Chapter 1 Epithelium and Epithelial Glands Flashcards
What are the four basic types of tissues?
- epithelial
- connective
- nervous
- muscle
What are three general functions of epithelium?
- absorption
- secretion
- provide a barrier
What are three specialized functions fo epithelium?
- transport molecules across epi
- prevent transport of materials across epi = selective permeability
- sensory
What are the 5 basic characteristics epithelium tend to share?
- Cells are adjacent to each other
- associated with a complete or partial basement membrane
- Epithelium is avascular
- associated with vascular connective tissue
- cells are help together by cell junctions
Basement membranes -
- Complete basement membranes have # parts, List each and what they are produced by
- Partial basement membranes have only ___
- what are 4 functions of a basement membrane?
- 2, basal lamina - epithelium, reticular lamina - fibroblasts in the CT
- basal lamina, ex lungs
- provides a surface for epithelial cell attachment, molecular filter (limited), limits stretch, directs migration of cells
Because epithelium is avascular how to cells obtain nutrition?
diffusion
What are 2 functions of CT?
- privides nutrition
2. source of defensive cells
What are four types of cell junctions?
- Zonula occludens
- Zonula Adherens
- Macula Adherens
- Gap Junctions
Zonula Occludens -
1. = ___
2 these junctions involve the sharing of intrinsic membrane proteins ___ adjacent cells
3. List 2 functions
- tight junction
- between
- provides stong attachment and prevents the passage of materials b/w cells
Zonula Adherens -
- =____
- these are regions consisting of (2)
- what are cadherins?
- marginal bands (microfiliments) which attach the ___ to the ___ at these areas
- List two functions
- adhesion belt
- cadherins and marginal bands
- linkage proteins b/w cells
- cytoskeleton to the cell membrane
- strong attachment and provide cell structural stability
Macula Adherens -
- =___
- Function?
- desmosome
2. provides strong attachment
Gap Junctions -
- # ___ (proteins) arranged in a cylinder
- the ___ of the openings can be controlled by the cell
- connexon = ___
- list two functions
- 6 connexins
- size
- 1 complete structure
- strong attachment and transport materials b/w cells
What are the three parts of the junctional complex starting from the free cell?
- zonula occludens
- zonula adherens
- macula adherens
What are the two junctions that hold the epithelium to the basement membrane and the CT below?
hemidesmosomes and focal point contacts
What are hemidesmosomes?
help to connect epithelial cells to the basal lamina; essentially half a desmosome
Explain focal point contacts
integrin (a transmembrane protein of the cell membrane) binds to structural CT glycoproteins and also connects to cytoskeleton
- ___ is an autoimmune skin disease causing large blistering lesions that burst, but DO heal
- Cause?
- Bullous Pemphigoid
2. antibodies bind to come proteins in hemidesmosomes
- ___ is and autoimmune skin disease causing skin blistering that DO NOT heal easily; excessive bleeding likely, can be fatal
- Cause?
- Pemphigus Vulgaris
2. antibodies bind to some parts of desmosomes
- ___ is and acute bacterial infection of the small intestines
- Cause?
- Cholera
- toxins disrupt proteins in zonula occludens which permits the loss of water and electrolyes from the CT below the epithelium
What are the four types of simple epithelium and what is it?
- simple cuboidal
- simple columnar
- ciliated pseudostratified columnar epithelium (respiratory epithelium)
It is epithelium that is a single cell thick
Simple Squamous -
- List three example locations
- what is it?
- what are two functions
- lung, parietal layer of the Bowman’s capsule in the kidney, and serosa on the outside of organs
- a single layer of flattened cells
- living filter and provide a barrier
Simple Cuboidal -
- Three example locations
- What is it?
- Three functions
- exocrine ducts, thryroid follicular cells, and kidney tubules
- a single layer of cube chaped cells; nucleus occupies much of the cell cytoplasm; typically looks liek a square when sectioned for a slide
- absorption, secretion and provide a barrier
Simple Columnar -
- four examples
- what is it?
- three functions
- stomach, small intestines, gallbladder, larger exocrine ducts
- a single layer of cells that have height; more cell cytoplasm than simple cuboidal; typically look rectangular when sectioned for a slide
- absorption, secretion, and provide a barrier
Respiratory Epithelium -
- three example locations
- has # types of various hts so it can have the appearance of ___
- What are the three types?
- trachea, respiratory region of nasal cavity, bronchi
- 3, stratified epithelium
- Goblet, ciliated columnar and basal cells
Goblet Cells -
- What is it?
- function?
- modified columnar cell
2. produce mucus
Ciliated Columnar Cells -
- Columnar cells that conatin ___
- Cilia are anchored in the apex of the cell by ___
- function?
- cilia
- basal bodies
- move mucus over the surface
Basal Cells -
- ___ shaped cells that DO NOT reach the surface
- function?
- short pyramidal
2. to be the stem cell for this type of epithelium (divide and change into another cell type)
- What are finger like projections at the apical surface on some epithelial cells?
- also called?
- function?
- two example locations
- microvilli
- brush border or a striated border
- increase surface area so as to increase absorption
- kidney tubule cells, small intestines
- extremely long microvillie; usually fewer present than microvilli; not related to true cilia
- non ___ and quite rigid with ___ core
- Function?
- two example locations
- stereocilia
- motile, actin
- usually to increase surface area
- epididymis, cochlear hair cells
- thin apical hair like extensions of the cytoskeleton
- function?
- Cells have many ___
- basal bodies block the free surface so there is NO ___ or ____
- two example locations
- cilia
- move something over a surface
- mitochondria
- absorption or secretion
- trachea, fallopian tube (oviduct)
- Surface layer of glycoproteins and carbohydrates that covers some epithelium
- produced by ___
- two functions
- two example locations
- glycocalyx
- epithelial cells
- protection and cell recognition (other possible functions: cell adhesion and hold enzymes
- stomach and small intestines
Stratified Epithelium -
- ___ thick
- named for ?
- all have a ___ function
- two or more cell layers
- shape of its superficial cells
- protective
What are the five types of stratified epithelium?
stratified squamous and keratinized stratified squamous, stratified cuboidal, stratified columnar, transitional (urinary)
Stratified Squamous -
- located (4)
- what is it?
- function
- problems or limitations (2)
- esophagus, oral cavity, tongue, vagina
- multiple layers of cells that tend to flatten out from basal layer to superficial layer; superficial layer of cells are flat and alive
- protection from abrasion/friction
- no protection from drying, limited thickness so protection is limited
Keratinized Stratified Squamous -
- location (1)
- What is it?
- function
- What are the 5 layers in the epithelium of the skin?
- skin
- 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 nonliving layer of keratin
- protection in a dry environment
- stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum
Stratum Basale -
- AKA ___
- ___ layers of ___ which are?
- germinativum
2. 1-2, keratinocytes, mitotic and closest to the dermis
Stratum spinosum -
- multiple layers of “___” keratinocytes that produce (2)
- keratinocytes have ___ that radiate outward from the nuclear region
- thickness?
- spiny shaped, lipids and keratohyaline vacuoles
- cytokeratin tonofilaments
- thickness of this layer can vary
Stratum granulosum -
- uppermost ___ layers of flattened living keratinocytes that contain ___
- ____ will occur from these cells
- 2-5, flattened condensed keratohyaline granules
2. exocytosis of lipid filled lamellar granules
Stratum lucidum -
- thin layer of recently dead or dying keratinocytes present only in ___
- this layer is ___
- (2) are not present
- thick skin
- not easy to see
- nucleus and organelles
Stratum corneum -
- layer of (3)
- thickness?
- list three functions
- dead cells, keratin and lipids
- varies
- prevents water loss, provides a barrier to microbes, protects against abrasion
Stratified Epithelium -
- (2) contribute ___ to this epithelium by ?
- Cells have a ___ life cycle
- epidermal pegs (rete ridges), strength, increasing surface area for attachment of the epithelium to the CT below
- 28 day
What are three other types of cells?
- Melanocytes
- Langerhans cells
- merkel cells
Melanocytes -
- protect against ___
- layer found in ___
- how to the function?
- Skin color is greatly influenced by (3)
- melanocyte numbers in humans?
- UV radiation
- stratum basale
- keratinocytes phagocytize the cytoplasmic tips of the melanocytes containing the melanosomes with the melanin
- Environmental influences, genetics, and number of blood vessels in dermis
- about equal in all humans
Examples/explain -
- Environmental influences
- genetics
- increased UV light exposure will increase melanocyte numbers and increase melanin
- eumelanin (darker) or pheomelanin (reddish), placement of melanin, destruction rate of melanin by lysosomes
Langerhans Cells -
- What do they do?
- ___ cells
- layer found in ___
- recognize and process external foreign antigens
- antigen presenting cells (APC)
- stratum spinosum
Merkel Cells -
- AKA ____
- provide ___
- layer found in ___
- associated with ____
- epithelial tactile cells
- touch receptors
- stratum basale
- free nerve endings
Clinical point of interest -
- melanocyte numbers ___ when exposed to UV light repeatedly
- Langerhans cells ___ with repeated UV exposure
- increase
2. decrease
Stratified Cuboidal -
- location (2)
- # layers of cells
- basal layer is typically ___, superficial layer of cells is ___ in shape, common or no?
- 2 functions
- larger ducts in sweat glands and salivary glands
- 2
- flattened, cuboid, not common
- to increase protection and provide a barrier
Stratified Columnar -
- location (3)
- # layers of cells
- basal layer is ___ in shape, superficial layer is ___ in shape, common or no?
- List three functions
- Commonly found epithelium type?
- large ducts in pancreas, parts of the male urethra, conjunctiva of the eye
- 2
- flattened to cuboid, columnar, very rare
- to increase protection, provide a transition b/w epithelial types and provide a barrier
- NOT a commonly found epithelium type
Transitional -
- AKA (2)
- locations (1)
- ___ layer(s) of cells
- list three functions
- urinary or urothelium
- most of urinary tract
- multiple
- provide protection, stretch, barrier
Transitional -
- List three specializations
- We need this due to?
- Prevents?
- -thin, fenestrated basement membrane
- large, rounded superficial cells
- well developed zonula occludens
- fenestrated basement membrane
- wastes/urine from seeping b/w epi cells
Transitional -
- Unusual Superficial Cell feature?
- Cells obtain more oxygen because (2)
- some binucleate superficial cells
2. fenestrated basement membrane, when stretched the diffusion distance is decreased
Psoriasis vulgaris -
- what is it?
- ___ keratinocyte life cycle (___)
- cell accumulate in ___
- ____ in dermal papillae
- cyclic and etiology?
- patchy skin lesions
- accelerated, 1 week
- stratum corneum
- inflammation
- unknown
Freckles -
- spots with extra ___; especially in ___
- and increase in ___ w/o an increase in ___
- tend to fade in ___ and darken with ___
- pigment, fair skinned
- melanin, melanocyte numbers
- winter, sun exposure
Vitiligo -
- patches which lack ___
- unknown cause but often associated with ___
- such as?
- melanocytes
- systemic diseases
- hypothyroidism, hyperthyroidism, diabetes, Addison’s disease, pernicious anemia, leprosy
Moles -
1. discolorations due to ___
a proliferation of melanocytes
Malignant Melanoma -
- melanocytes become ___ and invade ___
- very ___ and ___
- treatment
- mitotically active, dermis
- invasive and metastatic
- surgery and chemotherapy
Albinism -
- Cause?
- MC form?
- melanocytes fail to produce melanin
2. tyrosinase (enzyme) is missing from melanocytes, tyrosinase is a catalyst in the conversion of tyrosine to melanin