Digestive System

Question 1

How much of our bodies are composed of water?

Answer 1

65%

Question 2

What percent of water makes up the composition of certain tissues and organs

Answer 2

60%-90%

Question 3

List four functions of water

Answer 3

1) dilutes waste substances and transports them out of bodies
2) Acts as an important dissolving agent or solvent, so that substances can be transported within bodies and through cell membranes
3) functions as a lubricant (saliva, mucous)
4) acts as a temperature regulator (as perspiration evaporates from the skin)

Question 4

List four ways that water can enter the body.

Answer 4

1) absorbing it
2) drinking it
3) entering bodies from the food of a plant or animal
4) dehydration synthesis

Question 5

What is ingestion?

Answer 5

The process of taking in nutrients into a body.

Question 6

What is the first stage of digestion?

Answer 6

Physical or Mechanical

Question 7

What happens during the first stage of digestion?

Answer 7

-chewing or grinding of food is done to make a smaller form

Question 8

What do the churning and grinding actions of the stomach or gizzard do?

Answer 8

Help breakdown further (phase 1)

Question 9

What is phase two of digestion?

Answer 9

Chemical

Question 10

What is the main component of chemical breakdown (phase two)?

Answer 10

Enzymes

Question 11

What are hormones used for in the second stage of digestion?

Answer 11

To stimulate the enzyme secreting glands to help in digestion.

Question 12

What are the three main functions of the human digestive system?

Answer 12

1) Injest food
2) break food down so nutrients can be ansorbed
3) eliminate what cannot be digested

Question 13

What do we digest?

Answer 13

• proteins
• carbs
• lipids

Question 14

What happens when we digest proteins?

Amino acids are absorbed through the what and carried into the what?

Answer 14

• Proteins are broken down into component amino acids in the stomach and small intestines
• Amino acids absorbed into blood stream through small intestine and carried to various body cells

Question 15

What happens when we digest carbs?

Where are simple carbs absorbed?

Answer 15

• Complex carbs are broken down into simple carbs in the stomach, small intestine, and mouth
• Simple carbs are absorbed in the small intestine and circulated throughout the body by the blood

Question 16

What happens when we digest lipids?
Where are lipids digested?
Fatty acids are absorbed in the what?
Fatty acids are broken down where?

Answer 16

• Digested in the small intestine into fatty acids and glycerol
• Fatty acids are absorbed in the small intestine and circulated in the blood throughout the body.
• Fatty acids are broken down in the liver to acetic acid

Question 17

What is acetic acid?

Answer 17

Source of fuel for liver-produces acetone as byproduct.

Question 18

What is acetic acid?

Answer 18

Acitic acid is a source of fuel for liver. Produces acetone as byproduct.

Question 19

What parts of the mouth begin mechanical digestion? How do they do this?

Answer 19

• The tongue and the teeth

- They crush the food into smaller pieces

Question 20

What glands supply saliva and mucous? Where are they located? What is the purpose of the saliva and mucous?

Answer 20

• The salivary glands and mucous glands
• They are located along the cheeks
• The mucous and saliva helps moisten and break up food

Question 21

What enzyme does saliva have? What does this enzyme begin?

Answer 21

• Amylase

- Begins the chemical digestion of starches

Question 22

What takes place after the food is broken up?

Answer 22

-Swallowing

Question 23

What happens once food is in the esophagus?

Answer 23

-Muscular movements called peristalsis moves the bolus downward through the cardioesopjageal sphincter into the stomach.

Question 24

What is stage one of digestion?

Answer 24

The mouth

Question 25

What is stage two of digestion?

Answer 25

The stomach

Question 26

What happens in the stomach?

Answer 26

-Both physical and chemical digestion occur

Question 27

How many muscle layers make up the stomach walls?

Answer 27

three muscle layer

Question 28

What are these muscles called?

Answer 28

- circular - longitudinal - oblique

Question 29

What do the muslces that line the stomach wall do?

Answer 29

Cause rhythmic contractions along the stomach's length resulting in the mixing of food, mucous, acid, and enzymes.

Question 30

What is the pH in the stomach?

Answer 30

2

Question 31

What do the glands in the stomach do?

Answer 31

Secret chemicals called gastric juices due to neural and hormonal factors.

Question 32

What does hydrochloric acid do? Hint: 4 things

Answer 32

Helps the enzymes to: 1) Dissolve minerals 2) Kill bacteria 3) Regulate the pyloric valve 4) Stops the action of amylase that began in the mouth

Question 33

What does the enzyme pepsin do?

Answer 33

Pepsin breaks down proteins into short chain amino acids.

Question 34

What does the enzyme gastrin do?

Answer 34

Gastrin acts on the fats and oils.

Question 35

What does mucous act as?

Answer 35

Mucous acts as a lubricant and as a protector of the stomach wall from the actions of al acids and enzymes. Without mucous, acid would eat through the stomach wall.

Question 36

Is digestion one continuous cycle, or does it pause?

Answer 36

It is one continuous cycle.

Question 37

How many litres is the stomach?

Answer 37

1.5-2.0 litres

Question 38

How long may food remain in the stomach?

Answer 38

2 to 3 hours

Question 39

What happens when food has reached the acidity level?

Answer 39

It leaves the stomach through the pyloric sphincter and enters the small intestine.

Question 40

What is food called once it reaches the small intestine?

Answer 40

Chyme

Question 41

What is stage three of digestion not possible without?

Answer 41

- pancreas - liver - gallbladder

Question 42

What is the longest part of the digestive tract? How long is it?

Answer 42

- The small intestine | - 7m in length. 2.5 cm in diameter

Question 43

What did mechanical digestion push further through the small intestine. What was it due to?

Answer 43

- chyme | - peristalsis

Question 44

What does the acidity of the chyme stimulate? Where does this happen?

Answer 44

- the secretion of 2 hormones | - glands in the first part of the small intestine or duodendum

Question 45

What does one of the hormones produced by glands in the first part of the smal intestine act upon?

Answer 45

The adjacent pancreas causing it to produce pancreatic juice.

Question 46

Trace the path of pancreatic juice.

Answer 46

-makes its way from pancreas through a duct that joins with a bile duct from the liver.

Question 47

What do the two ducts form?

Answer 47

-the two ducts form one common duct that enters the duodenum a short distance below the pyloric sphincter

Question 48

What does the pancrease secrete? What do these hormones do?

Answer 48

- The hormones insulin and glucagon | - They regulate the amount of sugar in the blood

Question 49

What happens when glucose levels are high?

Answer 49

Insulin produced (causes insulin to be stored as glycogen).

Question 50

What happens when glucose levels are low?

Answer 50

When glucose elvels are low, glucagon is released (causes glycogen to be converted back into glucose).

Question 51

What does the OTHER hormone in the duodenum affect?

Answer 51

The liver

Question 52

What does the liver do?

Answer 52

The liver produces bile that is stored in the gallbladder.

Question 53

What is bile made up of? Hint: 2 things. | Explain what each are.

Answer 53

Bile is made up of bile salts that cause fats to emulsify or break up into find droplets. Bile is also made up of bile pigments, mainly red blood cells and hemoglobin, which is what gives the brownish colour to solid wastes or feces that are eliminated from the large intestine.

Question 54

What does the liver convert?

Answer 54

Excess monosaccharides into glycogen if there is sufficient amounts of glucose.

Question 55

Wht does the liver break down?

Answer 55

Excess amino acids and takes the excess nitrogen molecules and converts them to waste urea.

Question 56

What does the liver filter? What does it do to them

Answer 56

- drugs and alcohol | - neutralizes them

Question 57

What is the liver the final break down of?

Answer 57

The liver is the final breakdown of fats.

Question 58

What completes chemical digestion?

Answer 58

The pancreatic enzymes along with additional enzymes produced by the intestines.

Question 59

In small forms ______ are capable of being absorbed into the blood to be transported to other body areas?

Answer 59

- monosaccharides - amino acids - fatty acids - glycerol

Question 60

Where does the greatest amount of absorbtion occur?

Answer 60

The small intestine.

Question 61

What are the three parts of the small intestine. Briefly describe.

Answer 61

1) Duodenum (area where most chemical digestion occurs) 2) Jejunum (absorbtion of nutrients) 3) Ileum (absorbtion of nutrients)

Question 62

What does the small intestine have that increase the absorptiove area?

Answer 62

folds and twists

Question 63

What are the finger like projections called that increase the total absorptive area of the small intestine?

Answer 63

Villi

Question 64

What passes through the epithelial cells of the villi? Where do they pass into and by what?

Answer 64

- Glucose and other monosaccharides, amino acids and minerals - Into the blood capillaries - Diffusion and/or active transport

Question 65

What happens to the materials that cannot be digested or absorbed in the small intestine?

Answer 65

Thye move onto the large intestine (semi liquid).

Question 66

Where do the final stages of digestion take place?

Answer 66

The large intestine.

Question 67

How long is the large intestine?

Answer 67

1.5 m long. 6.5 cm in diameter

Question 68

What makes up the large intestine?

Answer 68

- colon - rectum - appendix

Question 69

How many hours after you have eaten do the final stages of digestion take place?

Answer 69

4-6 hours

Question 70

Do small or large amounts of digestion occur in the large intestien?

Answer 70

Small amounts

Question 71

What is the main role of the large intestine?

Answer 71

The main role of the large intestine is the reabsorption of water.

Question 72

How has water entered the system up until the point digestion reaches the large intestion? Have these been large amounts or small amounts of water?

Answer 72

- saliva - mucous - water - Large amounts

Question 73

Why does the large intestine reabsorb this water?

Answer 73

So you body does not lose it and become dehydrated.

Question 74

How long does chyme normally remain in the large intestine?

Answer 74

18 hours-2 days

Question 75

When chyme is in the large intestine, what is it converted from to?

Answer 75

It is converted from a watery consitency to the normally solid fecal matter.

Question 76

Where do solid wastes accumulate?

Answer 76

The final portion of the large intestine.

Question 77

How many spincters does the rectum have. What are they involved in?

Answer 77

- Two sphincters, one at the beginning and one at the end. | - They are involved in teh final elimination of wastes.

Question 78

What happens when the rectum expands?

Answer 78

When the rectum expands, it initiates a reflex for the final phincter to relax and waste is eliminated brom the body through the anus.