Chapter 9

Question 1

Nutrition

Answer 1

Unlike plants that can combine CO2 and water in the pretense of sunlight making organic molecules….
(Sunlight) CO2 + H2O ———> organic molecules
- humans must obtain organic molecules from food…
Human ———> Ingested foods (we are what we eat)

Question 2

Primary mechanisms of the digestive system

Answer 2

Ingestion - taking in food/nutrition
Digestion - large -> small
Motility - movement
Secretion - digestive juices (enzymes, acids, mucus, etc.)
Absorption - taking up nutrients
Elimination - Poop
Regulation - coordination of digestion activity

Question 3

Upper digestion tract

Answer 3

• the main organ of the digestive system forms a tube that goes all the way through the ventral cavities of the body, open at both ends
• this tube is squally referred to as digestive tract of alimentary canal

Question 4

Alimentary canal length

Answer 4

Approximately 30 feet in length

Question 5

Gastrointestinal tract (GI tract) refers to?

Answer 5

This refers to only the stomach and intestines

Question 6

Organs of the digestive system

Answer 6

Upper: mouth, pharynx, esophagus, stomach
Lower:
- small intestine: duodenum, jejunum, ileum
- large intestine: cecum, colon, rectum
- Anal canal
Accessory: salivary glands, tongue, teeth, liver, gallbladder, pancreas, appendix

Question 7

Serosa

Answer 7

“Serous layer”
- outermost later of the GI wall
- the serosa is actually the visceral layer of the peritoneum
- serous member that lines the abdominalpelvic cavity and covers the organs
- the fold of the serous membrane shown that connects the parietal and visceral portions is called a mesentery (binding and protective layer)

Question 8

Muscularis

Answer 8

“Muscular layer”
-thick layer of muscle tissue that wraps around the submucosa
-segmental contractions (muscularis externa) and peristaltic movements (physically pulverize and mix and churn food with digestive enzymes)
- muscle types: outer longitudinal, inner circular (sphincters), oblique (stomach)

Question 9

Submucosa

Answer 9

-layer of the digestive tube that is compassed of connective tissue
- contains numerous small glands, blood vessels, and parasympathetic nerves that form the submucosa plexus
- absorbed molecules contains blood vessels and lymph vessels, glands and nerves

Question 10

Mucosa

Answer 10

“Mucous layer”
-innermost layer of the GI wall, facing the lumen
-absorptive and major secretory layer
- types of cells found with or associated with the mucosa layer:
Chief cells - secrete pepsinogen
Parietal cells - secrete hydrochloric acids
Mucous cells - secrete mucus
Argentaffin cells - secrete serotonin and histamine
G-cells - secrete gastrin

Question 11

Layer of the mucosa layer

Answer 11

Epithelium: layer of non-keratinized, stratified squamous epithelium or simple stratified columnar epithelium (GI tract), interspersed itch goblet cells
Lamina Propria: loose connective tissue with some blood and lymph vessels
Muscularis Mucosa: thin layer of smooth muscle tissue in a constant state of tension, which create undulating folds, increasing the surface area for digestion and absoprtion

Question 12

Mouth -> teeth

Answer 12

Teeth:
-incisors - cutting and shearing food
Canines - (cupsids)- holding and tearing
Premolars (bicupsids)- crushing
Molars (millstone) - grinding

Question 13

Mouth -> tongue

Answer 13

Tongue:
-move food around in the mouth
- assist in the swallowing of food
- articulation in speech
- taste

Question 14

The mouth has?

Answer 14

Salivary glands - produce saliva. Salvia is a solvent which is involved in: cleansing teeth, dissolving food chemicals so they can be taste.
- contains enzymes which digest starch and mucus.
-lubricates the pharynx to facilitate swallowing
-secreted continuously
-> saliva flows from salivary glands to the mouth through ducts called (salivary ducts). Most saliva is produced by the three saliva glands: Parotid, submandibular, sublingual

Question 15

Pharynx

Answer 15

• the act of swallowing moves a rounded mass of food (Bolus) from the mouth to the stomach
• the bolus moves from the mouth, through the pharynx and through the esophagus

Question 16

Esophagus

Answer 16

• sits posterior in the neck
• a collapsible, muscular, mucosa-lined tube about 25cm long, extend from the pharynx to the stomach and pierces the diaphragm in its descend from the thoracic cavity to the abdominal cavity

Question 17

Stomach

Answer 17

• located below the diaphragm and liver, the digestive tube dilates into an elongated pouch like structure
• is approximately five sixths of it mass to the left of the median line
• Major division of the stomach: Fundus, Body, Pylorus (pylori sphincter)

Question 18

Chief cells
Parietal cells
Endocrine cells

Answer 18

Chief cells - secrete the enzymes of gastric juice (pepsinogen)
Parietal cells - secrete hydrochloric acid
Endocrine cells - secrete ghrelin (GHRL); hormone that stimulates the hypothalamus to secrete growth hormones and increase appetite and gastric
GEGCPHA

Question 19

Functions of the stomach

Answer 19

Food reservoir, secrete gastric juices, secretes intrinsic factors, performs a limited amount of absorption, produce the hormone gastric

Question 20

Divisions of the small intestine explained

Answer 20

Duodenum: shortest section of the small intestine (10”); attaches to the pyloric end of the stomach
Jejunum: the point at which the small intestine turns abruptly forward and downward
Ileum: 12’ long; minimal line of demarcation between the jejunum and ileum

Question 21

Wall of the small intestine

Answer 21

The intestinal lining has circular plicae or villi
Plicae: circular folds
Villi: projections from the folds of the intestinal wall; each villus contains an arterial, Venice, and lymph vessel (lacteal)
- epithelium cells of the villi contain absorptive cells

Question 22

Division of the large intestine

Answer 22

Cecum: 2-3” long; a blind pouch located in the lower right quadrant of the abdomen
Colon: ascending; transverse; descending; sigmoid
Rectum: the pact 7-8” of the intestinal tube

Question 23

Liver

Answer 23

-detoxification of the blood (hormones, drugs, etc)
- secretion of glucose, triglycerides, and ketone bodies
-production of plasma proteins
-bile production and secretion

Question 24

Pancreas

Answer 24

• production of pancreatic juice. Pancreatic juice contains various enzymes with specific digestive functions:
  -> amylase - digest starch
  -> trypsin - digest proteins
  -> lipase - digest triglycerides
  -> endocrine function - (secrete insulin and glucagon into the blood

Question 25

Gallbladder

Answer 25

• “sac-like” structure
  ‘ this organ stores and concentrates bile

Question 26

Vermiform appendix

Answer 26

-“worm-shape”
- 3-4” long found just behind the cecum
- the pep six serves a sort of “breeding ground” for non-pathogenic intestinal bacteria found throughout the colon

Question 27

mastication

Answer 27

chewing movements

Question 28

deglutation

Answer 28

swallowing: oral (mouth to oropharynx)

Question 29

pharyngeal

Answer 29

oropharynx to esophagus

Question 30

esophageal

Answer 30

esophagus to stomach

Question 31

mechanical digestion

Answer 31

mastication, deglutition, peristalsis, segmentation

Question 32

chemical digestion

Answer 32

hydrolysis, secretion

Question 33

the three stages of deglutition

Answer 33

1) oral stage
2) pharyngeal stage
3) esophageal stage

Question 34

propulsion

Answer 34

motility produced by smooth muscle
peristalsis - wavelike ripple of the muscle layer of a hollow organ
segmentation - mixing movements

Question 35

chemical digestion defined

Answer 35

all phases of chemical and mechanical digestion are aimed at or directed towards changing foods (molecules) into chemical forms that can diffuse through cells of the mucosa into the blood or lymph

Question 36

Diffusible forms for absorptions are:

Answer 36

carbohydrates: monosaccharides
proteins: amino acids
Lipids of fats: fatty acids and glycerol -> micelle

Question 37

absorption through chemical digestion

Answer 37

about 90% of all absorbed molecules (nutrients) takes place in the small intestine. The other 10% occurs in either the stomach or large intestine.
- absorption in the S.I. occurs, specifically, through the villi and depends on: diffusion, facilitated diffusion, osmosis, and active transport

Question 38

carbohydrate digestion

Answer 38

begins in the mouth and is finished in the small intestine
- Amylases: enzymes that assists in the breakdown of CHO; found in saliva and pancreatic juice

Question 39

protein digestion

Answer 39

proteases: catalyze the hydrolysis of proteins
Main proteases: pepsin, trypsin, chymotrypsin

Question 40

what does each kind of protease do in protein digestion

Answer 40

each kind of protease catalyzes the breaking apart of a specific kind of peptide bond

Question 41

lipid digestion

Answer 41

fats that are insoluble in water and must be emulsified
- emulsified: dispersed into very small droplets, before they can be digested. (Lecithin, Bile salts)
-micelles: tiny spheres that carry fat molecules
-lipase: main fat-digesting enzymes

Question 42

ASE =

Answer 42

Enzymes

Question 43

OSE =

Answer 43

Sugar

Question 44

Protein digestion begins and ends where

Answer 44

Protein digestion begins in the stomach and ends in the small intestine

Question 45

Lipid digestion begins and ends where

Answer 45

Lipid digestion begins in the duodenum and ends in the intestine