Histology exam 1 Flashcards
Resolution of Human eye, Light microscope, and Electron microscope
0.2 mm, 0.2 um (200 nm), and 0.2 nm (2 A angstroms)
Size of Red blood cell
7.8 um (micro-meters)
Most common fixative
Formalin (Formaldehyde)
Hematoxylin stains…….
Nucleic acids
Eosin stains…….
Proteins
Toluidine Blue
(+) charged basic dye, that stains acidic (-) charged molecules.
Also metachromasic (it can change color) to Purple for glycogen and other things.
H&E
Hematoxylin is a basic dye, that stains acidic molecules (dark blue color). Eosin is a acidic dye, that stains basic molecules (red-pink color).
- Does not detect sugars
Acidophilia or Acidophilic
Things that “love acid” and therefore are basic. They would be stained by Eosin.
Ex. Cytoplasmic or Secretory proteins (Proteins are basic)
Basophilia or Basophilic
Things that “love base” and therefore are acidic. They would be stained by Hematoxylin.
Ex. rER, heterochromatin, nucleoli (Nucleic acids are acidic)
Na+
K+
Cl-
Ca 2+
(Cytoplasmic [], Extracellular [] )
5-15 mM, 145 mM (Na+)
140 mM, 5 mM (K+)
5-15 mM, 110 mM (Cl-)
0.2 uM
mM = milli-Molar uM = micro-Molar
Micro-filaments
Made up of: Actin
Microtubules
Made up of: Tubules
Intermediate Filaments
Made up of: Inter Fil. proteins such as Keratin or Vimentin
Cytoskeleton
Made up of: Microfilaments, Microtubules, and Intermediate Filaments.
Cannot be seen on normal H&E stain with LM as it is smaller than 200 nm.
1 ) Allows for movement of stuff within cell
2) Separation of chromosomes during mitosis
3) Changes the cell shape during specific functions (phagocytosis, cytokineses)
Heterochromatin
Dark staining chromatin that is transcripionally inactive
Euchromatin
Light staining chromatin that is transcriptionally active
Nucleolus (Nucleoli)
Dark staining area within the Nucleus that is transcritionally active and synthesizes rRNA and assembly of ribosomal subunits.
Mitochondria
Makes heat
Double stranded CIRCULAR dna
Makes its own tRNA, rRNA, and mRNA
Residual Bodies / Lipofuscin
Lysosomes with undegraded substances. Are created to protect the cell from adverse effects of partially degraded molecules.
sER
Responsible for lipid synthesis, steps in hormone production (P450), and detoxification.
Site of Ca 2+ storage.
Secretory pathway (simple)
rER»_space; Golgi»_space; Vesicle»_space; Plasma membrane
N-linked Glycosylation
Added to the side chain of Asparagine. Occurs in the rER and is modified in the Golgi.
O-linked Glycosylation
Sugars are added to the oxygen atom in the side chains of serine, threonine, hydroxiproline, and hydroxylysine. Occurs in the Golgi and are not modified.
Endocytosis pathways
1) Recycling (Absorbed to be Excreted)
2) Transcytosis (Passing right through)
3) Degradation (Absorbed to be broken down)
Difference between recycling and transcytosis is where the vesicles end up. Recycling is on the same side (apical-apical). Transcytosis is on different sides (apical-basal).
Familia Hypercholesterolemia
Characterized by high serum cholesterol due to low LDL clearance by liver. Caused by mutations that impair normal receptor mediated endocytosis of LDL.
Epidermolysis Bullosa Simplex
EB Simplex is the most common form of EB and results in fragile skin due to absence of keratin 14 that keeps the intraepidermal layer together. Due to mutation of KRT14 gene.
Lipids stained with Toludine Blue are what color
black (appears as small black dots can be bigger)
4 types of tissue
Epithelial
Connective, (CT proper, Specialized CT [ adipose, blood, bone, cartilage, lymphatic, hemopoietic]
Nerve
Muscle
Name the junctions of an Epithelial cell from apical to basal**
1) Tight Junctions (Seals gap between cells)
2) Adherens Junctions (Connect actin filament bundle in one cell to another)
3) Gap Junctions ( Allow passage of stuff from one cell to another)
4) Desmosomes ( Connects intermediate filaments in one cell to another)
5) Hemidesmosomes (Connect epithelial cells to basal lamina)
What is/makes up the basal lamina
Basal Lamina is the ECM layer at the basal surface of all epithelial.
Made up of: Collagen 4 (forms a network rather than fibril) Laminin Nidogen Perlecan
Different classifications of epithelial
Simple squamous, Simple columnar, Simple cuboidal
Stratified squamous, Stratified columnar,
Stratified cubodial
What kind of epithelial is in the trachea
Psuedostratified columnar cells
Simple squamous epithelial that lines blood vessels
Endothelium
Simple squamous epithelial that lines body cavities
Mesothelium
Thin skin, Thick skin, Specific tissues (ex. Oral epithelium)
Keratinized (but thin layer), Keratinized (but thick layer)
Not Keratinized
Microvilla vs Cillia
Microvilla are made up of actin, non force generating
Cilia are made up of microtubules, force generating
Two kinds of glands
Exocrine and Endocrine
Exocrine glands
1) Secrete products into ducts
2) Have a secretory and duct portion
3) Secretory epithelium is called glandular epithelium
Exs: Acinus (have granules focused around the lumen at the center, mushroom shaped)
Endocrine glands
1) Do not have ducts
2) Secrete product into blood
3) Highly vascularized
Secretory Mechanisms**
Merocrine: “regular” normal exocytosis (endocrine glands only option)
Aporine: Whats being transported takes some of the membrane (Mammary)
Holocrine: Cell ruptures releasing its contents (Sebaceous)
Goblet cells
Unicellular exocrine glands in the epithelium that secrete mucus to their apical surface.
Tight junctions
Consist of Occludin, and Claudin
1) regulate diffusion between cells
2) separate apical and basolateral membranes
Adherin junctions
Consist of Cadherin proteins
1) provide strength by crosslinking actin filaments between cells
Adherin junctions
Consist of Cadherin proteins (catenins and vinculin)
1) provide strength by cross-linking actin filaments between cells
Desmosomes
Consist of non-classical Cadherins (desmocolin and desmoglein)
1) provide strength by attaching intermediate filaments
Gap Junctions
Consist of 2 connexons
1) Water-filled channels that transport small molecules
Intermediate Filaments
Formed by symmetrical monomers.
Non-charged ends so no motor proteins.
Main function is tensile strength and mechanical support.
Intermediate Filaments
Formed by symmetrical monomers.
Non-charged ends so no motor proteins.
Main function is tensile strength and mechanical support.
Main type is KERATINS which strength anchorage to desmosomes/hemidesmosomes.
Microfilaments
Formed by globular (G-actin) monomers.
Charged ends so motor proteins present specifically myosin.
Type 2 myosin is found in muscle.
Type 1 myosin is attach to membranes
Michrotubules
Formed with tubulin dimers.
Charged ends so motor proteins present specifically Kinesin and Dyneins.
No structural role they are the highways.
Kinesins move toward + end
Dyneins move toward - end
Primary Ciliary Dyskinesia
Absence of sperm motility due to dynein arm defects in the sperm flagella.
Connective Tissue vs Epithelia
Epithelia is not vascularized CT is
In CT cells are surrounded by extracellular matrix. In epithelia cells are linked together by junctions.
Loose CT
Characterized by more cells and less ECM
Dense CT
Characterized by more ECM and less cells.
Can be either irregular or regular.
Regular - collagen fibers are oriented in one direction (ex. tendon)
Irregular - collagen fibers are oriented in different directions (ex. dermis)
Fixed vs Wandering/Transient (?)
Fixed = unable to exit the tissue its in Wandering = Able to exit/enter a tissue
Extracellular Matrix (ECM)
Made up of: Fibers and Ground Substance
ECM is linked to (1) basal lamina and (2) external lamina synthesized by fat, muscle, and Schwann cells.
Ground Substance
Consists of: glycoasminoglycans (GAGs), proteoglycans (PGs), and multiadhesive proteins.
*Main function of GAGs and PGs is to organize water to resist compressive stress.
ECM is like (what real life thing)
Reinforced Concrete
Fibers: The steel bars. They resist tension and torsion
Ground substance: The concrete. It resists compression torsion and shear.
*Concrete is made up of: GAGs and PGs (aggregate), MAGs (cement), and tissue fluid (the water).
Reticular fibers
Consist of: Type 3 collagen.
Form networks and are made by reticular cells, fibroblasts, smooth muscle cells, and Schwann cells.
What type of collagen is in the basal lamina
Type 4
Vitamin C Deficiency causes what? why?
Causes Scurvy.
This is because weak fibrils lead to classic CT dysfunction.
Hydroxylase enzyme requires vitamin C to function. Hydroxylase is needed to make collagen.
Few hydroxylproline»_space; less stable collagen monomers»_space; Weak Fibrils
Few hydroxylysines»_space; fewer covalent crosslinks»_space; weak fibrils
Type 7 collagen
an anchoring fibril that links the basal lamina to CT.
Osteogenesis imperfecta (OI) []
Brittle bone disease (work)
Ehlers-Danlos syndrome (EDS)
(work)
Terminal Web
The attachment point for apical filaments within microvilli
Terminal Bar
A group of junctional complexes.
Elastic Fibers
Main function is to provide deformability and resilience rather than tensile strength.
Created by a Elastin core and microfibril sheath.
Scleroderma
Characterized by: Chronic inflammation stimulates fibroblasts to make excess collagen resulting in thickening/tightening of skin
Type 1 Collagen Synthesis
1) creation of pro-aplha chain
2) Hydroxylation of prolines and lysines (requires vitamin C and O2)
3) Self-assembly of 3 pro-alpha chains -> 1 procollagen triple helix
4) Secretion via merocrine secretion
5) Removal of propeptides to allow for polymerization
6) Self-assembly into fibrils.
7) Certain lysine and hydroxlysine side chains are turned into aldehydes to form covalent cross links (requires vitamin C and O2)
Marfan Syndrome
Mutations in the fibrillin 1 gene. This abnormal fibrillin prevents elastin protein assembly.
Type 1 Collagin
Found in: Bone, skin, tendons, ligaments
90% of body collagen
Made by: Fibroblasts, tendinocyte, osteoblast
Proteoglycans
Core proteins attached to GAGs important part of the ECM.
Glycosaminoglycans (GAGs)
Long oligosaccharide chains that are negatively charged and favor a highly hydrated state.
ex. Hyaluronan (hyaluronic acid), chondroitin sulfate, dermatan sulfate, keratan sulfate.
Hyaluronic Acid
a GAG that does not contain sulfate and not bound to a protein.
They organize water.
Multiadhesive proteins
Connect ground substance molecules to fibers in the ECM.
ex. Fibronectin
Tissue fluid
Created by blood plasma that seeps into CT from capillaries.
Carries nutrients and waste and eventually gets sent to the lymphatic capillaries where it becomes lymph.
Edema
Excess tissue fluid production without drainage.
What are the resident immune cells
Macrophage, Mast cell, and Plasma cell
What are the transient immune cells
Neutrophil, Eosinophil, Basophil, Lymphocyte
Layers of the Epidermis (apical to basal)
Stratum Corneum: Cornified layer with dead cells held together by desmosomes.
Stratum lucidum: Transition zone between live and dead cells.
Stratum granulosum:
Stratum spinosum: living cells or keratinocytes held together by desmosomes.
Stratum basale: Rests on the basal lamina contains stem cells.
4 major cell types in epidermal cells
Keratinocyte, Melanocyte (melanin producing cell), Langerhans cell (dendritic cells), Merkel cell (sensory amplifying cell)
Water barrier
Keratinocytes in the stratum corneum have a water barrier to prevent water loss.
consists of both proteins and lipids.
(specifically lipids are packaged into lamellar bodies by the golgi and sent to the extracellular lipid envelope)
Pemphigus Blistering Diseases
A group of diseases where antibodies are produced against desmoglein proteins which are essential for desmosomes. This weakens desmosomes and makes the epidermis unstable.
ex. pemphigus vulgaris
Bullous Pemphigoid
Antibodies are produced against hemidesmosomes. degrading proteins in hemidesmosomes leads to blistering due to the lifting of the basal layer.
Psoriasis
Caused by an excess proliferation of keratinocytes. Don’t allow keratinocytes time to apoptose leads to live cells in the corneum
Skin Cancers
Basal cell carcinoma: Most common, typically arises from follicular bulge.
Squamous cell carcinoma: Second most common atypical cells at all levels of epidermis.
Melanoma: Least common derived from melanocytes.
Melanocytes
Pigment producing cells in stratum basale. Difference in skin color is due to difference in rate of melanin degradation.
Different Sensory Receptors
Merkel cells, Meissner corpuscle, and Pacinian corpuscle
Merkel (stratum basale) & Meissner (papillae) cells detect touch.
Pacinian (dermis/hypodermis) senses pressure and vibration.
All are innervated by afferent neurons called (LTMR neurons)
Eccrine sweat glands
Secrete sweat onto skin surface for temp regulation.
Uses Merocrine secretion.
Innervated by sympathetic nervous system.
Apocrine sweat glands
Secretes proteins, lipids, carbohydrates into hair follicles to regulate growth of bacteria responsible for body odors
Uses Merocrine secretion.
Innervated by sympathetic nervous system.
Sebaceous glands
Functions - photoprotection, antimicrobial, and regulation of inflammation
Uses Holocrine secretion.
What are the types of cartilage?
Hyaline, Elastic, Fibrocartilage
What is a lacuna
A small space filled with a
Chondrocyte in cartilage
Osteocyte in bone
Bone vs Cartilage
Bone: Highly vascularized and innervated
Cartilage: Not vascularized and minimally innervated
Hyaline Cartilage
Function: Minimizes friction and resists compression.
Consists of: Type 2 collagen, ground substance, water 60%-80%.
Ex. Nose, larynx
Elastic Cartilage
Function: Provides flexibility
Structure: Hyaline artilage with elastic fibers. Type 2 collagen
Fibrous Cartilage
Function: Minimal blood/nerve supply, and resists mechanical stress.
Type 1 collagen
Intersitial growth
Cells divide in lacuna to form isogenous groups called nests. Inside growth.
Appositional growth
Cells divide in perichondrium. Outside growth.
Papillary dermis
Lies beneath the epidermis made up of loose CT
Specifics about eosinophils, neutrophils, Plasma Cells, Lymphocytes, Mast cell
Neutrophils are granulocytes with neutral staining granules and have 4 lobed nuclei.
Eosinophils are granulocytes with eosinophilic granules and a bi-lobed nucleous
Lymphocytes have a “halo”
Plasma Cell have basophilic cytoplasm, negative golgi, and a nucleous with a cart wheel heterochromatin pattern
