Test 3 Lecture

Question 1

what is digestion?

Answer 1

the mechanical and chemical breakdown of material

Question 2

what is motility?

Answer 2

movement of material from the oral cavity to the anus-

swallowing / peristalsis

Question 3

what is secretion?

Answer 3

exocrine release of substances into the lumen of the

digestive tract for chemical digestion

Question 4

what is absorption?

Answer 4

movement of material from the lumen into the blood

stream

Question 5

What is the alimentary canal/ GI tract?

Answer 5

a continuous tube that is about 30 feet in length and consists of the oral cavity, esophagus, stomach, small intestines, large int., and rectum

Question 6

what are accessory organs?

Answer 6

digestive organs outside of canal that communicate with GI tract via ducts. They include salivary glands, pancreas, liver, gallbladder, teeth, and tongue

Question 7

what are the four layers of the gastrointestinal tract?

Answer 7

tunica mucosa
tunica submucosa
tunica muscularis externa
tunica serosa (visceral peritoneum)

Question 8

describe tunica mucosa

Answer 8

a mucus membrane made up of moist epithelial tissue and loose connective tissue
Folding increases surface area

Question 9

describe tunica submucosa

Answer 9

areolar connective tissue that usually contains glands

Question 10

describe tunica muscularis externa

Answer 10

2 or 3 layers of smooth muscle (3 in stomach only)

Question 11

describe tunica serosa

Answer 11

connective tissue in the serous membrane. NOT in

esophagus/rectum-in theses regions it called tunica adventitia

Question 12

what are the features of smooth muscle?

Answer 12

No sarcomere arrangement, No striations
Many have no efferent innervation
Gap junctions, Arranged in sheets
Ability to stretch

Question 13

what are the two forms of contraction?

Answer 13

Peristalsis and segmentation

Question 14

what is peristalsis?

Answer 14

net movement of material towards rectum

Question 15

what is segmentation?

Answer 15

mixing and churning of material with no net movement

Question 16

list the features of the salivary glands

Answer 16

Slightly different secretions
Stimulated by parasympathetic
Release enzymes
Lubrication oral cavity

Question 17

what is the role of the submandibular salivary gland in the production of saliva?

Answer 17

it releases 70% of all saliva produced

Question 18

what is dentin?

Answer 18

dentin of teeth is similar to inorganic portion of bone

Question 19

what type of joint connects teeth to the mandible and maxilla?

Answer 19

gomphosis joint (this is the only example of gomphosis joint in the body)

Question 20

what are the funtions of incisors?

Answer 20

clipping/ cutting

Question 21

what are the functions of canines?

Answer 21

tearing/slashing

Question 22

what are the functions of premolars and molars?

Answer 22

mashing/grinding

Question 23

how many teeth do babies have? adults?

Answer 23

there are 20 deciduous teeth (baby teeth) and 32 permanent dentition (adult teeth)

Question 24

what are the features of the esophagus?

Answer 24

Tunica muscularis- superior 1/3 skeletal muscle
No serosa instead adventitia
About 1 ft long

Question 25

what are the features of the stomach?

Answer 25

Tunica muscularis has three layers of muscle Tunica mucosa has folds (rugae) when empty G cells release hormone, Gastrin Mucous layer protects epithelia of stomach from stomach acids Fluid leaving stomach is acid known as chyme

Question 26

what are the features of the small intestines?

Answer 26

* 90 percent of nutrient absorption (mostly in jejunum) * Contains plicae, villi, microvilli to increase surface area * Releases hormones CCK & secretin * Lacteal absorption of lipids * mucus and buffers (neutralize acid chyme)

Question 27

what differentiates the three sections of the small intestines?

Answer 27

``` Duodenum is 10 in long, Receives digestive juices from liver jejunum is 8 ft long ileum is 12 ft long Peyers patch more common in ileum ```

Question 28

what are the features and functions of the large intestines?

Answer 28

``` 5 ft long Larger diameter than small intestines Absorption of vitamins Reabsorption of water & electrolytes Compaction & storage of feces ```

Question 29

what is the function of valves?

Answer 29

Valves regulate passage of material from segment to segment

Question 30

where is the first valve of the digestive system located?

Answer 30

pharynx/ esophagus

Question 31

what is the cardiac sphincter?

Answer 31

the valve connecting the esophagus and the stomach

Question 32

what is the pyloric sphincter?

Answer 32

the valve connecting the stomach and the small intestines

Question 33

what is the iliocecal valve

Answer 33

the valve connecting the small and large intestines

Question 34

what are the three main functions of the liver?

Answer 34

metabolic regulation hematological regulation synthesis of bile and bile salts

Question 35

what are the features of metabolic regulation?

Answer 35

– absorbed nutrients are further metabolized in the liver – Toxins brake down – Fat soluble vitamins stored in liver

Question 36

what are the features of hematological regulation?

Answer 36

– Liver receives 25% of blood from aorta – breakdown of old/damaged blood cells – Makes plasma proteins

Question 37

what are the functions of synthesis of bile and bile salts?

Answer 37

– Bile-pH buffer neutralize stomach acid | – bile salts aid in break down of lipids

Question 38

what is the gallbladder responsible for?

Answer 38

storing and increasing concentration of bile | release of bile

Question 39

what are the functions of the pancreas?

Answer 39

Majority of pancreas has digestive (exocrine) function Releases pancreatic juice to the duodenum via pancreatic duct Majority of chemical digestion

Question 40

what enzymes are released in the oral cavity? how?

Answer 40

Amylase (metabolizes carbohydrates) and Lipase (metabolizes lipids) are released through the Salivary Glands

Question 41

what enzymes are released in the stomach? how?

Answer 41

Pepsinogen ( metabolizes proteins) are released from Chief Cells, mixes with HCL which come from Parietal Cells

Question 42

what enzymes are released in the duodenum? how?

Answer 42

Pancreatic Juice (metabolizes lipids, carbs, proteins) is released from Pancreas Brush-border Enzymes (metabolizes lipids, carbs, proteins) are released from Absorptive Cells Bile (emulsification of lipid) is released from Liver & Gallbladder