Histo

**Describe what occurs to the epithelial tissue in pemphigoid

Auto-antibodies develop against components of the basemement membrane that detatches the epithelial layer from the basement membrane leading to blistering - mucous membrane pemphigoid

Autophagosome TEM image

Autophagosome TEM image

Describe the basement membrane: - describe the basal lamina and reticular lamina layers - does it act as a selective filtration barrier?

Basal lamina: - epithelial-derived, type IV collagen, laminin, proteoglycans Reticular lamina: - fibroblast-derived, type III collagen/reticular fibers, fibronectin Basement membrane acts a selective filtration barrier (e.g. kidney glomerulus) Control of differentiation (growth and tissue repair)

Describe enzymatic receptors (e.g. tyrosine-kinase receptor) and RAS signaling and PI-3-kinase Akt pathway

Binding of a growth factor causes dimerization/autophosphorylation of tyrosine residues. This will then lead to RAS mediated proliferative pathway which can lead to augmented proliferative signaling (e.g cancer) PI-3-kinase Akt pathway promotes cell survival and growth

Describe the role of cAMP in GPCR activation and signaling and role of GPCR receptors and inositol phospholipids

Binding of an extracellular signal molecule to its GPCR leads to the activation of adenylyl cyclase and a rise in cAMP. The increase in cAMP concentration activates PKA in the cytosol and the released subunits then move into the nucleus where they phosphorylate a gene regulatory protein When inositol phospholipids are involved, the signal trasnduction will lead to a release of Ca2+ from the SER

Describe the biosynthetic-secretory (e.g. secreted to the plasma membrane), endocytic-degradative (e.g. secreted to the endosomes/lysosomes), or retrieval pathways associated with the golgi apparatus.

Biosynthetic-secretory: - secreted to the plasma membrane - e.g. packagin and secretion of zymogen granules in pancreatic acinar cells, NT secretion at synaptic cleft Endocytic-degradative: -Autophagocytosis --> Lysosomes --> Endocytic vesicles/endosomes --> Autophagosomes - endocytosis (e.g. phagocytosis, pinocytosis, receptor-mediated endocytosis/clathrin coat, calveole/calveolin coat) Retrieval pathway: - use of COPI coat for recycling of vesicles back to the ER from the cis golgi

Polarizing light microscopy allows the recognition of stained or unstained structures made of highly organized subunits/oriented macromolecules: - What is birefringence? --> What types of substances/molecules are easily viewed under Polarizing Light Microscopy?

Birefringence is the ability to rotate the direction of vibration of polarized light and it is a feature of crystalline substances or highly oriented molecules such as cellulose, collagen, MTs, and actin filaments

Describe tissue preparation for examination by light microscopy (FDCIES): - Describe the process of Fixation->Dehydration->Clearing->Infiltration->Embedding->Sectioning --> Describe what is used in each step and why

Fixation: - Cells/sample are placed in a fixative solution in order to preserve the life of the cells (formaldehyde in light microscopy)(Formalin aka 10% formaldehyde used in pathology) Dehydration: - lipids must be eliminated in order for the sample to be transparent - Lipids are removed via dehydration with ethanol - This step is skipped and Os Tetrx is used if lipids want to be seen? Clearing: - Xylene is used as the clearing step to remove the ethanol (it also allows the tissue to become transparent) Infiltration: - Sample is exposed to heat, which exposes the paraffin and will remove the xylene Embedding: - Cooling down of the sample so that it can be sectioned Sectioning: - sectioning/slicing of sample by a microtome machine

Mesenchymal cells give rise to many types of CT except (...)

EXCEPT macrophages or mast cells

Know functions of mitochondria

Energy/ATP production/oxidative phosphorylation Necrosis/apoptosis Heat production in brown lipids

Describe what the epimysium, perimysium, and endomysium cover?

Epimysium: - surrounds groups of fascicles to form an organ Perimysium: - surrounds fascicles (muscle fiber bundles) - blood vessels and nerves run through here - fibroblasts are located here (be able to identify them) Endomysium: - surrounds individual muscle fibers/muscle cells (these muscle cells/fibers contain bundles of the parallel myofibrils) - this includes the external (basal) lamina

Characteristics of epithelial cells - high or low cell:ECM ratio? - polarity? -derived from all three germ layers? - dysplasia? metaplasia? regeneration from wound repair?

Epithelial cells: - High cell:ECM ratio - polarity (because of tight junctions) - basement membrane - cohesiveness - avascularity - metaplastic (can transform from one epithelial cell type to another type) - regenerative (wound repair) - derived from all three germ layers - can undergo dysplasia (abnormal growth) due to having a high mitotic index

Exocrine vs endocrine glands

Exocrine glands become lumen that forms the duct of the gland - cells secrete from the apical layer into the duct - secrete mucin, sweat, oil, saliva, bile, pancreatic digestive enzymes - e.g. salivary gland, pancreas acinar cells Endocrine glands become an isolated glandular body with no lumen but are a mass of cells - cells secrete from the basal layer into the blood stream - secrete hormones - e.g. andrenal thyroid, pancreas islet of langerhans (insulin, glucagon)

Describe the use of H&E staining vs fluorescence microscopy in viewing of collagen of the periodontal ligament (PDL) - be familiar with the periapical lesion area in the image

Fluorescent staining allows for a much clearer/detailed view of the collagen fibers in the PDL than H&E (mainly eosin bc eosin stains collagen/proteins)

Describe the pericytes: - where are they found? - they are embedded within the endothelial (...) membrane - They are similar to (...) cells and have characteristics of (...) muscle

Found around blood capillaries, etc. They are embedded within the endothelial basement membrane They are similar to mesenchymal cells and have characteristics of smooth muscle cells and endothelial cells and can differentiate into those two types of cells

Fibroblasts in the dentinal pulp

Functin is to form and maintain the pulp matrix, which consists of collagen and ground substance When active, the fibroblats have a plump cytoplasm

Describe Simple Columnar: - Functions - Locations (large ducts, digestive tract/brush border, respiratory tract)

Functions: - absorption - secretion Locations: - large ducts - Digestive tract ---> microvilli- brush border of INTESTINE; goblet cells seen here - Respiratory tract ---> Ciliated cells

Describe Pseudostratified epithelia: - Functions - Locations (large ducts, respiratory tract/trachea, urinary tract, male reproductive system) - unique characterisics

Functions: - absorption - secretion Locations: - large ducts - respiratory tract (e.g. TRACHEA- if you see cilia and goblet cells its probably the trachea and pseudostratified epithelia) - Urinary tract - Male reproductive system May appeared layered, but they ALL touch the basement membrane/basal layer --> It is a single layer that appears multilayered --> NOT ALL cells reach the lumen!

What is a (irritation) fibroma and fibrosis

Fibrosis is deposition and overgrowth of excess fibrous CT that forms scar tissue because of injury, infection, allergy, or long-term inflammation. - Mechanisms of fibrosis include proliferation of fibroblasts, activation of macrophages and lymphocytes, and generation of novel myofibroblasts that, when activated, become the main collagen-producing cell Irritation fibroma is a very common reactive hyperplasia Fibrosarcoma (fibroblastic sarcoma) is a malignant tumor of fibroblasts that can occur in any area of the body. Histologically, most show a "herringbone" architectural pattern with presence of immature, proliferating fibroblasts that produce varying amounts of collagen

Describe Simple Squamos epithelia: - functions - locations (kidney renal corpuscle, lung alveoli, endothelium of heart and blood vessels, mesothelium (e.g. pleura/thoracic cavity, pericardium/heart, periteneum/abdominal cavity) - What happens in mesothelioma?

Functions: - diffusion - filtration - gas exchange Their nuclei (basophilic/hematoxylin stained) will look squished/squeezed in the heart pericardium and many other locations Mesothelium is a layer of simple squamous cells that line the body cavities (e.g. the pleura of the thoracic cavity, pericardium of the heart, and pertoneum of the abdominal cavity) Mesothelioma is a pathology that may arise from the parietal and visceral serous membranes of pleural, peritoneal, and pericardial cavities (mesothelium layers;simple squamos cell) - pleural mesothelioma arises from asbestos exposure

Describe Simple Cuboidal epithelia: - functions - locations (small glandular ducts, kidney tubules, thyroid: follicular cells) - Describe what occurs in the pathology of metaplasia --> What occurs to the cuboidal cells when there is hyperthyroidism and hypothyroidism

Functions: - secretion - absorption Locations: - small glandular ducts - kidney tubules - thyroid: follicular cells Pathology: Metaplasia (change in cell shape/nature) - hyperthyroidism: become COLUMNAR cells hypothyroidism: become SQUAMOS (square) cells

Golgi TEM

Golgi TEM

Describe H&E: - Which binds basophilic (i.e. acidic), anionic, negatively charged groups (DNA, RNA, PO4-)? - What parts of the cell does Hematoxylin bind to? - Which parts of the cell does Eosin bind to? - Which is an acidic dye (anionic dye)

Hematoxylin (blue, violet): - basic dye (cationic dye)(i.e. binds to acids, anions) - Binds to basophilic (i.e. acidic), negatively charged, anionic groups (e.g. DNA, RNA, PO4-) - stains in the nuclei/nucleosome and rough ER Eosin (pink): - Acidic dye (anionic dye) - Binds to acidophilic (i.e. basic), positively charged, cationic groups (positive amino groups in proteins, e.g. collagen, mitochondria) - stains portions of cytoplasm that contain proteins (e.g. secretory vesicles, zymogen granules)

Heterochromatin vs euchromatin

Heterochromatin indicates low metabolic and biosynthetic activity Euchromatin indicates higher metabolic and biosynthetic activity (i.e. protein synthesis/DNA transcription is occuring)

Describe: - hyperthyroidism/hypothyroidsim metaplasia - salivary duct metaplasia - cervix dysplasia

Hyperplasia of thyroid gland: cuboidal cells become columnar, papillary infoldings, compressed follicles Hyperthyroidism metabplasia (become columnar) Hypothyroidism metaplasia (become squamos) Salivary duct metaplasia - columnar cells of the salivary duct are not as resistant and become a more resistant nonkeratinized stratified squamos epithelia (more protective; this can also be seen in the respiratory tract of smokers) Cervical dysplasia: - seen in the external os of the cervix where there is a transformation zone where epithelium transitions into a stratified squamos epithelium

Image of PAS stain of glycogen inclusions in liver hepatocytes

Image of PAS stain of glycogen inclusions in liver hepatocytes and EM images

When is immunofluorescence used? When is immunoperoxidase used?

Immunofluorescence is used in fluorescent microscopy Immunoperoxidase is used in light microscopy (antibodies bind to peroxidase enzyme)

The most common example of an ungated channel is the (...)?

K+ leak channel is most common ungated channel

Describe keratinized vs non-keratinized stratified squamous epithelia: - Where is keratinized/non-keratinized located? - Describe the difference in the cell characteristics between the two - What is pyknosis?

Keratinized: - epidermis - cells at apical end are the most differentiated and least viable - anucleate apical cells - As cells migrate apically, nuclei undergo pyknosis: irreversible condensation of chromatin in the nucleus of a cell undergoing necrosis or apoptosis - The anucleate, apical cells are filled with keratin, which offers protection from penetrating chemical and physical injury and prevents water loss and are readily sloughed/exfoliated Non-keratinized: - oral cavity, esophagus, vagina - Nuclei are seen in upper/apical layer - have viable apical cells with nuclei

Lipid droplets (cellular inclusions) in adrenal cortex image

Lipid droplets (cellular inclusions) in adrenal cortex image

What is a lipoma

Lipomas are the most common mesenchymal soft tissue tumor in adults- are benign neoplasms

Describe the ground substance: - What major macromolecules is it made up of?

Macromolecules: - Glycosaminoglycans (GAGs) (long polymers of repeating dissacharide units; these are the structures that look like a brush in the image)(their chemical makeup are what allow water to be so present in the ETC/ground subsance - Proteoglycans (hyaluronan and GAG complex connected via a Link protein) - Multiadhesive glycoproteins --> e.g. fibronectin, laminin (these connect ECM elements to one another and to cells; connects to hemidesmosomes) (laminin is part of the basal lamina and ECM) ground substance helps confer resistance to compressive forces

Describe the function of intermediate filaments Describe their formation- do they have polarity?

Maintenance of cell shape and contact between adjacent cells and the extracellular matrix Intermediate filaments are polymers of the protein vimentin in cells of mesenchymal origin (fibroblasts and osteoblasts) In epithelial cells, intermediate filaments consist of cytokeratins Intermediate filaments will dimerize together-->form staggered tetramers-->form profilaments that show no polarity (unlike microtubules and microfilaments)-->protofilaments come together to form the full filament

(Mallor trichrome was not covered in the pre-exam review) Describe the mallory trichrome stain: - what is it used to stain? - How is Masson trichrome different?

Mallory trichrome is particularly useful in demonstrating cells and small blood vessels of connective tissue. - Nuclei stain purple - Cytoplasm, keratin, and erythrocytes stain bright red or orange - Collagen stains bright or light blue Similar stains, such as masson trichrome and gomori trichrome, yield comparable results except that collagen stains blue-green or green

Describe mast cells, what they secrete and metachromasia

Mast cells: - components of loose CT - have strong basophilic granules in their cytoplasm - secrete heparin (anticoagulant; sulfated GAG molecule) and histamine (promotes vascular permeability, dilation of small blood vessels->muscle relaxation, and smooth muscle contraction of lungs, uterus, and stomach)

Describe the function of microtubules What are they made of? What occurs if hydrolysis of GTP is faster than addition of G-subunits? What is the name of the MT organizing center?

Provide internal support for the cell, are the basis of motility for certain organelles, such as cilia Act as the "roadways" for transport of secretory vesicles and other organelles to move and organize them within the cell Microtubules are polymers of alpha- and beta-tubulin proteins - these proteins form a heterodimer with eachother and come together to form a cylindrical microtubules - G-units are added to the plus end - Dynamic instability of microtubules: If hydrolysis of GTP is faster than the addition of the G-units, the MT will fall apart - Normal treadmilling must occur Centrosomes are the MT organizing centers and contain two centrioles

Describe the two types of pinocytosis (receptor-mediated and fluid-phase endocytosis)

Receptor-mediated pinocytosis/endocytosis involves the use of clathrin coats (e.g. uptake of low density lipoprotein-LDL) Fluid-phase endocytosis/pinocytosis involves the use of calveolae protein coats

Describe Wright-Giemsa stain: - what is it used to stain? - What color do nuclei stain? - What color do erythrocytes stain?

Wright-Giemsa stain is widely used on fixed cells of blood or bone marrow smears to demonstrate types of blood cells Nuclei of luekocytes stain purple and erythrocytes stain uniformly pink or pinkish orange (RBCs do not have a nucleus)

Do microvilli contain microfilaments?

Yes, they contain an actin and myosin skeleton

Which cells are the predominant CT cell type? What is their function? What is their function in the gingiva and PDL?

fibroblasts - synthesize fibers and ground substance (i.e. the ECM) --> elastin, adhesive glycoproteins, growth factors, cytokines, collagenase - migrate and divide during wound healing - can be active or quiescent (euchromatic or heterochromatic) In the gingiva and PDL, fibroblasts maintain the integrity of the dento-gigival junction and the attachment of the tooth root to the bone by mediating collagen turnover. - gingival fibroblasts mediate the synthesis and remodeling of gingival fiber attachments that insert into the root surfaces of teeth (bulk is type I collagen) - homeostasis of the PDL is maintained by the fibroblasts

What are the fixed and wandering cells of the CT?

fixed: - fibroblast - pericyte - adipocyte wandering/transient: - leukocytes - mast cells - macrophages

What substance is uniquely found in mitochondria cells?

lipoic acid

What are the functions of the golgi apparatus?

modifies and packages products/proteins/enzymes of the ER so that they can be transported via vesicles to the biosynthetic-secretory (e.g. secreted to the plasma membrane via secretory vesicles), endocytic-degradative (e.g. secreted to the endosomes/lysosomes), or retrieval pathways

What is marfan syndrome?

pathology of the elastic connective tissue

What is the name of the complex that degrades proteins?

proteasomes degrade proteins that have been ubiquinated

Describe elastic CT: - requires special staining - present in lungs, skin, urinary bladder, walls of arteries, mesentery

resorcin fuchsin, aldehyde fuchsin, and orcein stains and hematoxylin

Summary of types of epithelia

summary

The nuclear lamina is made of (...) filaments (not covered in pre-exam review)

the nuclear lamina is made of intermediate filaments

describe the difference between primary, secondary, and tertiary lysosomes What stain is used to see lysosomes Describe the M6P pathway to get hydrolytic enzymes packaged into primary lysosomal vesicles from the golgi

Primary lysosomes: - have only the degradative enzymes (hydrolytic enzymes) present and no debri Secondary lysosomes: - mature lysosomes that contain the debri/digested material Tertiary lysosomes: - oldest lysosomes, have completed digestive functions and are prominent in long-lived cells and often accumulate lipofuscin (wear and tear pigment) Lysosomes can be visualized with a toluidine blue stain in kidneys (they do not stain well with H&E) - they can be seen using fluorescent dyes or TEM where they appear as very dark, electron-dense M6P pathway - a mannose-6-phosphate is added to hydrolytic enzymes which then allows them to become recognized by internal membrane receptors in the trans golgi that bud off to become primary lysosomes (i.e. contain only lysosomal enzymes)

Why is polarization of actin filaments important? Describe treadmilling

Polarization of the microfilaments allows for the directional growth and function of the actin filaments (e.g. functions as filapodia and lamellapodia, can change the shape of the cell) Treadmilling is the process by which G-actin subunits/monomers are added to the plus end of the actin filament (F-filament) and are removed from the minus end of the filament (assembly and dissasembly

Describe prophase, metaphase, anaphase, telophase steps in mitosis

(a) During the relatively long prophase, the centrosomes move to opposite poles, the nuclear envelope disappears by fragmentation, and the chromosomes condense and become visible. (b) At the short metaphase, the chromosomes have become aligned at the equatorial plate as a result of their attachments to the dynamic microtubules of the mitotic spindle organized by the centrosomes. The spindle consists of kinetochore microtubules, polar microtubules which interdigitate near the equatorial plate, and shorter astral microtubules anchoring the spindle to the cell membrane (c) During anaphase, the kinetochores separate and the chromatids (now called chromosomes themselves) are pulled on their microtubules toward each centrosome. (d) In telophase, the cell pinches itself in two by contraction of the F-actin bundle in the cell cortex, after which the chromosomes decondense, transcription resumes, nucleoli reappear, and the nuclear lamina and nuclear envelope reassemble. IMPORTANT: The mitotic spindle is a microtubule-based machine. Actin and myosin II in the contractile ring generate the force for cytokinesis.

Describe the location of: - gap junctions - porins - aquaporins - ion channels

- Gap junctions located between adjacent cells(connect cytoplasm of two cells) - Porins are larg permissive pores in mitochondrial outer membrane - Aquaporins are permeable to water, and impermeable to ions (seen in kidney tubules) - Ion channels are seen everywhere (lots in neurons and muscle cells)

Describe the fibers and ground substance in the pulp: - which collagen fibers are predominant (2) - ground substance is composed of..? - greatest concentration of collagen occurs in the most (...) portion of the pulp

- fibers are principally type I and type III - Greatest concentration of collagen generally occurs in the most apical portion of the pulp - Ground substance is composed of GAGs, multiadhesion proteins (fibrins, lamelinins), and water ---> These support the cells and act as the medium for transport and nutrient delivery

Know the cellular inclusions: - lipofuscin - hemosiderin - glycogen - melanin - fat droplets -->Which are pigmented?

- lipofuscin (wear and tear pigment found in tertiary lysosomes)(found especially in non-dividing cells such as neurons, cardiac muscle) - hemosiderin (RBC breakdown component that appears in macrophages of the liver and spleen) - glycogen (glucose stores for energy, liver, muscle) - melanin (tyrosine and tyrosinase dark brown granules that protect cells from UV radiation) - fat droplets (energy, cushion, heat)

General features of the degradative pathways (to lysosomes)

- use membrane-enclosed vesicles - coupled to lysosomal system - require acidification - use hydrolases for degradation

What allows cilia to move/beating motion?

Presence of microtubules: - contain an Axoneme made of nine doublets of A and B (incomplete) microtubules - Because of the structure and organization of the microtubules in the axoneme, when the MTs attempt to slide, they are not able to and it results in a bending motion that gives the "beating" motion of cilia updwards towards the entrance of the oral cavity - Kinesin and dynein motor proteins are present and transport proteins into and out of the structure

Does a passive transporter depend on the solute binding site being occupied?

Passive movement of solute by transporters is reversible and does not depend on whether the solute binding site is occupied

Phase-contrast microscope changes the (...) so that the human eye can see cells better What is the difference between Differential Interference Contrast (DIC) microscopy and phase-contrast microscopy images?

Phase-contrast microscope changes the amplitude so that the human eye can see cells better due to increased contrast Differential interference contrast microscopy (DIC) (does not have as much contrast as phase-contrast microscope) helps give a more 3D image by separating and recombining a polarized light beam

Pigment deposits: hemosiderin granulues image

Pigment deposits: hemosiderin granulues image

Pigment deposits: lipfuscin, melanin image

Pigment deposits: lipfuscin, melanin image

Microscopy: - A good objective must have a high (...) - What is resolving power? - Which instrument provides the highest resolution?

A good objective must have a high resolution (aka resolving power) Resolving power is the smallest distance between two structures at which they can be seen as separate objects TEM (transmission electron microscopy) has the highest resolution 0.2 millimeters- human eye 0.2 micrometers- light microscope 10 nm- SEM 0.2nm- TEM

Describe adipose tissue: - what type of CT is it? - difference between white and brown adipose tissue?

Adipose tissue - loose CT White adipose tissue: cells contain one Unilocular fat droplet Brown adipose tissue: contains several small lipid droplets and have mitochondria that play roles in thermogenesis

Apocrine and holocrine images

Apocrine in mammary gland Holocrine in oil/sebaceous glands

Describe the difference between carcinomas, adenocarcinomas, mesothelioma, transitional cell carcinoma, and what is epithelial dysplasia?

Carcinomas: malignant neoplasms of surface epithelium Adenocarcinomas: malignant neoplasms originating from glandular epithelium Exposure to asbestos causes pleural mesothelioma; an aggressive tumor Transitional cell carcinoma of the urinary tract Epithelial dysplasia is a premalignant change in epithelium

What are the key features of vesiclar transport?

Coats (clathrin, calveolin, COPI, COPII) - clathrin coats are used in receptor mediated endocytosis and for transport of vesicles to the early endosome/lysosomes - COPII to get vesicles from ER to cis golgi Small GTPases: - guide vesicle targeting SNAREs - snares mediate vesicle docking and membrane fusion to cell membrane

Describe collagen I biosynthesis in fibroblasts: - what is the entire process dependent on?

Collagen I biosynthesis is dependent on Vitamin C hydroxylation of prolyl and lysyl residues 1) alpha chains (filamentous peptides) 2) Procollagen molecule (triple helix) 3) Collagen molecule is formed as a result of the cleavage of the N- and C- terminus renders collagen insoluble 4) Collagen fibril forms when collagen molecules come together via covalent cross-links -->form in a staggered formation that results in a band appearance

Connective tissue proper can be classified as loose (areolar) or dense, mostly on the basis of the proportion and density of (...) components of the ECM

Connective tissue proper can be classified as loose (areolar) or dense, mostly on the basis of the proportion and density of fibrous components of the ECM

Describe constitutive and regulated secretion

Constitutive secretion is used primarily to replenish material in the plasma membrane and certain membrane-bound organelles Regulated secretion terminates at the secretory vesicles that store secreted material until a signal triggers fusion with the plasma membrane (e.g. extracellular hormone/NT signal will cause the fusion of a secretory vesicle with the PM)

Describe reticular CT: - what type of collagen does it contain? Does this form bundles? - what stain is used? - present in liver sinusoids, lymph nodes, bone marrow

Contains Type III collagen (does NOT form bundles) - Silver salt (argyrophilia) stains present in liver sinusoids, lymph nodes, and bone marrow

What are the principal functions of epithelial cells

Covering, lining, and protecting surfaces (e.g. epidermis) Absorption (e.g. intestinal lining) Secretion (e.g. parenchymal cells of glands) - All substances that enter or leave an organ must cross this type of tissue - They adhere strongly to one another and to a thin layer of extracellular matrix

In fluorescent microscopy, what does DAPI stain bind to?

DAPI binds to nucleic acids (e.g. DNA/RNA) Fluorescein-phalloidin are binding to actin filaments in this image

Describe dense irregular vs dense regular CT - where are they each located - which contain fibroblasts and which contain fibrocytes

Dense irregular: - seen in the dermis of skin (reticular layer), capsules of organs (e.g. testes) - commonly forms the layer beneath the epithelial lining of many organs and filling spaces between fibers of muscle and nerve. - contains fibers and ground substance in roughly equal parts - randomly arranged collagen - resists pull in different directions - most numerous cells are fibroblasts Dense regular: - parallel fibers - tendons, ligaments, cornea of eye - resists pull in one direction - contain collagen and elastic fibers - thin fenestrated sheets - most cells are fibrocytes (they replace unfunctional/damaged CT)

Glandular epithelium classifications Distance traveled: - autocrine - paracrine - endocrine - exocrine Nature of secretion: - serous - mucous - mixed - hormone

Distance traveled: - Autocrine (e.g. platelet cells) - Paracrine (e.g. tetses) - Endocrine (hormones via blood; e.g. adrenal, thyroid) - Exocrine (duct carries secretion; e.g. salivary) Nature of secretion: - Serous (proteins, zymogen granules with enzymes, sweat, water) - Mucous (rich in glycoproteins-PAS stain, lubrication, barrier) - Mixed (demilunes) - Hormone (endocrine)

Glandular epithelium classifications Mode of secretion: - merocrine - apocrine - holocrine Cell number: - unicellular (goblet cells secrete mucin) - mulitcellular: -->secretory unit (tubular, acinar, alveolar) -->duct (simple, compound)

Mode of secretion: - Merocrine (most common, exocytosis via secretory vesicles, salivary, parotid, pancreas, sweat) - Apocrine (goblet cell, ceruminous, axillary, mammary)(Pinching off of apical portion of secretory cell) - Holocrine (Disintegrating whole cells with contents that become the secretion)(Have a basal layer that is continuously being produced)(oily sebum from sebaceous gland of skin) Cell number: - unicellular (goblet cells secrete mucin) - mulitcellular: -->secretory unit (tubular, acinar, alveolar) -->duct (simple->ducts do not branch; compound-->ducts from several secretory units converge into larger ducts)

Know gingival squamous cell carcinoma: - what does it originate as? - what occurs and causes it to metastasize?

Most common oral cancer Originates as epithelial dysplasia and is characterized by proliferation of dysplastic squamos cells on the surface of the epithelial layer, which subsequently degrades the subepithelial basement membrane Degradation of the BM results in local destruction and distant invasion via metastasis --> this destruction of the BM is what causes the metastasis

What is a myxoma: - what causes it?

Myxoma is a pathology of the mesenchyme Odontogenic myxoma is a benign jaw tumor arising from embryonic CT (mesencyme)

Describe the NISSL stain (cresyl violet acetate): - what does it stain/bind to? - is it acidic or basic?

NISSL stain (cresyl violet acetate) binds to RER (clusters of free ribosomes/rRNA), polysomes, and nucleuolus. - thus you will only see this stain in the soma of neurons and in dendrites a little, but NOT axons It is a basic dye (i.e. binds to acidic/basophilic substances, anions)(similar to hematoxylin)(i.e. binds to basophilic structures- "base loving"-->these structures are acidic-->opposites attract)

Does the golgi apparatus stain well with H&E? Why? What does stain the golgi well

No, the golgi region will appear as a negative image near the nucleus - carbs are not stained well by H&E (will appear as negative/white areas in cells when they are stained w H&E) but are stained well by PAS staining or potassium dichromate and silver nitrate - But secretory vesicles released from the golgi that contain granules will often show as intensely eosinophilic structures (e.g. pink/eosinophilic areas of the zymogen granules in pancreatic acinar cells)

Which organelles have a double plasma membrane?

Nuclear envelope, mitochondria, and autophagic vacuoles

Summary of locations of: - loose (areolar) and dense (irregular, regular) CT - Specialized forms of CT (adipose, elastic, reticular) - Embryonic CT (mesenchyme, mucous)

Omentum: a sheet of fatty tissue that stretches over the abdomen Mucous (Wharton's jelly)

Describe role of osmium tetroxide in TEM

Osmium tetroxide acts as a fixative and stain (lipid stain) in order to provide contrast Will give a clear image of the membranes of the cell and its organelles in TEM: - It binds to unsaturated phospholipid polar head regions in the cell membranes (trilamellar membrane) thus providing detailed outlines of organelles in the cell (especially in TEM)

Describe the difference between P-type pump, F-type/V-type pump, and ABC transporter

P-type pump uses hydrolysis of ATP to change conformation to move ions across membrane (e.g. Na/K ATP-synthase) --e.g. Ca2+ pump in SR of muscle cells F-type/V-type pumps will synthesize ATP in response to the movement of H+ through the pump (e.g. proton pump in oxidative phosphorylation) ABC transporter primarily pump small molecules across membranes (not ions)

Describe the Periodic Acid-Schiff (PAS) stain (purple-magenta): - What structures and molecules does it stain?

PAS stain (purple-magenta) oxidizes and stains carbohydrates/sugars/glycogen -> cells filled with mucin granules, glycogen deposits, the glycocalyx, or carbohydrate-rich ETC structures such as the basement membranes. -->Goblet cells seen in the lining of the small intestine basement membranes (stains with PAS because they are carbohydrate-rich, especially in the renal corpuscles of the kidney)

Describe the components of the muscle fiber/cell: - sarcolemma (T-tubules) - nuclei - Sarcoplasm - Sarcosomes (mitochondria) - SR (terminal cisternae) - Collagenous external (basal) lamina

Sarcolemma (T-tubules) - The sarcolemma is the plasma membrane of the muscle fiber/cell - it is composed of T-tubules that transverse the muscle fibers along the myofibrils (form a muscle triad with the terminal cisternae/SR) Nuclei - skeletal muscle cells/fibers are multinucleated and their nuclei are pushed the the periphery of the muscle fibers Sarcoplasm - this is the cytoplasm of the muscle fiber Sarcosomes (mitochondria) - many mitochondria (heart muscle contains the most) SR (terminal cisternae) - This is the smooth endoplasmic reticulum of muscle cells and is extremely important as it acts as a store for Ca2+ - the terminal cisternae run on either side of the sarcolemma t-tubules (muscle triad) and will release Ca2+ in response to a depolarization current that runs down the t-tubules Collagenous external (basal) lamina - ECM that surrounds the sarcolemma and is apart of the endomysium - satellite cells are associated with the basal lamina (similar to pericytes sharing the basement membrane of endothelial cells)

What are silver or gold stains used for?

Silver or gold salts (stains) have been developed to demonstrate filamentous structures in neurons and fibers of reticulin (type III collagen) - they stain dark brown or black - these stains have been largely replaced now by immunohistochemical procedures

What are the functions of the smooth and rough ER? - Which synthesizes steroids/lipids? - Which is the site for N-linked glycosylation?

Smooth ER: - site of lipid synthesis (steroid secreting cells) and carbohydrate metabolism (glycogen to glucose in liver) - detoxification of drugs and alcohol (P450 enzyme in liver hepatocytes) - acts as a calcium store in muscle cells->sarcoplasmic reticulum Rough ER: - synthesis of transmembrane, secretory, and lysosomal proteins -->synthesizes proteins for secretion, incorporation into the plasma membrane, and as enzymes/hydrolases within lysosomes - has attached ribosomes hat function in transmembrane protein synthesis - Site of N-linked glycosylation

Image of adherens junctions, spot desmosomes, hemisesmosomes, and tight junctions

Spot desmosomes/Macular adherens and their intermediate filaments (IF) Hemidesmosomes (H) connected to integrin to the basal lamina (type IV collagen)

(Probably don't need to know this) Describe combinations of stains: picrosirius-hematoxylin (PSH): - what color does it stain collagen and what color cytoplasm? - Is collagen stained with picrosirius red birefringent?

Stains collagen red and cytoplasm a lighter violet or pink - nuclei will be purple if also stained with hematoxylin Under the polarizing microscope, collagen stained with picrosirius red is birefringent and can be detected specifically

Describe the specializations at the apical domain: Stereocilia: - what is their purpose/function - do they contain MTs? - Where are they located?

Stereocilia: - present in the epididymis - Role is to increase the absorptive surface area - similar to microvilli in that they contain actin filaments, but No MTs - They are much longer than microvilli and often have distal branching

Stratified Cuboidal and Stratified Columnar epithelium - locations for each

Stratified Cuboidal: - Sweat Gland - Esophagal mucous gland/duct Stratified Columnar: - Male urethra - Palpebral conjuctiva (eye lid)

What do Sudan black and Oil Red O stain? - how do you obtain a cell sample that contains lipids and which step are they normally removed in?

Sudan black and Oil Red O stain lipids Lipids are normally not present in tissue samples because the lipids have been removed during the dehydration process with ethanol. In order to preserve the lipids, the dehydration process is eliminated and the sample is frozen/prepared as a cryosection in order to preserve the lipids in the sample and then will be stained with sudan black, oil red O, (or Osm Tetrx?)

TEM image of plasma membrane with visible actin filaments

TEM image of plasma membrane with visible actin filaments

Electron microscopy: - Describe the main difference between TEM and SEM - Which has the highest resolution/resolving power? - In order to increase the resolution (resolving power), you must use a smaller or larger wavelength?

TEM images come out in 2D (you need a thin/ultrathin specimen), but have the highest resolution/resolving power and allow you to see details and borders of the organelles. Osmium tetroxide is used as heavy metal stain and a fixative for lipids in TEM SEM uses a metal coat (gold) and gives you a 3D surface image of the sample (use a thick tissue sample) In order to increase the resolution, you must use a much smaller wavelength (resolution is inversely proportional to wavelength)(DeBroglie wavelength associated with electrons is a thousand times smaller than 1eV photon-->photons used in light microscopy) A main difference between SEM and TEM is that SEM creates an image by detecting reflected or knocked-off electrons, while TEM uses transmitted electrons (electrons that are passing through the sample) to create an image.

(not covered in pre-exam review) The phospholipid distribution within the plasma membrane is asymmetric or symmetric? Where are glycolipids found?

The phospholipid distribution is asymmetric Phosphatidyl(P)-choline and sphingomyelin are overrepresented in the outer leaflet P-serine (negative charge) and P-ethanolamine are predominately found on the inner leaflet Glycolipids occur only on the outer face where they contribute to the extracellular glycocalyx - glycolipids and glycoproteins form the glycocalyx (cell coat)(this is part of the cell membrane)

What cells do all CT arise from? What cells does connective tissue consist of? The functions of CT depend largely on the properties of the (...), which predominates.

The undifferentiated mesenchyme Connective or supportive tissues consist of cells, both fixed and wandering, and an ECM composed of fibers embedded in an amorphous ground substance - Cells of the CT include fibroblasts, mast cells, macrophages, plasma cells, adipocytes, and pericytes The many functions of CT depend largely on the properties of the ECM, which predomiates.

What are resorcin fuchsin, aldehyde fuchsin, and orcein used to stain?

These are used to stain elastin and distinguish elastic structures from collagen. Most of which stain the elastin-rich structures brown or shades of purple

Describe the interecellular adhesions, other junctions and their respective proteins: Tight Junctions Anchoring junctions: - zonula adherens - macular adherens (spot desmosomes) - hemidesmosomes Gap junctions

Tight junctions: - made up of occludin proteins and hold adjacent cells together tightly and prevent paracellular transport through the apical surface, but not necessarily the basement Anchoring junctions (made up of cadherins and catenin proteins): Zonula adherens - belt-like and are connected to actin filaments inside the cell Macular adherens: - spot desmosomes; located to a specific spot and are connected to intermediate filaments that are connected to other macular adherens Hemidesmosomes: - connect the cell with the basal lamina (made up of integrin proteins that connect with the ECM) Gap junctions: - form channels that connect the cytoplasm of one cell to the cytoplasm of the adjacent cells via connexin proteins

Describe toluidine blue (aka pararosaniline-toluidine blue)(PT): - what does it stain? (toluidine blue was NOT covered in the pre-exam review) - what is metachromasia? (occurs to mast cells)(this was)

Toluidine blue is commonly used for differential staining of cellular components, particularly cytoplasmic granules (e.g. mast cells) Mast cells have prominent metachromatic granules. - Metachromasia is the property whereby the granules stain with a color different from that of the dye itself. Toluidine blue stains chromatin shades of purple and cytoplasm and collagen a lighter violet. This stain penetrates more readily than H&E and are used primarily with acrylic resin-embedded sections to provide better detail of cell and tissue structures.

Describe Transitional Epithelium (Eurothelium): - Functions (absorption, secretion) - Locations (urinary system- ureters, urethra, urinary bladder) - What do the cells look like when the bladder is stretched/unstretched?

Transitional epithelium/eurothelium ONLY appears in the urinary system Unstretched (empty bladder/contracted): - the epithelium is compressed together and appears to be taller/have more layers because the cells become dome-shaped Stretched (filled bladder/distended): - distended urothelium appears to have fewer layers with flat, squamous-like apical cells

Describe the regulation of cell cycle checkpoints with cyclin-dependent kinases - where are the three cyclin checkpoints in the cycle?

Transitions in the cell cycle from one phase to the next are regulated by protein kinases (cyclin-dependent kinase, Cdk) whose activity depends on a special class of proteins, cyclins G1/S-Cdk checkpoint: - is the environment favorable? If so, proceed to S-phase (DNA replication phase) S-Cdk: - present from the beginning and throughout the S-phase and until metaphase-anaphase transition/checkpoint of the mitotic (M) phase M-Cdk/G2 checkpoint: - Is DNA replicated? - Is the environment favorable? - If so, then enter into the Mitotic (M) phase

Describe location of Type I, II, III, and IV collagen

Type I- tendons, organs capsules, dermis Type II- cartilage Type III- reticular fibers Type IV- basal lamina

(probably won't be on exam) What type of collagen attaches the basal lamina to the underlying connective tissue? (note: it is not the collagen present in the reticular lamina)

Type VII collagen attaches the basal laminae to underlying connective tissue Basal lamina contains type IV collagen Reticular lamina contains type III collagen

Describe the active transport of coupled-transporters (uniport, symport, antiport)

Uniport: transport of a single solute from one side to the other Coupled carries: - symport: transfer two different solutes simultanously to the same side of the membrane - antiport: transfer of solutes in opposite directions simultaneously --> coupled carries transport is driven by the coupling of the uphill transport of one solute with the downhill transport of another solute

What occurs if a person has a Vitamin C deficiency? What are the oral manifestations?

Vit C deficiency will result in scurvy - lack of Vit C prevents ability for collagen to synthesise (Vit C cannot be used in hydroxylation of prolyl and lysyl residues) - results in nonhydroxylated, unstable collagen fibrils that fail to form a triple helix and have low tensile strength Oral manifestations include swollen bleeding gingiva and loss of teeth due to defects in periodontal collagen fibers