Chapter 24 - The Digestive system - part 3

Question 1

All blood leaving the absorptive surfaces of the digestive tract enter….

Answer 1

the hepatic portal system which flows into the liver

Question 2

Bile salts break what down and what is this process called?

Answer 2

bile salts break lipid droplets apart. this is called emulsification

Question 3

describe the structure of the gallbladder

Answer 3

hollow, pear-shaped muscular sack

Question 4

Where is chemical digestion basically completed?

Answer 4

at the small intestine

Question 5

What increases absorptive effectiveness in the small intestine?

Answer 5

movement of the mucosa (microvilli, villi, plicae circulares)

Question 6

the movements of the mucosa do what to the intestinal contents?

Answer 6

stir and mix

Question 7

name the 3 regions of the small intestine from proximal to distal

Answer 7

duodenum, jejunum, ileum

Question 8

how is the small intestine adapted for the absorption of nutrients?

Answer 8

-the walls of the small intestine have folds called plicae circulares

-the tissue that covers the plicae circulares forms fingerlike projections (villi)

-The epithelial cells that cover the villi have an exposed surface covered by microvilli

-the small intestine has a very rich supply of blood vessels and lymphatic vessels which transports the nutrients that are absorbed

Question 9

Does a high fat meal raise or lower the level of cholecystokinin in the blood?

Answer 9

raise

Question 10

How would the pH of the intestinal contents be affected if the small intestine did not produce secretin?

Answer 10

the hormone secretin stimulates the pancreas to release fluid high in buffers to neutralize the chyme that enters the duodenum from the stomach. the pH of the intestinal contents would be lower than normal if the small intestine did not produce secretin

Question 11

the digestion of which nutrient would be most impaired by damage to the exocrine pancreas?

Answer 11

lipids because the pancreas is the primary source of lipases

such damage would also reduce carbohydrate and protein digestion but not as much because these enzymes are produced by other digestive structures

Question 12

the salivary glands produce enzymes that break down which biomolecule(s)

Answer 12

starch (carbohydrates)

Question 13

the small intestine produces enyzmes that break down which biomolecule(s)

Answer 13

carbohydrates and proteins

Question 14

the stomach produces enzymes that break down which biomolecule(s)

Answer 14

proteins

Question 15

what is the shape of the large intestine

Answer 15

horse shoe shape

Question 16

the large intestine begins at the ___ and ends at the ____

Answer 16

begins at the ileum and ends at the anus

Question 17

the large intestine can be divided into 3 parts:

Answer 17

1. The pouchlike cecum
2. the colon (the largest portion)
3. the rectum

Question 18

Where in the large intestine does compaction begin?

Answer 18

the cecum

Question 19

the cecum receives and stores materials arriving from where?

Answer 19

the ileum

Question 20

where is the appendix attached to?

Answer 20

the cecum

Question 21

the colon has a ___ diameter and ____ wall than the small intestine

Answer 21

larger diameter and thinner wall

Question 22

What is the name of the pouches in the wall of the colon?

Answer 22

Haustra

Question 23

What is the functional purpose of the Haustra?

Answer 23

to permit expansion and elongation

Question 24

what creates haustra?

Answer 24

muscle tension in the teniae coli (3 longitudinal bands of smooth muscle)

Question 25

Name the 4 regions of the colon

Answer 25

Ascending colon Transverse colon Descending colon Sigmoid colon

Question 26

the sigmoid colon empties into the....

Answer 26

rectum

Question 27

the ascending colon turns into the transverse colon at the....

Answer 27

right colic flexure

Question 28

the transverse colon turns into the descending colon at the...

Answer 28

left colic flexure

Question 29

the taeniae coli are just deep to the...

Answer 29

serosa

Question 30

where does the descending colon become the sigmoid colon

Answer 30

at the sigmoid flexure

Question 31

what forms the last 15cm of the digestive tract?

Answer 31

the rectum

Question 32

what is the last portion of the rectum?

Answer 32

the anal canal

Question 33

what is the exit of the anal canal?

Answer 33

the anus

Question 34

Describe the structure of the anus

Answer 34

epidermis is KERATINIZED and identical to the surface of the skin

Question 35

how many anal sphincters are there? name them

Answer 35

2 internal anal sphincter external anal sphincter

Question 36

differentiate between the internal anal sphincter and external anal sphincter

Answer 36

internal anal sphincter -circular muscular layer -involuntary control -made up of smooth muscle external anal sphincter -encircles DISTAL portion of anal canal -under voluntary control -made up of skeletal muscle

Question 37

does the large intestine contain villi?

Answer 37

NO

Question 38

The large intestine contains a lot of which type of cell?

Answer 38

goblet cells

Question 39

WHY does the large intestine contain so many goblet cells?

Answer 39

mucus provides lubrication for the fecal material

Question 40

what are vitamins?

Answer 40

organic molecules that are important as cofactors or coenzymes in many metabolic pathways

Question 41

what is important for the large intestine to be able to absorb vitamins?

Answer 41

microbiome -microbes (bacteria, fungi, viruses)

Question 42

Bacteria in the colon make 3 vitamins that supplement the diet:

Answer 42

vitamin k vitamin b5 biotin

Question 43

vitamin k is __ soluble

Answer 43

fat

Question 44

biotin is ___ soluble

Answer 44

water

Question 45

vitamin b5 is __ soluble

Answer 45

water

Question 46

Why is vitamin K important?

Answer 46

the liver needs it to synthesize the 4 clotting factors, including prothrombin

Question 47

why is biotin important?

Answer 47

important for glucose metabolism

Question 48

why is vitamin b5 important?

Answer 48

required in the manufacture of steroid hormones and some neurotransmitters

Question 49

bacteria convert bilirubin (organic waste) to which 2 things?

Answer 49

urobilinogens and stercobilinogens

Question 50

what is the fate of some of the urobilinogens?

Answer 50

absorbed into the bloodstream and excreted through the urine

Question 51

urobilinogens and stercobilinogens that remain in the colon are converted to....

Answer 51

urobilins and stercobilins (by exposure to oxygen)

Question 52

what 2 reflexes move material into the cecum while we eat?

Answer 52

gastroileal and gastroenteric reflexes

Question 53

why is movement from the cecum to the transverse colon very slow?

Answer 53

to allow hours for water absorption

Question 54

what mechanism moves material along the length of the colon?

Answer 54

peristaltic waves

Question 55

what mechanism mixes contents of the adjacent haustra

Answer 55

segmentation

Question 56

movement from the transverse colon to the rest of the colon results from....

Answer 56

POWERFUL peristaltic contractions (mass movements)

Question 57

what is the stimulus of these powerful peristaltic contractions?

Answer 57

the distension (swelling) of the stomach and duodenum

Question 58

"the stimulus of powerful peristaltic contractions that produce movements from the transverse colon to the rest of the colon is stimulated by distention of the stomach and duodenum." THIS STIMULUS IS RELAYED OVER....

Answer 58

intestinal nerve plexuses

Question 59

distension of the rectal wall initiates....

Answer 59

defecation reflex

Question 60

the defecation reflex involves two ____ ____ loops which are both triggered by the stimulation of ____ receptors in the rectum

Answer 60

positive feedback stretch

Question 61

Identify the 4 regions of the colon

Answer 61

ascending colon transverse colon descending colon sigmoid colon

Question 62

What are some major histological differences between the large intestine and small intestine

Answer 62

large intestine --- diameter is wider and walls are thinner and LACK VILLI. abundance of mucus cells and intestinal glands

Question 63

Differentiate between haustral churching and mass movements

Answer 63

mass movements - occur a few times per day throughout the transverse colon and distal portions of the large intestine. Strong peristaltic contractions move material along the length of the colon in haustral churning, segmentation movements mix the contents of the nearby haustrs

Question 64

a balanced diet contains....

Answer 64

carbohydrates lipids proteins vitamins minerals water

Question 65

molecules that are absorbed into the bloodstream do one of 2 things:

Answer 65

-broken down to provide energy for ATP synthesis -used to synthesize carbohydrates, proteins, and lipids

Question 66

Digestive enzymes break molecular bonds in large organic molecules through a process called....

Answer 66

hydrolysis

Question 67

Carbohydrases break bonds between.....

Answer 67

simple sugars

Question 68

Proteases break bonds between....

Answer 68

amino acids

Question 69

Lipases separate __ from __

Answer 69

fatty acids from glycerides

Question 70

digestive enzymes are secreted by which 4 structures?

Answer 70

salivary glands stomach pancreas tongue

Question 71

does facilitated diffusion require ATP

Answer 71

NO

Question 72

What component of food would increase the number of chylomicrons in the lacteals?

Answer 72

fats

Question 73

the absorption of which vitamin would be impaired by the removal of the stomach?

Answer 73

vitamin b12. absorption of vitamin b12 requires intrinsic factor , produced by the parietal cells of the stomach

Question 74

why is it that diarrhea is potentially life threatening but constipation (infrequent defecation) is not

Answer 74

an individual with diarrhea loses fluid and electrolytes faster than it can be replaced. The resulting dehydration can be fatal constipation can be uncomfortable, but it does not interfere with any life supporting processes. The few toxic waste products that should have been eliminated through the digestive system can instead move into the blood and be eliminated by the kidneys

Question 75

identify general digestive system changes that occur with aging

Answer 75

-decreased secretory mechanisms -decreased gastric and intestinal movement -decreased division of epithelial cells -loss of muscle tone -cumulative damage becomes more apparent -cancer rates increase -dehydration occurs as a result of decreased osmoreceptor sensitivity

Question 76

identify the functional relationships between the digestive system and other body systems

Answer 76

the digestive system absorbs organic substrates, vitamins, ions, and water required by cells of all other body systems

Question 77

what body systems may be affected by inadequate calcium ion absorption?

Answer 77

skeletal, muscular, nervous, endocrine, and cardiovascular systems