Digestive System Part A

Question 1

2 divisions of organs in the digestive system?

Answer 1

1.) alimentary canal (GI tract)
2.) accessory digestive organs

Question 2

name 8 organs that make up the Alimentary Canal

Answer 2

1.) mouth
2.) pharynx
3.) esophagus
4.) stomach
5.) small intestine
6.) large intestine
7.) rectum
8.) anus

Question 3

name the 5 accessory digestive organs

Answer 3

1.) teeth
2.) tongue
3.) gallbladder
4.) salivary glands
5.) pancreas

Question 4

6 food processing steps

6 essential activities involved in processing food in the digestive system

Answer 4

1.) ingestion
2.) propulsion
3.) mechanical breakdown
4.) digestion
5.) absorption
6.) defecation

Question 5

6 food processing steps

describe #1 ingestion

Answer 5

• eating

Question 6

6 food processing steps

describe #2 propulsion
includes what?

Answer 6

• movement of food through the digestive tract
• includes peristalsis (wave-like contraction) that moves food along the tract

Question 7

6 food processing steps

what is peristalsis?

Answer 7

• series of wave-like muscle contractions that move food along the digestive tract
• but it does not break down the food

Question 8

6 food processing steps

describe #3 mechanical breakdown

Answer 8

• physical breakdown of food into smaller pieces
• includes chewing, mixing food with saliva, and segmentation
• happens in small and large intestines

Question 9

6 food processing steps

what is segmentation in the intestines?

Answer 9

• muscles in the small and large intestines contract and relax to mix and break down food w/ digestive juices to digest

Question 10

6 food processing steps

describe #4 digestion

Answer 10

• breaking down macromolecules (carbohydrates, lipids, proteins) into their smallest form (monomers) through catabolic steps

Question 11

6 food processing steps

What are the 3 macromolecules that are broken down during digestion?

Answer 11

1.) carbohydrates
2.) lipids
3.) proteins

Question 12

6 food processing steps

what are the smallest forms or monomers that macromolecules are broken down into during digestion?

Answer 12

• carbohydrates = monosaccharides
• proteins = individual amino acids
• lipids = fatty acids and glycerol

Question 13

6 food processing steps

how are carbohydrates broken down during digestion?

Answer 13

• polysaccharides to disaccharides to monosaccharides

Question 14

6 food processing steps

how are proteins broken down during digestion?

Answer 14

• from large chain proteins to individual amino acids

Question 15

6 food processing steps

how are lipids broken down during digestion?

Answer 15

• broken down during digestion from triglycerides to monoglyceride & fatty acids

Question 16

6 food processing steps

describe #5 absorption

Answer 16

• process of absorbing nutrients from the small intestine into the bloodstream for use by the body

Question 17

6 food processing steps

describe #6 defecation

Answer 17

• elimination of undigested food and waste materials from the body in the form of feces

Question 18

6 processing steps

what is the difference between peristalsis and segmentation in terms of their role in digestion?

Answer 18

• peristalsis is the major means of propulsion of food through the digestive tract
• segmentation aids in mechanical breakdown by mixing food with digestive juices

Question 19

6 processing steps

how does peristalsis differ from segmentation in terms of their muscle contractions?

Answer 19

• peristalsis involves alternating waves of contraction and relaxation in the muscles of the digestive tract
• segmentation involves localized constriction of the intestine

Question 20

relationship of digestive organs to peritoneum

what is the peritoneum?

Answer 20

• a serous membrane that lines the abdominal cavity
• covers most of the abdominal organs

Question 21

relationship of digestive organs to peritoneum

2 things peritoneum consist of

Answer 21

1.) visceral peritoneum
2.) parietal peritnoeum

Question 22

relationship of digestive organs to peritoneum

what is the visceral peritoneum?

Answer 22

• the membrane that covers the external surface of most digestive organs

Question 23

relationship of digestive organs to peritoneum

what is the parietal peritoneum?

Answer 23

• membrane that lines the body wall of the abdominal cavity

Question 24

relationship of digestive organs to peritoneum

what is the peritoneal cavity?

Answer 24

• fluid-filled space between the visceral and parietal peritoneums

Question 25

relationship of digestive organs to peritoneum

what is the purpose of the peritoneal cavity?

Answer 25

• contains fluid that lubricates the mobile organs in the abdomen
• reduces friction during movement

Question 26

relationship of digestive organs to peritoneum

what is the mesentery?

Answer 26

• double layer of peritoneum that extends from the body wall to the digestive organs,
• provides routes for blood vessels, lymphatics, and nerves.
• consists of 2 layers of peritoneum fused back to back

Question 27

relationship of digestive organs to peritoneum

what is the purpose of the mesentery?

Answer 27

• holds the digestive organs in place, stores fat
• provides a route for blood vessels, lymphatics, and nerves to reach the digestive organs

Question 28

relationship of digestive organs to peritoneum

where does the mesentery originate and insert?

Answer 28

• originates from the body wall
• inserts into the digestive organs, such as the small intestine

Question 29

relationship of digestive organs to peritoneum

what is meant by the term retroperitoneal?

Answer 29

• refers to organs that are located outside, or posterior to, the peritoneum

Question 30

relationship of digestive organs to peritoneum

which 4 organs fall under the term retroperitoneal?

Answer 30

1.) kidneys
2.) most of the pancreas
3.) duodenum
4.) parts of the large intestine

Question 31

histology of alimentary canal

what are the 4 tunics which all digestive organs have?

list them from innermost to outermost

Answer 31

1.) mucosa
2.) submucosa
3.) muscularis externa
4.) serosa

Question 32

histology of alimentary canal

which tunic layer is responsible for segmentation and peristalsis?

Answer 32

• muscularis externa layer is responsible for segmentation and peristalsis

Question 33

histology of alimentary canal

what is another name for the serosa layer?

Answer 33

• visceral peritoneum

Question 34

enteric nervous system

what is the name of the nervous system associated with our GI tract and is also called the “gut brain”?

Answer 34

Enteric nervous system (ENS)

Question 35

enteric nervous system

which autonomic nervous system division (sympathetic vs parasympathetic) stimulates versus inhibits digestive processes?

Answer 35

• parasympathetic system enhances digestive processes
  PARASYMPATHETIC REST & DIGEST
• sympathetic system inhibits digestion

Question 36

salivary glands

what are the 4 functions of saliva?

Answer 36

1.) cleansing the mouth
2.) dissolving food chemicals for taste
3.) moistening food and compacting it into a bolus
4.) beginning the breakdown of starch with the enzyme amylase

Question 37

salivary glands

what does saliva do to the mouth?

Answer 37

• cleanses the mouth

Question 38

salivary glands

what does saliva do to food chemicals?

Answer 38

• dissolves food chemicals for taste.

Question 39

salivary glands

what does saliva do to food?

Answer 39

• moistens and compacts food into a bolus

Question 40

salivary glands

what enzyme does saliva contain and what does it do?

Answer 40

• enzyme amylase
• begins the breakdown of starch

Question 41

digestion in the mouth

what mechanical digestion process occurs in the mouth?

Answer 41

• mastication or chewing, which forms a bolus

Question 42

digestion in the mouth

salivia + food = _____________

Answer 42

bolus

Question 43

digestion in the mouth

bolus = __________ + ___________

Answer 43

saliva + food

Question 44

digestion in the mouth

salivia + food = _____________

Answer 44

bolus

Question 45

digestion in the mouth

what 2 chemical digestion processes occur in the mouth?

Answer 45

1.) salivary amylase acts on starches/carbs to break them down
2.) lingual lipase is secreted but not active yet

Question 46

digestion in the mouth

does absorption occur in the mouth?

Answer 46

• no

Question 47

digestion in the mouth

what is the function of salivary amylase in the mouth?

Answer 47

• to break down carbs/starches

Question 48

digestion in the mouth

when does lingual lipase become active?

Answer 48

• becomes active in the acidic environment of the stomach to break down triglycerides

Question 49

pathway of food from the mouth to the stomach

Answer 49

mouth → pharynx → esophagus → stomach

more details:

Mouth: Mechanical digestion begins as food is chewed and mixed with saliva, which contains salivary amylase that begins to break down carbohydrates.

Pharynx: The food bolus is then moved by the tongue and pharyngeal muscles to the pharynx, which is the area at the back of the throat where the pathways for food and air cross.

Esophagus: From the pharynx, the food bolus moves through the esophagus, which is a muscular tube that connects the pharynx to the stomach. The movement of food through the esophagus is facilitated by rhythmic contractions of smooth muscles in the walls of the esophagus, known as peristalsis.

Stomach: Once the food bolus enters the stomach, it is mixed with gastric juices, which contain hydrochloric acid and digestive enzymes like pepsin, that further break down the food into a liquid called chyme. The stomach also mechanically breaks down the food by churning it with its muscular walls.