Exam 1 Flashcards
what are the four basic tissue types
epithelial, connective, nervous, muscle
what is the main function of nervous tissue
transmission of mental impulses
was the main function of muscle tissue
provides strong contractions and allows movement
what are the general functions of epithelium
absorption, secretion, provide a barrier
what is absorption
the primary function of epithelium most often in the small intestine, colon and skin
where does epithelium secrete
stomach and endocrine glands
what are specialized functions of epithelium
transport molecules across the epithelium, prevent transport of materials across epithelium, sensory
what is selective permeability
prevention of transport of materials across epithelium
what are the five basic characteristics of epithelium
cells are adjacent to each other. They associate with complete or partial basement membrane. Epithelium is avascular nutrition is obtained via diffusion. it is associated with vascular connective tissue. Cells are held together by cell Junctions
what are the two parts of the complete basement membrane
basal lamina produced by epithelium, and reticular lamina produced by fiber in the connective tissue
what is the partial basement membrane consisted of
the basal lamina layer only
what are the functions of the basement membrane
provides a surface for epithelial cell attachment, molecular filter, limits stretch, directs migration of cells (around healing)
epithelium is avascular how does it obtain nutrition
diffusion
what are the functions of vascular connective tissue
provides nutrition, and is a source of defensive cells (healing after damage)
what does zonula mean
girdle
types of cell Junctions
zonula occludens, Zona adherens, macula adherens, Gap Junctions
what does zonula occludens mean
tight Junction
what are zonula occludents
Junctions that involve the sharing of intrinsic membrane proteins between adjacent cells, these junctions have interacting proteins
what are the two functions of zonula occludens
provides a strong attachment and prevents the passage of materials between cells
what does zonular adherence mean
adhesion belt
what are the two regions of the Zona adherens
cadherins and marginal bands
what are the cadherins of the zonula adherens
linkage proteins between cells
what are the marginal bands of a zonula adherens
microfilaments which attach the cytoskeleton to the cell membrane
what are the two functions of the zonula adherence
strong attachment and to provide cell structure stability
what is a macula adherens
desmosome
what is the function of the macula adherens
provides strong attachment
what are the two functions of Gap Junctions
strong attachment and transport materials between cells (gap size varies, cells can control size of opening)
describe the Gap Junction
six connexins (or proteins) arranged in a cylinder. The size of the openings can be controlled by the cell. A connexon is one complete structure
what is the junctional complex
three Junctions in the following order beginning with the free cell surface: 1, zonula occludens. 2, Zona adherens. 3, macula adherens
note: Hemi desmosomes and focal point contacts are Junctions that hold what
the epithelium to the basement membrane and the connective tissue below
what is a Hemi desmosomes
they hope to connect epithelial cells to the basal lamina. Essentially a half a desmosomes
what is a focal point contact
an integrin (a transmembrane protein of the cell membrane) binds to structural connective tissue glycoproteins and also connects to cytoskeleton
what is bullous pemphigoid
an autoimmune skin condition causing large blistering lesions that burst but do heal
what is the cause of bullous pemphigoid
antibodies bind to particular proteins in Hemi desmosomes
what is pemphigus vulgaris
an autoimmune skin disease causing skin blistering that do not heal easily; excessive bleeding is likely. Can be fatal.
what is the cause of pemphigus vulgaris
antibodies bind to parts of desmosomes
what is cholera
acute bacterial infection of the small intestines
what is the cause of Cholera
toxins disrupt proteins in zonula occludens which permits the loss of water and electrolytes from the connective tissue below the epithelium
what are the types of epithelium
simple epithelium and stratified epithelium
what is simple epithelium
epithelium that is a single cell thick. All cells contact the basement membrane
what is simple squamous
a single layer of flattened cells
what is the function of simple squamous
provides a living filter, a barrier, and secretion
what are example locations of simple squamous epithelium
the lungs(has exchange cells), parietal layer of the Bowman’s capsule in the kidney, serosa (visceral peritoneum) on the outside of organs
what is simple cuboidal epithelium
a single layer of cube-shaped cells the nucleus app occupies much of the cell cytoplasm. Typically looks like a square when sectioned for a slide. these cell types have increased cytoplasm and more organelles.
what are the functions of simple cuboidal epithelium
secrete, absorb, provide a barrier
what are example locations of simple cuboidal epithelium
exocrine ducts, thyroid follicular cells, kidney tubules
what is simple columnar epithelium
a single layer of cells that have height, more cell cytoplasm than simple cuboidal. Typically look rectangular when sectioned for a slide
what are example locations of simple columnar epithelium
the stomach, small intestines, gallbladder, large exocrine ducts
what is ciliated pseudostratified columnar epithelium
also known as respiratory epithelium, this epithelium has three cell types of various heights so it can have the appearance of a stratified epithelium
what are the cell types of respiratory epithelium
goblet cells, ciliated columnar cells, basal cells
what are example locations of ciliated pseudostratified columnar epithelium
trachea, respiratory region of nasal cavity, bronchi
what are goblet cells
tall cells seen and respiratory as well as GI and other bodily locations, they have a modified columnar cell shape
what is the function of goblet cells
produce mucus
what are ciliated columnar cells
columnar cells that contain cilia (which are anchored in the apex of the cell by basal bodies)
what is the function of ciliated columnar cells
to move the mucus over the surface
what are basal cells
short pyramidal shape cell that does not reach the surface
what is the function of basal cells
to be the stem cell for this type of epithelium.
what are the surface specializations for simple epithelium
microvilli, stereocilia, cilia, glycocalyx
what is microvilli
difficult to discern from cilia, these finger-like projections at the apical surface on some epithelial cells are also called brush border or a striated border
what is the function of microvilli
to increase surface area which increases absorption
what are example locations of microvilli
kidney tubules cells, small intestines
what are stereocilia
extremely long microvilli (misnomer). Usually fewer present than in microvilli not related to true cilia. non-motile, quite rigid with actin core.
what is the function of stereocilia
usually to increase surface area
what are example locations of stereocilia
epididymis, cochlear hair cells
what are cilia
difficult to discern from microvilli, they are thin apical hair like extensions of the cytoskeleton.
what is the function of cilia
to move something over a
what are example locations of cilia
trachea, oviduct
what are two important things about cells with cilia
increased mitochondria due to high energy requirements, basal bodies block the free surface so there is no absorption or secretion
what is a glycocalyx
surface layer of glycoproteins and carbohydrates that covers some epithelium, network-like material, produced by epithelial cells
what are the functions of a glycocalyx
protection via extra layer, cell recognition. other possible functions include cell adhesion and holding enzymes
what are example locations of glycocalyx
stomach and small intestines
what is stratified epithelium
epithelium that is two or more cell layers thick named for the shape of its superficial cell, all have a protective function.
what is stratified squamous epithelium
multiple layers of cells that tend to flatten out from basal layer to superficial layer. superficial layer of cells are flat and alive
what is the function of stratified squamous epithelium
protection from abrasion in moist environment
what are example locations of stratified squamous
esophagus, oral cavity, tongue, vagina
what are limitations to stratified squamous
no protection from drying, limited thickness so protection is limited (nutrition through diffusion, superficial cells are alive).
what is keratinized stratified squamous
multiple layers of cells that also tend to flatten from basal layer to superficial layer of cells, superficial cell layer is covered by an added non-living layer of keratin.
what is the function of keratinized stratified squamous
protection in a dry environment
what is a layers of keratinized stratified squamous of the skin
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum.
what is the stratum basale
one to two layers of keratinocytes which are mitotic and closest to the dermis
what is the stratum spinosum
multiple layers of “spiny shaped” keratinocytes that produce keratin. Keratinocytes have cytokeratin tonofilaments that radiates outward from the nuclear region. Thickness of this layer can vary.
what is stratum granulosum
uppermost 2 to 5 layers of flattened living keratinocytes that contain flattened, condensed keratohyalin granules. Keratin production continues, lipids produced as well. Exocytosis of lipid filled lamellar granules will occur from the cells
what is the stratum lucidum
thin layer of recently dead or dying keratinocytes present only in thick skin. This layer is not easy to see, nucleus and organelles are not present, protects against shearing action against high-use areas of hands and feet
what is the stratum corneum
layer of dead cells, keratin and lipids. Thickness of this layer varies
what are the three functions of stratum corneum
prevents water loss, provides a barrier to microbes, protects against abrasion
what do epidermal pegs and dermal papillae do?
contribute strength to keratinized stratified squamous epithelium by increasing surface area for attachment of the epithelium to the connective tissue below
what is the cell cycle length of keratinized stratified squamous epithelium
roughly 28-day life cycle
what are other cells found in keratinized stratified squamous epithelium
keratinocytes, melanocytes, langerhans cells, Merkel cells.
what is a keratinocyte
typical cell type which divides in stratum basale, produces keratin and keratohyalin granules and lipids when in stratum granulosum
what are melanocytes
cells which protect against UV radiation. Found in Stratham basala. Keratinocytes phagocytize the cytoplasmic tips of melanocytes containing melanosomes with melanin
what is skin color greatly influenced by
environment , genetics, number of blood vessels in dermis
how does environment affect skin color
increase UV light exposure will increase melanocyte numbers and increase melanin production
how does genetic influence skin color
placement of melanin, destruction rate of melanin by lysosomes, eumelanin which is darker or pheomelanin which is redder
melanocyte note
melanocyte numbers are about equal in all humans
what are langerhans cells
these antigen presenting cells recognize and process external foreign antigens. They are found in the stratum spinosum. They are an epidermal dendritic cell
what are Merkel cells
epithelial tactile cells which provide touch receptors associated with free nerve endings. They are found in the stratum basale
what is stratified cuboidal epithelium
two layers of cells. Basal layer is typically flattened. Superficial layer of cells is cuboid and shape. uncommon.
what are example locations of stratified cuboidal epithelium
larger ducks and sweat glands and salivary glands
what is the function of stratified cuboidal epithelium
to increase protection and provide a barrier
what are stratified columnar epithelium
two layers of cells with a basal layer flattened to cuboid in shape. Superficial layer is columnar and shape. Very very rare.
what are example locations of stratified columnar epithelium
large ducts in pancreas, parts of the male urethra, conjunctiva of the eye
what are functions of stratified columnar epithelium
to increase protection, provide a barrier, to provide a transition between epithelial types
what is Transitional epithelium
AKA urinary epithelium, includes multiple layers of cells. Multiple functions, extremely specialized.
what are the functions of transitional epithelium
provide protection, to stretch, serve as a barrier
what are the specializations of transitional epithelium
a thin fenestrated basement membrane, large rounded superficial cells, well-developed zonula occludens
what are the specializations of transitional epithelium
a thin fenestrated basement membrane, large rounded superficial cells, well-developed zonula occludens
why is a well-developed Zola occludents important in transitional epithelium
to keep cells attached to each other since they are not tightly attached to the fenestrated basement membrane, and to prevent waste or urine from seeping between epithelial cells
what is an unusual feature of transitional epithelium
some binucleated superficial cells
what is psoriasis vulgaris
patchy skin lesions. accelerated keratinocyte life cycle, one week 4 times faster than the usual 28 days. Cells accumulate in stratum corneum, inflammation in dermal papillae is seen, cyclic and etiology is unknown.
what are freckles
spots with extra pigment, especially in the fair-skinned. An increase in melanin without an increase in melanocyte numbers.
what is vitiligo
patches with black melanocytes. Unknown cause but often associated with systemic diseases such as hypothyroidism, hyperthyroidism, diabetes, Addison’s disease, pernicious anemia, and leprosy.
what are moles
AKA naevi. Discoloration due to a proliferation of melanocytes
what is malignant melanoma
melanocytes that have become mitotically active and invade the dermis. Very invasive and metastatic. Treatment includes surgery and chemotherapy.
what is albinism
skin condition in which melanocytes failed to produce melanin. tyrosinase enzyme is missing from melanocytes. Tyrosinase is a catalyst in the conversion of tyrosine to melanin
