Histology

Question 1

Which epithelia is most likely to be composed of simple cuboidal cells?

Answer 1

Ducts and tubules

• collecting tubules
• salivary and pancreatic secretory ducts

Question 2

Which epithelia is most likely to be composed of simple cuboidal cells?

Answer 2

Absorptive surfaces = GI tract and stomach

Question 3

Which filaments maintain the structure of mcirovilli?

Answer 3

Actin filaments

Question 4

What are goblet cells?

Answer 4

They are modified columnar cells which secrete mucous

Question 5

How do goblet cells stain with H and E stain?

Answer 5

Poorly due to mucous being ‘washed out’

Question 6

Which epithelia is most likely to be composed of pseudostratified epithelia?

Answer 6

The respiratory tract

Question 7

What filaments give cilia their shape and what is the arrangement of these filaments?

Answer 7

Cilia have a core or X20microtubules

Arranged of X9 pairs circling a central pair

Question 8

What are the X4 main layers of the respiratory system?

State what each of these layers contains.

Answer 8

1) mucosa
= epithelium
= lamina propria

2) Submucosa
3) cartilage/smooth muscle
4) Adventitia

Question 9

What type of epithelia are found in the respiratory tract?

Answer 9

Pseudostratified columnar epithelia with cilia and goblet cells

Question 10

What type of epithelia are found in the oesophagus?

Answer 10

Stratified squamous epithelia (non-keratinising)

Question 11

What type of epithelia does skin have?

Answer 11

Stratified squamous epithelia (keratinising)

Question 12

What does keratinising mean?

How will these appear under microscopy?

Answer 12

It means the top layers are dead keratinised cells with no nuclei due to keratins being linked with disulphide bonds

Flat and thin

Question 13

What is transitional epithelium?

Where is it found?

Answer 13

Epithelium that can be distended

Only found in the urinary tract

Question 14

What colour is the connective tissue when stained?

Answer 14

Usually pale as it does not stain well and mainly consists of extra-cellular matrix

It’s few cells are highly scattered (fibroblasts)

Question 15

In connective tissue, what is ground substance?

Answer 15

A watery gel of proteiglycans synthesised from glycosaminoglycans (GAG’s)

Question 16

What is extracellular matrix?

Answer 16

Proteins embedded in the watery gel ground substance (GAG’s)

Question 17

What are the main proteins found in the ECM?

Answer 17

Elastin
Collagen
Fibronectin
Laminin

Question 18

What do fibroblasts do?

Answer 18

Synthesise ECM (ground substance) and collagen

Question 19

Other than fibroblasts, what other cells are permanently found in connective tissue?

Answer 19

Adipose cells

Question 20

What are the X3 types of connective tissue?

Give examples of each.

Answer 20

1) basal lamina
2) loose (areolar) = mesentery and hypodermis
3) dense

Question 21

Dense connective tissue is further subdivided into?

Give examples of each.

Answer 21

1) regular
= tendon/ligament

2) irregular
= dermis of skin

Question 22

Which appear thicker under microscopy, collagen or elastic fibres?

Answer 22

Collagen fibres

Question 23

What would dense, regular connective tissue look like?

Answer 23

Parallel collagen fibre bundles with fibrocytes in between

Question 24

What are tendons mainly made from?

Answer 24

Collagen fibres

Question 25

Can skeletal muscle cells divide? If not what overcomes this?

Answer 25

No Satellite cells

Question 26

What is the structure of muscle from sarcomeres to the whole muscle?

Answer 26

Sarcomeres Multiple sarcomeres = myofibril Multiple myofibrils = myofibre (muscle fibres) Multiple muscle fibres are bound together into fascicles Fascicles join to make the muscle

Question 27

Which types of muscle does NOT have gap junctions?

Answer 27

Skeletal, the other X2 types do

Question 28

What would you look for under microscopy to see skeletal muscle?

Answer 28

- striated cells | - multinucleate with nuclei at peripheries

Question 29

What would you look for under microscopy to see cardiac muscle?

Answer 29

- uninucleate cells with centrally locates nuclei - striated - intercalated discs

Question 30

What would you look for under microscopy to see smooth muscle?

Answer 30

- no striations - uninucleate with centrally located nucleus - spindle shaped cells (tapered ends)

Question 31

What is the name of the connective tissue which capsules around cartilage?

Answer 31

Perichondrium

Question 32

What cells are located in perichondrium and what do they do?

Answer 32

Fibroblasts which produce chondrocytes which themselves produce cartilage

Question 33

What is growth called when it occurs from the outside in, as seen with chondrocytes synthesising cartilage?

Answer 33

A positional growth

Question 34

Cartilage has X2 types of growth, what are these?

Answer 34

Apositional and interstitial growth

Question 35

What type of growth does bone undergo?

Answer 35

Apositional only

Question 36

Where about a do blood vessels run with regards to cartilage?

Answer 36

In the perichondrium

Question 37

In haversack systems, what is the name of the central canal which is encircled with bone?

Answer 37

Haversian canal

Question 38

What is the name of the concentric circles of bone which surround the Haversian canal? How many of these surround each canal?

Answer 38

Lamellae 4-20

Question 39

What do haversian systems carry?

Answer 39

Vessels and nerves But NOT lymphatics

Question 40

What is an alternative name for the Haversian canals?

Answer 40

Osteons

Question 41

What structure connects Haversian canals transversely? What is their function?

Answer 41

Volkman’s canals Allow blood to pass between Haversian canals

Question 42

What is the name of the remnants of osteons/Haversian canals which are currently ‘turning over, found between fully developed osteons?

Answer 42

Interstitial lamellae

Question 43

What are the X2 patterns in which lamellae are laid down within bone?

Answer 43

1) Haversian systems | 2) circumferential around the edge of bones

Question 44

What are lacunae?

Answer 44

Small gaps between concentric circles of lamellae collagen which house osteocytes

Question 45

What are osteocytes?

Answer 45

Osteoblasts (bone matrix secreting cells) which have synthesised matrix then embedded themselves in it

Question 46

What are the small cavities which extend lacuna to lacuna?

Answer 46

Canaliculi

Question 47

What bone cells degrade old bone to make room for new osteoblasts?

Answer 47

Osteoclasts

Question 48

What are the X4 main layers of the GI tract? What does each layer contain?

Answer 48

1) mucosa - epithelium - lamina propria - muscularis mucosae 2) Submucosa 3) muscularis externa (propria) 4) Adventitia or serosa

Question 49

How would you decide when the Submucosa layer of the GI tract starts under microscopy?

Answer 49

The layer becomes much white and fewer cells are apparent

Question 50

How does the epithelium specialisations of the GI tract change as it progresses?

Answer 50

1) it begins as protective 2) then turns secretory 3) then absorptive 4) finally returns to protective

Question 51

Which plexus of nerves is found in the Submucosa?

Answer 51

Meissner’s plexus

Question 52

What does the muscularis mucosae delineate between?

Answer 52

The end of the mucosal layer (1st layer) and the submucosa (2nd layer)

Question 53

What is another name for the muscularis externa?

Answer 53

Muscularis propria

Question 54

How many layers does the muscularis externa have? What are they?

Answer 54

1) inner circular layer of muscle | 2) outer longitudinal layer of muscle

Question 55

Where is Auerbach’s plexus of nerves situated?

Answer 55

Between the inner circular and outer longitudinal layer of the muscularis externa layer of the GI tract

Question 56

How thick would the Adventitia / serosa layer appear under microscopy?

Answer 56

Thin, almost a small edge!

Question 57

What cells line the Adventitia/serosa?

Answer 57

Simple, squamous mesothelium

Question 58

What is the epithelium of the oesophagus?

Answer 58

Stratified, squamous epithelium (for protection) NON-KERATINISING!

Question 59

What does the epithelium change to at the gastro-oesophageal junction?

Answer 59

It changes to simple, columnar epithelium

Question 60

Which part of the GI tract has an extra layer? What is this layer?

Answer 60

The stomach A inner oblique muscle layer within the muscularis externa (is the most inner layer)

Question 61

Which stomach cells secrete pepsinogen?

Answer 61

Chief cells

Question 62

Which stomach cells secrete HCl?

Answer 62

Parietal cells

Question 63

Which cells of the gastric pit are most likely to line the top and sides of the pit?

Answer 63

Neck mucous cells

Question 64

Which cells of the gastric pit are most likely to line the isthmus? What do these look like under microscopy? What do they secrete?

Answer 64

Partial cells Like fried eggs, large and round HCl and intrinsic factor

Question 65

Which cells of the gastric pit are most likely to line the lower regions of the gastric glands? What do these look like under microscopy?

Answer 65

Chief cells Nasally located nuclei and dense with granules Pepsinogen

Question 66

What are alternate names for chief cells?

Answer 66

Peptic or zymogenic cells (as they contain zymogen granules)

Question 67

What is an alternative name for parietal cells?

Answer 67

Oxyntic cells

Question 68

How would identify a specimen between: 1) Caria mucosa or stomach 2) body mucosa of stomach 3) pyloric mucosa of stomach

Answer 68

1) Caria mucosa or stomach = glands are sparse 2) body mucosa of stomach = glands are densely packed 3) pyloric mucosa of stomach = very deep pits

Question 69

What is the epithelium of the small intestine?

Answer 69

Simple columnar (same as stomach) but with a brush boarder of microvilli (surface specialisation)

Question 70

In the small intestine, what is the difference between plicae circularis and villi?

Answer 70

Plica = evaginations of the whole mucosa layer and some of the submucosa Villi = evaginations of the mucosa layer only

Question 71

What lies between villi in the small intestine?

Answer 71

The crypts or leiberkühn

Question 72

What cells are found in the crypts of leiberkühn? Where are these found within the crypts What do these do? What do they look like under microscopy?

Answer 72

Paneth cells Found in the lower 1/3 They release digestive enzymes They have a nasally located nuclei and stain bright pink!

Question 73

What feature do small intestine epithelia have to prevent digestive enzymes destroying host tissues?

Answer 73

Glycocalyx

Question 74

Does the small intestine have goblet cells?

Answer 74

Yes

Question 75

Other than paneth cells, what other cells are found deep in the lower 1/3 of the crypts of leiberkühn? What is their function? What do they look like under microscopy?

Answer 75

Endocrine cells They release multiple hormones They stain very light in their cytoplasm

Question 76

What glands are found distinctively in the duodenum? What do they look like?

Answer 76

Brunners glands They are found in the submucosa but pierce the muscularis mucosae and drain into the crypts

Question 77

What other distinguishing feature does the duodenum have?

Answer 77

Leaf shapes villi

Question 78

Does the jejunum have brunners glands?

Answer 78

No

Question 79

What do jejunum villi look like?

Answer 79

Long, tall and thin (NOT leaf shaped!)

Question 80

What is found in the ileum that is not found in the duodenum and jejunum? Which layer is this found in?

Answer 80

Peyers patches Then lamina propria

Question 81

What do ileum villi look like?

Answer 81

Much shorter

Question 82

What does the appendix look like under microscopy?

Answer 82

It has lots of tiny dots (lymphocytes)

Question 83

What does the epithelial layer of the large intestine look like?

Answer 83

No villi Lots of goblet cells for mucous secretion

Question 84

What is different about the muscular layer in the large intestine?

Answer 84

Teniae colicand haustra

Question 85

What does the epithelium change to at the ano-rectal junction?

Answer 85

Changes to stratified squamous epithelium

Question 86

What will be seen in the muscle layer of the anal canal?

Answer 86

The internal and external sphincters