# Lectures 12 & 13: Histology: Tissues, Epithelium, and Glands Flashcards

1
Q

How was the meter defined?

A

10-7 distance from the equator to the north pole

2
Q

What is the smallest unit of measure the eye can see

A

1 mm

3
Q

How big is an RBC?

A

7-9 micrometers in diameter

4
Q

How thick is the plasma membrane?

A

7.5-10 nanometers thick

5
Q

What is an angstrom?

A

10-10 meters

6
Q

By how much does the eye fixture of an LM usually magnify the sample?

A

x10

7
Q

What part of the LM can make the magnification vary?

A

The objective lenses

8
Q

What is the equation to calculate the resolution of the LM?

A

Resolution = wavelength x 0.61 / numerical aperture

9
Q

How does the aperture affect the resolution?

A

The larger the aperture, the worse the resolution (more blurry)

10
Q

What is the resolution of LM?

A

0.2 microns

11
Q

What is the magnification of LM?

A

x1,500

12
Q

What is the definition of resolution?

A

The ability to distinguish 2 pts that are close together

13
Q

Explain how the TEM works

A
1. Heat up cathode
2. Electrons come up through the cathode and accelerate towards the anode (+ charged)
3. E- go through the anode hole
4. The sample deflects or absorbs the beam and the beam of e-s goes through sections of a thin grid on which the sample is held
5. Beam is reflected on a fluorescent screen releasing photons by different lenses

Whole unit is in a very high vacuum

14
Q

What replaces the LM objective lenses in the TEM?

A

The objective lens, the intermediate lens, and the projector lens

15
Q

What is the resolution of TEM?

A

1-1.45 nm

16
Q

What is the magnification of TEM?

A

x500,000

17
Q

Describe how SEM works

A

Similar to TEM: cathode that releases e- when heated (thermyonic emission) towards an anode and passes through electromagnbetic lenses that focus beam on sample. Instead of going through the sample, the beam causes the sample to emit secondary and reflected electrons. It scans the surface but does not go through like in the TEM and as it scans, there is another beam pointing down and you can a 3D image of the surface topography of the sample

18
Q

What is the resolution of SEM?

A

2 nm

19
Q

What is the magnification of SEM?

A

x100,000

20
Q

Cell? Microscope?

A

RBC

LM

21
Q

Microscope?

A

TEM

22
Q

Cell? Microscope?

A

SEM

23
Q

Cell? Microscope? Stain?

A

Kidney

LM

H&E

24
Q

Cell? Microscope? Blue arrows? Black arrows? Dark black?

A

Kidney

TEM

Cilia

Mitochondria

Dark black: lysosomes

25
Q

Cell? Microscope?

A

Kidney

SEM

26
Q

What kind of prep needed for LM?

A
1. Fixation (w/ formaldehyde) and dehydration
2. Embedding (wax or plastic)
3. Sectioning (5-10 microns thick) with microtone and steel knives
4. Mounting and staining
27
Q

What microscopes require dehydration of samples? Why? What is water replaced with?

A

ALL

LM and TEM because the samples are embedded in plastic or wax which are not miscible with water

SEM because of vacuum environment

Replaced with organic solvent

28
Q

What is another term for LM?

A

Brightfield microscopy

29
Q

What are the 5 common LM stains? Describe each

A
1. Hematoxylin and eosin (H&E): H stains (-) charged and is basophilic and E stains (+) and is eosinophilic
2. Periodic Acid - Schiff: stains carbs
3. Aldehyde Fuchsin: stains elastic fibers and b-cells of the pancreatic islets
4. Orcein: stains elastic fibers
5. Silver: stains reticular fibers (collagen)
30
Q

What does PAS stain?

A

Carbs

31
Q

What does H&E stain?

A

H: nuclei

E: cytoplasm

32
Q

Cell? Microscope? Small arrows?

A

Trachea

LM

Small: bleached mucus glands due to dehydration (w/ cilia on the surfaces)

33
Q

Cell? Microscope? Arrows?

A

Trachea (with cilia)

TEM

Arrows: liquid preserved in the glands

34
Q

Difference between cilia and microvilia?

A

Microvilia are much smaller

35
Q

Cell? Microscope? Stain? A? F? D?

A

LM

Intestine cell

PAS

a: glycocalyx
f: mucins
d: lymphocytes

36
Q

Stain? Cell? Microscope?

A

LM

Silver

Golgi

37
Q

What prepartion is needed for TEM?

A
1. Fixation (with osmium tetroxide that preserves lipid) and dehydration
2. Embedding in beam capsules
3. Polymerization of capsules in oven
4. Remove sample from mold
5. Trim for ultrathin sectioning with diamong or glass knives
6. Sample collected on grids (many different types) in a boat of water
7. Staining to impart different electron density with heavy metals (lead and uranium salts) to different parts of the cell
38
Q

How is the fixation process different in LM and TEM?

A

LM: wax or plastic, thicker

TEM: only plastic, thinner, more sophisticated

39
Q

Microscope?

A

TEM

40
Q

A? B?

A

A: microvilli labelled with gold particles

B: aquaporins

41
Q

What is freeze fractioning?

A

Another EM technique where we fracture the cell through the middle of the bilayer and expose the proteins embedded in the membrane (E and P faces)

42
Q

What is the prep needed for SEM?

A
1. Fixation & dehydration (because it goes in a vacuum)
2. Coat it to accentuate the release of e-s from sample

THAT’S IT!!

43
Q

Which microscope requires the least prep?

A

SEM

44
Q

What is this?

A

Cilia on trachea (goblet cells)

45
Q

Electron beam different in SEM and TEM?

A

Nope

46
Q

Same fixation process in LM and TEM?

A

Nope

47
Q

At the LM level can you see ribosomes? Microtubule? Microfilament? Basal body?

A

No

No

No

YES!

48
Q

What are 8 characteristics of epithelial cells?

A
1. Cover/Line all surfaces in the body except for joint cavities
2. Lie on basal lamina of the basal membrane
3. Avascular
4. Polarity: apical and basolateral portions
5. Keratin filaments provide strength and desmosomes makes them act like a continuous sheet
6. Many have remarkable renewal capacity (like skin and intestines)
7. Derived from 3 germ layers: mesoderm, ectoderm, endoderm
8. Diversity in function: secretory, protective, absorptive
49
Q

Do epithelial cells have veins?

A

NOPE

50
Q

How do you distinguish the basement membrane from the basement lamina?

A

Membrane: you can see with LM

Lamina: EM level

51
Q

What are surface epithelia classified by?

A
1. # of cells in epithelium: simple/stratified
2. Height and shape of surface layer of cells: squamous/cuboidal/columnar
52
Q

Simple squamous epithelium: shape? what do they line? shape of nuclei?

A

Flat

Body cavities, blood vessels

Round nuclei

53
Q

Simple cuboidal epithelium: shape? shape of nuclei?

A

Cube

Flattened nuclei

54
Q

Simple columnar epithelium: shape? shape of nuclei?

A

Tall

Eliptical nuclei

55
Q

Type of epithelial cell?

A

Simple squamous

Blood vessel!!

56
Q

Type of epythelial cell? Where?

A

Simple cuboidal

Kidney collecting duct

57
Q

Why does the nuclei seem to be missing on certain cells?

A

Not part of the cut plane in sample

58
Q

Type of epithelial cell? Where?

A

Simple columnar

Small intestine

59
Q

What are the stratified epithelium cells named based on?

A

The surface cells

60
Q

What are the 3 types of stratified epithelium? Describe each

A
1. Stratified squamous/cuboidal/columnar
2. Ciliated pseudostratified: not actually stratified but nuclei are at different levels
3. Transitional: dome shaped (very unique) which can squeeze and slide over each other
61
Q

Where are transitional epithelium cells found?

A

62
Q

Type of epithelial cell? Where?

A

Stratified squamous (nonkeratinized)

Esophagus

63
Q

Type of epithelial cell? Where?

A

Stratified squamous keratinized

Thin skin

64
Q

Type of epithelial cell? Where? What is the pink?

A

Stratified squamous keratinized

Thick skin

Pink: epidermis

65
Q

Type of epithelial cell? Where?

A

Stratified cuboidal

Sweat gland duct

66
Q

Type of epithelial cell? Where?

A

Stratified columnar

Salivary gland duct

67
Q

Type of epithelial cell? Where?

A

Pseudostratified

Trachea (and all respitatory passages)

68
Q

Type of epithelial cell? Where? Arrow?

A

Transitional

Binucleation (common for transitional epithelial cells)

69
Q

What are glandular epithelia specialized for? 2 types? Main one?

A

Secretion

1. Parenchyma: secretory cells of the gland (main type)
2. Stroma: connective tissue in glands supporting the parenchyma
70
Q

What are the 2 main types of glands?

A
1. Endocrine: secretory product passes directly into blood
2. Exocrine: have ducts to convey product to surface of body or cavity or hollow organ
71
Q

How do we classify the different types of exocrine glands?

A
1. Shape: tubular (coiled or branched) or acinar
2. Compound (branching ducts)/Simple (only one duct)
72
Q

How can we categorize all glands regarding their secretion?

A
1. Type of secretion:
(a) Serous: watery secretion: acinar, stained, nuclei are round and located in center
(b) Mucous: viscous secretion: cytoplasm is bleached out during histo so you cannot stain it (appears clear), cuboidal cells w/ flat nuclei
2. Mode of secretion:
(a) Merocrine (most): product release w/o loss of membrane
(b) Apocrine: whole apical portion of cell is the product
(c) Holocrine: whole cell is the product
73
Q

What do you call the serous glands when connected to mucous glands?

A

Serous demilune

74
Q

What is the mode of secretion of mammory glands?

A

Apocrine

75
Q

What is the mode of secretion of sebaceous glands (skin: oily)?

A

Holocrine

76
Q

Black arrows? White arrows?

A

Microvilli brush border

Lymphocytes

77
Q

What are these? Where? What microscope?

A

Microvilli

Small intestine

SEM

78
Q

Each line?

A

Left to right:

Filaments

Terminal web

Microvilli

Cell coat

79
Q

Arrows?

A

Left to right:

Microvilli

Microfilaments

Cell coat (bottom)

80
Q

Black? Blue?

A

Cilia

Basal bodies

81
Q

Arrow? Yellow? Microscope?

A

Cilia (also very small microvilli above goblet)

Basal bodies

TEM

82
Q

What is this?

A

Cilia

83
Q

What is this? Where? Microscope?

A

Stereocilia in ductus epididymis

LM

84
Q

What is this? Where? Microscope?

A

Stereocilia

Ductus epididymis

SEM

85
Q

What is this? Where? Microscope?

A

Stereocilia

Ductus epididymis

TEM

86
Q

What is this? What do they do?

A

Microplicae: folds in surface of non keratenized squamous epithelium

Found in oral cavity vagina, anal canal, under the eye

Hold a layer of mucin to protect surfaces from trauma

87
Q

What microscope needed to see the ER?

A

EM

88
Q

What can you stain cells that have a cytoplasm rich in ribosomes?

A

Basophilic dyes (like hematoxylin) because RNA is extremely basophilic

89
Q

What is immunohistochemistry? 2 types?

A

Specific substances are stained in sections by the use of antibodies that are linked to a fluorescent compound or to an enzyme that can give rise to a colored precipitate in presence of a specific substrate

1. Direct method: primary antibody is labeled
2. Indirect method: second antibody directed toward the first is used to amplify the rxn