Digestive System

Question 1

Describe the Digestive System

Answer 1

the system of organs responsible for breaking down food molecules and absorbing nutrients

Question 2

Describe Digestion

Answer 2

the process of breaking down food into molecules that can be absorbed and used by the body

Question 3

Describe Nutrients

Answer 3

Molecules that must be absorbed for the body to function properly

Question 4

Describe the Alimentary Canal

Answer 4

a long, winding tract formed by the organs of the digestive system

mouth —> anus

9m (30ft) long

Question 5

Describe Absorption

Answer 5

the transport of digested nutrients from the digestive system to the circulatory system

throughout the entire alimentary canal there is nutrient absorption

Question 6

Describe Ingestion

Answer 6

the process of taking in food molecules

ingestion occurs at the mouth

Question 7

What does the mouth specialize in?

Answer 7

the digestion of Carbohydrates

Question 8

Describe the Salivary Glands

Answer 8

contained in the mouth

they release a series of substances collectively known as saliva

Question 9

Describe Saliva

Answer 9

activates taste buds

lubricates food so it doesn’t get stuck

uses enzymes to begin digestion

Question 10

Describe Amylase

Answer 10

the most important enzyme in the saliva

amylase breaks down starch (carbs)
into smaller polysaccharide chains

Question 11

Describe Chemical Digestion

Answer 11

Digestion using enzymes (or acid)

Question 12

Describe Mechanical Digestion

Answer 12

Digestion that occurs due to movement of tissue

the mouth is the primary site for mechanical digestion, performed by the teeth

Question 13

Name and describe the two types of teeth

Answer 13

Incisors- sharp teeth used to shred and tear food

Molars- flat teeth used to grind food

Question 14

Describe the Esophagus

Answer 14

the organ responsible for transporting food from the mouth to stomach

Question 15

Describe a Bolus

Answer 15

the compact ball of food that is formed after food is swallowed

Question 16

Describe Peristalsis

Answer 16

the use of muscle contractions to move food

synchronized contractions

Question 17

Describe Sphincters

Answer 17

a series of specialized muscles that restrict the movement of food or fluid

Question 18

Describe the Cardiac Sphincters

Answer 18

located at the bottom of the esophagus and controls how much food enters the stomach

name is bc of its location being so close to the heart

Question 19

Describe the Stomach

Answer 19

the primary site of food storage and specializes in the digestion of protein

Question 20

What are the two types of cells that line the stomach?

Answer 20

Parietal Cells

Peptic Cells (chief cells)

Question 21

Describe Parietal Cells

Answer 21

they produce Hydrochloric Acids (HCl), commonly called stomach acid

also secrete mucus to protect the stomach cells from being digested

Question 22

Describe Peptic Cells

Answer 22

they release an enzyme called Pepsinogen which becomes activated on acidic conditions to form the enzyme Pepsin

Pepsin breaks down proteins into short polypeptide chains

Question 23

Describe the pH of the stomach

Answer 23

the stomach has a pH of 2, which is extremely acidic and corrosive

due to the corrosiveness of the stomach, it also plays an important role in the immune system by dissolving pathogens in the body

Question 24

Describe Ulcers

Answer 24

a site where the mucus layer breaks down and stomach cells are exposed to HCl

Question 25

Describe the Pyloric Sphincter

Answer 25

it is located at the bottom of the stomach it controls how much digested food leaves the stomach

Question 26

Describe the Small Intestine

Answer 26

it is 2/3rds of the alimentary canal (6m or 20ft) **the primary site of absorption and the digestion of lipids**

Question 27

Name the 3 sections of the small intestine

Answer 27

duodenum jejunum ileum

Question 28

Describe the Duodenum

Answer 28

a short section (1ft) after the pyloric sphincter wraps around the pancreas

Question 29

Describe the Pancreas

Answer 29

the primary site of enzyme production in the digestive system enzymes are produced in the pancreas and transported to the duodenum

Question 30

Describe Peptidases

Answer 30

Peptidases are pancreatic enzymes that **specialize in breaking down polypeptide chains into smaller chains** (proteins) example Trypsin

Question 31

Describe Disaccharidases

Answer 31

**they break down short carbohydrate chains into single monomers** example lactase

Question 32

Describe Lipase

Answer 32

**they break down lipids into fatty acids and glycerol**

Question 33

Describe Emulsification

Answer 33

the process of breaking up fat globules lipids are **insoluble** and **form large globules in water**, the globules need to be **split into smaller droplets** increased surface area increases the reaction/digestion rate

Question 34

Describe the Bile

Answer 34

produced by the liver and stores in the gallbladder released into the duodenum where it emulsifies lipids doesn’t digest lipids just breaks them apart for lipase to interact with

Question 35

Describe the use of Bicarbonate Ions

Answer 35

**blood vessels along the duodenum pump in Bicarbonate Ions** (HCO3) to **counter the effects of HCl through a neutralization reaction** the **addition of bicarbonate increases the pH of the duodenum to 6**

Question 36

Describe the Jejunum

Answer 36

the primary site of nutrient absorption lined with villi

Question 37

Describe Villi

Answer 37

**thin tube like structures along the intestinal wall that maximize surface area** **nutrient monomers** (amino acids, etc) are **absorbed through the villi into the bloodstream** excess monosaccharides get stores in the liver as glycogen villi increase the absorption rate of nutrients small intestine would have to be 70m longer to get the same amount of nutrients

Question 38

Describe the Ileum

Answer 38

re-absorbs substances necessary for digestion (enzymes, bile, vitamins) that will be recycled

Question 39

Describe the Ileocecal Valve

Answer 39

controls the passage of fluid from the small intestine to the large intestine

Question 40

Describe the Large Intestine

Answer 40

also called the Colon **final major organ of the digestive system** **re-absorbs water that enters from the ileum**

Question 41

Describe how Diarrhea occurs

Answer 41

when waste passes too quickly through the large intestine, water will not be absorbed caused from excess gas, cramping etc

Question 42

Describe the Microbiome

Answer 42

the large intestine is **home to most of the body’s microbiome** **the collection of bacteria that live symbiotically with humans** the **bacteria in the large intestine are called Colonic Bacteria**

Question 43

Describe the role of Colonic Bacteria

Answer 43

to **digest most of the left-over bolus, extracting important vitamins** as their byproducts *creating vitamins

Question 44

What vitamins are created by Colonic Bacteria?

Answer 44

Vitamin B12 Vitamin K Riboflavin Thiamine

Question 45

Describe the Rectum

Answer 45

found at the end of the colon stores solid waste —> Feces

Question 46

Describe the Anus

Answer 46

the final sphincter of the Alimentary Canal where feces are excreted from the body