Introduction to Histology

Question 1

Typically how thin is a slice

Answer 1

4 microns

Question 2

How is bone examined

Answer 2

Demineralised - for thin sections

Ground down (has minerals) - thick slide

Question 3

What is the most common used dye in combination

Answer 3

Haematoxylin and Eosin(H&E)

Question 4

H&E

Structured stained
Colours

Answer 4

Nuclei - Blue
Cell cytoplasm - Pink
Extracellular fibres (e.g. collagen, elastic) - pink
Extra-cellular matrix - does not stain

Question 5

What does PAS stain highlight

Answer 5

Sugars

Good for
- goblet cells in small intestine
- glycosaminoglycans in intestinal brush border

Stains sugars rich magenta

Question 6

What does Van Gieson stain highight

Answer 6

Elastic

Can be difficult to see on H&E - appears as thick pink bands

See as wavy brownish bands

Question 7

What does trichrome stain highlight

Answer 7

3 types of cells
- Mucin = blue

Massons’s trichrome (most common)
- Stains variety of different tissues different colours in the same section

Question 8

What does Alcian blue stain highlight

Answer 8

Mucins

Question 9

What is size of a cell dependent upon

Answer 9

Function

Question 10

What is a small cell

Answer 10

Lymphocytes about 10um D with very little cytoplasm

Normally small if they need to move around the body

Question 11

What is a large cell

Answer 11

Motor neurons 100um wide with axons up to 1 metre in length

Question 12

What shape are blood cells usually

Answer 12

Spherical

Red blood cells = biconcave discs (appear round)

Question 13

What cells are fusiform

Answer 13

Smooth muscle cells/fibroblasts

Spindle shaped/elliptical

Question 14

How are you able to tell where one cell ends and the next starts

Answer 14

Most cells have one nucleus

Can infer where cell membrane is by distance between nuclei and dividing by two

Question 15

What are dormant/metabolically inactive cells

Answer 15

Generally smaller than metabolically active cells

Question 16

What are metabolically active cells

Answer 16

Have an abundance of cellular components due to being metabolically active e.g. mitochondria

Commonly have nucleoli - sites of DNA transcription into RNA

Question 17

What cells last for days

Answer 17

Lining of the gut (small and large intestine) approx. 4-5 days

Question 18

What cells last for months

Answer 18

Lots of tissues
e.g. blood, skin, connective tissue

Question 19

How long do red blood cells last for

Answer 19

120 days

Question 20

What cells last for years

Answer 20

Bones and tendons

Question 21

What cells last for nearly whole life

Answer 21

(limited regeneration)

Skeletal muscle

Question 22

What cells last for whole life

Answer 22

No capacity to regenerate

Nerves and brain
Cardiac (heart) muscle
Germ cells

Question 23

What is the nucleus

Answer 23

Brain of the cell

Surrounded by double nuclear membrane there are numerous small pores to allow passage pf ribosomal RNA and chemical messengers

Contains chromatin
Darked areas - heterochromatin
Lighter colours - euchromatin

Question 24

What is the nucleolus

Answer 24

1-3um in D

Site of ribosomal RNA formation

Question 25

What is the mitochondria

Answer 25

Powerhouse of cell Site of oxidation of phosphorylation Have own DNA Double membrane - inner membrane is highly folded (cristae - between = mitochondrial matrix) outside = smooth

Question 26

What is the function of associated enzymes in the outer membrane of the mitochondria

Answer 26

Lipid synthesis Fatty acid metabolism

Question 27

What is the function of associated enzymes in the inner membrane of the mitochondria

Answer 27

Respiratory chain ATP production

Question 28

What is the function of associated enzymes in the matrix of the mitochondria

Answer 28

TCA (Kreb's Cycle)

Question 29

What is the function of associated enzymes in the intermembranous space of the mitochondria

Answer 29

Nucleotide phosphorylation (ADP to ATP)

Question 30

What is the rough endoplasmic reticulum

Answer 30

Site of protein synthesis Highly folded flattened membrane sheets - studded with ribosomes

Question 31

What is smooth endoplasmic reticulum

Answer 31

Site of lipid synthesis Processes synthesised proteins Highly folded flattened membrane sheets - no ribosomes

Question 32

What is the Golgi apparatus

Answer 32

Parallel stacks of membranes Processes macromolecules synthesised in the ER Frequently not visible on light microscopy Particularly prominent in plasma cells (activated B lymphocytes) - seen as perinuclear 'hoff'

Question 33

What are vesicles

Answer 33

Very small spherical membrane-bound organelles Used for transport, storage and exchanging cell membrane between compartments

Question 34

Name the types of vesicles

Answer 34

Cell surface derived pinocytotic and phagocytotic vesicles Golgi-derived transport vesicles ER-derived transport vesicles Lysosomes Peroxisomes

Question 35

What are lysosomes

Answer 35

Derived from Golgi apparatus Site where proteins are degraded H+-ATPase on membrane creates low internal pH (5) Contain acid hydrolases that degrader proteins Initial hydrolase vesicles fuse with endosomes with the correct membrane proteins to produce endolysosomes

Question 36

What are peroxisomes

Answer 36

Small (0.5-1um) Membrane-bound organelles containing enzymes which oxidise long-chain fatty acids

Question 37

What is the cytoskeleton

Answer 37

Supports cell shape Comprised of different types of filaments

Question 38

What cell does not contain tubulin proteins

Answer 38

Red blood cells (do not divide)

Question 39

Where is cytokeratins found

Answer 39

Epithelial cells

Question 40

Where is desmin found

Answer 40

Myocytes (muscle cells)

Question 41

Where is glial fibrillary acidic protein found

Answer 41

Astrocytic glial cells (supportive cells of nervous system)

Question 42

Where is neurofilament protein found

Answer 42

Neurons

Question 43

Where is nuclear lamina found

Answer 43

Nuclei of all cells

Question 44

Where is vimentin found

Answer 44

Mesodermal cells

Question 45

What are the intermediate filaments of the cytoskeleton

Answer 45

Cytokeratins Desmin Glial fibrillary acidic protein Neurofilament protein Nuclear lamina Vimentin

Question 46

What are types of tissue

Answer 46

Epithelial Muscle Supporting tissues Nerves Germ cells

Question 47

What is the purpose of the epithelia

Answer 47

Protection Absorption Secretion

Question 48

What is a liquid connecting tissue

Answer 48

Blood

Question 49

Where are lymphocytes found in large numbers

Answer 49

Lymph nodes Tonsils Thymus Gland