digestion and absorption

Question 1

To bring essential nutrients into the internal environment so they are available to every cell in the body

Answer 1

Primary function of the digestive system

Question 2

Ingestion and digestion

Answer 2

Mechanisms used to accomplish the primary function of the digestive system

Question 3

movement of nutrients through the GI mucosa into the internal environment

Answer 3

absorption

Question 4

excretion of material that is not absorbed

Answer 4

elimination

Question 5

movement of the digestive tract

Answer 5

mechanical digestion

Question 6

chewing movements

Answer 6

mastication

Question 7

Process of swallowing; complex process requiring coordinated, rapid movements

Answer 7

Deglutition

Question 8

(mouth to oropharynx): voluntarily controlled; formation of a food bolus in the middle of the tongue; food is then moved into the oropharynx

Answer 8

oral stage

Question 9

(oropharynx to esophagus): involuntary movement; to propel bolus from the pharynx to the esophagus, the mouth/nasopharynx/larynx must be blocked; a combination of contractions and gravity move bolus into esophagus

Answer 9

pharyngeal stage

Question 10

(esophagus to stomach): involuntary(segmentation and peristalsis) movement; contractions and gravity move bolus through esophagus and into stomach

Answer 10

esophageal stage

Question 11

two main types of motility produced by the smooth muscle of the GI tract; can occur together in an alternating fashion

Answer 11

Peristalsis and segmentation

Question 12

wavelike ripple of the muscle layer of a hollow organ; progressive motility that produces forward movement of matter along the GI tract

Answer 12

peristalsis

Question 13

mixing movement; digestive reflexes cause a forward-and-backward movement with a single segment of the GI tract; helps break down food particles, mixes food and digestive juices, and brings digested food in contact with intestinal mucosa to facilitate absorption

Answer 13

segmentation

Question 14

emptying the stomach takes approximately 2 - 6 hours; while in the stomach, food is churned (propulsion and retropulsion) and mixed with gastric juices to form chyme; chyme is ejected approximately every 20 seconds into the duodenum; gastric emptying is controlled by hormonal and nervous mechanisms

Answer 14

gastric motility

Question 15

fats in duodenum stimulate the release of gastric inhibitory peptide, which decreases peristalsis of gastric muscle and slows passage of chyme into duodenum

Answer 15

hormonal mechanism

Question 16

enterogastric reflex; stretch and chemo- receptors in the duodenal mucosa are sensitive to presence of acid and distention; impulses over sensory and motor fibers in the vagus nerve cause a reflex inhibition of gastric peristalsis

Answer 16

nervous mechansim

Question 17

allows stomach to expand

Answer 17

rugae

Question 18

Intestinal motility includes

Answer 18

peristalsis and segmentation

Question 19

Segmentation in duodenum and upper jejunum mixes chyme with digestive juices from the

Answer 19

pancreas, liver, and intestinal mucosa

Question 20

changes in chemical composition of food as it travels through the digestive tract; these changes are the result of hydrolysis

Answer 20

Chemical digestion(starts in mouth)

Question 21

Carbohydrates are ___ compounds

Answer 21

saccharide

Question 22

Fats must be emulsified(water-soluble) by bile in small intestine before being digested
Pancreatic lipase is the main fat-digesting enzyme

Answer 22

fat digestion

Question 23

secreted by salivary glands

Answer 23

saliva

Question 24

secreted by gastric glands

Answer 24

gastric juices

Question 25

secreted by parietal cells

Answer 25

hydrochloric acid

Question 26

Intrinsic factor (secreted by parietal cells) protects

Answer 26

vitamin B12 and later facilitates its absorption

Question 27

B12 is important for production of

Answer 27

blood cells

Question 28

secreted by acinar and duct cells of the pancreas

Answer 28

pancreatic juices

Question 29

(e.g., trypsin and chymotrypsin) are enzymes that digest proteins and polypeptides

Answer 29

proteases

Question 30

are enzymes that digest emulsified fats

Answer 30

Lipases

Question 31

are enzymes that digest nucleic acids such as DNA and RNA-> down into nucleotides

Answer 31

Nucleases

Question 32

is an enzyme that digests starches

Answer 32

Amylase

Question 33

increases the pH for optimal enzyme function; its manufacture also helps restore normal pH of blood

Answer 33

Sodium bicarbonate

Question 34

secreted by the liver; stored/concentrated in the gallbladder

Answer 34

bile

Question 35

secreted by cells of intestinal exocrine cells

Answer 35

intestinal juices

Question 36

(psychic phase) parasympathetic fibers in vagus nerve conduct efferent impulses to the glands; stimulate production of gastrin (by G cells in the stomach)

Answer 36

Cephalic phase

Question 37

when products of protein digestion reach the pyloric portion of the stomach, they stimulate release of gastrin; gastrin accelerates secretion of gastric juice, ensures enough enzymes are present to digest food

Answer 37

Gastric phase

Question 38

mechanisms adjust gastric secretion as chyme passes to and through the intestinal tract; endocrine reflexes involving gastric inhibitory peptide, secretin, and CCK inhibit gastric secretions

Answer 38

Intestinal phase

Question 39

stimulated by several hormones released by intestinal mucosa

Answer 39

pancreatic secretion

Question 40

bile secreted continually by the liver; secretin and CCK stimulate ejection of bile from the gallbladder

Answer 40

bile secretion

Question 41

Passage of substances through the intestinal mucosa into the blood or lymph Most absorption occurs in the small intestine-> liver

Answer 41

process of absorption

Question 42

how sodium is transported

Answer 42

secondary active transport

Question 43

(coupled transport): how glucose is transported

Answer 43

sodium cotransport

Question 44

most absorption in

Answer 44

small intestine

Question 45

colon will release ___ if too fast colon will release ___ if to slow

Answer 45

diaherra hard

Question 46

The expulsion of feces from the digestive tract; act of expelling feces is called

Answer 46

defecation

Question 47

Defecation occurs as a result of

Answer 47

a reflex brought about by stimulation of receptors in the rectal mucosa

Question 48

contents of the lower part of the colon and rectum move at a slow rate = extra water is absorbed from the feces and hardened stool

Answer 48

constipation

Question 49

external are internal are

Answer 49

skeletal smooth muscle

Question 50

Rectum is empty internal are ___ and external is ___

Answer 50

contracted relaxed

Question 51

Rectum is full internal are ___and external are ____

Answer 51

relaxed contracted

Question 52

of the digestive system to overall homeostasis is to provide a constant nutrient concentration in the internal environment

Answer 52

primary contribution

Question 53

Absorption of nutrients Teeth and tongue, along with respiratory and nervous system, are important in producing spoken language Gastric acids help the immune system by destroying potentially harmful bacteria

Answer 53

secondary roles of digestive system