Digestive System

Question 1

What acronym can you use to remember the sequence of duodenum → jejunum →** ileum** in the small intenstine?

Answer 1

Dow Jones Industrial

Question 2

What are the objectives of the small intestine?

Answer 2

• neutralizing the highly acidic chyme from the stomach
• continuing chemical digestion
• vitamin & nutrient absorption

Question 3

This enzyme produced in the stomach is reponsible for the breakdown of fats

Answer 3

gastic lipase

When you think of stomach enzymes, think of pepsin and gastric lipase

Question 4

What prevents pepsin from immediately doing proteolytic activity when it isn’t necessary

Answer 4

Chief cells secrete its inactive form pepsinogen, which is cleaved under highly acidic conditions to become its active form, pepsin

Question 5

Enzymes secreted by the SI from its microvilli to digest fats and/or proteins

Answer 5

brush border enzymes

can be disarccharidases or peptidases

recall that disaccarides are a common form in which carbs are consumed

Question 6

List the functions of the pancreas wrt the digestive system

Answer 6

• helps duodenum digestion by secreting alkaline fluid containing digestive enzymes that can break down all major biomolecule classes
• lipases (fat)
• proteases (protein)
• amylases (sugars)

Question 7

What does bile consist of?

Answer 7

Bilurubin, bile salts, and some fats

bile emulsifies lipids and converts them to micelles

Question 8

How is highly acidic chyme from the stomach neutralized via other digestive system organs?

Answer 8

• pancreas secretes alkaline fluid rich with bicarbonate
• liver’s bile is slightly alkaline
• duodenum secretes bicarbonate buffer via Brunner’s glands

Question 9

Qhat region(s) of the small intestine are involved in nutrient absorption?

Answer 9

jejunum & ileum

Question 10

Cells of the intestinal lining, characterized by microvilli

Answer 10

enterocytes

Question 11

Name the regions of the large intestine in order (excluding the appendix)

Answer 11

1. cecum
2. ascending colon
3. transverse colon
4. descending colon
5. sigmoid colon
6. rectum

Question 12

What is the pouch connected with the ileum through the ileocecal valve?

Answer 12

the cecum

Question 13

Where is the largest community of bacteria in the human body located?

Answer 13

The gut microbiota is located in the large intestine

Question 14

What is the role of bile?

Answer 14

To emulsify lipids so that digestive enzymes can do their work

Question 15

Name the two hormones that regulate hunger

Answer 15

ghrelin & leptin

think “grrr” (I’m hungry!) for ghrehlin , and leptin is the opposite, it lets you know that you are full

Question 16

What hormone is released by the stomach and pancreas when the stomach is empty?

Answer 16

ghrehlin

ghrehlin promotes appetite

Question 17

Which hormone is secreted by adiptocytes and promotes feelings of satiety?

Answer 17

leptin

Question 18

What is this hormone?

G-cells in the stomach secrete a hormone that promotes digestion by stimulating parietal cells to secrete gastric acid (HCl)

Answer 18

gastrin

Question 19

Acidic chyme in the duodenum triggers the release of which hormone from S cells? What does this hormone do?

Answer 19

**secretin **triggers the secretion and release of bicarbonate rich mucus from the pancreas

think: pH regulator!

this is to neutralize the acidic chyme and promote the optimal functioning of the digestive enzymes that do their work in the small intestine

Question 20

This hormone is secreted by the small intestine and stimulates the release and secretion of digestive enzymes from the pancreas, and the release of bile from the gallbladder

Answer 20

cholecystokinin (CCK)

think: digestion helper!

Question 21

Which hormone produced from the GI system & hypothalamus helps slow down digestion by inhibiting the release of other hormones, and slowing the rate at which the stomach empties?

Answer 21

somatostatin

think: pumping the brakes on digestion

somatostatin also inhibits the release of growth hormone when released from the hypothalamus. This makes sense because GH is released from the hypothalamus
it’s released from the GI tract, pancreas, CNS, and hypothalamus!

Question 22

Part of the autonomic nervous system that regulates the digestive functions of the gastrointestinal tract

Answer 22

enteric nervous sytem

think: part of ANS involved in digestion

Question 23

Describe the general steps for carbohydrate absorption

include what they get broken down into, the cell transport used to get them across the membrane

Answer 23

1. Carbs → monosaccharides
   2.a 2º active transport coupled to Na+ gets glucose & galactose into epithelial cells
   2.b Facilitated diffusion used for fructose
2. Monosaccharides enter circulatory system via facilitated diffusion
3. Facilitated diffusion pushes monosaccharides in bloodstream

Question 24

Describe how lipids are absorbed

include what they get broken down into, the cell transport used to get them across the membrane

Answer 24

1. Lipids → micelles w/ aid of bile salts
2. Lipid molecules break away for epithelial cell absorption
3. Fats & cholesterol can diffuse through plasma membrane
4. Fats & fat soluable vitamins are combined into chylomicrons
5. Chylomicrons are released into interstitial space
6. Fat is transported from interstitial space → lacteals
7. Lipids pass through lymphatic system
8. Lipids eventually drain into venous system

chylomicrons = fat droplets

Small intestine epithelial cells combine fatty acids + monoglycerides = triglycerides to avoid the concentrations of fats to equalize, which would cause absorption to stop

Question 25

# Fill in the blank the hepatic portal vein runs from the capillaries of the ____ to the liver

Answer 25

** small intestine ** ## Footnote small intestine capillaries → hepatic portal vein → liver → hepatic portal *system*

Question 26

What is the benefit of the hepatic portal system? That is, blood from small intestine being processed by the liver before entering the circulatory system?

Answer 26

The liver can: * detoxify compounds * metabolize medications/drugs * store excess carbs as glycogen * store exess fatty acids as triglycerides * mobilize lipids into circulation as lipoproteins * breaking down glycogen to release glucose (if necessary)

Question 27

# fill in the blanks Proteins are broken down in the stomach by ____, and in the small intestine by ____ (name three)

Answer 27

**pepsin** in stomach; **trypsin** and **chymotrypsin**, and **carboxypeptidase** in small intestine

Question 28

____ is an enzyme that cleaves proteins on the carboxyl end of lysine or arginine (execept when followed by proline)

Answer 28

Trypsin | released in small intestine

Question 29

____ are a class of enzymes that break down proteins from the amino end

Answer 29

aminopeptidases ## Footnote it tells you what it does in the name.... *amino* peptidase , telling you it breaks down proteins at the amino end

Question 30

Describe the path of **proteins** as they go from your mouth to a state where they can be used in the body

Answer 30

1. Pepsin breaks down proteins in stomach 2. Small intestine uses trypsin and aminopeptidases for more breakdown 3. Single amino acid residues enter epithelial cells lining lumen of small intestine 4. Amino acids enter circulatory system

Question 31

Describe the path of **carbohydrates** as they go from your mouth to a state where they can be used in the body

Answer 31

1. **Salivary amylase** breaks downs starches → dissachharides 2. Small intestine breaks starches into monosaccharides via **pancreatic amylase** (one of many enzymes) 3. Monosaccharides enter epithelial cells of SI 4. Monosaccharides enter circulatory system 5. Cellulose and undigested starch → large intestine 6. "..." broken down or digested by gut flora → short-chain fatty acids

Question 32

Describe the path of **triglycerides** as they go from your mouth to a state where they can be used in the body

Answer 32

1. Digested in mouth by **lingual lipase** 2. **Pancreatic lipase** breaks down most of lipids in stomach 3. Resulting free fatty acids & monoglycerides are seperated by bile salts into micells 4. Lipids enter cells lining small intestine 5. Lipids packaged into **chylomicrons** 6. Chylomicrons are released into lacteals 7. Lacteals drain into lymphatic system

Question 33

# True or False It is possible to overdose on vitamin C

Answer 33

_False._ It is nearly impossible to overdose on **water-soluble vitamins** | Vitamins C & B in excess are excreted from the urine ## Footnote However, it is quite possible to OD on fat-soluble vitamins i.e A, D, E, & K

Question 34

# True or False Our bodies produce substantial amounts of vitamins

Answer 34

False. The vast majority of our vitamin levels are influenced by our diet | and sun exposure for vitamin D

Question 35

Vitamins and their derivates also serve as what type of biochemical actors in physiological reactions?

Answer 35

Coenzymes/cofactors ## Footnote i.e vitamin B2 (Riboflavin) is a coenzyme involved in the ETC

Question 36

# Name the vitamin Helps with vision (low-light and color)

Answer 36

Vitamin A | also good for healthy skin regeneration

Question 37

# Name the vitamin Helps calcium and phosphate absorption from the gut

Answer 37

Vitamin D

Question 38

# Name the vitamin Is an antioxidant; scavenges free-radicals

Answer 38

Vitamin E ## Footnote think: vitamin E and berrIES (berries have shit ton of antioxidants!)

Question 39

# Name the vitamin Helps to make various proteins that are needed for *blood clotting *and the building of bones

Answer 39

Vitamin K ## Footnote think!*** K***lotting

Question 40

# Name the vitamin Cofactor for reactions in collagen synthesis, and is also an antioxidant

Answer 40

Vitamin C ## Footnote think about skincare lol. Also, vitamin C and vitamin E work well on the skin together because they're both antioxidants!

Question 41

# Name the vitamin Coenzyme in important metabolic reactions | thiamine

Answer 41

B₁

Question 42

# Name the vitamin Coenzyme involved in ETC, precursor of FAD | riboflavin

Answer 42

Vitamin B₂

Question 43

# Name the vitamin Precursor of NAD and NADP | niacin, niacinamide

Answer 43

Vitamin B₃

Question 44

# Name the vitamin Required for synthesis of CoA, as well in metabolism

Answer 44

Vitamin B5

Question 45

# Name the vitamin Used as a coenzyme in many metabolic reactions | pyridoxine

Answer 45

Vitamin B6 | B6 and B1 serve the same function: coenzymes in metabolic reactions

Question 46

# Name the vitamin Cofactor for several *carboxylase* enzymes in metabolic reactions | biotin

Answer 46

Vitamin B7

Question 47

# Name the vitamin Ensures proper neurological development in pregnancy, required for fertility and RBC synthesis | folic acid

Answer 47

Vitamin B9

Question 48

# Name the vitamin Coenzyme in metabolic reactions, especially DNA synthesis and lipid/amino acid metabolism | cyanocobalamin + derivaties

Answer 48

B12

Question 49

Blood is filtered to form ____ in the kidneys

Answer 49

urine ## Footnote if your kidney is not doing alright, this is why you will find blood in urine (hematuria)

Question 50

The kidneys are supplied blood via the ____, and then drain into the ____

Answer 50

**renal arteries** supply kidneys with blood, **renal veins** are what the kidneys drain into

Question 51

The outside of the kidney is surounded by protective tissue called....

Answer 51

renal capsule

Question 52

The outer region of the kidney is called the ____ , and the inner region is called the ____

Answer 52

outer region: renal cortex inner region: renal medulla

Question 53

What functional region of the kidneys produce urine?

Answer 53

Nephrons

Question 54

The ____ is the part of the nephron that does initial urine filtration, while the ____ projects downwards into the medulla before returning up back to the cortex, at which point the urine drains into the ____

Answer 54

renal corpuscle, renal tubule, collecting duct

Question 55

The collecting ducts eventually drain urine into the ____, which becomes the ureter

Answer 55

renal pelvis ## Footnote collecting duct → medullary pyramids → minor calyces → major calyces → renal pelvis → ureter

Question 56

The ureters drain urine downwards from the kidney into the ____, which rests on the pelvic floor

Answer 56

urinary bladder

Question 57

Urine is released from the bladder into the ____, where it exists the body

Answer 57

Urethra

Question 58

The release of urine through the urethra is caused by the ____

Answer 58

urethral sphincter

Question 59

The renal corpuscle contains the ____ which is a bunched up set of capillaries through which water, ions, and small molecules filter out and are gathered into ____ , which wraps around it

Answer 59

**Glomerulus**: Bundled set of capillaries that are filtered into **Bowman's capsule**

Question 60

Blood is supplied to the glomerulus through an ____ and exits through an ____

Answer 60

afferent arteriole; efferent arteriole | fluid collected in Bowman's capsule is called **glomerular filtrate**

Question 61

What are the three main parts of the renal tubule?

Answer 61

proximal convoluted tube, loop of Henle, and distal convoluted tube

Question 62

Which major region of the nephron is reponsible for regulating water volume and urine concentration?

Answer 62

renal tubule

Question 63

Region of the kidney whose main functions are 1. filtering various substances in the blood and 2.) regulating fluid/salt content of urine

Answer 63

Nephron

Question 64

# Name the nephron region Large amounts of salts, water souluble vitamins, free amino acids, glucose, and water are reabsorbed here. Secretion of waste products into the urine also occurs here

Answer 64

proximal convoluted tube (PCT) ## Footnote Wastes excreted by the PCT include creatine, ammonia, and medications

Question 65

# Name the nephron region The main function is to **reabsorp water and salt** (reducing the amount of these ending up in filtrate) , and creating an **osmotic gradient** in the renal medulla

Answer 65

loop of Henle

Question 66

The deeper you go into the renal medulla, the [greater/lesser] the concentration of solutes

Answer 66

**greater** ; this facilitates the osmotic process throughout the loop of Henle

Question 67

Water is reabsorbed in the ____ of the loop of Henle, and salt is transported out of the ____

Answer 67

Water reabsorption: **descending limb** Salt leaves: **ascending limb**

Question 68

The process of using energy to generate an osmotic gradient that enables you to reabsorb water from the tubular fluid and produce concentrated urine

Answer 68

**countercurrent multiplier** ## Footnote [Khan academy article](https://www.khanacademy.org/test-prep/mcat/organ-systems/the-renal-system/a/renal-physiology-counter-current-multiplication)

Question 69

# Name the region of the nephron Is partly responsible for the regulation of potassium, sodium, (think: water regulation), calcium, and pH. Increases calcium reabosrption in presence of PTH. Can contribute to pH regulation by secreting or absorbing hydrogen ions as needed

Answer 69

distal convoluted tube (DCT)

Question 70

# Name the nephron region The main role is the reabsorption of water, through the action of anti-diuretic hormone (ADH) and aquaporins.

Answer 70

collecting duct

Question 71

# Name the hormone Promotes the secretion of sodium in the urine, which draws water with it, increasing the amount of H2O expelled in the urine and decreasing BP

Answer 71

**atrial natriuretic peptide (ANP)** | opposite of ADH

Question 72

What are the three main hormones that effect fluid balance?

Answer 72

Aldosterone, ADH, and ANP ## Footnote p.251 of BP

Question 73

The kidney secretes renin when....

Answer 73

When your **blood pressure drops too low** or when there's **not enough sodium** in your body, or when there is a lot of **sympathetic NS** signaling ## Footnote [Youtube link](https://youtu.be/fqOfOvwlz-g)

Question 74

Renin causes a hormone that is released from the liver to be cleaved to form another hormone. Which hormone is this?

Answer 74

**angiotensinogen ** | renin → angiotensinogen → angiotensin I ## Footnote [Youtube link](https://youtu.be/fqOfOvwlz-g)

Question 75

Angiotensin I is converted to angiotensin II by an enzyme called ____

Answer 75

**angiotensin-converting enzyme (ACE)** | ACE is released from the lungs ## Footnote [Youtube link](https://youtu.be/fqOfOvwlz-g)

Question 76

angiotensin converting enzyme (ACE) is released from which organ?

Answer 76

The lungs ## Footnote [Youtube link](https://youtu.be/fqOfOvwlz-g)

Question 77

# Name the hormone ____ increases BP via vasoconstriction and also triggers the release of aldosterone by stimulating the adrenal cortex

Answer 77

Angiotensin II ## Footnote [Youtube link](https://youtu.be/fqOfOvwlz-g)

Question 78

# Name the hormone Acts on the kidneys to ↑Na+ reabsorption which ↑ water reabsorption (in the presence of ADH), which ↑ plasma volume of blood which ↑ BP

Answer 78

aldosterone

Question 79

Describe vasopressin's role in regulating blood pressure wrt water and plasma volume of blood

Answer 79

↑ H2O retention = ↑ plasma volume of blood ↑ BP | vasopressin = ADH