Review of digestion and metabolism

Question 1

atoms form molecules which make up:

Answer 1

proteins and lipids that form cells and tissues and the glucose that is used for energy

Question 2

how do humans get atoms?

Answer 2

Since we cant make atoms or create energy we have to get them from other sources

Question 3

what does the GI tract consist of?

Answer 3

mouth, pharynx, esophagus, stomach, small and large intestine and the anus

Question 4

what body processes take place in the GI tract?

Answer 4

Digestion, absorption and excretion

Question 5

what is transit time?

Answer 5

The amount of time it takes food to pass the length of the GI tract

Question 6

what do feces consist of?

Answer 6

waste including unabsorbed food residue, bacteria and dead cells that leave the body

Question 7

when does digestion begin?

Answer 7

as soon as the food enters the mouth

Question 8

what does saliva do in digestion?

Answer 8

lubricates food with the enzyme amylase which breaks down carbs in the mouth

Question 9

in the stomach, gastric juice is released which contains:

Answer 9

• HCL (acidifying the stomach)
• Pepsinogen, inactive form of the enzyme pepsin

Once activated by HCL pepsin begins breaking down proteins

Question 10

in children, what enzyme is released and what does it do?

Answer 10

renin
- helps digest milk

Question 11

what churns the stomach content aiding in digestion?

Answer 11

powerful stomach muscles

Question 12

when does chyme leave the stomach?

Answer 12

After 2-6 hours and enters the small intestine

Question 13

in the small intestine, the pancreas releases:

Answer 13

• Bicarbonate (neutralizes acidic chyme)
• Enzymes that further break down carbs, proteins and lipids

Question 14

what does the gallbladder release?

Answer 14

bile salts

Question 15

what does the gall bladder do in the digestion process?

Answer 15

Emulsify lipids, separating them into smaller fat droplets which are more soluble and accessible to enzymes

Question 16

where does most absorption occur?

Answer 16

small intestine

Question 17

how long is the small intestine?

Answer 17

6 metres

Question 18

what 2 things increase there SA of the small intestine?

Answer 18

Villi and microvilli

Question 19

Single sugars, amino acids and short chain fatty acids enter where?

Answer 19

portal vein and go to the liver

Question 20

where do Long chain fatty acids enter?

Answer 20

lymphatic system and go directly into the bloodstream

Question 21

how long does it take chyme to move through the small intestine?

Answer 21

3-5 hours

Question 22

where do unabsorbed materials enter (since they do not go in small intestine)?

Answer 22

large intestine

Question 23

does the large or small intestine contain gut microbiome (large bacterial population)?

Answer 23

large

Question 24

gut bacteria break down unabsorbed food and can produce:

Answer 24

beneficial compounds for the body

Question 25

Biological material will stay in the large intestine for how many hours before being excreted?

Answer 25

24-36

Question 26

the GI tract acts as a barrier to what?

Answer 26

the outside world, inside your body

Question 27

The immune system is interconnected within the GI tract to prevent pathogens from entering body (phagocytes such as macrophages and lymphocytes such as B cells and T cells are present below the mucosa). T or F

Answer 27

T

Question 28

how does a food allergy occur?

Answer 28

when the immune system reacts to a protein in our food and triggers an immune response

Question 29

what percentage of Canadians have a food allergy?

Answer 29

7%

Question 30

Celiac disease is an example of a food allergy due to an immune response to what?

Answer 30

wheat protein gluten

Question 31

what is the benefit of commensal bacterial in the gut?

Answer 31

help fight pathogens by competing for nutrients

Question 32

The human gut contains an entire ecosystem of microorganisms. T or F

Answer 32

T

Question 33

what diseases have been been linked with gut microbiota?

Answer 33

Obesity, cancer, inflammation, CVD, liver disease

Question 34

what's the difference in the microbiome a baby has being born vaginally and C section?

Answer 34

vaginally: - have an initial microbiome that resembles the mothers vaginal microbiome C section: - have a microbiome that resembles the mothers skin microbiome

Question 35

what people would have greater quantity and variation in gut bacteria?

Answer 35

those who are lean

Question 36

what people harbour more pro inflammatory species?

Answer 36

Those with lower bacterial numbers (and higher BMI)

Question 37

what is lactase?

Answer 37

enzyme found in the small intestine that can break down lactose

Question 38

when is lactase highly expressed?

Answer 38

during infancy but typically decreases as child transitions to solid foods

Question 38

If the amount of lactase in the small intestine is insufficient to handle the lactose in the diet, some lactose will escape and enter where?

Answer 38

large intestine where bacteria will use it for energy

Question 39

what contributes to the autoimmune response in T1D?

Answer 39

A bacterial protein has a similar sequence to the human insulin epitope This bacteria may contribute an immune response to insulin and T1D onset

Question 40

when we eat, what enters the blood supply from the intestines? And what organ do they get to first?

Answer 40

glucose, fatty acids and amino acids - liver bc of portal vein

Question 41

nutrients are used in 3 different ways:

Answer 41

- Broken down for energy (catabolism) - Used to make new molecules (anabolism) - Stored for later use

Question 42

The energy obtained from breaking down glucose amino acids and fatty acids is converted to what?

Answer 42

ATP

Question 43

ATP contains high energy bonds that when broken down, release energy that can be used to:

Answer 43

- Synthesize new molecules - Fuel cellular and bodily functions

Question 44

Glucose is used in 3 diff ways:

Answer 44

- Oxidized for energy - Stored for later energy use as glycogen (carbs) or triglyceride (lipid) - Used to make new molecules

Question 45

what is the most important energy source?

Answer 45

glucose - brain an RBC use glucose for energy

Question 46

amino acids (protein) are used in 3 diff ways:

Answer 46

- Oxidized for energy - Used to make new proteins or molecules - Cannot be stored, all protein is functional

Question 47

fats are used in 3 diff ways:

Answer 47

- Oxidized for energy - Stored for later energy use as Triglyceride (lipid) in adipose tissue - Used to make new molecules

Question 48

once in the cells, nutrients are converted to what?

Answer 48

energy

Question 49

what is Acetyl-CoA?

Answer 49

is the hub of energy production in the cell

Question 50

Oxidation of macronutrients produces _________ which is exhaled by the lungs

Answer 50

carbon dioxide

Question 51

Deamination of amino acids produces ammonium, nitrogenous waste is filtered out by the kidneys and excreted in the urine. T or F

Answer 51

T

Question 52

glucose levels in the blood must remain ______ to keep body processes functioning by supplying energy to the brain and RBCs

Answer 52

near constant

Question 53

Substances are metabolized differently depending on:

Answer 53

how long it has been since a meal

Question 54

in the fasting state, are blood glucose levels high or low?

Answer 54

low

Question 55

glucagon is released from the pancreas in response to what?

Answer 55

low blood glucose levels and insulin is decreased

Question 56

how is energy supply maintained?

Answer 56

Fatty acids are broken down, providing energy to tissues that do not rely on glucose

Question 57

what is Glycogenolysis?

Answer 57

Liver stores of glycogen are converted to glucose but are limited **This supply is used first**

Question 58

what is Gluconeogenesis?

Answer 58

The use of non carbohydrate sources to produce glucose, this process ramps up as glycogen stores are being depleted

Question 59

what can be used as precursors for glucose?

Answer 59

Glycerol, lactate and amino acids

Question 60

Proteins are broken down and instead of being remade, what are used for energy?

Answer 60

amino acids

Question 61

what are ketone bodies produced by?

Answer 61

the liver from fatty acids as an alternative energy source for some tissues

Question 62

in what individuals is an intermittent fasting diet beneficial?

Answer 62

individuals with metablic syndrome

Question 63

During a prolonged fasted state, are blood glucose levels low or high?

Answer 63

remain low, glycogen has been depleted an there is limited excess protein to break down

Question 64

what is the goal for the body in the starvation period?

Answer 64

maintain an energy supply for essential tissues, the brain and RBCs

Question 65

why do ketone bodies build up in the blood?

Answer 65

from the breakdown of fatty acids - once concentration gets high enough, the brain will begin using them for energy in addition to the limited glucose available

Question 66

when does death occur from starvation?

Answer 66

When about 40% of body weight is lost - BMI women=11 - BMI men=13 30-50% protein loss, 70-95% of fat depleted

Question 67

how is the metabolic state of an individual determined?

Answer 67

Blood and urine levels of the different substances are used