Histology (complete) Flashcards
What are the steps in prepping a tissue for analyzing
- obtain the tissue
- quickly place in a fixative
- sectioning the sample
what does a fixative do in preparing a tissue
- coagulate cellular protein
- harden gels
- inactivate enzymes
What are the two main types of sectioning for a tissue sample
- longitudinal cuts
2. transverse cuts
What is a longitudinal section
a cut that is made with the long axis of the tissue
What is a transverse section
a cut that is made perpendicular to the long axis of the tissue
What is the name of the most common histological stain
Hemotoxylin and Eosin (H&E)
What color is the nucleus of a cell going to be colored if a Hemotoxylin and Eosin stain is used
Blue
what color is the cytoplasm of a cell going to be if a Hemotoxylin and Eosin stain is used
Red or pink
What color will muscle and collagen be if a Hemotoxylin and eosin stain is used
Pink
What are the 4 types of tissues in the body
- Epithelial
- Connective
- Muscular
- Nervous
Where does epithelial tissue come from (what germ layer)
All Three germ layers
What is epithelial tissue
Closely adhering sheets of cells
Is epithelial tissue vascular
no, it is avascular
is epithelial tissue single layered or does it have multiple layers
it can be single layered or have multiple layers
what are the 4 main features of epithelial cells
- Mostly uninucleate
- Polyhedral
- Polarized
- undergo regular turnover
What does it mean that epithelial cells are polarized
that different sides of the cell are not the same. it has specific sides that do specific things
what are the specific sides of epithelial cells
Apical
Basal
Lateral
What is the apical end of epithilial cells (what does it border)
the apical end of the cell faces outward, away from the basement membrane
what is the basal end of epithelial cells (what does it border)
the basal end of the cell borders, or is up against the basement membrane
Where is the basement membrane usually found
between the epithelial tissue and underlying tissue
Do epithelial cells usually undergo regular turnover
yes
What is the basement membrane
it is an extracellular selective filter between epithelium and connective tissues
what kind of cells is the basement membrane made from
it isn’t made from cells it is extracellular
What are the main components of the basement membrane
- collagen (type 4 and 7)
- proteglycans
- laminin
- entactin
- fibronectin
- underlying reticular fibers
What does the basement membrane control
- cellular growth
- cellular metabolism
- cellular differentiation
What are the three layers of the basement membrane
- lamina lucida
- lamina densa (basal lamina)
- lamina fibroreticularis
What are the two main types of collagen found in the basement membrane
type 4 and 7
What is another name for the lamina densa (middle layer of the basement membrane)
basal lamina
What is the order of the layers of the basement membrane from deepest to most superficial
lamina fibroreticularis
lamina densa (basal lamina)
lamina lucida
Where is epithelial tissue found
- covers body surfaces (inside and out)
- lines internal cavities
- inside of various organs and glands
- lines ducts
What is the main function of epithelial tissues
it is a Barrier
What are the 7 things epithelial tissues can do along with being a barrier
- protect
- absorb
- secrete
- transport
- contract
- filter
- sense
What is an example of epithelial tissue that protects
epidermal epithelium
What is an example of epithelial tissue that absorbs
intestinal epithelium
What is an example of epithelial tissue that secretes
glandular epithelium
What is an example of epithelial tissue that transports
respiratory epithelium
What is an example of epithelial tissue that contracts
myoepithelium
What is an example of epithelial tissue that filters
glomerular epithelium
What is an example of epithelial tissue that senses
neuro-epithelium
What are the three things upon which epithelial nomenclature is based
- cell layers
- cell shape
- surface modifications
What are the three primary cell shapes of epithelial tissues
- squamous
- cuboidal
- columnar
describe squamous shaped cells
short, Flat cells, like a pizza
Describe cuboidal shaped cells
cube shaped cells, like a cube
describe columnar shaped cells
tall skinny cells, like a pringles can
What is transitional epithelium
a special kind of epithelium that is stratified and has umbrella cells. It is found in the urinary system and can expand and recoil
Where is transitional epithelium found
urinary system:
- urinary bladder
- renal pelvis
- ureters
What is the function of transitional epithelium
it can expand and recoil after strecthing
What are umbrella cells and where are they found
they are long flat cells that lie at the most apical end of the transitional epithelium found in the urinary bladder, ureters, and renal pelvis
What are the three layer types of epithelial tissues
- simple
- stratified
- pseudostratified
what are the layers like in a simple epithelial tissue
a single layer of cells, all cells being roughly the same height (all cells attached to the basement membrane)
What are the layers like in stratified epithelial tissue
multiple layers of cells (only the deepest layer of cells are attached to the basement membrane)
what are the layers like in pseudo stratified epithelial tissue
it is one single layer of cells, but not cells are the same height, some are tall, some are short. it looks like it is stratified but it is not. (all cells are attached to the basement membrane)
Where is simple, squamous epithelium found, and what is its function
locations:
- lining of ventral body cavities
- lining of heart and vessels
- some parts of kidney tubules
- inner lining of the cornea
- exchange surfaces of the lungs
Functions:
- reduce friction
- controls vessel permeability
- absorption and secretion
Where is simple cuboidal epithelium found, and what is its function
locations:
- glands
- ducts
- some parts of kidney tubules
- thyroid gland
Functions
- limited protection
- secretion and or absorption
Where is simple columnar epithelium found and what is its function
Locations
- lining of stomach
- lining of gallbladder
- lining of intestines
- lining of uterine tubes
- kidney collecting ducts
functions
- protection
- secretion
- absorption
Where is pseudostratified ciliated columnar epithelium and what is its function
locations
- lining of nasal cavity
- lining of trachea and bronchi
- portions of the male reproductive tract
functions
- protection
- secretion
- move mucus (with cilia)
Where is stratified squamous epithelium and what is its function
locations
1. surface of the skin
2. lining of mouth, throat, esophagus
3, lining of rectum, anus, and vagina
functions
1. physical protection against abrasions, pathogens and chemical attack
Where is stratified cuboidal epithelium and what is its function
locations
1. lining of some ducts (rare)
function 2. protect, secrete, absorb
where is stratified columnar epithelium and what is its function
location 1. small areas of the pharynx and epiglottis 2. anus 3. mammary glands 4. salivary gland ducts 5, urethra
functions
1. protection
What are the three luminal surface modifications for epithelial cells
- microvilli
- stereocilia
- cilia
What is microvili, what is its function, and where is it found
- there are closely spaced finger like extensions
- increase the surface area thus increasing absorption
- it is found in the kidney and intestine
What is stereocilia and where is it found
- it is elongated microvilli
2. it is found in the epididymus, vas deferens, and sensory epithelium of the ear
what is another name for stereocilia
stereovilli
What is cilia, what is its function, and where is it found
- elongated motile extensions of the cell
- it moves fluids and particles
- it is found in the trachea, bronchioles, oviducts and other places
What are the things that make up cilia
microtubules
Can epithelial cells perform secretion
Yes
What two things control epithelial secretions
hormones and nervous activity
What 4 things can epithelial cells produce and secrete
- protein
- mucin
- lipid (steroids)
- Ions and water
What are the key features of epithelial cells that produce and secrete protein
- they have a well developed rough ER
2. they have considerable polarity (granules are located apically)
Where will you see the granules produced by epithelial cells that produce and secrete proteins
at the apical end of the cell
What are the key features of epithelial cells that produce and secrete mucin
- Well develop basal RER
- they have supranuclear golgi
- large clear apical secretory vesicles full of mucin
What is mucin
a proteoglycan that is up to 85% carbohydrate
What are glycosaminoglycans (GAGs)
repeating dissacharides
How many GAGs can be found per mucin monomer
hundreds
Are GAGs/mucin hydrophilic or hydrophobic
hydrophilic
what do GAGs/mucin become when fully hydrated
Mucus
What are the key features of epithelial cells that produce and secrete lipids/steroids
- have well developed smooth ER
2. have free lipids in vaculoles
What are the two types of glands
exocrine and endocrine
What are the three types of secretion by exocrine glands
- merocrine
- holocrine
- apocrine
What is a merocrine secretion from exocrine glands
when a product is delivered by vesicles and exits via exocytosis
What is an example of a gland that uses a merocrine secretion
salivary glands
what is a holocrine secretion
when a product accumulates and then is released when a cell undergoes apoptosis
What is an example of a gland that uses holocrine secretion
sebaceous glands (by hair follicles on the skin)
What is an apocrine secretion
a product accumulates in the apical portion of the cell, then it is released when the plasma membrane fuses around the product, and the apical end of the cell with the products breaks off, then breaks down
what is an example of a gland that uses apocrine secretion
mammary glands
What are the two types of products that can be secreted from exocrine glands
mucus secretions and serous secretions
What is a mucus secretion like
- viscous
- slimy
- glycosylated
Where do we have mucus secretions
- mucus from the goblet cells of the GI tract or trachea
- spithelial cells in the stomach
- sublingual salivary glands
What is a serous secretion like
- watery
2. poorly, or non glycosylated
Where do we have serous secretions
- sweat glands of the skin
- parotid glands
- pancreas
Are exocrine glands unicellular or multicellular
both
What is a unicellular gland
a single cell that both produces and secretes
what is an example of unicellular glands
goblet cells of the respiratory and GI tract
What are multicellular glands
glands composed of more than one cell
What are examples of multicellular glands
- intestinal glands
- sweat glands
- salivary glands
- mammary glands
What does a multicellular gland look like
a bunch of cells that invaginate into the tissue (resembles a mine)
What is the purpose of the invaginations seen in multicellular glands
to increase surface area
What are the two types of cells that can be found in multicellular glands
secretory cells
ductal cells
What is nomenclature of multicellular glands based on
- branched or non-branched DUCT (compound or simple)
- Shape of secretory portion (acinar or tubular)
- complexity of secretory portion (coiled or branched)
what is it called when a multicellular gland has a branched duct
a compound gland
what is it called when a multicellular gland doesn’t have a branched duct
simple
What are the two different shapes of the secretory portion of mutlicellular glands
tubular
acinar
what is the difference in shape between tubular glands and acinar glands
tubular glands are consistently shaped cells in the secretory portion of the gland
acinar glands have the deepest cells (the ones at the end of the gland’s duct) that are larger, this creates a bulge at the bottom of the gland
What are the different complexities of the secretory portion of multicellular glands
coiled or branched
What type of tissue makes up the major structural constituents of the body
connective tissue
Where does connective tissue come from (germ layer)
almost exclusively Mesoderm/mesenchyme
What are the three types of connective tissues
- connective tissue proper
- fluid connective tissue
- supporting connective tissue
What are the two main components of connective tissue
- Support cells
2. Extracellular matrix
what is the function of the support cells of connective tissues
it produces the abundant extracellular matrix
What are the three main components of the extracellular matrix of connective tissue
- connective tissue fibers
- ground substance
- extracellular fluid
What are the two types of fibers found in the extracellular matrix of connective tissues
- collagen
2. elastic fibers
What are the characteristics of collagen fibers
they are flexible with high tensile strength
What is tropocollagen
collagen fibers made up of a triple helix of intertwined polypeptides
What are the amino acids used in collagen
- glycine
- hydroxyproline
- hydroxylysine
- proline
how many different types of collagen are there
at least 19
what does type 1 collagen do
it is fibrous supporting tissue providing mechanical support and tensile strength
What does type 2 collagen do
its found in hyaline cartilage
what does type 3 collagen do
it is known as reticulin, it is delicate and forms a branched meshwork
what does type 4 collagen do
contributes to the mesh of basement membrane
what does type 7 collagen do
forms anchoring fibrils that link to the basement membrane
which two types of collagen are associated with the basement membrane
type 4 and type 7
Where do we find reticulin (type 3 collagen that is narrow and not bundled, forms a network)
in the lymph node and liver
What is the purpose of elastic fibers in the extracellular matrix
they allow a response to stretch and distension
what makes up elastic fibers
an elastin core and fibrin molecules
how do elastic fibers compare to collagen fibers
they are thinner
are branching patterns possible with elastic fibers
yes
What produces elastic fibers
fibroblasts and smooth muscle cells
Where can you find elastic fibers
large arteries
lung
trachea
What is the ground substance of the extracellular matrix
it is the fluid in which the components of the extracellular matrix sit
what are the characteristics of the ground substance
- viscous
- clear
- slippery
- High water content
- Low morphological structure
What are the functions of the ground substance
- diffusion of nutrients and wastes
- lubricant
- barrier
What is the primary component of the ground substance
proteoglycans
What are proteglycans
- large molecules
2. covalently bound GAG molecules with a protein core
What are the types of connective tissue proper
loose connective tissue
dense connective tissue
does dense, or loose connective tissue get subclassified into irregular and regual
dense connective tissue
What are the specialized connective tissues
- adipose
- cartilage
- bone
- blood
- hematopoetic tissue
- lymphatic tissue
what are the components of loose connective tissue
- collagen
- elastic
- watery matrix
- fibroblasts
- macrophages
- mast cells
- fat cells
How does dense connective tissue compare to loose connective tissue
Dense has fewer cells, and more abundant fibers
What is the fynction of connective tissue proper
resistance and protection
What is the dominant cell type in adipose tissue
adipocyte
what are the functions of adipose tissue
cushion
insulate
energy and water storage
endocrine tissue
what are the differences between brown and white adipose tissues
white has one large lipid droplet, brown has a few lipid droplets per cell
white is highly vascularized, but not as much as brown
brown adipocytes are smaller than white adipocytes
