MCAT Biology Digestive System Part 2

Question 1

The anus is derived from the __ during embryogenesis

Answer 1

blastopore

Question 2

In the small intestine the apical surface of epithelial cells have __ to increase their surface area

Answer 2

Microvilli

Question 3

The __ system stimulates motility and causes the sphincters to relax (allowing the passage of food through the gut)

Answer 3

Parasympathetic nervous system

Question 4

The submucosa plexus is found in the submucosa and helps to :

Answer 4

• regulate enzyme secretion
• gut blood flow
• ion/water balance in the lumen

Question 5

Exocrine glands are composed of special epithelial cells, organized into sacs called__

Answer 5

acini (Singular acinus)

Question 6

The three GI organs primarily involved in exocrine secretion include __,__, and __

Answer 6

• liver
• gallbladder
• pancreas

Question 7

Gastric glands secrete ___

Answer 7

acid, and pepsinogen

Question 8

The __ teeth (front teeth) are for cutting

Answer 8

incisors

Question 9

The __ teeth (canine teeth) are for tearing

Answer 9

Cuspids

Question 10

The __ teeth are for grinding

Answer 10

Molars

Question 11

___ hydrolyzes starch in the mouth breaking it into fragments

Answer 11

Salivary amylase (ptyalin)

Question 12

Salivary amylase breaks sugars down to dissacharides NOT monosaccharides that only occurs at the__

Answer 12

intestinal brush border

Question 13

Saliva also contains a small amount of __ for fat digestion

Answer 13

Lingual lipase

Question 14

Saliva also contains lysozyme which attacks ___

Answer 14

bacterial cell walls ( like in your tears too)

Question 15

The pharynx contains the openings to two tubes __ and__

Answer 15

trachea and esophagus

Question 16

The ___ is a cartilage-lined tube at the front of the neck that conveys air to and from the lungs

Answer 16

Trachea

Question 17

The ___ is a muscular tube behind the trachea which conveys food and drink from the pharynx (throat) to the stomach

Answer 17

Esophagus

Question 18

During swallowing, solids and liquids are excluded from the trachea by a flat cartilaginous flap called the __

Answer 18

epiglottis

Question 19

__ is secreted by chief cells in the stomach wall

Answer 19

Pepsin

Question 20

____prevents passage of food from the stomach into the duodenum

Answer 20

Pyloric sphincter

Question 21

Stretching or excess acidity in the duodenum inhibits ___

Answer 21

further stomach emptying, by causing the pyloric sphincter to contract

Question 22

__ is secreted by cells in the stomach wall known as G cells, it stimulates acid and pepsin secretion along with gastric motility

Answer 22

Gastrin

Question 23

The molecule ___ binds to parietal cells to stimulate acid release

Answer 23

Histamine

Question 24

Ulcer drugs (Tagamet) and (Zantac) function by blocking the binding of ___ to its receptor on parietal cells, resulting in less gastric acidity

Answer 24

Histamine

Question 25

Digestion is completed in the __ and ___

Answer 25

duodenum and jejunum

Question 26

The key feature that allows the small intestine to accomplish absorption is___

Answer 26

large surface area

Question 27

The surface area of the small intestine results from __ . ___ , and ___

Answer 27

1. length 2. Villi 3 . Microvilli

Question 28

What are three important structures of the villus of the small intestine that have big purposes

Answer 28

1. Capillaries, absorb dietary monosaccharides and AA's 2. Lacteals, absorb dietary fats 3. Peyer's patches are part of the immune system

Question 29

The villus of the small intestine contain ___ which absorb dietary monosaccharides and amino acids. They merge to form veins and merge with the large hepatic portal vein

Answer 29

Capillaries

Question 30

The villus contain small lymphatic vellels called ___ which absorb dietary fats

Answer 30

Lacteals

Question 31

The lacteals of the small intestin merge to form large lymphatic vessels which transport dietary fats to the ___ which empties into the bloodstream

Answer 31

Thoracic duct

Question 32

What two ducts empty into the duodenum

Answer 32

1. Pancreatic duct delivers exocrine secretions from pancreas 2. Common bile duct, which delivers bile

Question 33

Bile is a green fluid, bile acids are made from ___

Answer 33

cholesterol in the liver and are normally absorbed and recycled

Question 34

The bile has two functions :

Answer 34

1. vehicle for the excretion of waste products by the liver | 2. Essential for the digestion of fats

Question 35

The bile duct and the pancreatic duct empty into the duodenum via the same orifice, known as the __

Answer 35

Sphincter of Oddi

Question 36

Several different __ are responsible for hydrolyzing polypeptides to di- and tripeptides

Answer 36

Pancreatic proteases

Question 37

Trypsinogen is converted to trypsin by __ an intestinal enzyme

Answer 37

Enterokinase

Question 38

___ secreted by the duodenum causes the pancreas to secrete water and bicarbonate (high pH)

Answer 38

Secretin

Question 39

Gamma cells of the islet of Langerhans secrete ___ inhibiting many digestive processes

Answer 39

Somatostatin

Question 40

What three hormones have the ability to raise blood glucose levels?

Answer 40

1. Glucagon (polypeptide hormone from the pancreas) 2. Cortisol (steroid from the adrenal cortex) 3. Epinephrine (amino acid derivative from the adrenal medulla)

Question 41

___stimulates peristalsis in the intestine and inhibits stomach emptying

Answer 41

Cholecystokinin

Question 42

The exocrine activity of the liver is simple__

Answer 42

it secrtes bile

Question 43

What are the three ingredients of bile?

Answer 43

1. bile salts (anionic form) 2. Cholesterol 3. Bilirubin (from RBC breakdown)

Question 44

__ emulsifies large fat particles in the duodenum creating smaller clusters of fat particles called micelles

Answer 44

Bile

Question 45

A ___ is a large crystal formed from bile made with ingredients in incorrect proportions

Answer 45

Gallstone

Question 46

CCK and PNS stimulate contraction of the ___

Answer 46

gallbladder wall

Question 47

The __ in hepatocytes contains enzyme pathways that break down drugs and toxins into less toxic forms

Answer 47

Smooth ER

Question 48

When the stomach is empty, gastric cells produce the hormone __ to stimulate appetite

Answer 48

Ghrelin (Stimulates appetite)

Question 49

When the colon is full the jejunum (lower intestine) produces ___ to reduce appetite

Answer 49

Peptide YY reduces appetite

Question 50

The hormone __ produced by white adipose tissue (fat) is an appetite suppressant that acts as an adipostat, maintaining stable lipid contents in adipose tissue

Answer 50

Leptin

Question 51

__ is secreted in response to increased triglyceride levels and works to suppress appetite until appropriate levels are restores

Answer 51

Leptin

Question 52

The effects of leptin, ghrelin, and peptide YY on appetite are primarily mediated by the _____

Answer 52

arcuate nucleus of the hypothalamus

Question 53

As you swallow the upper esophagel sphincter__

Answer 53

relaxes

Question 54

Monosaccharides must be taken up into the intestinal epithelial cell by ___

Answer 54

active transport