FHMP 017 + 018 Tissues and Organs histology

Question 1

what is histology?

Answer 1

microscopic study of tissues

Question 2

What is histopathology?

Answer 2

microscopic examination of tissues for signs of disease

Question 3

describe light microscopy

Answer 3

• fresh tissue is soft so needs to be fixed to hard structure (fix to aldehyde)
• dehydrate in acetone and embed in wax
• cut into thin slices and place on glass slide
• use dyes to see better (coloured)
• can be alive or dead
• low resolution (200nm)

Question 4

describe electron microscopy

Answer 4

• Uses electron beams
• more dangerous
• resolution 0.2 nm
• black and white images
• cells are fixed
• transmission and scanning
• free electrons travel in waves, like light
• resolving power is greater because the wavelength of the electron beams are smaller
• fix in aldehyde and place in electron stain OsO4
• dehydrate in acetone and embed in plastic and cut thin slices then place on copper grid

Question 5

what is H + E stain?

Answer 5

• Haematoxylin dye + eosin dye
• haematoxylin = dyes nuclei dark purple
• eosin = dyes cytoplasm pink/red

Question 6

what are the 5 primary tissues?

Answer 6

• connective
• epithelial
• muscle
• nerve
• blood

Question 7

what are the different types of connective tissue?

Answer 7

1. connective tissue proper = loose (areolar, reticular), dense (regular -tendons-, irregular - dermis
2. specialised connective tissue = adipose, blood, lymphoid
3. supporting connective tissue = cartilage, bone

Question 8

what are the different types of epithelia?

Answer 8

• simple (1 layer)
• stratified (more than 1 layer)
• squamous ( flat)
• cuboidal (cuboid shape)
• columnar (tall)
• pseudostratified (1 layer but looks like multiple due to long cells with nuclei at different levels)
• transitional (changes shape with environment)

Question 9

Where are simple squamous cells found?

Answer 9

lines air sacs of lungs, inner lining of heart and blood vessels, serous membranes, inner ear drum

Question 10

Where are stratified squamous cells found?

Answer 10

Epidermis of skin (keratinised), lining of mouth, tongue, throat, larynx, oesophagus, canal vagina (nonkeratinised)

Question 11

Where are simple columnar cells found?

Answer 11

lines gastrointestinal tract from stomach to anus, uterus, uterine tubes

Question 12

Where are stratified columnar cells found?

Answer 12

male urethra, mammary gland duct

Question 13

Where are simple cuboidal cells found?

Answer 13

lines surface of ovary, kidney tubules, kidney, thyroid, mammmary glands, salivary glands, small ducts

Question 14

Where are stratified cuboidal cells found?

Answer 14

larger ducts in sweat glands and salivary glands

Question 15

Where is pseudostratified epithelium found?

Answer 15

trachea, respiratory tract

Question 16

Where is transitional epithelium found?

Answer 16

urinary bladder, renal pelvis, ureters

Question 17

what are the different types of muscle tissue?

Answer 17

skeletal, cardiac, smooth

Question 18

What is nervous tissue?

Answer 18

a tissue consisting of neurons and the cells that support them

Question 19

what is blood tissue?

Answer 19

Connective tissue with a liquid extracellular matrix called blood plasma

Question 20

what are some problems with multicellularity?

Answer 20

• cells need to communicate (need to use nerves, hormones, local signals, gap junctions)
• cells must adhere to one another (meshwork of large extracellular molecules such as collagen, extracellular matrix and specialised adherens/anchoring junctions between plasma membranes)

Question 21

What is the extracellular matrix?

Answer 21

• nonliving material found between cells in connective tissue
• synthesised by fibroblasts
• contains collagen, elastin and proteoglycans
• cells are anchored to the ECM and cytoskeleton through receptors in their surface

Question 22

What are anchoring junctions?

Answer 22

• They attach cells to other cells or basement membrane and they transmit stresses via the cytoskeleton. -They are made up of actin filaments and intermediate filaments
• desmosomes = between adjacent cells
• hemidesmosomes = between cell and extracellular matrix

Question 23

What are the layers above and below the epidermis?

Answer 23

• keratin on top
• then epidermis with desmosomes between cells
• then ECM receptors attach the desmosomes to connective tissue (always below epithelia)

Question 24

what happens if cellular adhesion is disturbed?

Answer 24

• Pemphigus / blistering disease, where skin epithelial cells split apart and form blisters
• Cancer - without cell adhesions easier for cancer to metastasize

Question 25

what colour is cartilage dyed?

Answer 25

blue

Question 26

what does adipose tissue look like under a microscope?

Answer 26

white round circles alone or in a group

Question 27

what do blood vessels look like under a microscope?

Answer 27

round red circles ( look at the layers in the wall )
large + thin walls = vein
large and thick walls = artery
very small and thin walls = capillary

Question 28

what does smooth muscle look like?

Answer 28

Fiber thickest in middle, tapered at each end, with one centrally positioned nucleus; not striated

Question 29

what does skeletal muscle look like?

Answer 29

striated, multi-nucleated (eccentric), fibers parallel