26: Transport & Digestion of Nutrients

Question 1

gastrointestinal (GI) tract

Answer 1

The digestive system is centered around this tube

Question 2

segments of the tract

Answer 2

in order beginning at the mouth, the oral cavity, pharynx (throat), esophagus, stomach, small intestine, large intestine (colon), rectum and anus

Question 3

Accessory organs associated with the GI tract

Answer 3

salivary glands, teeth, tongue, liver, gallbladder and pancreas

Question 4

Foods taken into the body must be broken down examples

Answer 4

proteins into amino acids, fats into fatty acids and glycerol, and complex carbohydrates into simple sugars

Question 5

digestion

Answer 5

Foods taken into the body must be broken down

Question 6

absorption

Answer 6

The breakdown products must then be transferred into the blood

Question 7

defecation

Answer 7

That which is not absorbed is processed for this

Question 8

mesentery

Answer 8

This membranous web, supports all of the blood vessels, lymphatic vessels and nerves that extend to the intestines

Question 9

mesenteric arteries

Answer 9

Blood low in nutrients is carried to the intestines through these that branch directly off the abdominal aorta

Question 10

mesenteric veins

Answer 10

Intestinal capillary beds, described later, receive nutrients absorbed from the gut and transport them through these

Question 11

hepatic portal vein

Answer 11

carries blood into the liver

Question 12

hepatic vein

Answer 12

Blood from the liver containing the processed nutrients is transported into the inferior vena cava by this

Question 13

Teeth

Answer 13

begin the mechanical digestion of food

Question 14

deciduous

Answer 14

20 baby teeth erupt

Question 15

permanen

Answer 15

They are later replaced by the 32 permanent teeth-eight in each quadrant

Question 16

Teeth quadrants,

Answer 16

beginning at the front and moving back, there are 2 incisors, the cutting teeth; 1 cuspid or canine, the tearing teeth; 2 premolars or bicuspids, the grinding teeth; and 3 molars or tricuspids, also for grinding. The last molar in each quadrant is the wisdom tooth

Question 17

Chemical digestion

Answer 17

begins as saliva is mixed with the food

Question 18

Saliva

Answer 18

is secreted by three pairs of exocrine salivary glands: parotid, submandibular, sublingual

Question 19

parotid glands

Answer 19

in each cheek below and anterior to the ears

Question 20

submandibular glands

Answer 20

in the posterior lower jaw

Question 21

sublingual glands

Answer 21

in the anterior part of the lower jaw under the tongue

Question 22

salivary ducts

Answer 22

Saliva enters the oral cavity through

Question 23

salivary amylase

Answer 23

an enzyme that breakdowns the complex carbohydrate called starch into the disaccharides called maltose.

Question 24

tongue

Answer 24

helps to position food in the oral cavity for chewing and swallowing

Question 25

Taste buds

Answer 25

on the surface of the tongue function as chemoreceptors, helping us to identify the nature of substances we are taking into the mouth

Question 26

pharynx

Answer 26

throat

Question 27

esophagus

Answer 27

connects the pharynx to the stomach, 10 inches

Question 28

mucous membrane (mucosa)

Answer 28

The inner lining of the tract, in esophagus

Question 29

submucosal tissue

Answer 29

containing blood and lymph vessels and nerves, in esophagus

Question 30

visceral muscle

Answer 30

of esophagus, The inner layer is a circular layer and the outer layer runs longitudinally.

Question 31

fibroserous layer or serosa

Answer 31

the outer tissue layer of esophagus

Question 32

mucus

Answer 32

The only secretion of the esophagus

Question 33

peristaltic contractions

Answer 33

The movement of food downward toward the stomach and then on through the rest of the digestive tract is caused by waves of muscle contractions

Question 34

segmentation contractions

Answer 34

Multiple rings of muscle sometimes contract simultaneously, helping mix the contents with digestive juices. These back-and-forth contractions

Question 35

stomach regions

Answer 35

The four regions of the stomach, shown in the figure, are the cardia, the fundus, the body and the antrum.

Question 36

stomach layers

Answer 36

(mucosa, submucosa, muscular layers, serosa) and oblique muscle layer below the circular and longitudinal,

Question 37

goblet cells

Answer 37

secrete mucus

Question 38

parietal cells

Answer 38

secrete hydrochloric acid (HCl)

Question 39

peptic cells

Answer 39

that secrete a digestive precursor enzyme called pepsinogen, breaks down large proteins

Question 40

rugae

Answer 40

the walls of the empty stomach form thick folds

Question 41

chyme

Answer 41

partially digested food

Question 42

intrinsic factor

Answer 42

secretion, required for vitamin B-12 absorption

Question 43

Cephalic Phase

Answer 43

This phase is reflexly initiated by the sight and smell of good food, stimulating secretory activity and muscle contractions even before the food has entered

Question 44

Gastric Phase

Answer 44

The presence of food in the stomach initiates this phase. The lower region of the stomach secretes the hormone gastrin into the blood

Question 45

gastrin

Answer 45

When the blood containing gastrin reaches the fundus and body of the stomach, it causes secretion of gastric juices

Question 46

histamine

Answer 46

HCl secretion is mediated by it

Question 47

Intestinal Phase

Answer 47

Chyme entering the small intestine stimulates it to release the hormone cholecystokinin.

Question 48

cholecystokinin

Answer 48

Besides exerting control on the pancreas and gallbladder, cholecystokinin inhibits gastric digestion in the stomach.

Question 49

enterogastric nerve reflex

Answer 49

distension of the small intestine produces, causing reduces gastric activity by inhibition of the parasympathetic nerves to the stomach

Question 50

pyloric sphincter

Answer 50

Emptying of the stomach is controlled by the this muscle located between the stomach and small intestine

Question 51

duodenum

Answer 51

first part f the small intestine, It's less than a foot in length,

Question 52

jejunum

Answer 52

making up about 2/5 of the remaining length of the small intestine

Question 53

ileum

Answer 53

last part f the small intestine

Question 54

villi

Answer 54

the millions of finger-like projections that line the inner wall These projections increase the surface area of the small intestine for more efficient absorption of nutrients,

Question 55

pancreas

Answer 55

The pancreas is a flat, glandular organ located below the stomach, two juices

Question 56

Pancreatic juice one

Answer 56

The first is a watery type rich in bicarbonate ions that neutralizes the acidic chyme entering the duodenum

Question 57

second type of pancreatic juice

Answer 57

an enzyme rich mixture.

Question 58

pancreatic duct

Answer 58

the pancreas to release enzymes into the duodenum through this

Question 59

amylase

Answer 59

for digestion of starch to the maltose

Question 60

enzymes sucrase, maltase and lactase

Answer 60

that convert these disaccharides to the monosaccharides of glucose, fructose, and galactose

Question 61

proteases

Answer 61

including trypsin, chymotrypsin and carboxypeptidase, to complete the digestion of peptides entering from the stomach

Question 62

lipase

Answer 62

that digests emulsified fat to fatty acid and glycerol

Question 63

Bile

Answer 63

Fat digestion is facilitated, is produced by the liver and stored in the gallbladder

Question 64

Bile salts and lecithin

Answer 64

in bile act to emulsify fats, that is, break them down into tiny fat droplets

Question 65

Secretin

Answer 65

stimulates the liver to produce bile from the steroid molecule cholesterol