Exchange and transport - DIGESTION AND ABSORPTION Flashcards

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1
Q

Where is amylase produced?

A

Pancreas/salivary gland

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2
Q

Where are the sites of action for amylase?

A

Duodenum/mouth

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3
Q

What are the 3 enzymes that break down carbohydrates?

A

Salivary amylase, pancreatic amylase, maltase

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4
Q

Where is maltase secreted?

A

Lining of the ileum

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5
Q

Where is lipase produced?

A

pancreas

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6
Q

What is the difference between exopeptidase and endopeptidase?

A

Exopeptidase hydrolyses the end of the polypeptide chains whereas endopeptidase hydrolyses within the polypeptide chains

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7
Q

What is digestion?

A

A process where large, insoluble biological molecules in food are hydrolysed into smaller, soluble molecules that can be absorbed across the cell membrane into the blood stream.

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8
Q

What effect does the pH of the stomach have on amylase?

A
  • Denatures amylase
  • Starch is no longer hydrolysed
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9
Q

What are membrane bound disaccharidases?

A
  • Enzymes that are attached to the epithelial cells that line the ileum
  • Break disaccharides into monosaccharides in the small intestine
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10
Q

Hydrochloric acid is produced in the stomach. What is its role?

A

It provides the optimum pH for the enzymes in the stomach and kills harmful pathogens.

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11
Q

Describe the role of the enzymes of the digestive system in the complete breakdown of proteins (PPQ)

A
  • Endopeptidases; Break bonds in the central region of protein molecules
  • Exopeptidases; Break bonds at the end of protein molecules
  • Dipeptidases; Break bonds in dipeptides to form amino acids
  • Hydrolysis of peptide bonds
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12
Q

Describe the processes involved in the absorption of the products of protein digestion (PPQ)

A
  • Amino acids move in with sodium, via protein
  • Co transport of sodium down conc. gradient and amino acids against conc. gradient
  • Sodium removed by active transport into blood
  • Maintaining low conc. of sodium
  • Amino acids move into blood by facilitated diffusion
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13
Q

Describe the role of bile in digestion and absorption of triglycerides (PPQ)

A
  • Emulsifies lipid drops into smaller droplets
  • Increases surface area of droplets
  • Increases rate of digestion by lipases
  • Bile forms micelles; To transport monoglycerides and fatty acids - because bile is amphipathic
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14
Q

Describe the processes involved in the absorption of the products of triglyceride digestion (PPQ)

A
  • Micelle collides with cell membrane
  • Monoglycerides and fatty acids enter cell by simple diffusion
  • Reformed into triglycerides in the smooth endoplasmic reticulum
  • Combined with proteins to form chylomicrons
  • Exocytosis of chylomicrons
  • Chylomicrons enter the lacteals/then enter blood
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15
Q

What are some adaptations of the ileum?

A
  • Villi (and microvilli) increase surface area; for increased diffusion
  • Epithelial cells are very thin; reducing diffusion distance
  • Concentration gradient is maintained
  • Many capillaries
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16
Q

What are exocrine glands?

A

Secrete substances directly into the blood

17
Q

What are endocrine glands?

A

Secrete substances into ducts on the epithelial cells