Lab 4 - Examination of Four Major Tissue Types Flashcards
Any organ/structure in the body is composed of 2 cell types
Parenchymal cells
support cells
Parenchymal cells
carry out the major function of that organ/structure
Support cells
provide the structural scaffolding and metabolic support of the organ. Support cells and their ECM are commonly known as connective tissue
What determines the appearance of the ECM
the arrangement of the fibrillar proteins of the ECM and the relative amount of fibrillar protein and glycoasaminoglycans (GAGs) determines the appearance on the ECM.
four catergories of connective tissue
CT porper
Cartilage
Bone
Adipose
CT proper =
loose and dense
loose = reticular, areolar
dense = regular, irregular
Fibroblast
need to make proteins (collagen and elastin) so there is lots of rER
Dense CT
they have very little space between them
Dense regular CT
They are regularly aligned, same direction
Dense irregular CT
They are haphazardly arranged
pink/red fibres =
collagen
brown/black/purle =
elastin
a lot finer in structure than collagen
Very few elastin fibres … in dense regular CT
collagen fibres run in thick parallel bundles, therefore provide great tensile strength when pulling force is applied in one direction
Present in tendons, most ligaments
Baking the bones
Baking deanaures the organic component i.e. it denatures the protein, therefore the collagen is destryed removing the tensile strength so the bone becomes very brittle
Vinegar bath for the bones
Acetic cides degraded the inorganic part of bone i.e. calcium salts dissolved by vinegar thus making matrix less rigid and apparently bendy
only collagen layers are left
affects the calcium phosphate in the bone
Dense CT ECM features
Densely packed parallel collagen fibres, a few elastin fibres therefore withstands tensile stress when pulled in one direction
Hyaline cartilage ECM features
Collagen fibres present but form amorphus matrix, chondrocytes lie in the lacunae therefore resists compressive stress i.e. firm but flexible
Compact bone ECM features
Hard calcified matrix, osteocytes lie in lacunae within matrix, therefore supports and protects and acts as a lever
Adipose tissue ECM features
Sparse matrix containing a lot of adipocytes filled with large lipid droplets therefore it is a food reserve and it supports and it insulates
Focal densities
Anchors the bundles of contractile filaments to the cell (anchors actin)
Fibroblasts function
manufactures the required proteins such as collagen
sarcomere is from
one Z line to the next and it contains overlapping thick filaments (A band) and the thin filaments (I band)
Thick filaments
myosin
THin filaments
actin
Changes to sarcomere bands and lines
A band stays at constant width, but the I band narrows pulling the Z lines closer together
Through which type of junction does excitation spread?
gap junctions
Fascia adherens
where actin filaments insert into the z lines
desmosomes
anchoring points for intermediate filaments
Appearance of skeletal, cardiac and smooth
Skeletal = elongated unbranched cylindrical cells
Cardiac = elongated branched cylindrical cells
Smooth = small elongated spindle shaped cells
Nucleus of skeletal, cardiac and smooth
SK = Multinucleate, nuclei flattened and lie just beneath the sarcolemma
C= One or occasionally 2 nuclei, are centrally located
S= Uninucleate, nuclei elongated and centrally located
Striations of skeletal, cardiac and smooth
SK = Striations from presence of regularly arranged contractile proteins. Has sarcomeres consisting of thick myosin filaments and thin actin filaments. C= Striations, from presence of regularly arranged contractile proteins similar to skeletal muscle, however form a branching 3D network.
S= No striations, contractile proteins crisscross the cell inserting into focal densities in the cytoplasm and to the cell membrane.
Contraction of skeletal, cardiac and smooth
SK = V oluntary. Contraction when thick and thin filaments slide over each other. The sarcomere shortens and thus the muscle fibre shortens. Muscle fibres can contract individually.
C= Involuntary. Similar to skeletal muscle except have intercalated discs at the Z lines joining cells, so when one cell contracts other cells contract almost simultaneously.
S= Involuntary. Contraction when thick and thin filaments slide over each other, changing cell shape from elongated to round. Cells bound together in bundles so act together.
Excitation of skeletal, cardiac and smooth
SK = Excitation spread through T tubules and SAR, no gap junctions.
C= Excitation spread through T tubules and SAR and gap junctions
S= Excitation spread through gap junctions and SAR, no T tubules.
Mitochondria and glycogen granules of skeletal, cardiac and smooth
SK = Many mitochondria and numerous glycogen granules therefore lots of aerobic activit C= Abundant mitochondria and numerous glycogen granules therefore lots of aerobic activity.
S= Sparse mitochondria and few glycogen granules therefore mainly anaerobic activity.
Connective tissue components of skeletal, cardiac and smooth
SK = Epimysium, perimysium, endomysium.
C= Endomysium attached to fibrous skeleton of the heart
S= Endomysium.
Epidermis from most superficial
Stratum corneum (several layers of flat dead scaly cells)
Stratum lucidum (thin translucent layer)
Stratum granulosum = 2-3 layers of darkly stained cells
Stratum spinosum (8-10 layers pulled into a ‘spiny’ shape by desmosomes
Stratum basale = single layer of dividing cells
Dermis from most superficial
Papillary region = loosely arranged tissue
Reticular region = denser arranged tissue
come lets grab some beers
corneum lucidum granulosum spinosum basale
The dermis is
always there
blood vessels in the
dermis
Sensory nerve endings are found
in the dermis
hypodermis is predominantly composed of
adipose tissue
how would the skin layers appear if a basal blister had formed?
A basal blister would result in separation of the dermis from the epidermis; the desmosomes the junctions holding the adjacent cells together, would be damaged, and the layers of the epidermis would be raised up off the dermis
dermis and epidermis rubbing and fluid forms between which reults in the desmosomes being damaged
Gomori trichrome
stain useful for distinguishing nuclei (red) and muscle fibres (purple) and connective tissue (blue)
GOmori trichrome works best on which section
cardiac tissue
The muscle fibers are now more clearly identifiable, in addition to surrounding connective tissue. Nuclei can also be seen in relation to specific muscle cells.
myocytes = 1-2 nuclei
Spleen
Red or white pulp
Immune cells - lymphoid = white
Red = blood vessels
Liver
Homogeneous = same
Hepatocytes
Ducts for bile
