Histology

Question 1

What is the oral cavity, oropharynx and laryngopharynx lined with?

Answer 1

generally non keratinised stratified squamous epithelium

Question 2

what is the nasal cavity and nasopharynx lined with?

Answer 2

respiratory epithelium

Question 3

What type of cells is the tongue made of?

Answer 3

anterior 2/3 - stratified squamous epithelium, thin on ventral surface, thick and with papillae on the dorsal surface

posterior 1/3 - covered by smooth stratified squamous epithelium which, except for the circumvallate papillae, lacks papillae but does have substantial lymphoid aggregates in the submucosa

Question 4

What is included in the pharynx?

Answer 4

ring of lymphoid tissue composed of the palatine tonsils, lingual tonsils, tubal tonsils and pharyngeal tonsils (adenoids)

Question 5

What are 4 major layers in the digestive tract called?

Answer 5

1. mucosa
2. submucosa
3. muscularis externa
4. serosa or adventitia

Question 6

what are the three parts of the mucosa called?

Answer 6

epithelium - sits on a a basal lamina
lamina propria - loose connective tissue
muscularis mucosae - thin layer of smooth muscle

Question 7

what is the submucosa made of?

Answer 7

loose connective tissue

Question 8

what is the muscularis externa made of?

Answer 8

two thick layers of smooth muscle, an inner circular layer and an outer longitudinal layer

Question 9

what is the serosa or adventitia?

Answer 9

outer layer of connective tissue that either suspends the digestive tract or attaches it to other organs

Question 10

Where are glands in the submucosa found?

Answer 10

oesophagus

Question 11

what does the surface of the stomach look like?

Answer 11

flat surface but with holes in it - called gastric pits

Question 12

what is found at the bottom of gastric pits?

Answer 12

1-7 gastric glands

Question 13

what are gastric pits lined by?

Answer 13

surface mucous cells

Question 14

what is the isthmus mostly made of?

Answer 14

mostly parietal cells and stem cells

Question 15

what is the neck of gastric glands made of?

Answer 15

neck mucous cells and parietal cells

Question 16

what is the fundus (base) of the gastric glands made of?

Answer 16

chief cells with a few parietal cells and enteroendocrine cells (also called neuroendocrine cells)

Question 17

what do parietal cells do?

Answer 17

produce hydrochloric acid

Question 18

what do chief cells?

Answer 18

digestive enzyme secreting cell

Question 19

what is unusual about the muscularis externa of the stomach?

Answer 19

has an additional layer, this layer is oblique and located internal to the circular layer. this layer aids the churning action of the stomach

Question 20

what is the most common type of cell in the small intestinal epithelium?

Answer 20

enterocytes

Question 21

what cells are there in the small intestinal epithelium?

Answer 21

enterocytes, goblet cells, paneth cells, enteroendocrine cells and stem cells

Question 22

what is the acidic, partly digested semifluid material the duodenium recieves from the stomach called?

Answer 22

chyme

Question 23

what other region apart from the oesophagus has glands in the submucosa?

Answer 23

duodenum

Question 24

what are the glands in the duodenum called? what do they do?

Answer 24

brunner’s glands - when stimulated by the presence of chyme they produce a thin, alkaline mucous to neutralise the chyme

Question 25

what are peyer's patches?

Answer 25

areas of relatively large aggregations of lymphoid tissue

Question 26

what are the two types of cells in the large intestinal epithelium?

Answer 26

absorption cells and goblet cells

Question 27

what do goblet cells in the large intestinal epithelium do?

Answer 27

secrete mucus to lubricate the colon

Question 28

what are the 3 muscular strips of the large intestine called?

Answer 28

teniae coli

Question 29

what is the digestive tract nervous system called?

Answer 29

enteric nervous system

Question 30

what is the interconnected network of fibres that controls gut motility called?

Answer 30

myenteric plexus

Question 31

what is a group of neurons living outside the brain or spinal cord called?

Answer 31

ganglion (plural is ganglia)

Question 32

what is the network of neurons which controls the muscle of the muscularis mucosae and helps regulate secretion called?

Answer 32

submucosal plexus

Question 33

how do the liver and pancreas develop?

Answer 33

outgrowth from the gut

Question 34

what is the parenchyma of the liver and pancreas composed of?

Answer 34

glandular epithelial cells

Question 35

what is the liver capsule made of?

Answer 35

collagenous connective tissue, which is covered by a layer of mesothelial cells derived from the peritoneum.

Question 36

what are the segments of the liver called?

Answer 36

lobules

Question 37

what does each lobule of the liver have?

Answer 37

a branch of the hepatic vein called the centrolobular vein (or central vein) at its centre and portal triads at each corner

Question 38

what are portal triads?

Answer 38

points of blood entry

Question 39

what do portal tracts/triads include branches of?

Answer 39

hepatic portal vein hepatic artery bile ductule

Question 40

what is the bile ductule lined by?

Answer 40

simple cuboidal cells called cholangiocytes

Question 41

what are the main cells of the liver?

Answer 41

hepatocytes

Question 42

what are the blood channels in the liver called?

Answer 42

sinusoids

Question 43

what are sinusoids lined with?

Answer 43

endothelial cells

Question 44

what is the narrow space between the lining cells of the sinusoids and the hepatocytes called?

Answer 44

space of Disse (or the perisinusoidal space)

Question 45

what is the parenchyma of the liver supported by?

Answer 45

reticular fibres, type III collagen as well with some type I collagen

Question 46

what are the cells found scattered in the space of disse called?

Answer 46

hepatic stallate cells

Question 47

what are hepatic stallate cells?

Answer 47

modified fibroblasts and make connective tissue. store vitamin A within fat droplets in their cytoplasm.

Question 48

what can happen to hepatic stallate cells in some pathological conditions?

Answer 48

they can transform into myofibroblasts and produce scar tissue in the liver

Question 49

what type of cells are scattered in the sinusoids?

Answer 49

resident macrophages called kupffer cells.

Question 50

what do kupffer cells do?

Answer 50

remove particulate matter from the blood and help remove worn out red blood cells

Question 51

What is bile?

Answer 51

alkaline solution containing water, ions, phospholipids, bilirubin and bile salts.

Question 52

what is bilirubin?

Answer 52

pigment which results from the breakdown of haemoglobin in the spleen, it is the principle cause of the brown colour of feaces.

Question 53

what are bile salts important for?

Answer 53

emulsification of fats in the digestive system

Question 54

which cells produce bile?

Answer 54

hepatocytes

Question 55

what does bile flow via?

Answer 55

bile canaliculi

Question 56

what is the bile canaliculi?

Answer 56

small channels formed by tight junctions in the cell membranes of adjacent hepatocytes.

Question 57

what is the gall bladder made of?

Answer 57

it is a muscular sac lined by simple columnar epithelium backed by a lamina propria of loose connective tissue rich in blood vessels and lymphatic vesselsm a coat of smooth muscle and an outer collagenous layer of adventitia.

Question 58

what does the gall bladder do?

Answer 58

stores bile and modifies it.

Question 59

what is the name of the hormone which stimulates the gall bladder to contract and deliver bile to the duodenum?

Answer 59

cholecystokinin

Question 60

what is the inflammation of the gall bladder called?

Answer 60

cholecystitis

Question 61

what are the small scattered islands of tissue in the endocrine pancreas called?

Answer 61

islets of langerhans

Question 62

what are the islets of langerhans do?

Answer 62

produce hormones such as insulin and glucagon.

Question 63

why does the pancreas not digest itself?

Answer 63

the enzymes are proenzymes until they arrive at the duodenum.

Question 64

what happens when the pancreatic secretions reach the duodenum?

Answer 64

an enteropeptidase converts the inactive proteolytic enzyme trypsinogen into the active form, trypsin. this begins a cascade that results in the activation of other enzymes.

Question 65

what are the ducts in the pancreas called?

Answer 65

centroacinar cells

Question 66

what is the hepatopancreatic ampulla (of vater)?

Answer 66

the main pancreatic duct joins the common bile duct and opens into the duodenum a papillae