the epithelium found in serous membranes lining the ventral body cavity and covering its organs
Description of stratified squamous epithelium:
thick membrane composed of several layers; basal cells are cuboidal or columnar and metabolically active; surface cells are squamous; in the keratinized type, the surface cells are active in mitosis and produce the cells of the more superficial layers
Description of simple columnar epithelium:
Single layer of tall cells with round to oval nuclei; some cells bear cilia; layer may contain mucus-secreting unicellular glands (goblet cells)
Function of simple columnar epithelium:
Absorption; secretion of mucus, enzymes and other substances; ciliated type propels mucus (or reproductive cells) by ciliary action
Location of simple columnar epithelium:
Nonciliated type lines most of the digestive tract (stomach to anal canal), gallbladder and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes and some regions of the uterus
forms the superficial region of the skin, called the epidermis
stratified squamous epithelium
Function of stratified squamous epithelium:
protects underlying tissues in areas subjected to abrasion
Location of stratified squamous epithelium:
nonkeratinized type forms the moist linings of the esophagus, mouth and vagina; keratinized variety forms the epidermis of the skin, a dry membrane
a protein that helps form hair, nails and your skin’s outer layer (epidermis)
keratin
Function of pseudostratified ciliated columnar epithelium:
lines the nasal cavity, trachea, bronchi, and parts of the male reproductive tract
pseudostratified ciliated columnar epithelium
Location of pseudostratified ciliated columnar epithelium:
the outermost layer of skin on your body
epidermis
the process in which the outermost cells of the epidermis in vertebrates are replaced by cells containing keratin
keratinized
Description of pseudostratified ciliated columnar epithelium:
Description of transitional epithelium:
transitional epithelium
Function of transitional epithelium:
Location of transitional epithelium:
