Test 1 - Lecture 1 & 2 Flashcards
What are the two items that make up a tissue?
- cells
- extracellular matrix (proteins & fibers)
What are the 4 basic tissue types?
- epithelial
- connective
- nervous
- muscle
What are the 3 important qualities of tissue?
- structure
- function
- location
Where can one find epithelium?
- covers body surfaces
- lines cavities
- makes up glands
What are some functions of epithelium?
- protection
- containing body fluids
- absorption & secretion
What are the 3 ways of classifying epithelium and the categories within each.
- number of cells (simple & stratified)
- cell shape (squamous, cuboidal, columnar)
- location (endothelium, mesothelium)
Endothelium
lining of vascular system
Mesothelium
lining of body cavities
What is connective tissue?
extracellular matrix
What are the functions of connective tissue?
- mechanical reinforcement
- immune system functions
- transportation and diffusion of wastes and nutrients
- storage of energy
What differentiates loose and dense connective tissue?
loose - loosely arranged collagen fibers and cells (most epithelia rests on it)
dense - lots of collagen few cells
What are the specialized forms of connective tissue?
- bone
- cartilage
- blood
What is the cell of muscle tissue?
myocyte
What are the two proteins are in large abundance in cells of muscle tissue?
- myosin
- actin
How is muscle categorized?
- striated - voluntary (skeletal & cardiac)
- smooth - involuntary
Describe a neuron/nerve cell
axon, cell body, dendrite
What is the CNS?
central nervous system - brain & spinal cord (neuroglial)
What is the PNS?
peripheral nervous system - peripheral nerves (Schwann & satellite cells)
What are functions of supporting cells in the nervous tissue?
- separate neurons from each other
- produce myelin sheath
- active phagocytosis
- contribute to the blood brain barrier in CNS
What does the term “ganglia” refer?
aggregations of nerve cell bodies in PNS
What are the embryonic origins of tissues?
- ectoderm
- endoderm
- mesoderm
What are the tissue types that arise from the ectoderm?
surface ectoderm (epidermis and assc. parts such as hair, nail, glands)
neuroectoderm (brain and nervous system)
What are the tissue types that arise from the endoderm?
embryonic gut (digestive, liver, pancreas, respiratory)
What are the tissue types that arise from the mesoderm?
- notochord
- somites (muscle, excretory, glands)
- mesenchyme (dermis, circulatory, bones, cartilage)
What are the 4 main stages of tissue preparation for microscopy?
- fixation
- embedding
- sectioning
- staining
What is an artifact?
an unwanted structure only visible due to an error in the tissue prep and staining process
Describe tissue preparation briefly.
- remove tissue from animal
- cut tissue into pieces
- fixation (still has water)
- dehydration (remove water with increasing amounts of alcohol)
- embedding in parafin
- sectioning with microtome
- rehydrate and dehydrate (remove wax)
- mount & stain sections on glass slides
When considering the fixation process, why should specimens be fixed immediately after they are obtained from the organism?
too take a “snapshot” of the exact moment the tissue was removed
What are possible artifacts from fixation and how would they arise?
consistency/quality varies - swelling of cells from too much water and shrinking of the cells from too little water
During tissue embedding, why must the sample be completely dehydrated before introducing a wax embedding material like paraffin?
because the paraffin is non-polar and not soluble in water
Describe longitudinal, oblique, and transverse sections
- longitudinal: cut in half
- oblique: cut at an angle (b/w other 2)
- transverse: horizontal/cross-section
Consider routine H&E staining. Why would tissue be dehydrated and treated with a chemical like Xylene after staining, but before applying a mounting medium?
Because the first stain hematoxylin in water-soluble, so sample needs to be rehydrated and the second stain Eosin is in alcohol and is not water-soluble so must be dehydrated
Acidic dyes
carry a net negative charge and react with cations - ex: Eosin (Na+ dye-)(pink)
Basic dyes
carry a net positive charge and react with anions - ex: Hematoxylin (Dye+Cl-)(blue)
Will H&E stain glycogen or for lipids? Why or why not?
No, lipids have no charge and will not stain with H&E
What would you propose to use as a staining procedure(s) for glycogen and for lipids?
permanganate or osmium
Briefly describe how immunohistochemistry allows for one to image via microscopy.
- Localizes a specific protein in a tissue session
- Diagnostics for tumors
- Detects infectious disease in tissues
What is Fluorescence In Situ Hybridization, and where is it useful?
fluorescent dyes + nucleotide probes - making it possible to visualize multiple probes at a time for genetic testing
When would an electron microscope be needed (instead of light microscope)?
increases resolution by a factor of 10^3
Where is a phase contrast microscope useful?
living cells & tissues
Where is a dark field microscope useful?
urine crystals, spirochetes, syphilis
Where is a UV Microscope useful?
nucleic acids (specifically purine & pyrimidine bases of nucleotides), proteins that contain certain amino acids, and determine amount of DNA/RNA in certain cells
What is useful about confocal microscopy?
allows visualization of specimens in 3D
What is atomic microscopy?
used for studying surface topography at molecular & atomic resolutions
- nonoptical microscope
- works like a fingertip
- great for living cells & surroundings environment (doesn’t have to be in a vacuum but can be in water)
