week 4 Flashcards
What must happen before specimens can be studied under microscope?
Specimen must be preserved and stained. Different parts of cells take up different dyes
acidic stains
negatively charged molecules
Basic stains
positively charged molecules
How are tissues stained for transmission electro microscopy? How does the stain work?
Heavy metal salts. Metals give contrast by deflecting electrons in the beams to different extents. Produces shades of grey because electron waves don’t have color.
scanning electron microscopy
3d pics of unsectioned tissue surface.
Artifacts
minor distortions in tissues caused by preservation
epithelial tissues
cover or line body cavities.
Types of epithelial tissues
- covering and lining membranes
- Glandular epithelium
Covering and lining epithelium
- Makes outer layer of skin
- lines body cavities
- covers organs and walls of organs
Glandular Epithelium
Fashions glands of body
T/F: Nearly all substances received or given off by the body must pass through and epithelium
True
Roles of epithelium
- Protection
- Absorption
- Filtration
- excretion
- Secretion
- Sensory reception
Five distinguishing characteristics of epithelium
- Polarity
- Specialized contacts
- Supported by connective tissue
4.Avascula but innervated - Regeneration
What is Apical-Basal Polarity of epithelium?
has apical and basal layers
Apical surface
not attached to surrounding tissue. Exposed to either outside of body or cavity of internal organ
basal surface
attached to underlying connective tissue
Most apical surfaces have
microvilli
microvilli
fingerlike extensions of plasma membrane. Increase surface area
Brush border
large amounts of microvilli found in absorbing or secreting tissues
cilia
tiny hailike projections that can help propel substances
basal lamina
noncellular, adhesive supporting sheet made of gycoproteins. Next to basal surface of epithelium. Filters which molecules from connective tissue can enter epithelium. Helps transport epithelial cells for wound repair
Specialized Contacts of epithelial tissue
except for glandular epithelium, epithelial cells fit cosely to make continous sheets. Joined by tight juctions and desmosomes.
All epithelial rest upon and are supported by ___________ tissue
connective
Basement membrane
Between epithelial and connective tissues
basement membrane purpose
- helps resist stretching and tearing
- Defines epithelial boundary
parts of basement membrane
basal and reticular lamina
reticular lamina
layer of extracellular material. Has fine layer of fine collagen proteins
Important characteristic of cancerous epithelial cells?
They can’t respect the basement membrane boundary and penetrate tissues underneath
What does avascular but innervated mean?
No blood vessels, but it does have nerve fibers.
What gives epithelial cells nourishment?
Blood vessels in connective tissues
Regeneration of epithelial tissue
highly regenerative.
What causes epithelial cells to regenerate?
exposure to friction, destruction of apical basal polarity and lateral contacts
Simple epithelia
single cell layer
Where is simple epithelia found?
where absorption, filtration and secretion occur
Stratified epithelia
two or more cell layers stacked on top of each other. Where protection is important. Skin surface, lining of mouth.
squamous, cuboidal, columnar
flat disc like, cube shaped, column shaped
stratified epithelia are named after
shape of cells in apical layer
Stratified epithelia naming convention
shape of cells in apical layer
Endothelium
inner covering. Single layer of squamous cells that line the walls of the heart, blood vessels and lymphatic vessels
Mesothelium
Found in serous membranes lining ventral body cavity and covering its organs
capillaries consist exclusively of
endothelium
functions of simple cuboidal epithelium
secretion and absorption. Ducts of glands and kidney tubules
Simple columnar epithelium function
absorption and secretion. has dense microvilli on absorbative cells. Has tubular glands that secrete mucus containing intestinal juice. Some have cilia that move substances along
Where to find simple columnar epithelium
lines digestive tract from stomach to rectum.
Pseudostratified columnar epithelium function
secretes or absorbs substances. lines most of respiratory tract
Most widespread of the stratified epithelium?
stratified squamous epithelium
describe stratified squamous epithelium
free squamous surface cells, cells of deeper layers are cuboidal or columnar.
Where is stratified squamous epithelium found
wear and tear. External surface of skin extends a little into every body opening that is continous with the skin. Outer layer is keratinized.
Keratinized
surface cells contain keratin
stratified cuboidal epithelium found in
ducts of larger glands. Swaet glands and mammary glands. Rare. two layers of cuboidal cells
Stratified columnar epithelium location
limited distribution. Pharynx, male urethra, lining glandular ducts. Transition areas, junctions between other types of epithelia. Only apical layer is columnar
Transitional epthelium
forms lining of hollow urinary organs. stretches. Apical cell shape varies on degree of distension
Gland
one or more cells that secrete a particular product
aqueous fluid that contains proteins. Comes from glands. Can release lipid or steroid rich secretions
secretion
Is secretion passive or active
active
secretion can refer to
both the glad’s product and the process of making the product
How are glands classified?
endocrine and exocrine & unicellular or multicellular
which glands are scattered within epithelial sheets
unicellular
which glands form by invagination “inward growth” of an epithelial sheet into connective tissue
multicellular
How are exocrine glands formed?
retain connecting cells, which form a duct that transports secretions to the epithelial surface
endocrine glands formation
lose ducts during development. Secrete hormones into interstitial fluid. These hormones then enter the blood.
Which are ductless glands and why?
endocrine glands are “ductless”. They lose their ducts during development.
How do endocrine glands respond?
- Make hormones and put them out through exocytosis,
- Hormones go into blood or lymphatic fluid and travel to targets.
ex. hormones made by intestinal cells cause pancreas to release enzymes
diffuse endocrine system
hormone producing cells can be scattered such as those in digestive tract or in brain
exocrine glands
secrete products onto body surfaces or into body cavities. secretions are carried to a site via a duct. .
endocrine glands
ductless, empty their hormonal products into blood
unicellular exocrine glands
mucous cells and goblet cells, in intestinal and respiratory tract
mucin
made by unicellular exocrine cells. dissolves in water to form mucus
goblet cells
make mucous
multicellular exocrine glands parts
- epithelium derived duct
- secretory unit surrounded by supportive connective tissue. Forms fibrous capsule that divides gland into lobes
Structral classification of multicellular exocrine glands
simple
compound
simple multicellular exocrine glands
unbranched duct
compound multicellular exocrine glands
branched duct
tubular glands
secretory cells form tubes
alveolar/acinar glands
secretory cells form small sacs
merocrine glands
produce secretions intermittenly; secretions don’t accumulate in gland. Products are secreted by exocytosis as they are produced
“merely secrete”
which glands are merocrine glands
pancreas, most sweat glands, salivary glands
holocrine glands
accumulate products until they rupture. Replaced by division of underlying cells
holocrine gland secretions include
synthesized product + dead cell fragments.
example of holocrine glands
sebaceous glands
apocrine glands
accumulate products but just beneath free surface. eventually, apex of cell pinches off. Releasing secretory granules and cytoplasm. Cell repairs damage and it repeats. Maybe mammary gland lactation
Most abundant and widely distributed tissue in the body
connective tissue
major functions of connective tissue
- binding and supporting
- protecting (skeleton)
- insulating
- storing reserve fuel (fat)
- transporting substances within the body (blood)
Common characteristics of connective tissues
- Extracellular matrix
- common origin
extracellular matrix
nonliving. Made of ground substance and fibers; separates living cells
Extracellular matrix function
bear weight, withstand tension, bear physical trauma and abrasion
common origin of connective tissue
all connective tissues come from the mesenchyme (embryonic tissue)
t/f different connective tissues have different vascular supplies
true. Cartilage is avascular, dense connective is poorly vascularized,
three main components of connective tissues
ground substance, fibers and cells
areolar connective tissue
“prototype” connective tissue
ground substance
unstructured material that fills the space between cells . Contains fibers. Has 3 components.
interstitial fluid
Large amounts of fluid found in space around cells. Acts as molecular sieve through which nutrients and dissolved substances can diffuse between blood capillaries and the cells
Cell adhesion proteins
connective tissue glue lets connective tissue cells to attach to extracellular matrix
Proteoglycans
has protein core. Large plysaccharides (glycoaminoglycans) are attached. chondroitin sulfate and hyluronic acid stick out of protein core, like fibers of a bottle brush. GAGs trap water. The higher GAG content, the more viscous the ground substance.
Connective tissue fibers
proteins that provide support. Collagen, elastic, reticular
strongest and most abundant connective tissue fibers
collagen
collagen fibers
extremely tough, high tensile strength. Made by cross-linked fibrils wound together. Stronger than steel
Elastic fibers
Fiber made from elastin protein, gives rubbery and resilient quality to matrix
Elastic fibers found in
Skin, lungs and blood vessel walls
reticular fibers
short, fine fibers. Mafe of different collagen. Branch extensively to make networks. Surround small blood vessels, support soft tissue organs. most common where connective tissue is close to other tissue types
-blast
immature
-cyte
mature
fibroblasts
Young, actively mitotic cells that makes fibers of connective tissue
fibrocytes
Mature fibroblast; maintains matrix of fibrous connective tissue
chondroblasts
mitotically active cell of cartilage
Chondrocytes
mature cell of cartilage
Osteoblasts
Bone forming cells
Osteocytes
mature bone cells
can cells revert back to blast form?
yes, usually in case of injury
hematopoietic stem cell
blood forming cell; not located in blood; doesn’t make plasma matrix of that tissue
adipocytes
fat cells
WBCs
tissue response to injury
mast cells
cluster along blood vessels. detect microorganisms, initiate local inflammatory response
mast cell cytoplasm contains
granules
What do granules contain?
chemicals that mediate inflammation, especially in severe allergies
Heparin
anticoagulant chemical. Prevents blood clotting when free in bloodstream. Human mast cells regulate action of other mast cell chemicals
Histamine
makes capillaries leaky
proteases
protein degrading enzymes
macrophages
devour foreign material. Large
mesenchymal cells
star shaped.Mde during early weeks of embryonic development. some remain to provide a new source of cells in new connective tissues
Connective tissue proper
all mature connective tissues except for bone, cartilage and blood
loose connective tissues
areolar, adipose, reticular
dense connective tissues
dense regular, dense irregular, elastic
most widely distributed connective tissue in the body
Areolar connective tissue. Most widely distributed connective tissue in the body. universal packing material
Which connective tissue binds body parts togetherwhile allowing them to move freely over one another?
Areolar connective tissue
What is the connective tissue that most epithelia rest on?
Areolar connective tissue
which tissue is present in all mucous membranes as the lamina propia?
Areolar connective tissue
reticular connective tissue
Loose network of reticular fibers in gel-like ground substance. fibers form soft internal skeleton that supports other cell types. Including WBCs, mast cells, macrophages.
Location of loose reticular connective tissue
lymphoid organs (lymph nodes, bone marrow, spleen)
dense regular connective tissue
parallel collagen fibers Made of fibroblasts.
Function of dense regular connective tissue
attaches muscles to bones or to muscles. attaches bones to bones. Withstands great tensile stress when pulling force is applied in one direction.
location of dense regular connective tissue
tendons, most ligaments, aponeuroses
Dense irregular connective tissue
Primarily irregularly arranged collagen fibers; fibroblast is major cell type
function of dense irregular connective tissue
withstands tension exerted in many directions; provides structural strength
location of dense irregular connective tissue
fibrous capsule of organs and joints; dermis of skin; submucosa of the digestive tract
dense elastic connective tissue description
high proportion of elastic fibers
function of dense elastic connective tissues
allows tissue to recoil after stretching. Maintains pulsatile of blood flow through arteries. passive recoil of lungs
Location of desnse elastic connective tissue
Walls of arteries. Within ligaments associated with the vertebral column. Within walls of bronchial tubes
Hyaline cartilage
imperceptible network made by chondroblasts
Function of hyaline cartilage
supports and reinforces; serves as resilient cchion ; resists compressive stress.
location of hyaline cartilage
ends of long bones, embryonic skeleton. Coatal cartilages. cartilage of nose, trachea and larynx
elastic cartilage
similar to hyaline cartilage but more elastic fibers in matrix
function of hyaline cartilage
maintains shape of a structurewhile allowing great flexibility
location of elastic cartilage
supports pinna and epiglottis
fibrocratilage
matrix similar to but less firm than that in hyaline cartilage. Thick collagen fibers predominate
Function of fibrocratilage
tensile strength lets it absorb compresive shock
location of fibrocartilage
intervertebral discs; pubic symphysis, disc of knee joints
bone
hard, calcified matrix, containing many collagen fibers. Osteocytes lie in lacunae. Very well vascularized.
function of bone
supports and protects. Provides levers for muscles to act on
Blood connective tissue
Red and white blood cells in a fluid matrix (plasma). transports respiratory gases, nutrients, wastes. within blood vessels
functions of areolar connective tissue
-supporting and binding other tissues (job of the fibers)
-holding body fluids (ground substance’s role)
-defending against infection. (Activity of WBCs and macrophages)
-storing nutrients in adipocytes
holds more fluid than the entire bloodstream
areolar connective tissue
all body cells obtain their nutrients from and release their wastes into
tissue fluid
Flat branching cells that appear spindle shaped
fibroblasts
Why is the ground subtsance of areolar connective tissue viscous?
high concentration of hayluronic acid
Adipose tissue highly vascularized yes or no?
yes
How much of the body is adipose tissue in the average person?
18%
Adipocytes are what percentage of adipose tissue?
90%
adipose tissue accumulates where?
where areolar connective tissue is plentiful, but usually in subcutaneous tissue
What does adipose tissue do ?
shock absorber, insulation, energy storage. Prevents heat loss from body
Other sites where fat accumulates
around kidneys, behind eyeballs, abdomen and hips
large fat deposits serve, small fat deposits serve
entire body, needs of highly active organs(heart, lymph nodes, muscles, bone marrow)
white fat
nutrients for other cells
brown fat
abundant mitochondria, use lipid fuels to generate heat instead of generating ATP. Heat produced warms rest of body.
brown fat locations
babies who can’t shiver
in adults: collarbones, neck, abdomen, around spine
reticular connective tissue
connective tissue with a fine network of fibers. Make internal supporting framework of lymphoid organs
in which direction is tension distributed in dense regular connective tissue
single
What is between collagen in dense regular connective tissue
rows of fibroblasts
is dense regular connective tissue vascularized?
no
What does dense regular connective tissue make
tendons
aponeuroses
ligaments
Tendons
cords that attach muscles to bones
Aponeuroses
flat, sheet-like tendons that attach muscles to other muscles or to bones
Ligaments
bind bones together at joints. More elastic fibers than tendons. Slightly more stretchy
where is dense irregular connective tissue found
where tension is exerted from many directions. Found in the skin as leathery dermis. Forms fibrous joint capsules and fibrous coverings that surround some organs.
what two things does cartilage resist?
tension and compression
How does cartilage receive nutrients
diffusion from blood vessels located in the connective tissue layer.
What percentage of cartilage is water?
80%
What lets cartilage “bounce back”?
fluid matrix. Also helps nourish cells
gristle or hyaline cartilage
most abundednt cartilage in the body. Loots of collage fibers. Not apparent, matrix appears glassy. 1-10% chondrocytes.
epiphyseal plates
actively growing regions near ends of long bones
elastic cartilage
cartilage with abundant elastic fibers; more flexible than hyaline cartilage
What happens to cartilage during old age
loses ability to divide. Injured cartilage heals slowly. Old cartilage can ossify
lacunae
house osteocytes. Make up the matrix
makes organic portion of bony matrix
osteoblasts
osteons
look like tree rings. Concentric rings of bony matrix.lamellae. surrounding central canals. Central canals contain blood vessels and nerves
Why is blood considered a connective tissue?
comes from mesenchyme. Consists of blood cellssurrounded by matrix called plasma
Most blood cells are
red blood cells
Are muscle tissues well vascularized or poorly vascularized?
well vascularized
Which tissues are responsible for most types of body movement
muscle tissues
myofilaments
filament that makes myofibrils. Made of actin and myosin
muscle fiber is aka
muscle cell
is skeletal muscle striated or non-striated? uni-nucleate or multinucleate
striated, multinucleate
appearance of cardiac muscle
branching, striated, uninucleate, involuntary
smooth muscle appearance
spindle shaped, central nuclei, no striations
intercalated discs
special connections between cardiac muscle cells that have gap junctions and desmosomes
smooth muscle is found in
walls of hollow organsother than heart.Digestive and urinary tract organs, uterus, blood vessels. squeezes substances by contracting and relaxing
neurons
highly specialized nerve cells that generate and conduct nerve impulses
dendrites
respond to stimuli
axons
transmit electrical impulses over subtsancial distances within body
neuroglia
nonconducting cells that support, insulate and protect neurons
types of covering and lining membranes
cutaneous, mucous, serous
covering and lining membranes have two parts
epithelium bound to a connective tissue proper
cutaneous membrane
skin. made of keratinized squamous epitheliumattached to thick later of connective tissue. Epidermis and dermis.
mucous membranes
line body cavities that are open to exterior
serous membranes
line cavities closed to exterior
mucosa does not refer to cell composition, t/f?
t. Most have squamous or simple columnar epithelia
Lamina propia
loose connective tissue supporting an epithelium; part of a mucous membrane (mucosa)
mucous membranes adapted for
absorption and secretion. Some secrete mucous, but it is not a requirement. The one of urinary tract does not.
serosa membranes layers
visceral layer and parietal layer. Simple squamous epithelium on thin areolar connective tissue.
How is serous fluid made?
mesothilial cells add hyauronic acid to the fluid that filters from the capillaries in the connective tissue. Results in thiin clear serous fluid . lets layers slide against eachother
pleurae
line thoracic wall and cover lungs
pericardium
encloses heart
peritoneum
encloses abdominopelvic viscera
inflammatory response
nonspecific reaction, develops where tissues are injures
growth factors
wound hormones, stimulates cells to divide and migrate
regeneration
replace destroyed tissue with same kind of tissue
Fibrosis
replaces destroyed tissue with scar tissue (dense connective tissue)
factors that determine whether regeneration or fibrosis
type of tissue damaged and severity of injury.
what happens during inflammation
trauma causes injured tissue cells, mast cells and others to release inflamatory chemicals. wbcs, clotting proteinsand plasma proetins seal injured area. scab forms
What happens during organization stage of tissue repair
- clot replaced by fragile capillaries, restores vascular supply.
- Fibroblasts produce growth factors and collagen fibers that bridge the gap. Fibroblasts destroy themselves when done
- macrophages destroy debris
- surface epithelium move over fragile granulation tissue
What happens during the regeneration and fibrosis phase?
- fibrosed area pulls margin of wound together
- Epithelium thickens under scab and detaches
- fully regenerated epithelium with underlying scar tissue results. Depends on severity of wound
granulation tissue
delicate pink tissue . Contains capillaries from nearby areas. create a new capillary bed. The fragility of granulation tissue is why people bleed when someone picks at a scab
simple infections heal by
regeneration (pimple or sore throat)
Severe infections
lead to clot formation or scarring
Which tissues regenerate well
epithelial tissues, bone, areolar, dense irregular connective tissue, blood forming tissue
moderate capacity of regeneration
smooth muscle, dense regular connective tissue
weak regenerative capacity
skeletal muscle and cartilage
no functional regenerative capacity
cardiac muscle, nervous tissue in the brain and spinal cord. (routinely replaced by scar tissue)
What happens to fibrous mass over time?
Becomes pale and compact. can’t do functions of tissue it replaced.
Why is scar tissue bad in certain organs?
inhibits function
reduces internal volume. prevent substances from moving through the organ. prevent it from receiving signals.
What happens if scar tissue in heart
muscle’s ability to contact is damaged, can lead to progressive heart failure.
What happens in irritated visceral organs following abdominal surgery
adhesions, scar tissues connects organs together. prevent intestine from churning. immobolize joints
cancer
sequence of alterations turn normal cell to killer
neoplasm
caused by unregulated cell division. abnormal mass of proliferating cells
benign neoplasms
stay in one place
malignant neoplasms
cancers, spread to other organs
often encapsulated, grows slowly
benign neoplasm (seldom kills host)
which neoplasm has cells that resemble immature cells that grow relentlessly
malignant neoplasms
metastasis
travel via blood or lymph to make secondary cancer masses
effects of cancer cells
weight loss, tissue wasting. Contribute to death
Carcinogenesis
changes in dna (mutations)
defenses against carcinogens
- liver deactivates many carcinogens
- DNA repair mechanisms
- immune system cells
oncogenes
cancer causing genes
proto-oncogenes
benign forms of oncogenes in normal cells.
Proto-oncogenes code for
proteins essential for cell division, cellular growth and cellular adhesion
What causes a protooncogene to turn into an oncogene?
fragile sites break off when exposed to carcinogens. May switch on dormant genes that allow cells to become invasive and metastasize
tumor suppressor genes
act as breaks. Products of their genes inhibit cell growth and division.
Over half of all cancers involve the loss of
tp53
TP53 function
codes for a protein that stops cell division in cells whose DNA has been damaged. If damage cannot be repairedthe protein triggers apoptosis
Are cancers genetically distinct?
yes
Human cancers share what?
mutations in a common set of key pathways controlling cell growth and cell division. The seeds of cancer are in our own genes
adenoma
neoplasm of glandular epitelium
How many people develop cancer in US and canada?
Almost half of all people and 1/5 die from it
Leukoplakia
white patches in mouth caused by the chronic irritation of ill-fitting dentures. Lesions may progress to canceror may revert to normal if irritant is removed.
mammography
x ray examination of breast tissue for cancer cells
Ways to test for cancer
examine testicles for lumps, examine blood for cancer markers, check fecal samples for blood
biopsy
surgically removing a tissue sample and examining it microscopically for malignant cells.
How are biopsy tissues tested?
chemical or genetic analysis of sample. Checking to see which genes are on or off
Polyp
small, benign growth of mucosal cells.
Common areas for cancer to originate from
skin, colon, lung, breast, prostate
How is cancer treated?
Surgically, followed by irradiation and chemotherapy.
How does interrupting the signaling pathways work?
Can determine which signaling pathways are disrupted and select appropriate drugs to target those pathways in an individual’s particular cancer.
How does cancer immunotherapy work?
Antibodies that block specific receptors on cancer cells. Various methods to activate the immune system to kill cancer cells
Primary germ layers
One of first parts of embryonic development: ectoderm, mesoderm, endoderm.
ectoderm
makes epidermis, skin and nervous tissues
mesoderm
makes skeleton and muscles
endoderm
embryonic germ layer. Makes lining of digestive tube and associated structures
When have all primary tissues appeared?
end of second month of development
Which cells remain mitotic and produce the rapid growth that occurs before birth?
tissue cells
When does the division of nerve cells stop?
During the fetal period
Which tissues are highly mitotic in adults?
Epithelial and blood forming tissues
How do glandular cells of liver regenerate?
Division of mature, specialized cells
Which tissues have abundant stem cells
Epidermis of skin,
Lining of intestine
Stem cells
Unspecialized cells that divide to produce various kinds of more specialized cell types
When a DNA mutations more likely?
During advanced age
Adenocarcinoma
Malignant neoplasm of glandular epithelium
Autopsy
Examination of the body, it’s organs, it’s tissues to determine cause of death. Aka necropsy
Carcinoma
Cancer that arises in epithelium, 90% of human cancers
Healing by first intention
Simplest type of healing. Edges of wound are joined bu sutures or staples. Only small amounts of granulation tissues are formed
Healing by second intention
Wound edges remain separated, large amounts of granulation tissues bridge gap. How unattended wounds heal. Slower than attended. Larger scars
Keloid
Abnormal proliferation of connective tissue during healing of skin wounds. Causes big scar mass
Lesion
Injury that affects tissue over a specific size
Marfan’s syndrome
Genetic disease.. abnormal connective tissues due to fibrillin problems. Loose jointedness, long limbs, spider-like fingers and toes, visual problems, weakened blood vessels (especially aorta). Poor connective tissue reinforcement
Osteogenesis imperfecta
Brittle bone disease
Defective collagen production
Weak bones that break easily. 30 or more fractures during lifetime 1/20000 births
Pathology
Scientific study of changes in organs and tissues produced by disease
Pus
Tissue fluid, bacteria, dead and dying tissue cells, WBCs, macrophages in inflamed area
Sarcoma
Cancer in mesenchyme derived tissues. Connective tissues and muscle
Scurvy
Lack of vitamin c needed to make collagen..blood vessel disruption, delay in wound healing, weakness of scar tissue, loosening of teeth
VAC
Vacuum assisted closure
Healing practice for open skin wounds and skin ulcers. Induces healing when all other methods fail. Covering wound with special sponge and sucking through sponge. Because the skin stretches, fibroblasts make more collagen and new blood vessels are formed . More blood into injured area which promotes healing
