Quiz 1 Flashcards
level of ogranization
atoms, molecules, organelles, cells, tissues, organs, systems, organism
cells
smallest unit of living matter
200 diff types in the body
tissues
collection of similar cells = simple tissues
collection of different cell types = comound tissues
4 types of tissues
epithelial
connective
nerve
muscle
organs
anatomically distinct groups of tissues working to perform specific functions
systems
collection of organs working together for a similar or related roles
histology definition
study of cells and tissues
relationship between structure and function of tissue
tissues structure that are not seen by naked eye
basis for histopathology
pathology
study of diagnosis of disease
3 types of light microscopy
bright feild
phase contrast
differential interference contrast microscopy
bright field microscopy
can see natural colours or stained samples
specimens appear dark on a bright background
phase contrast microscopy
based on difference in refractive indexes
optic converts the differences in RI to differences in brightness therefore nucleus can be distinguished from the cytoplasm
differential interference contrast microscopy
makes specimen 3D based on differences in refractive index
difference is converted into detectable amplitude differences
may not actually represent the specimen in real life
staining in light microspcopy
basic dyes/cationic dyes - stain RNA/DNA because of their negative charge
e.g: hematoxylin
acidic dyes (negative charge) - stain basic residues such as protein e.g: eosin
H&E staining causes nuclues and ribosomes to stain blue and cytoplasm and collagen red or pink
magnification and resolution
magnification = how many times larger an image is
resolution is the ability to distinguish between two separate points
resolution on a light microscope vs electron microscope
light microscope:
dependent on wavelength of light - if the object is big enough to interfere with a wavelength in the spectrum then the image is able to be seen
electron microscope:
wavelengths are 10 000 times shorter and therefore EM has higher resolution
what limits resolution
+ know how to calculate
numerical aperture: the ability of the lens to collet thelight and the wavelength of light
lenses with NA values over one require oil
types of EM
Scanning EM (SEM)
- reflected off surface
- 3D image
Transmission EM (TEM)
- pass through
- 2D image
- best resolution
where is epithelial tissue located?
external and internal surfaces of the body - covering body surfaces, lining body cavities, forming glands
means that anything in/out must pass through the epithelial tissue
located on a basement membrane/ basal lamina
how does epithelial tissues get nutrition?
they are a vascular
dependent on loose connective tissue to supply nutrients and oxygen as well as remove by-products
major functions of epithelial tissue
coverings or linings = protection
absorption (intestine)
secretion (glands)
sensation and contraction
basal lamina
lies at interface between epithelial cells and connective tissue
two basal laminas can fuse in places when no intervening connective tissue is present
characteristics of epithelium
sheets of cells held together tightly by junctions
they can shed and renew
composed of polarized epithelial cells, specialized to perform a variety of functions such as regulation of passage
simple squamous epithelial cells
single layer of flattened cells - look like fried eggs
can do simple secretion and filtering
located in places where the passage of chemicals is rapid such as:
- making up endothelial lining of lymphatic vessels
- alveoli of lungs
- lining of capillaries
- some parts of the kidney glomerulus and tubules
simple cuboidal epithelial cells
allow passage of chemicals
thicker than squamous therefore have protective function
complex function in secretion compared to squamous
also have role in absorption
located in the secretory part of most glands and kidney collecting tubules
simple columnar epithelial cells
nucleus is elongated and near the basement membrane
active in absorption and secretion
have enough energy to carry out complex tasks
can have microvilli (sm intestine) or cilia (bronchioles)
pseudo-stratified columnar epithelium
single layers of cells that appear to be multilayered
some cells may not reach the top
nucleus in different locations
ciliated form is found in the trachea
stratified squamous cell epithelium
multilayered
means squamous on top
most common stratified epithelial
provide increased protection and durability
what is stratified epithelium
named based on the multilayered cell type on the TOP
what is stratified epithelium
named based on the multilayered cell type on the TOP
must be two or more layers
stratified cuboidal epithelium
found in the ducts of sweat glands and not commonly anywhere else
stratified columnar epithelium
found in large excretory ducts of some glands and in the cavernous urethra
transitional epithelium
top layer is able to change
find this in organs where the ability to stretch is needed such as the bladder which must expand and contract
specializations of apical epithelial cell surfaces
cilia - bronchiole
microvilli - sm. intestines
specializations of lateral epithelial cell surfaces
TYPES OF CELL JUNCTIONS:
occluding/tight junctions
adhering junctions ( zonula adherens)
desmosomes (macula adherens)
communicating ( gap junctions
specializations of basal epithelial cell surfaces
adhering to basal lamina via hemi-desmosomes
tight junctions
appear as fusions
but the junctions are formed from two proteins occulin and claudin
attached to actin
tight junctions
form a barrier - restricts passage of water, electrolytes and other small molecules
present in all types of epithelial cells
appear as fusions
but the junctions are formed from two proteins occulin and claudin
attached to actin
adhering junctions
adhering
stick adjacent cells to each other via cadherin
attached to actin filament all around the cells
desmosomes
attachment
not all around cells - look like spots/plauqes
cells can have a space between spanned bycadherin and intermediate filaments (cytokeratin in epithelia)
gap junctions
communication
pores formed by arrangement of 6 connexin proteins - permit passage of ions and other molecules
cell adhesion on basal surface
anchors cells to the basal lamina through laminin
held together by integrins
anchored to keratin filaments within cell
what is an epithelial gland
one or more cells that secrete a fluid (sweat, saliva) or chemical message such as a hormone
how are epithelial glands classified?
development of the gland - exocrine or endocrine
shape of the gland
the mechanism of excretion
exocrine vs endocrine glands
exocrine glands- secrete onto a surface of epithelium (can be internal or external) therefore they have ducts
endocrine glands have lost contact with epithelium and therefore must secrete into vessels
development of exocrine glands
step 1: localized proliferation in the epithelium and the beginning of the epithelial cell down growth into the underlying connective tissue
step 2: epithelial downgrowth continues
Step 3: secretory portion develops which is where the thing being secreted is made
development of endocrine glands
secretory portion of one cell is surrounded by capillaries and then the gland just forms
exocrine glands
have ducts
secrete to outside
can secrete: mucus (glycoprotein rich), serous (watery and proteins), and sebaceous (rich in lipids)
example of odd gland = goblet cell, unicellular and secretes mucus
different types of exocrine glands + how to draw them
simple tubular simple coiled tubular simple branched tubular simple branched acinar compound tubuloacinar compound tubular compound acinar
endocrine glands
no ducts
secrete hormones into the bloodstream
can act on near targets (paracrine) or far targets (neuroendocrine)
different types of connective tissue
loose connective - dermis layer of skin
fibrous connective tissue - forms tendons
adipose tissue
cartilage - at the end of bones
bone
blood - includes RBCs and WBCs - transports gasses, nutrients, waste, immune functions, wound healing
functions of connective tissue
maintenance and provision of form in the body - structural form by bones and cartilage
provides support through connecting organs and tissues via a matrix
tissue capsules encase our organs - provide structural support
stroma - not attached to organs but provides structural framework that aids in organ function
site for storage of fat (adipose tissue)
protects body against infection (white blood cells)
reduces friction on joints (cartilage)
repair after injury - fibroblasts remodel tissue that was damaged
what do ligaments do
hold bone together
what do tendons do
attach muscle to bone
components of connective tissue
cells
ground substance
fibers
fibroblasts
make: collagen, elastin, proteoglycans, and glycoproteins
remodel damaged tissue
most common type of cell in connective tissue proper (loose connective tissue)
mast cells
release histamine and heparin during inflammatory response
adipose cells
fat storage
plasma cells
immune response/antibodies
draw the differentiation from mesenchymal stem cells to connective tissue
see notes
draw the differentiation of WBCs and RBCs from hematopoietic stem cell
see notes
ground substance of connective tissue
= extracellular matrix - outside of cell but part of tissue
lg molecules called glycosaminoglycans (GAGs) link together = larger molecules called proteoglycans (protein core)
- molecules are good at absorbing water = 90% of the extracellular matrix is water
can have different shapes and properties thus impacting what can pass through the matrix
glycosaminoglycans (GAGs)
- gags can attach to core proteins and are resistant to compressive forces
- long, unbranched polysaccharides consisting of repeating disaccharide unit
- attract and retain water
types of fibres of connective tissue
collagen fibers
reticulate fibres
elastic fibres
collagen fibres
produced by fibroblasts
collagen fibres have a cord shape that is 1-20 microns wide
wide and wavy in appearance
stain pink in H&E staining by eosin
most abundant protein in body and extracellular matrix (30%)
25 diff types
great tensile strength
reticular fibres
produced by reticular cells which are a type of fibroblast
made of mostly type 3 collagen - attached to other collagen fibres, proteoglycans and glycoproteins
very thin fibres
elastic fibres
produced by fibroblasts and smooth muscle cells
may be stretched up to 150% of its original length
coiled and branched
three classes of connective tissue
proper
supporting
special
connective tissue proper
two types = loose and dense 3 components: 1) cells - mainly fibroblasts 2) ground substance/ matrix that is homogenous and may be fluid, gel like, or solid 3) extracellular fibres
loose connective tissue
many cells, little fibres (compared to dense) that are loosely arranged
cells: fibroblasts + infiltrating leukocytes
fibres: collagen, elastic, reticular
matrix: abundant, moderately fluid
locations:
- areolar: very loose tissue surrounding organs - attaches epithelial to underlying tissue
- reticular: internal skeleton of some organs such as the spleen or lymph nodes
dense connective tissue
more fibres but less matrix and fewer cells compared to loose
cells:
fibres: collagen
matrix: limited
two types: regular and irregular
how is connective tissue classified
relative amount/type of matrix
type and arrangement of fibres
abundance and kinds of cells
dense regular connective tissue
located in the tendons and ligaments
collagen fibres are packed densely and arranged in parallel
attenuated fibroblasts are located in the narrow spaces between collagen fibres
very resistant to tensile forces in one direction but still allow some stretch
dense irregular connective tissue
located in joints and dermis of the skin
dense woven network of collagen and some elastic fibres in a viscous matrix
collagen fibres are arranged in bundles - irregular interwoven bundles confer great tensile strength in all directions
impact resistant and has strength in all directions
fibroblasts, mast cells, macrophages, and pericytes
capsules and dermis of many organs
adipose tissue
two types = brown fat and white fat
stores energy, protects and insulates
white adipose cells
synthesis and storage of fat
what most adults have
made of triglycerides (high energy source)and glycogen (less efficient)
they are unilocular-one big glob of fat causes nucleus and cytoplasm to be pushed into a corner
normally dont divide - if adult gains weight the cell will increase in size x4 before dividing
brown adipose cells
main purpose is thermoregulation
it is mainly important for newborns and animals leaving hibernation
adults have some
it is multilocular - has many fat droplets
types of blood cells
erythrocyte (RBC) - function is O2 and CO2 transport
Leukocytes (WBC) - immunity
Platelets - function in blood clotting
blood
is considered connective tissue bc it has an extracellular matrix
living cells = RBCs and WBCs
fluid portion (extracellular matrix) = plasma - 92% water
no fibres in the blood matrix
blood components
46-63% plasma
37-54% formed elements:
- 99% RBCs
- less than 1% WBCs
- less than 1% platelets
special connective tissue
blood and adipose tissue
supporting connective tissue
bone and cartilage
3 types of cartilage
hyaline
fibrous
elastic
cartilage
avascular and aneural
more flexible than bone but less flexible than muscle
resilient and smooth tissue
rubber like padding on ends of long bones and at joints
structural component of the nose, ear, trachea and ribcage
what cell type is found in cartilage
chondrocytes
found in healthy cartilage and lacunae (voids in matrix)
produce and maintain the matrix which is mostly collagen and proteoglycans
hyaline cartilage
most common
located in joints and respiratory passages
matrix is abundant and is gelatinous- has little to no fibres
therefore has less strength
chondrocytes are spaced apart
fibrocartilage
between vertebrates and in the knee
the most strong
matrix is in moderate amount but has a lot fo fibres (collagen)
causes the chondrocytes to be the most spaced apart in all three types
elastic cartilage
in outer ear
most flexible
matrix is limited but has elastic fibres (little to none) therefore has a lot of flexibility
chondrocytes are close together
osteoarthritis vs rheumatoid arthritis
osteoarthritis - cartilage is thinned out at joints causing bone on bond interaction = pain
rheumatoid arthritis - swollen and inflamed synovial membrane - causes bone erosion and can result in disfigurement
two types of bone
compact bone and spongy bone
compact bone
also called cortical bone
made of osteons
shaft of bones
strong - therefore has functions to support the whole body
spongy bone
called cancellous bone
made of trabeculae
at end of the bones
porous - therefore has a large surface area which allows bone marrow to develop in this region
function of bone in the body
provides stability
allows for movement with attachment of muscles
storage of essential minerals
bone composition
proteins and minerals
60% of bone weight is minerals - mainly calcium and phosphate
remainder is water and matrix- formed before the mineral is deposited, considered to act as a scaffold
90% of matrix proteins are collagen
bone matrix
intracellular calcified material
provides hardness and resistance to bone tissue
contains minerals such as calcium and phosphorous
also have organic components = collagen and ground matrix which contains proteoglycans and glycoproteins
3 types of bone cells
osteocytes, osteoblasts, osteoclasts
canaliculi
microscopic canals that radiate out from the lacunae
to allow cell communication
lamellae
concentric layers of the osteon
essentially one disc of the bone
osteoblasts
synthesize the organic components of the matrix (collagen, proteoglycan, glycoproteins)
on the surface of bone surface
differentiate into osteocytes
osteocytes
derived from osteoblasts
found in lacunae
role is maintenance and mineralization of bone/extracellular matrix
osteoclasts
multi nucleated cells - made of fused macrophages
function is to reabsorb bone tissue by eating the extracellular matrix
bone remodelling
lifelong process - first year of like almost 100% of the skeleton is replaced
in adults - 10% of compact and 40% of spongy bone is replaced each year
tissue is removed from skeleton and replaced by new bones
control reshaping and replacement of bone following injuries like microdamage and fractures
maintain calcium homeostasis
occurs in spongy and compact bone
calcium homeostasis
maintains the amount of biologically active calcium within a narrow range - this is required for functions such as signal transduction, nerve activation and muscle contraction
process involves 4 components: serum calcium, serum phosphate, 1,25-dihydroxyvitamin D3 and parathyroid hormone
where is and how is most calcium stored in the body?
99% of calcium is stored in bone
in the form of phosphate and hydroxide salts - predominantly as hydroxyapatite
very small amount of calcium is available for exchange in the serum
osteoperosis
decreases bone strength increases the risk of broken bones
caused by an imbalancce between bone resorption and bone formation
the imbalance is a result of not enough calcium through the diet so the body takes calcium from the bones
types of muscle tissue
smooth muscle
skeletal muscle
cardiac muscle
smooth muscle
lack striated appearance
single nuclei
surround blood vessels and small intestine
skeletal muscle
striated appearence
long fused cells causes mutliple offset nuclie
movement of skeleton
cardiac
has intercalated disc
branched cells
contraction of the heart
single offset/central nuclei
striated appearance (actin and myosin nuclei
nerve tissue
made of neurons
regulates and controls bodily functions
main tissue component of the central and peripheral nervous systems
neuron
receive and transmit nerve impulses
axons send signals and dendrites receive
bundles of axons = nerve
neuroglia
support neurons by providing nutrients and also propagate the nerve impulse
