Exam 1 Flashcards
What 2 interacting components are tissues made of?
Cells and extracellular matrix (ECM)
Describe light microscopy.
Light beam is transmitted through a tissue.
T/F: Bright field microscopy is a type of light microscopy.
True
What does a bright field microscope require?
Staining
What is the difference between phase contrast and fluorescence microscopy?
Phase contrast: light changes its speed when passing through structures with different refractive indices and observe living non-stained structures.
Fluorescence: affinity of fluorescent compounds for specific cell components.
What are some advantages of light microscopy?
Inexpensive, rapid diagnosis, observe living specimens
What are some disadvantages of light microscopy?
2-D image, limited resolving power due to wavelength of light, needs maintenance, requires quality analysis and control
What are some advantages of using a dissecting scope?
Inexpensive, practical, 3-D image, microsurgery
What are some disadvantages of using a dissecting scope?
Low resolving power, needs maintenance
Which type of electron microscopy is based on the interaction of electrons and tissue components?
Transmission electron microscopy (TEM)
What can the viewer see on a SEM?
Only external structures (scans the surface)
What conditions have to be met in order to see a specimen under the microscope?
Specimen must…
- Be well preserved (fixation)
- Thin to allow transmission of light (microtome)
- Enough contrast to observe details (staining)
What is the most common survey routine staining method?
Hematoxylin- Eosin (H + E)
What is histochemical staining method used to demonstrate?
Chemical constituients DNA, RNA, lipids, glycogen, carbohydrates and elements such as Ca
What color is DNA stained?
Basophilic = Blue
In a Hematoxylin - Eosin stain what are the possible colors and what do they indicate?
Red/ pink = Acidophilic or Eosinophilic
Blue/ purple = Basophilic
T/F: Basic dyes like Hematoxylin stain acidic structures: DNA, RNA, acid proteins; and Acid dyes like Eosin stain basic structures: collagen, hemoglobin, protein amines.
True
What are 2 examples of special stains discussed?
Silver stain and elastic fiber’s stain
What is silver stain used for?
Reticular fibers, nerve fibers
What does the periodic acid Schiff (PAS) stain for?
- Basement membrane and localize carbohydrates
- Goblet cells stain magenta
- Mucus in respiratory tract
What can histochemistry be used to demonstrate?
Rapidly dividing chromosomes of DNA, carbohydrates like glycogen in the liver, lipids in tissues, spinal cord gray matter with myelin lipid
Describe fluorescence microscopy.
– Blue fluorescence binding to nuclear DNA.
– Green fluorescent dye binds to actin filaments.
What is the difference between immunohistochemistry and immunocytochemistry?
Histo= tissue Cyto= cell
What are the basic constituents of a cell?
- cytosol (hyaloplasm)
- organelles (cell organelles)
- cell inclusions (paraplasm)
Hyaloplasm
Basic structureless cytoplasm
Paraplasm
Cell inclusions: secretory granules, glycogen, lipid droplets, lipofuscin, melanin
Nucleus
Contains genetic info, double envelope for eukaryotes
Examples of multi-nucleated cells?
Skeletal muscle cells, osteoclasts, precursors of platelets
What are the two types of chromatin?
Heterochromatin (inactive) vs. Euchromatin (active)
T/F: Chromatin is eosinophilic.
False, basophilic
In a liver cell, for example, would the chromatin be heterochromatin or euchromatin?
Euchromatin, it is active
The most euchromatic cells are?
- Neurons
- Hepatocytes (liver cells)
- Pancreatic acinar cells
- Sertoli cells
What are 4 functions of the cell membrane?
- Communication
- Intercellular connection
- Physical barrier
- Selective permeability
Describe the basic structure and function of mitochondria.
Self-replicating, circular DNA, double membrane with cristae, produce ATP, inherited from mother
Roles of mitochondria?
ATP generation, cell death necrosis, cell death apoptosis
What is the endoplasmic reticulum?
Network of intercommunicating channels
What does the region on the ER that is rough contain?
Polyribosomes
Functions of smooth ER?
- Lipid biosynthesis
- Detoxification
- Sequestration of calcium ions
Functions of rough ER?
- Segregate proteins not destined to the cytoplasm
- Glycosylation of glycoproteins
- Synthesis of phospholipids
- Assembly of multichain proteins
Describe the golgi apparatus.
Collection of membrane- bound flattened sacs ‘cisternae’, modifies and packages proteins
Describe lysosomes.
- Secretory vesicles/ granules, membrane bound
- Have hydrolytic enzymes
- Pinocytosis, phagocytosis
- Intracellular digestion
If material remains permanently, is known as?
Lipofuscin
Ex. cardiac cells, neuron
Why are lysosomes commonly seen in neutrophils?
Fight against bacterial agents
What are proteasomes?
Small enzymatic complexes for intracellular digestion that requires ubiquitin protein
Ubiquitin
Small globular protein present in all eukaryotic cells.
What is the primary function of proteasomes?
Recycling amino acids from endogenous proteins
What are peroxisomes?
Contain the enzyme ‘catalase’ which can degrade intracellular hydrogen peroxide
What are the different types of secretory vesicles/ granules?
Lysosomes, proteasomes, peroxisomes
What are the 3 constituents of cytoskeleton?
Microfilaments, intermediate filaments, microtubules
Describe the microfilaments.
Actin: thin, 5-7 nm diameter
Myosin: thick, 15 nm diameter
How big are intermediate filaments?
6-12 nm diameter
Tonofilaments (cytokeratins)
Keratinizing and non-keratinizing epithelia
Vimentin
- Mesenchymal cells
- Fibroblasts, chondroblasts, osteoblasts, macrophages, endothelial cells, vascular smooth muscle cells
Desmin
- Muscle
- Striated and smooth
Neurofilaments
-Neurons
Glial filaments
- Glial cells
- Astrocytes
In microtubules, how are doublets linked?
Dynein arms
What are some inclusions discussed?
Pigments, Glycogen, Lipid droplets
What are the different types of pigments?
Melanin, lipofuscin, lutein, hemosiderin
T/F: Glycogen is present in highly energetic types of tissues, like the liver and muscle.
True
What are some surface projections discussed?
Microvilli, cilia, stereocilia
Microvilli
Small, absorptive, form a brush boarder
Digestive tract, kidney
Increase surface area -> more absorption
Cilia
Motile projections (they move!), longer, less dense, easier to observe under LM, come from basal bodies
Stereocilia
Nonmotile projections, absorptive
Cell shapes
Squamous, cuboidal, columnar, spindle, cylindrical, multipolar, round
Nuclear shape
Round, elongated, polymorphonuclear
Nuclear position
Central, eccentric/hypolemmal, apical vs. basal
Epithelial cells have…
- Apical (free) surface
- Lateral surfaces
- Basal surface
Tissue
Anaggregationofcellsandextracellularsubstances.
Epithelium
Atissuecomposedofclosely aggregatedcellswithverylittleextracellularsubstance.
What are the 4 basic types of tissue?
o Epithelialtissue
o Connectivetissue
o Musculartissue
o Nervoustissue
What are the 3 categories of epithelia?
Surface or lining, glandular, and special
Where is surface epithelia found?
Lining luminal organs, tubular structures and body cavities
What is the function of glandular epithelia?
Synthesize, store and release their product -> secretion
What are the functions of epithelial tissue?
- Protection
- Secretion
- Absorption
- Diffusion
- Friction Reduction
- Cleaning
- Sensation
Which type of epithelium promotes diffusion of gases, liquids and nutrients?
Simple squamous epithelium
What are the 3 germ layers in a developing embryo that contribute to formation of epithelia?
- Ectoderm
- Mesoderm
- Endoderm
List some characteristics of epithelium.
Covers surfaces and lines lumens, high cell density, little intercellular space, basement membrane present, avascular lining epithelium, few nerve endings
What is the difference between epithelial cells and mesenchymal cells?
Epithelial cells: High cell density, little intercellular matrix
Mesenchymal cells: Few cells, lots of intercellular matrix
Where does the basal lamina lie?
Lies at the interface of epithelial and connective tissue.
T/F: Small blood capillaries always enter an epithelium across a basal lamina.
False, they never do
Basement membrane
When components of a basal lamina are distinguishable under light microscopy
What are the roles of the basal lamina?
Provide structural support, act as selective barrier for epithelial layer
T/F: Basement membrane is a semi-permeable barrier.
True
Which type of stain is used for basement membrane?
PAS (Periodic Acid Schiff) for carbohydrates
What causes epithelial cells to be cohesive?
- Transmembrane glycoproteins
- Cadherins
- Folds of PM b/w adjacent cells form intercellular adhesions
What are 3 types of intercellular junctions?
Tight junctions, desmosomes, gap junctions
Which type of intercellular junction formsa continuous
hermeticsealaroundthecell, and prevents leakage?
Tight junctions
What is another name for anchoring junctions?
Desmosomes
What type of junction adheres epithelial skin cells?
Desmosomes
What is another name for gap junctions?
Communicating junctions
What do gap junctions provide from one cell to the next?
Cytoplasmic channels or tunnels
Describe simple squamous epithelium.
Composed of flat, elongated cells, round nucleus centrally located
Where is simple squamous epithelium located?
Lining moist internal surfaces, alveolar walls, lumen of blood vessels, capsule of renal glomeruli
Where is simple cuboidal epithelium found?
Lining ducts of glands, choroid plexus in brain, lining follicles of thyroid gland, lens of eye
Describe simple columnar epithelium.
Tall, narrow cells with ovoid nucleus near base of cell
Where is simple columnar epithelium found?
– Liningtheluminalsurfaceofstomach,smalland
largeintestine,gallbladder
– Liningtheuterusanduterinetube
What is pseudostratified epithelium composed of?
A single layer of irregularly shaped and sized cells
How are cells arranged in pseudostratified epithelium?
All cells contact the underlying basement membrane, but not all reach the surface
Where can one find pseudostratified epithelium?
Nasal cavity, upper respiratory tract, male repro
What is stratified squamous epithelium?
Epithelium composed of several layers of cells
What are the 2 types of squamous epithelium?
Keratinized and non-keratinized
T/F: There are nuclei present in keratinized epithelium.
False
What is another name used to describe transitional epithelium?
Urothelium
Where is transitional epithelium found?
Lines urinary passages
How can glandular epithelium be classified?
1. Classificationaccordingtothenumberofcellsinthegland unicellularormulticellular 2. ShapeofDuct 3. ShapeofAdenomere 4. TypeofProduct 5. ModeofSecretion
What are unicellular glands and give an example.
Found in epithelial lining and glands of intestine and respiratory tract. Ex Goblet cells (mucinogen granules) in the colon
Adenomere
Cluster of epithelial cells and the functional unit
What do ducts do?
Convey products to needed locations
What are the 2 types of ducts?
Simple= one opening draining the gland Compound= many branches
What are the 3 shapes of adenomeres?
Tubular- straight or coiled
Acinar- pie shaped, small lumen
Alveolar- large lumen
What are the 4 types of products?
Serous- watery
Mucous- viscous
Mixed- both
Sebaceous- oily
Serous gland
- cells have round nuclei
- cytoplasm is basophilic in basal portion and acidophilic in the apical part
- zymogen granules
- sweat
Mucous gland
- cells have flat, heterochromatic nuclei at the base of each cell
- vacuolated cytoplasm (frothy) and pale
- mucinogen granules are not detectable with routine staining
Mixed gland
- mucous and serous cells sharing a common duct system
- saliva
Sebaceous gland
- centrally located nucleus
- cytoplasm is pale and foamy
- skin
4 Modes of secretion?
Merocrine, apocrine, holocrine, endocrine
Merocrine
- smooth lumen
- no cytoplasm lost producing secretion
Apocrine
- apex bulges, some cytoplasm lost producing secretion
- predominant sweat gland, prostate gland, mammary gland
Holocrine
entire cell is the product
Endocrine
secreted product is directed toward vasculature
Myoepithelial cells
Contractile, associated with salivary, mammary and sweat glands
Functions of connective tissue
- Connect
- Suspend, give form, subdivide
- Insulation and storage
- Defend
- Provide nutrition
- Repair and regeneration
What are the 2 components of connective tissue?
Cells and matrix
2 Cells of connective tissue
- Embryonic mesenchyme cells: Resident cells
2. Hematopoietic stem cells: Transient cells
What are some examples of resident cells?
Fibroblasts, reticular cells, adipocytes, mesenchymal cells, macrophages, mast cells
-Always there
What are some examples of transient cells?
Plasma cells, leukocytes
What do fibroblasts form?
Collagenous, elastic and reticular fibers of the matrix
What is an inactive fibroblast known as?
Fibrocyte
Describe the role of macrophages in CT.
- Resident phagocytic cell of CT
- Originates from monocytes in blood, enters CT, termed macrophage
- Can proliferate locally
- Survive in tissue for months
- May be named by location
What are 3 components in the matrix?
Fibers, ground substance, tissue fluid
3 types of fibers in matrix?
Collagen, elastic, reticular
What is ground substance?
Amorphous, formed by principal cells of tissue, contain GAGs, Proteoglycans, Glycoproteins
Describe tissue fluid
A solution that bathes and surrounds the cells and fibers, comes from plasma of blood
Differentiate between collagen and elastic fibers.
C: white, tensile, strong, no stretch
E: yellow, weak, stretch and recoil
Which are the most numerous fibers in CT and bone?
Collagen fibers
Collagen type 1
found in bone, dentin, dermis, tendons
(fibrocartilage); resists tensile forces
Collagen type 2
forms fibrils found in cartilage, resists
compression
Collagen type 3
reticular fibers found in stroma of expandable organs- spleen, LN, liver, CVS, lymphatics
Collagen type 4
basement membranes
What is an important cofactor in synthesizing collagen?
Vitamin C
Where are elastic fibers found?
Aorta, lungs, vocal cords, dermis, pinna of ear, epiglottis
Which stain is used for reticular fibers?
Silver stain
Where are reticular fibers found?
Form a network of cells in lymph node, spleen, and bone marrow
Properties of ground substance allows for what?
- Binding of water
- Resisting compressive forces
- Cell adhesion to fibers
- Cell migration
- Barrier to bacterial/ venom penetration
What are some common macromolecules of ground substance?
GAGs: HA sulfate, chondroitin sulfate, keratan sulfate, dermatan sulfate, heparan sulfate
Glycoproteins: Fibronectin, Laminin
How are proteoglycans formed?
By covalently linking GAGs to protein core
-Regulate passage of molecules and cells in intercellular space
What do structural glycoproteins do?
Proteins with attached carbohydrates, help to attach cells to each other and to ECM
What is CT fluid composed of and what is its function?
- Nutrients, dissolved gases, derived from plasma
- Bathes matrix and cells, aids in removing waste
- Fluid movement and prevention of edema
What are the types of proper CT?
- Loose CT (areolar)
- Dense CT
- Reticular CT
- Adipose CT
Differentiate between loose CT and dense CT.
L: Ubiquitous, loosely arranged fibers, cell constituents vary with location
D: Irregular and regularly arranged, densely packed fibers, strong
Function of bone
Rigid protective and supporting framework for soft tissues
Function of cartilage
Semi-rigid support to specific sites: respiratory tract, external ear, joints
Functions of joints
Composite structures which unite bones and can provide varying degrees of movement
What do ligaments provide?
Stability of joints
What do tendons provide?
Strong, flexible connections b/w muscles and bones
Describe cartilage
-Avascular, semi-rigid form of CT characterized by
absence of blood vessels, lymphatic vessels and nerves.
-Supports soft tissues, important in bone growth.
-Composed of cells embedded in ground substance
and CT fibers
Cartilage arises from what?
Mesenchymal cells- stem cells of bone and cartilage
Perichondrium
Cells have cartilage forming potential; precursors of chondrocytes. Resembles mature fibroblasts
T/F: The inner layer of perichondrium is cellular and it is present in all hyaline cartilages except on articular surfaces.
True
What is ground substance composed of?
Sulfated polysaccharide units GAGs (ex. chondroitin sulfate, keratan sulfate)
What is responsible for the strong and flexible
property of cartilage?
Proteoglycans
Within normal articular cartilage,
there is only one type of highly
specialized cell?
The chondrocyte
What is the ECM that surrounds each chondrocyte?
Territorial matrix
Why is the cartilage matrix more basophilic?
Due to high concentrations of GAGs
Growth of cartilage occurs in 2 manners?
- Interstitial growth from within the cartilage
2. Appositional growth at the periphery
The classification of cartilage is based on what?
Based mainly in the amount of collagen or elastic fibers present within the extracellular matrix.
What are the 3 types of cartilage?
- Hyaline cartilage
- Elastic cartilage
- Fibrocartilage
What is the most common type of cartilage?
Hyaline cartilage
How is mature hyaline cartilage characterized by?
Small aggregation of chondrocytes embedded in an amorphous matrix of ground substance reinforced by collagen type II fibers.
Where is hyaline cartilage found?
Fetal axial and appendicular skeleton. Growth plates – physis. Articular cartilage. Costo-chondral junctions. Nasal septum, larynx, tracheal rings, bronchi.
T/F: Articular cartilage has perichondrium.
False, it does not. Therefore healing capability is reduced