[SEC 3] CHAPTER 5 - Nutrition In Humans

Question 1

what is the role of bile salts in fat digestion?

Answer 1

bile salts emulsify fats into tiny fat droplets in the duodenum

Question 2

what does lipase do to emulsified fats?

Answer 2

lipase digests emulsified fats into fatty acids and glycerol

Question 3

what happens to fatty acids and glycerol in the villus?

Answer 3

they diffuse into the epithelial cells and recombine into minute fat globules

Question 4

where do the minute fat globules go after reforming in the epithelial cells?

Answer 4

they enter the lacteal and are transported via the lymphatic system

Question 5

what happens to fats after being transported by the lymphatic system?

Answer 5

they are discharged into the bloodstream and transported to the liver to be stored or broken down

Question 6

what happens to excess glucose in the liver?

Answer 6

it is converted to glycogen

Question 7

what do the blood capillaries in the small intestine form?

Answer 7

they join to form the hepatic portal vein

Question 8

how are glucose and amino acids transported to the liver?

Answer 8

through the hepatic portal vein after being absorbed into the bloodstream

Question 9

what happens in the liver before glucose and amino acids enter main circulation?

Answer 9

assimilation of glucose and amino acids occurs

Question 10

what is glucose used for in assimilation?

Answer 10

glucose is used for respiration to release energy for cellular activities

Question 11

where is excess glucose stored in the body?

Answer 11

excess glucose is converted to glycogen and stored in the liver and muscles

Question 12

what are animo acids used for after absorption?

Answer 12

amino acids are used to form proteins (eg. enzymes or hormones) and new protoplasm for growth and tissure repair

Question 13

what are fats used for in the body?

Answer 13

fats are used to synthesize cell membranes

Question 14

Where are excess fats stored in the body?

Answer 14

Excess fats are stored in adipose tissues.

Question 15

What are the functions of adipose tissues under the skin?

Answer 15

They insulate the body against excessive heat loss.

Question 16

Besides under the skin, where else are adipose tissues found?

Answer 16

Around the heart and kidneys.

Question 17

What is egestion?

Answer 17

Egestion is the removal of undigested food from the body via the anus.

Question 18

Where is undigested food temporarily stored before egestion?

Answer 18

In the rectum.

Question 19

What is the process of removing undigested food through the anus called?

Answer 19

egestion (Defecation)

Question 20

How does the liver help regulate blood glucose when it is too high?

Answer 20

The pancreas secretes insulin, which stimulates liver cells to convert excess glucose to glycogen for storage.

Question 21

What hormone is involved when blood glucose levels are too low?

Answer 21

Glucagon.

Question 22

What does glucagon do in the liver?

Answer 22

It stimulates liver cells to convert glycogen back to glucose.

Question 23

What happens to excess amino acids in the liver?

Answer 23

They are deaminated; amino groups are converted to urea, and the remains become glucose.

Question 24

What happens if the liver has excess glucose from deaminated amino acids?

Answer 24

Glucose is converted to glycogen and stored.

Question 25

What enzyme breaks down alcohol in the liver?

Answer 25

Alcohol dehydrogenase.

Question 26

What is cirrhosis and what causes it?

Answer 26

Cirrhosis is liver damage from prolonged alcohol abuse, where liver cells are destroyed and replaced with fibrous tissue.

Question 27

Name two effects of excessive alcohol on the nervous system.

Answer 27

Reduced self-control and increased reaction time.

Question 28

Where are worn-out red blood cells destroyed?

Answer 28

In the spleen.

Question 29

What happens to haemoglobin from worn-out red blood cells?

Answer 29

It is sent to the liver, where it is broken down; iron is stored, and bile pigments are formed.

Question 30

What is ingestion?

Answer 30

The intake of food through the mouth.

Question 31

What is digestion?

Answer 31

The breakdown of large food molecules into smaller, soluble food molecules with the help of enzymes.

Question 32

What is physical digestion and what does it achieve?

Answer 32

It breaks up large food pieces into smaller ones to increase surface area to volume ratio for faster enzyme action.

Question 33

What is chemical digestion and what does it achieve?

Answer 33

It breaks down large food molecules into smaller, soluble ones so they can be absorbed into the blood and cells.

Question 34

What are the roles of the teeth, salivary glands, and tongue in digestion?

Answer 34

Teeth break up food, salivary glands secrete saliva containing salivary amylase, tongue mixes food and forms boli for swallowing.

Question 35

What is peristalsis?

Answer 35

Rhythmic, wave-like muscular contractions that move and mix food along the alimentary canal.

Question 36

What is the function of the stomach in digestion?

Answer 36

Physical digestion mixes food; chemical digestion uses pepsin and hydrochloric acid to break down proteins.

Question 37

What is chyme and how does it enter the small intestine?

Answer 37

Chyme is partly digested food from the stomach that enters the duodenum when the pyloric sphincter relaxes

Question 38

What are the three digestive juices involved in the small intestine?

Answer 38

Bile (emulsifies fats), intestinal juice (contains multiple enzymes), pancreatic juice (contains amylase, lipase, trypsin).

Question 39

What is the role of bile in digestion?

Answer 39

It emulsifies fats into tiny fat droplets, increasing surface area for enzyme action.

Question 40

What enzymes digest carbohydrates in the small intestine?

Answer 40

Pancreatic amylase converts starch to maltose, maltase converts maltose to glucose.

Question 41

What enzymes digest proteins in the small intestine?

Answer 41

Trypsin breaks proteins into polypeptides, erepsin breaks polypeptides into amino acids.

Question 42

What enzymes and processes digest fats?

Answer 42

Bile emulsifies fats; lipase (from pancreas and intestine) breaks the emulsified fats into fatty acids and glycerol.

Question 43

What is absorption and where does it occur?

Answer 43

It’s the uptake of small, soluble food molecules into the blood and cells, primarily in the small intestine.

Question 44

Why is the small intestine long (around 6m)?

Answer 44

To provide sufficient time for the absorption of digested food.

Question 45

What is the function of the villus structure?

Answer 45

One-cell thick wall allows fast diffusion, capillaries absorb glucose/amino acids, lacteal absorbs fats.

Question 46

How do folds in the inner wall of the small intestine aid absorption?

Answer 46

They increase the surface area for the absorption of food molecules.

Question 47

What are villi and how do they help absorption in the small intestine?

Answer 47

Villi are finger-like projections that increase the surface area for absorption of food molecules.

Question 48

What is the function of microvilli on the villi in the small intestine?

Answer 48

Microvilli further increase the surface area for absorption of food molecules.

Question 49

Why are the walls of the villi one-cell thick?

Answer 49

To shorten the distance for food molecules to pass through, allowing faster absorption into the bloodstream.

Question 50

Why is the villus richly supplied with blood capillaries and lacteals?

Answer 50

To carry absorbed food away continuously and maintain a concentration gradient for diffusion.

Question 51

What is the function of blood capillaries in the villi?

Answer 51

They carry away glucose and amino acids, helping to maintain a concentration gradient.

Question 52

What is the function of the lacteal in the villus?

Answer 52

It absorbs fats (in the form of fat globules) into the lymphatic system.