Development and Organisation of the Alimentary System, Liver & Pancreas

Question 1

Accessory Organs of the gut

Answer 1

• salivary glands
• liver & gall bladders
• pancreas

Question 2

Where do mouth parts develop from?

Answer 2

branchial arches

Question 3

Where (other than the mouth) forms from the branchial arches?

Answer 3

• ear
• hand
• neck

Question 4

Describe mesoderm

Answer 4

• middle developmental layer between the ectoderm and endoderm
• gives rise to the skeleton, muscle, heart and bones

Question 5

What are indents in the branchial arches known as?

Answer 5

pharyngeal clefts or grooves

Question 6

What are supplied by a cranial nerve in branchial arches?

Answer 6

cartilage and muscular components

Question 7

How many pharyngeal arches are there in branchial arches?

Answer 7

6

Question 8

How many clefts are there in branchial arches?

Answer 8

4

Question 9

What develops from the first branchial arch?

Answer 9

1. skin of jaw
2. salivary glands
3. tooth enamel
4. buccal cavity

Question 10

What develops from the 1st cleft of branchial arches?

Answer 10

• external components of middle ear
• tympanum

Question 11

What develops from the 1st pouch of branchial arches?

Answer 11

auditory tube

Question 12

What develops from the 2nd, 3rd and 4th branchial arches?

Answer 12

skin of the ear & neck

Question 13

What develops from the 2nd pouch of branchial arches?

Answer 13

tonsils & lymphatics

Question 14

What develops from the 3rd pouch of branchial arches?

Answer 14

thymus & thyroid

Question 15

What develops from the 4th pouch of branchial arches?

Answer 15

thyroid

Question 16

What 3 “parts” are in each branchial arches?

Answer 16

1. nerves
2. arteries
3. cartilage

Question 17

What does the gut develop as?

Answer 17

an endodermal tube

Question 18

What surrounds the endoderm?

Answer 18

Splanchnic mesoderm

Question 19

What forms muscle & connective tissue?

Answer 19

Splanchnic mesoderm

Question 20

What provides nutrients to the embryo as the placental plate develops?

Answer 20

a yolk sac

Question 21

At what week of embryo development do accessory organs appear?

Answer 21

week 6

Question 22

What are the 4 layers of the gut wall?

Answer 22

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

Question 23

Describe mucosa

Answer 23

• lines the gut lumen
• has 3 layers
• has a thin ring of longitudinal smooth muscle
• contains mucus and electrolyte-secreting glands
  -surface normally highly folded to increase digestive surface area

Question 24

Describe submucosa

Answer 24

• thick layer of connective tissue
• provides structural support and elasticity
• contains submucosal nerve network

Question 25

Describe muscularis externa

Answer 25

- has inner ring of circular smooth muscle - has outer ring of longitudinal muscle - contracts tube diameter - constricts gut length

Question 26

Describe serosa

Answer 26

- outer connective tissue layer - secretes fluid to lubricate organs of the coelom - attached to mesenteric membranes

Question 27

What is the primary region of nutrient absorption?

Answer 27

the small intestine

Question 28

What increases the absorptive area in the small intestine?

Answer 28

circular folds, villi, and microvilli

Question 29

What are villus lined with?

Answer 29

epithelial cells and mucus-secreting cells

Question 30

What is contained within villus?

Answer 30

- an arterial and venous circulation - a lymphatic vessel

Question 31

What is the lymphatic system prominent in?

Answer 31

lipid absorption

Question 32

Describe the crypt of lieberkuhn

Answer 32

- site of enterocyte - a site of water and mucus secretion

Question 33

What is the primary function of the large intestine

Answer 33

water re-absorption and drying of feces

Question 34

Where does the liver develop from?

Answer 34

ventral hepatic bud from foregut endoderm

Question 35

What is the liver organized into?

Answer 35

units called lobules

Question 36

What is each lobule in the liver fed by a branch of?

Answer 36

the hepatic artery and the portal vein

Question 37

Where is bile stored?

Answer 37

the gall bladder

Question 38

What is a sinusoid?

Answer 38

blood from the hepatic artery and portal vein that flows into the same capillary vasculature

Question 39

Where does the alimentary tube develop from?

Answer 39

the cephalic and caudal parts of the embryo

Question 40

Where does the pancreas develop from?

Answer 40

dorsal & ventral pancreatic buds

Question 41

What is the pancreas organized into?

Answer 41

exocrine and endocrine structures

Question 42

How is the exocrine pancreas organized?

Answer 42

as a series of glands along the pancreatic duct which drains into the duodenum

Question 43

Describe duct cells in the exocrine pancreas

Answer 43

- exist at the base of each gland - secrete bicarbonate - the bicarbonate neutralizes digestive juices from the stomach

Question 44

Describe acinar cells in the exocrine pancreas

Answer 44

- at the head of each gland - secrete digestive enzymes into the duct

Question 45

Where does the exocrine pancreas develop from?

Answer 45

the ventral pancreatic bud

Question 46

Where does the endocrine pancreas develop from?

Answer 46

the dorsal pancreatic bud

Question 47

What are islets of Langerhans in the endocrine pancreas?

Answer 47

a series of secretory islets perfused by a capillary network

Question 48

What do islet cells do?

Answer 48

secrete metabolic hormones (insulin, glucagon and somatostatin)