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Histology Module 1 things
UTHSCSA SoM Histology Module 1
Terms in this set (70)
common process used in LM staining
formalin fixed cells
Tissues stained with hematoxylin (basic dye, stains DNA) and eosin (acid dye, stains most everything else).
common process used in EM staining
glutaraldehyde/osmium tetroxide fixed cells.
Tissues stained with lead or uranium.
four major cell types
Cell Membrane/plasmalemma components
Two sheets of phospholipids "amphipathic" with a polar head and non polar tail.
Head: Glycerol phospho-conjugated with nitrogenous compound (serine, choline)
Tail: two long chain fatty acids covalently linked to glycerol component of polar head.
Types of integral membrane proteins and what they do
1.) Channel-forming proteins: selectively transport charged molecules in/out of cell- glucose, aa's, Ca+2
2.) Receptor Proteins: ligand binding membrane proteins and a "signal transducing mechanism". includes adenoreceptor and cAMP systems.
3.) adhesion proteins: many superfamilies of proteins including selectins, integrins and cadherins.
Types of membrane transport
1.) passive diffusion: works with conc. gradient.
2.) facilitated diffusion: works with concentration gradient. helps larger molecules move across
3.) active transport: costs energy, moves against gradients with "pores".
4.) bulk transport: secretion of large or small particles. Formation of vesicles.
components of the cellular matrix
organelles, inclusion bodies, cytoskeletal elements (microtubules, microfilaments, intermediate filaments).
components of nucleus
membranic envelope, nucleoprotein, RNA. Nucleoprotein refers to both echromatin (active) and heterochromatin (inactive - black colored).
Additionally, heterochromatin can be either constitutive- inactive for life (or at least a long time) or facultative (becomes active to act as RNA template.
Refers to the idea that when multiple X chromosomes are present, one will remain condensed as "Barr body".
Nuclear envelope structure
double membranes, continuous with ER. inner membrane has attachment proteins for filamentous proteins called "lamins"; important for maintaining shape.
structure/function of Smooth ER
NO ribosomes. involved in lipid synthesis and glycogen metabolism. Detoxification of metabolites, drugs, alcohol. Regulates calcium ion distribution
Structure/function of Rough ER
HAS ribosomes. initial deposit place for new proteins. pass into "reticulum lumen". Only involved with secretory and membrane proteins (cytoplasmic proteins are made on free ribosomes). Sends on to golgi with transfer vesicles.
function of Golgi apparatus
Takes proteins from RER and further modifies (glycosylation). These proteins go into vesicles and are either secretory granules or lysosomes.Make sure you know difference between cis (forming/convex side) and trans (maturing/concave side).
Constitutive vs. regulated secretion
Constitutive: unregulated, products tend to accumulate in cell.
Example: extracellular matrix produced by fibroblasts
Regulated: regulated, periodic.
Example: secretory granuals.
lysosomes: function, types
contains 40 or more hydrolase enzymes, importantly "acid phosphatase".
Types: primary lysosomes: new, small, powerful
secondary: primary lysosome +phagosome (has ingested material
tertiary bodies (also called residual) :Older, may contain material called "lipofuscin".
Cause of Tay-Sach's disease
In lysosomes, deficiency in hexosaminidase A results in accumulation of ganglioside, a normally metabolizable material
formes from SER. involved in oxidation of fatty acids for energy/heat production. produce hydrogen peroxide. Defects can result in accumulation of fatty acids in cells (adrenoleukodystrophy).
cytosolic protein complexes that have a core particle and a regulatory particle. Ubiquitin is used to target a molecule for degredation. Usually smaller proteins are destroyed by this.
Mitochondrial layers and features
1.) Outer membrane - permeable to small ions, site of enzymes used for selected lipid substrates.
2.) Inner mitochondrial membrane - impermeable to small ions, thinner. Form cristae ,site of aerobic respiration enzymes. Attachement site for elementary particles (coupling for ETC)
3.) Mitochondrial matrix - amorphous material. stores ca2+ molecules, Kreb cycle stuff. location of mito DNA and ribosomes.
Lipid droplets (adipose), glycogen granules (in liver cell especially). Also pathological inclusion bodies.
microtubules structure, function
Found everywhere except RBCs. Polymerize out from the Microtubule Organizing Center (MTOC). composed of an alpha-beta tubulin heterodimer and 13 tubulin filaments in a spiral. Function is related to MAPs- act as a railtrack for proteins to move along - aid movement of cilia, cell support, cell division, movement of organelles.
Microtubule Associated Proteins (MAP)
associated with microtubules via copolymerization with alpha-beta dimer. Each MAP only moves in one polar direction, but can be either polar direction.
Structure of cilia/flagella
9 microtubule doublets ( complete microtubule + atached incomplete microtubule). 9X2 + 2 arrangement (axoneme and dynein arms). the proximal axoneme of the cilium is a basal body, the distal axoneme extends into the cytoplasm and cell membrane.
9 microtubule triplets with NO centrally located microtubules or dynein arms. Usually present as a pair, and are responsible for "nucleation". Also act as site of growth of spindle microtubules for cell division. Finally, nesprin (on the outside of nucleus) and sun (inner side of nucleus) help centrioles keep nucleus in a special site of a cell.
inhibits tubulin polymerization used to treat gouty arthritis pain and inflammation. Inhibits leukocyte migration and phagocytosis.
Found in every cell. helps with various types of intracellular networks. Muscle cells especially use actin and myosin for contraction. Also work with cytokinesis, locomution of motile cells, the terminal web to attach the zonula adherens, organelle movement and microvilli function. IMPORTANT: help with neutrophil movement for inflammation. Defects in this can lead to some bacterial infection (especially with diabetes mellitus).
Actin-scavenger system / actin toxicity
Actin released from dying cells into extracellular spaces. Lots of this can lead to shock, hepatic necrosis, respiratory syndromes and pregnancy issues. Also can interrupt vascular flow.
To prevent this, gelsolin attaches to actin filament and disassembles to G actin complex .this is bound to Gc Protein, and the complex is taken up by hepatocytes for degredation and excretion.
help position various organelles. Involves 2 coiled polypeptides; non-polar. Often found with microtubules. Specific cell types have specific types of filaments (see pg. 27).
Cancer example- can be used to find origin of the growth.
Alzheimer's disease : pts. with this have "neurofibrillary tangles" in cytoplasm of neuron. These are neurofilaments all tangled together. Down's syndrome has similar issues.
Cell Adhesion Molecules (CAMs)
immunoglobulin (Ig): bind integrins or other Ig CAMs.
Integrins: binds Ig CAMs or extracellular matrix
Cadherins: binds other cadherins between cells at cell junctions. remember that they will have e or n or p in front of it depending on what they belong to (epithelial, neurons and placenta).
Selectins: bind fucosylated carbohydrates (mucins). will also have letters in front of it - (e for endothelial, l for leukocytes and p for platelets)
USES: cell migration, holding tissues together, inflmamation, wound healing.
zonula occludens ("tight junctions")
virtually impermeable to fluid. many sealing strands interconnected that transverse both membranes. Major types the claudins and occludins. they also block the movement of membrane proteins between the apical and basolateral sufaces and stop ions from travelling as well.
zonula adherens ("belt junctions")
protein complexes comprised of cadherin, alpha catenin and beta catenin. adherens may serve to maintain actin contractile rings.
macula adherens ("spot junctions" or desmosomes)
spot like adhesions randomly arranged on lateral sides of plasma membranes. Help resist shearing forces found in squamous epithelium and in muscle tissue. If these are torn apart, then fluid can move in between the layers, forming blistering. DISEASE: pemphigus vulagaris - pts. with this will often have antibodies to desmosomal cadherns.
gap junctions ("nexus")
protein complex (connexon) forms a transmembrane hemipore that allows for ion transfer between the two cells. allows for coordination of contraction of cardiac muscle cells, secretion of hormones from endocrine cells, cell proliferation between basal cells in epidermis of skin, signaling between adjacent neurons and astrocyte activity to regulate adjacent neurons.
functional efficiency of a nucleus
the measure of effective regulation of the activities of the cell's genetic material.
parts of nucleus
-inner membrane (defines the nucleus)
-outer membrane (continuous with RER)
-nuclear pores - channels for passive diffusion and regulated movement of bigger things
levels of DNA packing
1.) wrapped around 8 histones
2.) made into solenoids- helical structure w/ 6 nucleosomes per turn
3.) superhelical loops
4.) condensation into chromosomes (99% of total DNA - last 1% is in mitochondria)
the four types of chromosomes
1.) telocentric- the end of the chromosome is at the centromere. Rare
2.) Acrocentric - p arm has nub, then stalks (13, 14, 15, 21, 22). includes stalks and satellites.
3.) Submetacentric - p and q are assymetric but both present
4.) metacentric- p and q are roughly same size.
nucleolus structure function
"ribosome producing complex". common for protein producing cells. Prominent nucleoli can be found in neurons and Sertoli cells, "bulls-eye" regions. stalks of acrocentric chromosomes often have clusters of these, called "nucleolar organizer regions" (NOR). fade during cell division, reappear afterwards (since it becomes active).
formed of 8 spokes and a plug inside. transport stuff by either passive diffusion (small molecules, ions) or by active transport (via imortin alpha/beta). impaired transport can lead to lots of diseases. BRCA1, for instance, sometimes can't get into nucleus, and buildup in cytoplasm can point to breast cancer.
nuclear matrix components
lamin A, B, and C (for structure of nucleus)- anchor chromatin to inner membrane, keep structure. During prophase mitosis, lamins are phoshorylated, allowing membrane to be broken up and chromos to escape.
Outer nuclear membrane has nesprins (connect to actin cytoskeleton), centriole mictrubules and organelles.
Inner membrane has emerin, member of nuclear lamina-associated protein family. Dreifuss-Emery muscular dystrophy can occur as mutation in emerin gene.
stages of cell cycle
1.) G0 - nondividing cell or cell population; inactive.
2.) G1 - pre -DNA replication - variable length of time; will either go to S or go to G0.
3.) S phase - DNA replication (a few hours)
4.) G2 phase - post DNA replication phase - usually 2-3 hours.
Initiation of cell division
both external and internal stimulation. Growth factors from outside, and an intracellular second messenger system. Also cyclin from witihin increases during g1 phase, which promotes cdc2+/CDC28 kinase, itself a component of Maturation Promoting Factor (MPF).
role of p53 gene activation
if activated, cell with either arrest its cell cycle or commit apoptosis. p53 is expressed in response to DNA errors and depending on severity of issue, cell will stall or be destoyed.
signs of terminating cell division
started by growth inhibiting factors (TGB-beta, interferons and tumor necrosis factor).
1.) decreased cyclin levels
2.) spindle function
3.) maybe others?
when two acrocentric chromosomes fuse near centromeric region and lose short arms. Makes a karotype of 45 chromosomes. Commonly is 13 & 14. leads to healthy child but the child more likely to produce crazy children.
Epithelial derivations and locations
Ectoderm (forms epidermis of skin)
Endoderm (luminal lining of GI tract)
Mesoderm (lining of cardiovascular system - "endothelium" and lining of body cavities- "mesothelium"). Note that these two are not called "true" epithelia.
"true" epithelial cancer vs. cancer in mesoderm derived tissues
"true" refers only to cercinomas, found in ectoderm and endoderm derived tissues. Mesoderm derived tumors are referred to as "sarcomas".
Characteristics of epithelium
2.) minimal interaction with connective tissue
3.) polarized cells (can tell apical from basal)
4.) cell to cell junctions present
5.) cytokeratin defining intermediate filament
6.) innervated by non-myelinated free nerve endings
7.) basement membrane separates epithelium from CT.
basal lumina composition
Type IV collagen and laminin
Type III and VI collagen
Places where classifications of Epithelia lie
1.) simple squamous epithelium - found in endothelium, mesothelium, nephron (where materials need to be transported quickly
2.) simple cuboidal epithelium. found in ducts, thyroid follicles, primary ovary. (absorption, secretion, transport)
3.) simple columnar epithelium - found in GI tract, uterine lining, collecting tubules of kidney
4.) stratified squamous epithelium - found in epidermis, esophagus
5.) stratified cuboidal epithelium - found in late primary follicles, larger gladular ducts
6.) stratified columnar epithelium - rare in humans, some large ducts - well defined nuclei.
7.) pseudostratified columnar epithelium - epididymis, respiratory. no pattern to nuclei.
8.) transitional epithelium- dome shaped surface found in urinary system to expand the bladder.
secretory epithelia (glands) classification (structure)
composed of duct and secretory unit, generally. can be unbranched ducts ("simple"), branched ducts ("compound"), tubular secretory units, acinar secretory units (mucous), or coiled units (sweat)
exocrine gland classifications (modes of secretions)
can be Merocrine (eccrine) : fusion of secretory vesicles with cell membranes "exocytosis". EXAMPLE : anterior pituitary secretion of TISH
more specific Merocrine classifications
-serous secretion (watery stuff- pancreas)
-mucous secretion (viscous - serves to lubricate - Brunner's glands in duodenum
-Seromucous secretion (serous and mucous acini both - submandibullar gland)
Apocrine: release of secretory inclusions along with apical cytoplasm and cell membrane. EXAMPLE : mammary gland secretion of lipids w/milk
Holocrine : secretory product retained wihtin cell which dies - entire product released.
Endocrine gland regulatory factors
1.) metabolic (glucose or insulin)
2.) other hormones (pituitary TSH)
3.) nervous system (pregang. symp. axons).
1.)synthesized in the RER as a large , triple helixed "preprocollagen" molecule.
2.) modified in RER into procollagen - transferred to Golgi
3.) Golgi modifies, secretes from cell with a protease
4.) OUTSIDE cell, protease converts procollagen into tropocollagen , which self-assembles into collagen fibrils EXTRACELLULARLY
connective tissue components
collagen, proteoglycans (GAGs) (link collagen fibers together). GAGs exhibit lots of - charges, attracts cations and water. makes a hydrated gel.
collagen fibers- structure and function
Synthesized in fibroblasts, some smooth muscle cells, osteoblasts and chondroblasts. Found in all connective tissues. Genetic defects cna cause Ehlers-Danlos syndrome and Stickler syndrome.
Reticular fibers- structure, etc.
Type III collagen. Functions with "scaffolding" of lymphoid tissues and bone marrow. Made by fibroblasts in loose CT and by reticular cells in lymphoid tissues. Highly glycosylated.
Elastic fibers- structure, function
Amorphous protein "elastin" with microfibrillar glycoprotein, "fibrillin". Made by smooth muscle cells, fibroblasts, chondroblasts. Not easily seen. NOT technically a collagen. Highly pliable and elastic.
Fibroblast seen in loose CT and damaged CT - it's active and will be fatter and lighter in color.
Fibrocytes seen in dense CT. will be narrow and dark.
BOTH synthesize all major components of extracellular matrix.
produces reticular fibers in hematopoietic and lymphoid tissues. Phagocytize antigenic material, collect antigent, activates immune cells. Found near immune system cells
types of connective tissue
Dense irregular tissue- nondirectional, like deep CT of skin, organ trabeculae.
Dense regular tissue - directional. Tendons, ligaments
Specialized connective tissues (adipose, blood, cartilage and lyphatic tissue).
Loose connective tissue - "fewer fibers, more cells")
store energy in form of lipids and cushions body. Can be brown (multiocular) or white (unilocular). Fat stored either subcutaneous fat or intra-abdominal fat. more adipose = more aromatase and estradiol.
loose connective tissue
comprised of fibroblasts which produce extracellular matrix. Usually highly vascular, adjacent to epithelia, provide physical barrer if laceration occurs. Inflammation actions occur here.
derived from bone marrow probably. Abundant granules seen in cytoplasm (heparin and histamine)
derived from monocytes. phagocytic once active, removes bacteria, detrius. might fuse with others to become "mega cell", multinucleated. "junky" cytoplasm
formed from B-lymphocytes. Primary source of circulating antibodies. abundant in GI tract. "clock faced" ovoid and abundant RER.
derived from circulation- may be T or B lymphocyte. present in various numbers under normal conditions. small round cell with dark nucleus.
derived from circulation, migratory, shortlived. multilobed nucleus
derived from circulation. seen in large numbers with allergic reactions. Bilobed nucleus, bright red cytoplasmic granules.
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