1 - Cells & tissues Flashcards
levels of structural organization
chemical, cellular, tissue, organ, organ system, organismal
cell definition
structural and functional unit of life
cell diversity
over 200 types of cells that differ in shape, size and funciton
generalized cell - common structures and functions of human cells
plasma membrane, cytoplasm, nucleus
histology definition
study of tissues
tissues are
groups of cells similar in structure that perform common or related function
nervous tissue is responsible for?
control, regulation through internal communication
types of muscle tissue
skeletal, cardiac and smooth
connective tissues are responsible for?
Supporting, protecting and binding other tissues together
four basic tissue types
epithelial, connective, muscle and nervous tissue
epithelial tissue definition
a sheet of cells that lines the body’s surface and or lines a body cavity
the covering and lining of the epithelium creates?
boundaries
what epithelium creates secretion
granular epithelium
six epithelial functions
protection, absorption, filtration, excretion, secretion and sensory reception
what is the basal lamina
noncellular, underlying supportive sheet of primarily glycoproteins
two function of basal lamina?
filter and scaffold
how is epithelial tissue nourished?
through diffusion from connective tissues
what is an important feature of cancerous epithelial cells?
they fail to respect the boundary imposed by the basement membrane
how are epithelial cells classified?
by cell shape and layer
what are the cell shapes?
squamous, cuboidal and columnar
what are the cell layers?
simple epithelia and stratified epithelia
simple epithelia characteristics
single layer of cells
stratified epithelia characteristics
2 or more layers of cells
in stratified epithelia, how is it classified?
by cell shape in apical layer
endothelium
lining of the blood vessels and heart
mesothelium
epithelium of serous membranes in ventral body cavity
major role of stratified epithelial tissues
protection
stratified epithelial tissues characteristics and function
two or more cell layers, regeneration from below from basal cell and migrate up. Protection is major function
endocrine glands
release product (hormones) directly into blood - ductless
exocrine glands
release products into ducts
unicellular exocrine glands
multicellular exocrine glands
4 types of simple epithelia
simple squamous, cuboidal, columnar and pseudo stratified columnar epithelium
simple squamous epithelium function
allows for diffusion and filtration where protect is to important - secretes lubricating substances in serosae
serosae
Serous membrane - outer lining of organs and body cavities of the abdomen and chest, including the stomach
simple cuboidal epithelium function
secretion and absorption
simple columnar epithelium function (non ciliated)
absorption, secretion of mucus, enzymes and other substances
simple columnar epithelium function (ciliated)
propels mucus by ciliary action
stratified squamous epithelium function
protects underlying tissues in areas subjected to abrasion
types of cell shapes in stratified squamous epithelium
free surface squamous, deeper layer cuboidal or columnar
What is the most wide spread stratified epithelia?
stratified squamous epithelium
granular epithelium
one or more cells that makes and secretes an aqueous fluid (secretion)
what are glandular epithelia classified by?
site of product release (endocrine or exocrine) and relative number of cells forming the gland
all endocrine glands are?
multicellular
unicellular exocrine glands definition
one cell, no ducts and is usually just a goblet cell
multicellular exocrine glands
epithelium derived duct and secretory cells - surrounded by supportive connective tissue to deliver blood vessels and nerves
goblet cell consists of what organelles?
microvilli, Golgi apparatus, rough ER, nucleus, secretory vesicles containing mucin
classification of multicellular glands consist of?
structure and type of secretion
structures of multicellular glands
simple (unbranched duct) or compound (branched)
types of secretion for multicellular glands
merocrine, holocrine, apocrine
merocrine
most common, secretes products by exocytosis as produced
merocrine gland examples
pancreas, salivary glands
holocrine
accumulate products within then ruptures
holocrine gland examples
sebaceous glands only
apocrine
accumulates products within then apex pinches off
the apocrine causes controversy because?
it might not exist in the body
is mammary gland apocrine or merocrine?
apocrine
5 types of connective tissue
mesenchyme, CT proper, cartilage, bone and blood
main functions of CT
binding/support, protection, insulation, storage and transportation
what are the three structural elements of CT
ground substance, fibres, cells
what is ground substance in CT
interstitial fluid, cell adhesion proteins and proteoglycans
the ground substance acts as a what?
molecular sieve for substances to travel between blood capillaries and cells
ground substance allows the CT to ___ to the matrix?
attach
what are some of the adhesion proteins that help cells attach to the CT elements?
fibronectin and laminin
what are proteoglycans?
provides hydration and swelling pressure to the tissue for withstanding compressional forces
types of fibres in CT
collagen, elastic and reticular
collagen fibers
high tensile strength
elastic fibers
allows for stretching and recoil
what is the structure of elastin?
coiled
reticular fibers
thin collagenous protein, fine network to support blood vessels and soft tissues
CT is ___ cells surrounded by ____ (depending on tissue type)
living, matrix
blasts (cell)
actively dividing/synthesizing cells during growth and repair
cytes (cell)
primarily provide a level of maintenance
three kinds of loose CT
areolar, adipose, reticular
areolar CT function
wraps and cushions organs, important for inflammation, holds and conveys tissue fluid
adipose CT function
provides reserve food fuel, insulates, supports and protects organs
reticular CT function
forms soft internal skeleton (stroma) that supports other cells, like WBT, mast cell and macrophages
three types of dense CT
dense regular, dense irregular, elastic
dense regular CT function
attaches muscle to bone and/or muscles, bone to bone, withstands great stress when force is in one direction
tendons attach what to what?
muscle to bone
ligaments attach what to what?
bone to bone
aponeuroses attach what to what?
muscle to muscle
dense irregular CT function
withstands tension exerted in many directions and provides structural strength
elastic CT function
allows tissue to recoil after stressing, maintains flow of blood through arteries and helps in passive recoil of the lungs after inspiration
what is the major cell type in dense regular and irregular CT?
fibroblast
dense regular CT location
tendons, most ligaments and aponeuroses
location of dense irregular CT
on the fibrous capsules of organs and of joints, dermis and submucosa of digestive tract
location of elastic CT
walls of large arteries, within certain ligaments on vertebral column and walls of bronchial tubes
what is cartilage made up of?
collagen fibres and a bit of elastic fibres & made up of up to 80% water
What does cartilage ground substance contain?
GAGs, chondroitin sulfate, hyaluronic acid and chondronectin
how would you describe cartilage?
tough but flexible
what are the three types of cartilage?
hyaline cartilage, elastic cartilage, fibrocartilage
types of bone cells
osteoblasts, osteocytes, osteoclasts
osteoblast defintion
bone producing cell, matures into osteocyte
osteocytes
mature bone cell
where are osteocytes located?
space in the bone matrix called lacunae
osteoclasts function
degrade bone to initiate normal bone remodelling and mediate bone loss in pathologic conditions
How do osteoclasts mediate bone loss by pathologic conditions?
by increasing their resorptive activity
blood function
transport respiratory gases. nutrients, wastes and other substances
why is blood classified as connective tissue?
it consists of cells surrounded by a non living fluid matrix
what is the nonliving fluid matrix in blood called?
blood plasma
what is the finer components in the blood?
soluble protein molecules
when are the diner components of the blood visible?
during clotting
what are the subclasses of bone tissue?
compact and spongy
what cells are in the blood?
RBC, WBC, platelets
what is the bone matrix composed of?
gel-like ground substance calcified with inorganic salts and collagen fibres
what is the matrix of blood made up of?
plasma and no fibres
where is simple squamous epithelium located?
kidney glomeruli, air sacs of lungs, lining of the heart, blood and lymph vessels
where is simple cuboidal epithelium located?
kidney tubules, ducks and secretory portions of small glands and ovary surface
where is simple columnar epithelium located? (ciliated)
small bronchi, uterine tubes and some areas of uterus
where is simple columnar epithelium located? (non-ciliated)
lines most of digestive tract, gallbladder and excretory ducts of some glands
Where is pseudostratified columnar epithelium located? (ciliated)
trachea and most of upper respiratory tract
Where is pseudostratified columnar epithelium located? (non-ciliated)
In sperm-carrying ducts and ducts of large glands
how is epithelial tissue supported by the CT? What does it involve?
basement membrane = basal lamina and underlying reticular CT
what is an important feature of cancerous epithelial cells?
they fail to respect the boundary imposed by the basement membrane
What are specialized contacts of epithelial tissue?
cells fit closely together and form a continuous sheet
transitional epithelium is a type of —— epithelium
stratified
what is the function of transitional epithelium ?
to change shape in response to stretching
how does transitional epithelium look when 1) stretched and 2) relaxed
squamous, cuboidal
—– epithelial tissue is stronger than simple epithelia
stratified
stratified squamous epithelium is located in places for the purpose of
wear and tear
what is the most widespread of stratified epithelia
stratified squamous
