Microscopic Anatomy Overview Flashcards
Cytology
Cells
Histology
Tissues
Organology
Organs
Histological specimen preparation steps
- Fixation
- Dehydration
- Infiltration and embedding
- Sectioning
- Staining
Fixation
Tissue at room temperature will decay, need to preserve it
Dehydration
Need to get rid of the water, replace water with organic solvent like alcohol
Infiltration and embedding
- May be brittle because of the alcohol
- Replace alcohol with a medium to form a stable block of thick tissue that is not decaying or dehydrating
Sectioning
Cut it so light can go through it
Staining
Adds contrast
Microscopy/imaging
Look at it
Hematoxylin
Binds to negatively charged components of the cell, nucleic acids
What are examples of nucleic acids that hematoxylin binds to?
- Nuclear chromatin
- Nucleolus
- Rough endoplasmic reticulum: Ribosomes
Basophilic
Base loving, structures that stain blue/purple with hematoxylin
Eosin
Binds to positively charged or neutral components of the cell, proteins
What are examples of proteins that eosin binds to?
- Cytoplasm
- Cytoplasmic filaments
- Mitochondria
- Secretory vesicles
- Collagen fibers
Transmission Electron Microscopy
- Illumination source is a beam of electrons through a vacuum
- Black and white, 2D
Scanning Electron Microscopy
- Specimen coated with a thin layer of metal that electrons bounce off of
- Is scanned by lense
- Reflected electrons gather to produce the image on a screen
- 3D
Artifacts
Any alteration of normal morphological or cytological features of cells or tissues
Examples of artifacts
- Tissue shrinkage
- Redistribution of cell structures
- Loss of cell components
- Extraction of cellular contents
- Mechanical consequences of sectioning
Stroma
The supportive framework of an organ, usually composed of connective tissue
Parenchyma
Functional tissue of an organ, cells
Lumen
Cavity or channel within a tube or hollow organ
Medulla
Inner core of an organ
Cortex
Outer portion of an organ
Proximal
Towards the center or point of origin
Distal
Away from the center or point of origin
Superficial
Towards the outside of the body or organ
Deep
Towards the inside of the body or organ
Basal
Towards the base
Apical
Towards the tip
Cross section/transverse section
Cut in half
Longitudinal section
Cut on long axis
Oblique section
Angled
Cells vary in…
- Size
- Shape
- Internal structure
- Function
- Turnover rate
What cells lack nuclei
RBCs
What cells have more than one nucleus?
Cementoblast
Nucleus
- Governs cell structure and function
- Contains hereditary material: DNA
- Produces ribosomes (rRna) and messenger RNA (mRNA)
Chromatin
Coiled strands of DNA and protein
Euchromatin
- Looser coiled chromatin
- Easier to copy
- Lighter areas within nucleus
Heterochromatin
- Tightly coiled
- Electron dense
- Are dark spots on images
Active nucleus
- Pale staining
- Has more euchromatic
- Probably being transcribed into RNA
Inactive nucleus
- Dark staining
- Heterochromatic
- Not dead
- Chromatin is crumpled up
Nucleolus
- Site of ribosome production
- Site of messenger RNA (mRNA) synthesis
Is the nucleolus well developed in active or inactive nuclei?
Active
Nuclear envelope
- Surrounds the nucleus
- Double membrane
Nuclear pores
For messenger RNA to leave nucleus and for things to come in
Plasma membrane
Forms semipermeable barrier at the cell surface to regulate the passage of large or charged molecules
Phospholipid bilayer
Two phospholipids together
Passive transport
No energy
Simple diffusion
High to low flow, no help needed
Carrier protein
- Can be active or passive based on if energy is needed
- Gate like structure
Active transport
Energy required
Channel protein
Opens up to allow certain things through
