Lab Practical -digestive terms

Question 1

walls of hollow organs-inner to outer

Answer 1

1. Mucosa (lining)
2. Submucosa
3. Muscularis Externa

Question 2

Mucosa (lining)

Answer 2

• made of epithelium over a thin layer of connective tissue called the lamina propia
• the digestive organs have a thin layer of smooth muscle called the muscularis mucosa- the muscle layer pulls the lining into folds like the rugae of the stomach & plicae circularis of the sm. intestine

Question 3

Submucosa

Answer 3

• the submucosa is made of dense regular connective tissue
• it is rich in blood, lymph, nerves.
• it is often in digestive system, filled with glands
• in digestive organs, the submucosal plexus, a network of nerves responsible for stimulating glandular secretion is found here

Question 4

Muscularis Externa

Answer 4

• AKA muscularis
• 1+ layers of smooth muscle
• in places along the tract, circular layer often thickens to form sphincters that act as valves to prevent backflow and control food passage between organs
• in digestive system, the inner layer is circular and outer, longitudinal -in urinary-reverse
  *Stomach: 3 layers- oblique, circular, longitudinal
  Bladder: 3 layers- longitudinal, circular, longitudinal

Question 5

Serosa or Adventitia

Answer 5

• organs covered by serous membranes have serosa
• those covered by connective tissue have adventitia
• some organs, like the bladder + L.intestine, have a serosa in some areas and an adventitia in others

Question 6

2 groups of organs in digestive system

Answer 6

1. Alimentary canal

2. Accessory organs

Question 7

Alimentary Canal

Answer 7

• Mouth->Pharynx(oropharynx & laryngopharynx)-> esophagus-> stomach-> small intestine-> large intestine-> anus
• AKA GI Tract
• ~30’ long in a cadaver

Question 8

Accessory organs

Answer 8

• tongue
• teeth
• gall bladder
• liver
• pancreas

Question 9

Mouth

Answer 9

• oral cavity, buccal cav.
• bounded by lips, cheeks, palate, and tongue
• lining of stratified squamous epithelium
• continuous w/ oropharynx through the fauces

Question 10

tongue

Answer 10

• made of intrinsic muscle (longitudinal, vertical, and transverse skeletal muscle fibers)
• attached to bones of the skull or the soft palate by extrinsic muscle
• intrinsic muscle change shape, extrinsic change position

Question 11

Salivary glands

Answer 11

• Extrinsic (Parotid, Submandibular, and Sublingual; all paired): secrete watery slaiva containing SALIVARY AMYLASE, which breaks down starch and glycogen, as well as mucus to help bind food particles and aid in swallowing

Question 12

teeth

Answer 12

• mammals have both primary (deciduous) and secondary ( permanent) teeth
• 32 secondary teeth total; 16 on each jaw
• per jaw front to back: 4 INCISORS( for biting), 2 CUSPID( for tearing), 4 BICUSPID & 6 MOLARS (for grinding)

Question 13

enamel

Answer 13

• hardest substance in body, covers outside of tooth

- enamel producing cells die when tooth erupts

Question 14

dentin

Answer 14

• protein-rich, bone-like material beneath enamel cap, forms bulk of tooth
• new dentin formed throughout adult life

Question 15

Pulp cavity

Answer 15

• containing PULP
• beneath the dentin , the pulp cavity contains the connective tissue, blood vessels and nerve fibers that supply the tooth
• the pulp cavity extends into the ROOT, forming the ROOT CANAL

Question 16

Pharynx

Answer 16

-common passage from mouth for food and air; the oropharynx and laryngopharynx play a role in food passage

Question 17

Esophagus

Answer 17

• muscular tube, 10” long
• muscosa- strat. squamous epithelium
• the muscularis is a skeletal muscle for the upper third; a mix of the skeletal & smooth in the middle third, and entirely smooth in the inferior third
• the esophagus has an adventitia
• it is posterior to the trachea & heart, and passes through the diaphragm at the esophageal hiatus
• the esophagus joins the stomach at the CARDIAC ORIFICE, which is guarded by the CARDIAC (GASTROESOPHAGEAL)SPINCTER

Question 18

Stomach

Answer 18

• at the stomach, the digestive mucosa switches to simple columnar epithelium, rich in goblet cells. Thys type of epi. continues to the level of the anal canal, where there is a switch back to stratified sqaumous
• J-shaped, 10” long

Question 19

4 regions of the stomach

Answer 19

1. fundus
2. cardia
3. body
4. pylorus

Question 20

2 stomach curvatures

Answer 20

1. greater omentum- hangs from the greater curvature over the small intestine, then goes superiorly to wrap the transverse colon
2. lesser omentum- runs from the lesser curvature of the stomach to the liver

Question 21

gastric pits

Answer 21

• stomach:
• in muscularis
• deep pits that lead into gastric glands that produce gastric juice
• cells in this area produce mucus to protect the stomach wall as well as HCl and digestive enzymes

Question 22

Gastric Ulcers

Answer 22

• occur when the stomach wall becomes eroded
• most ulcers are linked to eh presence of the acid-resistant bacteria “ Helicobacter pylori”, that destroy the mucosal layer in the stomach

Question 23

Small intestine

Answer 23

• major digestive and absorptive organ
• 20’ long in cadaver
• 3 regions: Duodenum(1st 10”) , Jejunum(8’ long), Ileum(12’ long)

Question 24

Duodenum(1st 10”)

Answer 24

• Hepato pancreatic ampulla enters here
• the sphincter of Oddi controls it
• the hepato pancreatic ampulla is formed by the covergence of the common bile duct from the liver and the pancreatic duct

Question 25

Ileum(12' long)

Answer 25

- it enters the L.intestine at the ileocecal valve - the sm. intestine is supported by the mesentary - mucosal folds of the sm. intestine are plicae circularis- these are finger-like projections called villi - at center of each 1mm high villus is a central lacteal + capillary beds - the villi are made, exteriorly of columnar epithelial cells- each of these cells has its membrane pleated into folds called MICROVILLI- these increase surface area to aid on absorption of digestive products

Question 26

Large Intestine

Answer 26

Regions are: caecum-> ascending colon-> transverse colon-> descending colon->sigmoid colon->rectum-> anal canal -contains goblet cells * be able to label a diagram of L. intestine

Question 27

liver

Answer 27

- largest internal organ - 4 lobes: right, left caudate, left caudate & quadrate - blood flow to and from the liver is from 2 sources: the hepatic artery, hepatic portal vein - blood leaves the liver through hepatic vein - the bile ducts carry bile to the right and left hepatic ducts, which fuse to for the COMMON BILE DUCT

Question 28

Hexagonal lobules

Answer 28

- functional units of the liver - at each six corners of the lobule is a triad - a triad consists of a branch of the hepatic artery, and the bile duct

Question 29

Pancreas

Answer 29

- the pancreas is both exocrine and endocrine - the organ is tadpole-shaped and lies partially retroperitoneal, with its tail posterior to the spleen and stomach and its head in the curve of the duodenum

Question 30

Islets of Langerhans

Answer 30

- in Pancreas | - functional endocrine units, these produce the hormones insulin and glucagon, which aid in metabolism of sugars

Question 31

Acini

Answer 31

- in Pancreas - functional exocrine units are circular rings called acini - each acini empties into a interlobular duct, these ducts eventually converge to form the main pancreatic duct

Question 32

pancreatic juice

Answer 32

- drained from hepatopancreatic ampulla into duodenum to aid in digestion * only exocrine units of the pancreas drain into the pancreatic duct, the endocrine secretions go directly into the blood