Histology Intro Flashcards
What is the outermost of the 3 primordial germ layers of embryonic development?
Ectoderm.
Which class of tissue can arise from all 3 primordial germ layers?
Epithelium tissue.
Which class of tissue only develops from the ectoderm?
Nervous tissue.
Which lens of a light microscope focuses the light from the source into a cone which will illuminate the specimen.
The Condenser lens.
Smallest distance that can be seen between two visibly separate objects?
Resolution
Process in microscopy histoprep cutting the tissue thin enough to transmit light through?
Sectioning.
What form of electron microscopy shows the surface features of what is being studied?
Scanning electron microscopy (SEM).
What type of molecule primarily makes up the backbone of the cell membrane?
Phospholipids.
Intercellular-junction where the two adjacent cell membranes fuse at a point, becoming one membrane which also holds the cells together?
Tight Junction/ Zona occludens.
What form of transport of large molecules across a membrane has three types? What are they?
Endocytosis:
- Phagocytosis.
- Pinocytosis.
- Receptor mediated.
What is translation?
Which organelle is primarily involved?
mRNA–> Proteins.
Done by ribosomes.
Which organelle has a maze of parallel internal membranes which connect the nucleus to other cellular structures and the cell membrane?
The Endoplasmic Reticulum.
Which organelle packages cellular products?
Golgi Apparatus.
What is smallest of the three classes of cytoskeletal components found in animal cells?
Microfilaments ~7nm.
What are the three components of the cytokeleton?
Microtubules 25nm.
Intermediary Filaments 10nm.
Microfilaments ~7nm.
9 pairs of microtubules arranged in a ring around a central pair of microtubules forming the core of a flagellum or cilium?
Axoneme.
What type of cytoplasmic inclusion is golden-brown in color and has a high iron content?
Hemosiderin- Iron containing pigment. Usually comes from the disintegration of RBC’s which contain ferritin- a protein that stores iron.
What is a cytoplasmic inclusion?
A non-living substance stored in the cytoplasm and are not bound by membranes.
What gives rise to all cells in the body at first?
A fertilized egg cell which is totipotent.
What population of cells is segregated early in development and retains it’s totipotentiality?
Germ Line Cells.
What 3 things develop at gastrulation?
The germ layers: Ectoderm, Mesoderm, and Endoderm.
When does gastrulation occur?
3-8 weeks in vertebrates, this is the process of the blastula (2 layers.) becoming a gastrula (3 germ layers)
What are the two layers of the blastula?
The Inner Cell Mass (ICM/ or Embryoblast.) and the Trophoblast (Outer layer.).
What cellular regions usually stain darker with a basic stain and why?
Chromatin, nuclear proteins, and phosphate groups. Basic stains are positively charged (Cationic) while these components have a (-) charge.
What cellular regions usually stain with an acidic stain and why?
Cytoplasm, muscle, collagen and connective tissue. Acidic stains have a (-) charge and are attracted to (+) tissues.
What can affect the charges of tissues and therefore the staining?
PH.
What are these: Fuchsin, Toluidine blue and Methylene blue
Naturally basic stains.
What is eosin stain?
An Acidic Anionic Stain.
What is H & E?
Widely used stain combination: Haematoxylin (basic) & Eosin (acidic)
What is PAS?
Periodic Acid Schiff: A (red-purple light pink) stain used that highlights fungal cells walls, mucins, glyocgen, etc.
Plasmalemma?
The cell membrane.
What is the small darkly stained body within a nucleus?
The nucleolus.
What is a common component of dehydration of specimens?
Ethly Alcohol.
What are two common embedding media?
Paraffin wax and epoxy.
Class of membrane protein which does not extend in the hydrophobic tail portion of the membrane?
Peripheral Proteins.
They are not embedded in the cell membrane.
Class of membrane protein which extends into the hydrophobic tail region of the membrane?
Type that extends all the way through?
Integral proteins, embedded into the membrane.
Integral which extends all the way through is a Transmembrane protein.
What is typically located on the external surface of the plasmallema forming glycoproteins/ lipids, and often serves as a receptor site?
Carbohydrates.
Intercellular-junction where the two adjacent cells communicate via channels/ passageways.
Gap junctions/ Nexus/ communicating junctions/ macula communicans.
Usually for ions.
Cells are ~2nm apart.
Bridges are called connexons.
Intercellular Junction which holds 2 cells together using proteinaceous filaments between two proteins units on the P-face
Desmosomes/ Zona Adherens.
Gap of ~5nm between cells.
P-Face?
Protoplasmic face of the membrane, the inner side.
Osmosis?
Passive Movement of solvent molecules across the concentration gradient of a membrane.
Dialysis?
Movement of solute molecules.
Facilitated Diffusion?
Passive Movement of solvent molecules though a transmembrane protein.
Movement of large particles out of the cell?
Exocytosis.
Usually secretory products or waste.
Difference between phagocytosis and pinocytosis?
Lysosomes are not needed for pinocytosis since what is being brought in is already in solution and will just diffuse into the cytosol.
Classification of tissue that can have one or multiple layers, with cells closely. packed together- little extracellular matrix.
Epithelial tissue.
What is at the base of the flagella or cilia?
A basal body, which is organized like a centriole and serves as an anchor for the flagellum or cilium.
What is a cytoplasmic inclusion contained in membrane limited granules and can determine skin, hair, eye etc, color?
What is the granule called? where is the granule found?
Melanin, found in melanosome granules, which are within melanocytes.
What is a cytoplasmic inclusion which is golden brown, the end product of lysosomal activity and accumulates as the cell ages?
Lipofuschin. (may also be found in membraneous vesicles.)
Most commonly seen as light brown granules in H&E stained hepatocytes.
What is the storage form of glucose within cells?
Glycogen.
What things give rise from the ectoderm?
