Body Systems: Digestion (Digestion) Flashcards

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1
Q

The small intestine is composed of 3 sections:

A

Duodenum, Jejunum, Ileum.

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2
Q

In what part of the small intestine does most digestion occur?

A

In the Duodenum.

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3
Q

Chyme (from stomach) moves through the small intestine by:

A

Peristalsis.

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4
Q

Small intestine (Physical digestion)=

A

Segmentation= chyme sloshing back and forth.

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5
Q

Ridged inner lining of the small intestine are covered in tiny projections called:

A

Villi, which are covered in micro villi.

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6
Q

What do villi and micro villi do?

A

Increase the surface area of the small intestine.

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7
Q

Each villus is supplied with:

A

Capillary networks and lymph vessels called lacteals.

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8
Q

What do capillary networks do?

A

Allow fluid and gas exchange to occur with blood stream.

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9
Q

What do lacteals do?

A

Transport products of fat digestion.

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10
Q

The pancreas:

A

Releases enzymes to the small intestine.

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11
Q

Enzymes chemically digest:

A

Proteins (trypsin), carbs (amylase), lipids (lipase).

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12
Q

Protein digestion in the small intestine (1):

A

Chyme enters the small intestine soaked in HCl and pepsin (from gastric secretions). The HCl triggers the conversion of the hormone prosecretin into secretin.

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13
Q

What is secretin?

A

Secretin: tells pancreas to release bicarbonate ions (HCO3-).

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14
Q

Protein digestion in the small intestine continued (2):

A

Bicarbonate ions (HCO3-) —> to increase the pH from 2.0 to 9.0 (becomes more basic).
-Secreted from pancreas.
-Basic pH inactivates (released in stomach).

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15
Q

Protein digestion in the small intestine continued (3):

A

Trypsinogen —> gets converted into trypsin by the enzyme enterokinase. (Secreted from small intestine).
-Secreted from pancreas.
-Chemical digestion of long chain proteins.

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16
Q

What’s the full process of protein digestion in the small intestine:

A

1.Chyme enters the small intestine soaked in HCl and pepsin (from gastric secretions). The HCl triggers the conversion of the hormone prosecretin into secretin. Secretin: tells pancreas to release bicarbonate ions (HCO3-). 2.Bicarbonate ions (HCO3-) —> to increase the pH from 2.0 to 9.0 (becomes more basic).
-Secreted from pancreas.
-Basic pH inactivates (released in stomach).
3.Trypsinogen —> gets converted into trypsin by the enzyme enterokinase. (Secreted from small intestine).
-Secreted from pancreas.
-Chemical digestion of long chain proteins. 4.Erepsin —> completes the protein digestion by breaking down shorter chain peptides and converting them into amino acids.
-Secreted by both the pancreas and the small intestine.

17
Q

Protein digestion in the small intestine continued (4):

A

Erepsin —> completes the protein digestion by breaking down shorter chain peptides and converting them into amino acids.
-Secreted by both the pancreas and the small intestine.

18
Q

Carbohydrate digestion in the small intestine:

A

The pancreas also releases amylase enzyme. Continues chemical digestion of complex carbs in the small intestine into disaccharides. Small intestine releases disaccharidase enzyme (lactase, maltase, sucrase) to break them down into monosaccharides. Completes the chemical digestion of carbs.

19
Q

What converts pepsinogen into its active form pepsin?

A

HCl.

20
Q

What converts the hormone prosecretin into its active form secretin?

A

HCl.

21
Q

What converts trypsinogen into its active form trypsin?

A

The enzyme enterokinase. (Secreted from the small intestine).

22
Q

Lipid digestion in the small intestine:

A

Pancreas releases lipases which break down lipids (fats). Two types: 1.Pancreatic lipases- breaks down fats into fatty acids and glycerol. 2.Phospholipases- break down phospholipids.

23
Q

The liver:

A

Breaks down components of hemoglobin from blood. Converts glycogen to glucose and glucose to glycogen depending on the bodies blood sugar needs. Stores vitamins A, B12, and D. Detoxifies harmful substances in the body by making them soluble and therefore will dissolve in blood and eliminates in urine. (Ex. Alcohol). Secretes bile, which is made up of bile pigments (waste products) and bile salts.

24
Q

Gallbladder:

A

The liver produces bile salts, which are stored in the gallbladder when not needed. When fats are present in the small intestine, hormone cholecystokinin (CCK) is released by the small intestine triggering the release of bile salts from the gallbladder.
-Emulsify large fat globules into smaller droplets = greater surface area for lipases to digest.

25
Q

Liver and gallbladder problems (Gallstones):

A

Hard masses in the gallbladder. Cholesterol in bile can precipitate out and form crystals. Block bile duct. Impairs fat digestion.

26
Q

Liver and gallbladder problems (Jaundice):

A

Build up of bile pigments in the blood.

27
Q

Liver and gallbladder problems (Cirrhosis):

A

Alcohol and hepatitis C can destroy liver tissue. Cirrhosis of the liver: chronic inflammation of liver (due to major damage).

28
Q

Large intestine (1):

A

Digestion does not occur in the large intestine. Concentrates and eliminates wastes. Undigested chyme passes down to the colon. Water and salt are absorbed, bacteria tries to digest remaining waste.

29
Q

Large intestine continued (2):

A

Remaining undigested waste and bacteria passes to the rectum. Cellulose cannot be broken down by humans but provides “roughage”. As waste builds up in the large intestine, receptors provide information to central nervous system to prompt bowel movement. Feces moves out anus via peristalsis.

30
Q

Full function of large intestine:

A

Digestion does not occur in the large intestine. Concentrates and eliminates wastes. Undigested chyme passes down to the colon. Water and salt are absorbed, bacteria tries to digest remaining waste. Remaining undigested waste and bacteria passes to the rectum. Cellulose cannot be broken down by humans but provides “roughage”. As waste builds up in the large intestine, receptors provide information to central nervous system to prompt bowel movement. Feces moves out anus via peristalsis.

31
Q

Full Lipid digestion in the small intestine:

A

The liver produces bile salts which are stored in the gallbladder when not needed. When fats are present in the small intestine, hormone cholecystokinin (CCK) is released by the small intestine triggering the release of bile salts from the gallbladder. Bile salts emulsify large fat globules into smaller droplets = greater surface area for lipases to digest. Pancreas releases lipases which break down lipids: 1.pancreatic lipases- breaks down fats into fatty acids and glycerol. 2. Phospholipases- break down phospholipids.

32
Q

Hormones-control of digestion (Gastrin):

A

Produced as the walls of the stomach are distended by presence of food.
-Signals the parietal cells of the stomach to release HCl (aq).

33
Q

Hormones-control of digestion (Secretin):

A

Released from the duodenum when stomach acid and chyme move from the stomach to the small intestine.
-Initiates the release of bicarbonate ions from the pancreas that raise the pH of the small intestine.
-Inhibits contraction of the stomach to prevent additional chyme from entering the duodenum.

34
Q

Hormones-control of digestion (CCK):

A

Released from the duodenum after consumption of a fatty meal.
-Stimulates gallbladder to contract and release bile into the duodenum to digest fats.
-Slows digestion and allows more time for fat to be digested and absorbed.