Visualizing Cells and Tissues

Question 1

1. Describe briefly the process of tissue processing for preparation and examination by light and electron microscopy

Answer 1

Tissue processing
a tissue specimen is obtained through-biopsy,excision,resection

1. Fixation-prevents decay ( ex. Formalin)
2. Embedding- used to attach to slide ( ex. paraffin)
3. Sectioning- sliced into thin 1-2 cell thick mounted on slide
4. Staining and contrast- stains bind to different cellular components

Then it is ready to be examined by microscope

Question 2

2. Elaborate on the different types of tissue sections that can be generated for tissue analysis

Answer 2

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

Question 3

3. How are liquid tissues prepared for visualization

Answer 3

prepared as smears •

Tissue is rubbed and spread across the slide rather than sliced

Question 4

4. State four types of light microscopy

Answer 4

Bright-field microscopy

Phase-contrast microscopy

Nomarski differential-interference-contrast microscopy

Dark-field microscopy:

Question 5

5. What are the advantages of fluorescence microscopy?

Answer 5

– Sensitivity:“glow” against dark background

– Cells may be fixed or living

Question 6

6. Briefly describe the principle of how a fluorescence microscope works

Answer 6

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)

Question 7

7. What are the advantages of confocal and deconvolution microscopy as compared to fluorescence microscopy?

Answer 7

It overcomes limitations such as

• blurred images
• thick specimens

Question 8

8. State differences between SEM and TEM microscopy.

Answer 8

-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

Question 9

9. What are the four primary tissue classes?

Answer 9

• Epithelial Tissue

Connective Tissue

• Nervous Tissue
• Muscular Tissue

Question 10

10. What do you understand by the term “Histology”

Answer 10

–Study of tissues and how they are organized into organs

Question 11

11. State and briefly describe the three primary germ layers

Answer 11

– 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

Question 12

12. State general characteristics of epithelial tissue

Answer 12

• consists of layers of closely adhering cells
• flat sheet with upper surface exposed to the environment or an internal body cavity
• no blood vessels

Question 13

13. What is the difference between simple vs stratified epithelia

Answer 13

simple- contains one layer of cells, named by shape of cells

stratified- contains more than one layer, name by shape of surface cells

Question 14

14. State a representative characteristic, location and function of simple squamous epithelium

Answer 14

characteristic- single row of flat cells

location-external surface of small intestine, air sacs of lungs, endothelium, and serosa

function- secretes lubricating substances/ fluid

Question 15

15. Briefly describe the stratified epithelia tissue

Answer 15

• more than one layer thick

- named for shape of surface cells- excepton is transitional epithelium

Question 16

16. State a representative characteristic, location and function of transitional epithelium

Answer 16

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

Question 17

17. Briefly describe with examples the characteristic and function of connective tissues

Answer 17

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

Question 18

18. State the four categories of connective tissues

Answer 18

A. Fibrous connective tissue B. Adipose connective tissue C. Supportive connective tissues (cartilage and bone) D. Fluid connective tissue (blood)

Question 19

19. Describe three cells of fibrous connective tissues

Answer 19

• 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

Question 20

20. Describe two types of fibrous connective tissues

Answer 20

loose connective- gel-like ground subsance
types: areorlar, reticular

dense connective- fibers fill spaces between cells
types: dense regular connective, and dense irregular connective

Question 21

21. State a representative characteristic, location and function of adipose tissue

Answer 21

characterisitic= dominated by adipocytes, had empty looking cells with then margins

location=- subcutaneous fat beneath skin and organ packing

function - energy storage, insulation, cushioning

Question 22

22. State characteristic features of cartilage tissue

Answer 22

• stiff connective tissue with flexibly rubbery matrix
• cartilage is produced by chrondro blast
• rarely exhibits blood vessels
• types of cartilage vary with fiber types

Question 23

23. State a representative characteristic, location and function of cartilage tissue

Answer 23

characterisitic= rarely exhibits blood vessels

location= ends of bones at movable joints

function= supports airways, eases joint movements

Question 24

24. State characteristic features of bone

Answer 24

• hard connective tissue that composes the skeleton
• spongy bone-spongy in appearance
• compact bone- solid in appearance

Question 25

25. State characteristic features of blood

Answer 25

- fluid connective tissue that travels through blood vessels - provide clotting, immune functions, carry o2 and co2 - cellular components- erythrocytes, leukocytes, and platelets

Question 26

26. State characteristic features of muscle tissue

Answer 26

- elongated cell stimulate to contract - exert physical force on other tissues - had 3 different types of muscle tissues, skeletal, cardiac, and smooth

Question 27

27. State characteristic features of nervous tissue

Answer 27

-specialized for communication by electrical and chemical signs, in brain and spinal cord, has neurons and neurolglia

Question 28

28. State a representative characteristic, location and function of nervous tissue

Answer 28

characterisitic= consists of neurons and neuroglia location- brain and spinal cord function= provides communication by electrical and chmeical signals

Question 29

29. State a representative characteristic, location and function of cardiac muscle tissue

Answer 29

characteristic-Cells are branched cylinders with one central nuclei location- walls of the heart function- as it contracts, it propels blood into the circulation; involuntary control