Visualizing Cells and Tissues Flashcards
- Describe briefly the process of tissue processing for preparation and examination by light and electron microscopy
Tissue processing
a tissue specimen is obtained through-biopsy,excision,resection
- Fixation-prevents decay ( ex. Formalin)
- Embedding- used to attach to slide ( ex. paraffin)
- Sectioning- sliced into thin 1-2 cell thick mounted on slide
- Staining and contrast- stains bind to different cellular components
Then it is ready to be examined by microscope
- Elaborate on the different types of tissue sections that can be generated for tissue analysis
Longitudinal section – tissue cut along longest direction of organ
- Cross section – tissue cut perpendicular to length of organ
- Oblique section – tissue cut at angle between cross and longitudinal section
- How are liquid tissues prepared for visualization
prepared as smears •
Tissue is rubbed and spread across the slide rather than sliced
- State four types of light microscopy
Bright-field microscopy
Phase-contrast microscopy
Nomarski differential-interference-contrast microscopy
Dark-field microscopy:
- What are the advantages of fluorescence microscopy?
– Sensitivity:“glow” against dark background
– Cells may be fixed or living
- Briefly describe the principle of how a fluorescence microscope works
A light source goes through the microscope’s first barrier filter in which only blue light passes (450&490 nm)
light goes to beam splitting mirror where (510= transmitted)
light then goes to second barrier filter, where unwanted fluorescent signals are filtered, and an emission is observed (520-560 nm)
- What are the advantages of confocal and deconvolution microscopy as compared to fluorescence microscopy?
It overcomes limitations such as
- blurred images
- thick specimens
- State differences between SEM and TEM microscopy.
-sem uses scattered electrons, focuses on sample surfaces, more of the sample can be analyzed at a time
tem uses transmitted electrons, shows details of internal composition, has higher resolution, less of the sample can be analyzed at a time
- What are the four primary tissue classes?
• Epithelial Tissue
Connective Tissue
- Nervous Tissue
- Muscular Tissue
- What do you understand by the term “Histology”
–Study of tissues and how they are organized into organs
- State and briefly describe the three primary germ layers
– ectoderm (outer) • forms epidermis and nervous system
– endoderm (inner) • forms mucous membrane lining of the respiratory system and digestive glands
– mesoderm (middle) becomes mesenchyme collagen fibers and fibroblasts in gel matrix • gives rise to muscle, bone, blood
- State general characteristics of epithelial tissue
- consists of layers of closely adhering cells
- flat sheet with upper surface exposed to the environment or an internal body cavity
- no blood vessels
- What is the difference between simple vs stratified epithelia
simple- contains one layer of cells, named by shape of cells
stratified- contains more than one layer, name by shape of surface cells
- State a representative characteristic, location and function of simple squamous epithelium
characteristic- single row of flat cells
location-external surface of small intestine, air sacs of lungs, endothelium, and serosa
function- secretes lubricating substances/ fluid
- Briefly describe the stratified epithelia tissue
- more than one layer thick
- named for shape of surface cells- excepton is transitional epithelium
- State a representative characteristic, location and function of transitional epithelium
characteristic= resembles stratified squamous and stratified cuboidal epithelium, cells are round and not flat
location= ureter, bladder, umbilical cord
function= forms mucos lining of the ureters, allows for filling of urinary track
- Briefly describe with examples the characteristic and function of connective tissues
characteristics=
• Widely spaced cells separated by fibers and ground substance • Most abundant and variable tissue type • Usually cells not in direct contact with each other, separated by matrix
functions=
–connects organs (tendon connect muscle to bone) –gives support and protection (physical and immune) –stores energy and produces heat –movement and transport of materials
- State the four categories of connective tissues
A. Fibrous connective tissue B. Adipose connective tissue C. Supportive connective tissues (cartilage and bone) D. Fluid connective tissue (blood)
- Describe three cells of fibrous connective tissues
- Adipocytes: fat cells, store triglycerides
- Plasma cells: arise from WBCs, synthesize antibodies
- Macrophages phagocytize foreign material and activate immune system – arise from monocytes (WBCs)
- Fibroblasts produce fibers and ground substance
- Describe two types of fibrous connective tissues
loose connective- gel-like ground subsance
types: areorlar, reticular
dense connective- fibers fill spaces between cells
types: dense regular connective, and dense irregular connective
- State a representative characteristic, location and function of adipose tissue
characterisitic= dominated by adipocytes, had empty looking cells with then margins
location=- subcutaneous fat beneath skin and organ packing
function - energy storage, insulation, cushioning
- State characteristic features of cartilage tissue
- stiff connective tissue with flexibly rubbery matrix
- cartilage is produced by chrondro blast
- rarely exhibits blood vessels
- types of cartilage vary with fiber types
- State a representative characteristic, location and function of cartilage tissue
characterisitic= rarely exhibits blood vessels
location= ends of bones at movable joints
function= supports airways, eases joint movements
- State characteristic features of bone
- hard connective tissue that composes the skeleton
- spongy bone-spongy in appearance
- compact bone- solid in appearance
