Chapter 2 Flashcards
Where does Histology come from
greek word histos meaning tissues
what is a tissue
a group of similar cells and extracellular products that perform a common function
what are the four types of tissue in the body
- Epithelial tissue
- connective tissue
- muscle tissue
- nervous tissue
extracellular matrix
a substance produced by the cells of a specific tissue and can contain protein, salts, H2O, and dissolved macromolecules
what do tissues vary in
- structure, function, and content in their ECM
what are the characteristics of epitheial tissue
Avascularity
Polarity
Attachments
Cellularity
High regeneration capacity
Innervation
epithelial tissue
- lines every body surface and all body cavities (if there is a opening or cavity will have epithelial tissue)
- majority of glands are derived from epithelial tissue
does epithelial tiessue have an extracellular matrix
no there is little not ECM
attachment as a characteristic of epithelial tissue
- basal surface of the cell is attached to a thin basement membrane
avascularity as a charcateristic of epithelial tissue
all epithelial tissues lack blood vessels
- receive their nutrients by diffusion from underlying connective tissues
basement membrane
an acellular structure produced by both epithelial and underlying connective tissue cells
- provides support and anchoring of epithelial tissue
- acts as a barrier to regulate passage of molecules
polarity as a characteristic of epithelial tissue
have an apical surface and basal surface where they attach to underlying cells
cellularity as a characteristic of epithelial tissue
composed almost entirely of cells with little extracellular matrix
- cells are tightly packed together and bound together by intercellular junctions
do all cells have a basal or apical surface
no if they are not simple epithelial tissue some cells may only have a basal surface, some may not have either
innervation as a characteristic of epithelial tissue
richly innervated to detect changes in environment at a body or organ region
high regeneration capacity as a characteristic of epithelial tissue
- apical surface exposed to environment epithelila cells die frequently
- must be able to regenerate as quickly as they are lost
what are the functions of epithelial tissue
physical protection
selective permeability
secretion
sensation
physical protection as a function of epithelial tissue
keep systems protected from dehydration , abrasion, physical, chemical, or biological damage
selective permeability as a function of epithelial tissue
regualte the passage of certain molecules in and out certain region of the body
secretion as a function of epithelial tissue
some epithelial cells called exocrine cells produce secretions such as sweat or oil
sensation as a function of epithelial tissue
possess nerve endings that can detect light, taste, sound, smell, and hearing
classifications of epithelia by layers
- simple epithelia
- stratified epithelia
- pseudostratified epithelia
simple epithelia
single layer of cells with all cells having an apical surface and attached to the basement membrane
stratified epithelium
two or more layers of cells, not all have apical surface nor do all cells attach to basement membrane
pseudostratified epithelium
cell nuclei give the appearance of a multilayered epithelium but not all cells reach the apical surface
types of cell shape for epithelia classification
- squamous
- cuboidal
- columnar
squamous cell shape
flat, wide, and somewhat irregular in shape
cuboidal cell shape
about the same size on all sides, nucleus centrally located
columnar cell shape
taller than they are wide, nucleus is oval and located in the basal region of the cell
types of simple epithelium
- simple squamous
- simple cuboidal
- simple columnar, non ciliated
- simple columnar, ciliated
types of stratified epithelium
- stratified squamous, keratinized
- stratified squamous, nonkeratinized
- stratified cuboidal
- stratified columnar
other types of epithelium
- pseudostratified columnar (always columnar)
- transitional (cells change shape)
glands
individual cells or multicellular organ performing a secretory function
what is the funtion of glands
produce mucin, hormones, enzymes and waste products
what are the two categories of glands
exocrine and endocrine glands
endocrine glands
do not posses ducts and secrete directly into the interstitial fluid or the bloodstream
exocrine glands
posses ducts and their cells secrete their products into the ducts
connective tissue
most diverse, abundant, widely distributed and structurally varies of all 4 tissue types
what does connective tissue act as
“glue” (ligaments and tensons) and “filler” (adipose tissue)
what are the characteristics of connective tissue
Cells
protein fibers
ground substance
cells as a characteristic of CT
different cells for different types of connective tissue
protein fibers as a characteristic of CT
strands that are used to provide support and stability
ground substance as a characteristic of CT
mixture of proteins and carbohydrates w/ variable amounts of salts and water
what would tissue be like without ground substance
would be inflexible and dense
what is the Extracellular matrix made out of
the protein fibers and the ground substance
functions of connective tissue
Storage
immune protection
transport
physical protection
binding of structures
support and structural framework
how does connective tissue develop
- arises from the mesoderm (middle layer of an embryo)
- with two types of embryonic connective tissue
what are the two embryonic connective tissue
mesenchyme and mucous
mesenchyme
the source of all adult connective tissue
what is another word for mesenchyme cells
StEM cells
mucous
found in the umbilical cord
different classifications of connective tissue
- connective tissue proper
- supportive connective tissue
- fluid connective tissue
what are the groups of cells in connective tissue
resident cells and wandering cells
resident cells function and appearance
appearance is stationary
functions to maintain and repair extracellular matrix and store materialwa
what are examples of resident cells
fibroblasts, fixed macrophages, and mesenchymal cells
what are wandering cells appearance and function
appearance is moving through connective tissue
functions to repair damaged extracellular matrix and active in immune response
what are examples of wandering cells
mast cells, plasma cells, free macrophages, and other leukocytes
what are the types of fibers of connective tissue proper
collagen fibers
elastic fibers
reticular fibers
collagen fibers
long unbranching strong flexible and resistant to stretching
what percent of of protein fibers in the human body are collagen fibers
about 25%
elastic fibers
thinner than collagen, stretch easily, branch and rejoin
what do elastic fibers allow for
structures like blood vessels to stretch and relax
reticular fibers
thinner than collagen fibers, forms branching woven framework
where is reticular fibers found in
the stroma of organs with abundant spaces
ground substance
combination of proteins and carbs, with a gelatinous texture, this combined with the fibers allow for tissue stability
what does differing contents of the ground substance result in
will result in the type of connective tissue
if more gelatinous/semifluid will be more like adipose tissue if less then will be more like bone
what are the two categories of connective tissue
loose connective tissue and dense connective tissue
what are the characteristics of loose connective tissue
they have fewer fibers and more ground substance
what is the function of loose connective tissue
serves as the body’s packing material with spaces around organs
tyes of loose connective tissue
areolar connective tissue
adipose connective tissue
reticular connective tissue
what is areolar connective tissue
contains fibroblasts, lesser amounts of collagen and elastic fibers, with viscous ground substance
where is areolar connective tissue located
located around nerves, subcutaneous layer, and vessels
describe the look of areolar connective tissue
collagen and elastic fibers are visibly present with fibroblasts
what is adipose connective tissue
the connective tissue of adipose tissue that is composed of adipocytesweh
where is adipose connective tissue found
in the subcutaneous layer surrounding kidneys and other selected organs
descirbe the structure of adipose connective tissue
roundish shaped adipocytes with blood vessels
what is reticular connective tissue
connective tissue found in stroma of spleen and liver and other lymphatic organs consisting of a meshwork of reticular fibers, fibroblasts and leukocytes
what is dense connective tissue
has more fibers than loose and less ground substance, protein fibers are densly packed together (mostly collagen)
what are the types of dense connective tissue
- dense regular connective tissue
- dense irregular connective tissue
- and elastic connective tissue
dense regular connective tissue
collagen strands densly packed together side by side parellel to the direction of force/stress
what is the function of dense regular connective tissue
provides great strength and flexibility primary in a single direction
what are examples of dense regular connective tissue
tendons and ligament
dense irregular connective tissue
densly packed collagen that is interwoven, irregularly clumped and projects in all directions
where is dense irregular connective tissue found
in the dermis (the inner most layer of skin) and the capsule of organs
elastic connective tissue
elastic and collagen fibers arranged irregularly
what is the function of elastic connective tissue
provides framework and supports organs
where can elastic connective tissue be foun
the walls of large arteries
supporting connective tissue
another type of connective tissue
what are the types of supportive connective tissue
cartalige and bones
what is cartilage
firm gel-like extracellular matrix composed of protein and ground substance that help to support and withstand deformation
what are the cells of cartilage
chondrocytes which are found in the spaces called lacunae
what are the types of cartilage
- hyline cartilage
- fibrocartilage
- elastic cartilage
hyaline cartilage
slippery and smooth tissue that is located on the distal and proximal ends of bones and in between ribs to help absorb force
what is the most common type of cartilage
hyaline cartilage but it also the most weakest
what does hyaline cartialage look like
lots of ECM with chondrocytes and the lacunae floating around
fibrocartilage
densely woven collagen fibers contribute to the durability, more collagen, less ground substance
where is fibrocartilage mostly found in
the vertebral column (between discs) and between the hip bones
elastic cartilage
has abundant elastic fibers with the chondrocytes
what is the difference between elastic CT proper and elastic cartialge
Elastic CT proper has fibroblasts instead of the chondrocytes
what are the cells of bones called
cells are called osteocytes
what is the ECM of bones
mixture of collagen and calcium salts
what does the ECM of bones do
provides flexibility from organic components and compressional strength
what is the structure of a calcified matrix called in a bone
an osteon
spongy bones
- the inner part of bones
- helps to lessen the weight of a bone but still support
compact bone
surrounds spongy bone and is tough and compact
fluid connective tissue
refers to the blood
what are the components of fluid connective tissue
plasma, erythrocytes, leukocytes, and platelets
what is plasma
watery ground substance containing protein fibers
erythrocytes
red blood cells
leukocytes
white blood cells
platelets
fragments of blood cells involved in blood clotting
what is the fluid distribution in the body
TBW = 60%
1/3 of TBW is ECF and 2/3 of TBW is ICF
7% of ECF is Plasma and 28% is ISF
of the ECF what is plasma considered
intravascular
of the ECF what is ISF considered
extravascular
what is a part of ISF
- Cerebral spinal fluid
- fluid in the eyes and ears
- serous fluid
- synovial fluid
what happens to the tissues when they age
they change in form, size, and number
metaplasia
epithelia lining the respiratory airways of people who smoke change from pseudostratified ciliated to stratified squamous
hypertrophy
an increase in the size of existing cells
hyperplasia
an increase in the number of cells in the tissue
neoplasia
out-of-control growth which results in the formation of a tumor
atrophy
shrinkage of tissue by cell size or number
what are the types of body membranes
epithelial membranes and CT membranes
what are the types of epithelial membranes
Cutaneous, mucous, and serous
what are the types of CT membranes
synovial
cutaneous membranes
- epidermis of skin
- stratified squamous keratinized epithelium
mucous membranes
- epithelial cells resting on a CT membrane
- lines all body cavities that open to body exterior
- secretes mucous to prevent cavity from drying out or trapping particles
serous membrane
simple squamous epithelium
synovial membrane
- lines the cavities of freely moving parts that are not open to exterior
- loose areolar CT, elastic fibers, fat
- has synovial fluid which lubricates and nourishes cartilage
