Human Digestive System

Question 1

What is the function of the human digestive system?

Answer 1

The digestive system digests large, insoluble food molecules such a s proteins into smaller, soluble food molecules such as amino acids, which can easily pass through the partially permeable cell surface membrane and be absorbed into our cells

Question 2

What is peristalsis

Answer 2

When the muscles in the front of the food relaxes while the muscles behind the food contract to push food down the alimentary canal, and also to enable food to mix with digestive juices and move food along the gut

Question 3

Digestion in the mouth

Answer 3

*physical digestion- teeth chew to grind and cut the food into smaller pieces

*chemical digestion- salivary amylase found in the saliva (produces by salivary glands). Also softens and lubricates food for easier swallowing

Question 4

Digestion in the oesophagus

Answer 4

Physical or chemical digestion does not occur in the oesophagus, as peristalsis only occurs to transport food from the mouth to the stomach

Question 5

Digestion in the stomach

Answer 5

Physical digestion- stomach is a muscular bag that contracts and relaxes to break down food into even smaller pieces and mixes with the stomach juices

Chemical digestion: stomach juice contains protease which digest proteins into polypeptides.

Gastric juice also contains hydrochloric acid which activates the protease to digest the proteins into polypeptides—> there is a thick layer of mucus to protect the stomach from the acid

Question 6

What are the enzymes found in pancreatic juice?

Answer 6

PAL —> protease, amylase, lipase

Question 7

What is found in intestinal juice?

Answer 7

PML —> protease, Maltese, lipase

Question 8

What is the purpose of bile

Answer 8

Bile emulsifies fats —> bile breaks down large fat droplets into smaller fat droplets for an increased surface area to volume ratio to speed up the rate at which lipase digests fats into glycerols and fatty acids

Question 9

Digestion of fats into glycerol and fatty acids

Answer 9

Lipase in intestinal juice and pancreatic juice digests fat molecules into fatty acids and glycerol

Question 10

Digestion in small intestine from maltose into glucose

Answer 10

Amylase in the pancreatic juice and salivary amylase from the mouth earlier on digests starch into maltose. Maltase in the intestinal juice digests maltose into glucose

Question 11

Digestion of proteins into amino acids

Answer 11

Protease in the pancreatic juice_+ gastric juice from earlier on in the stomach digests proteins into polypeptides. Protease in the intestinal juice digests polypeptides into amino acids

Question 12

How are the end products of digestion absorbed into the body cells?

Answer 12

By diffusion or active transport

Question 13

What are the adaptations of the small intestines for faster absorption of small and soluble food molecules?

Answer 13

1. Small intestines are long and coiled to provide enough time for the food to be absorbed into the bloodstream
2. Presence of finger-like projections called the villus for an increased surface area to volume ratio for faster absorption

Question 14

What is found inside the villus?

Answer 14

1. One-cell think epithelium wall for faster diffusion of the digested food molecules
2. Blood capillaries network to transport amino acids and glucose
3. Lacteal to transport the fatty acids+glycerol