IF-AT 4 Histology

Question 1

steps for microscopy

Answer 1

1. collection: tissue taken from biopsy
2. fixation: stabilize tissue and kill infectious agents
3. embedding: support tissue with removable medium (OCT)
4. sectioning: slice into 8-10 micrometer sections
5. mounting: place tissue on glass slides
6. staining: add colored chemicals for contrast
7. microscopy: view tissue section under microscope

Question 2

important parts of microscope:

Answer 2

• condenser: focuses light on slide
• iris diaphragm: changes diameter of light beam
• arm: connects base to lenses and supports head
• head: connects to nosepiece
• body: just below occular lenses, connects them to head

Question 3

how do stains work?

Answer 3

• bind to cellular substances
• utilize ionic bonds

Question 4

types of stains and what they bind

Answer 4

• hematoxylin: basic stain (+) which binds basophilic elements (-) like proteoglycans and nucleic acids, and colors them blue/purple/black
• eosin: acidic stain (-) which binds acidophilic elements (+) like collagen and RBCs, and colors them pink/orange/red

Question 5

levels of organization in the body (7)

Answer 5

1. atoms
2. molecules
3. organelles
4. cells
5. tissues
6. organs
7. organ systems

Question 6

4 kinds of tissues in the body

Answer 6

• epithelial (skin, lining of hollow organs): lining, protection, absorption/secretion
• connective (bones, tendons, fat): support, protection, connection
• muscle (skeletal, cardiac, smooth): contraction, moving substances or the body
• nervous (brain, spinal cord, nerves): sensation, reaction, communication, processing

Question 7

5 characteristics of epithelial tissues

Answer 7

1. polarity: apical and basal surface
2. avascular but innervated
3. can regenerate
4. specialized contacts
5. supported by connective tissues

Question 8

simple squamous advantages

Answer 8

• maintaining barrier while allowing passive transport
• diffusion and filtration

Question 9

simple cuboidal advantages

Answer 9

• active transport
• absorption and secretion

Question 10

simple columnar advantages

Answer 10

• high energy absorption (microvilli)
• cilia movement
• secretion with Goblet cells

Question 11

stratified squamous advantages

Answer 11

• many layers of squamous cells!!
• maintaining barrier that doesn’t allow passage of substances
• protection from water and abraison

Question 12

stratified cuboidal advantages

Answer 12

• 2 layers of cuboidal cells
• transition between simple cuboidal and outer surface
• mammary and sweat glands
• good for secretion with added protection from abraison

Question 13

pseudostratified columnar epithelium advantages

Answer 13

• rare! single columnar layer but nuclei at different spots makes it appear stratified
• cilia movement
• in airway and uterus!

Question 14

transitional epithelium

Answer 14

• stratified epithelium with large apical and smaller basal cells
• ability to change shape quickly while maintaining tight adhesions!
• unique to excretory system!!

Question 15

4 features that distinguish epithelial tissue from other types

Answer 15

1. cellularity
2. basement membrane
3. lumen
4. apical/basal surfaces

Question 16

features on apical surface of some epithelia

Answer 16

• stereocilia
• microvilli
• keratin