Digestive System

Question 1

Digestive system

Answer 1

Specialized to ingest, breakdown food

Digestion involves with physical and chemical breakdown
Physical: chewing, churning, and segmenting
Chemical: hydrolysis

Question 2

Mouth

Answer 2

Idea, smell or taste of food trigger salivary glands to secrete saliva

Salivary amylase breaks down starch into simple sugars

Teeth chew food

The tongue rolls the food into a ball and is pushed into the back of the throat

Question 3

Oesophagus

Answer 3

As the bolus enters the esophagus, the epiglottis( flap of skin)covers the trachea( windpipe)

• Epiglottis ensures that the food will not enter the trachea

A muscular portion of the gastrointestinal track through which peristalsis occurs

• parastalsis: wavelike, muscular contractions with push the bolus down.

Question 4

Oesophagus to stomach

Answer 4

To pass into the stomach, the bolus passes through the oesophageal sphincter
Relaxation allows food in
Contraction Prevent the acidic contents of the stomach to come out

Question 5

The stomach

Answer 5

Can hold approximately 2 to 4 L of food

• physical digestion occurs through waves of peristalsis in the stomach
• Gastric juices mixes with the food producing chyme
  . Gastro juices are made up of water, mucus, salts and hydrochloric acid.

Question 6

Pepsin

Answer 6

Protein digesting enzyme
- Digest stomach proteins because
- Little gastric juice until food is present
- From stomach cells, secrete mucus, which prevents gastric juices from harming the cells of the stomach lining
- Pepsi is produced in the form of hexen that remains inactive until hydrochloric acid is present

Question 7

Small intestine

Answer 7

Measures 7 m in length
- Some physical digestion takes place by segmentation
- Main function is to finish digestion modules, and begin absorption of the subunits of macromolecules into the bloodstream

Question 8

Pepsin and HCL in the small instestine

Answer 8

Once food reaches a small intestine, it is covered in hydrochloric acid and pepsin

• Small intestine for decks itself from the acid by the release of bicarbonate ions from the

Question 9

Villi

Answer 9

Long finger like tubes, which increased the surface area of the small, small intestine

• Membranes of the villi that line a small intestine unfolded to the surface area as microvilli
• each bill has a capillary network that intertwines with limp vessels called lacteals

Question 10

Pancreas

Answer 10

Pancreatic secretions contain enzymes which breakdown proteins, carbohydrates, and lipids
- Into the small intestine

Question 11

Proteases

Answer 11

Digest proteins into amin( trypsin)

Question 12

What enzyme digest carbohydrates

Answer 12

Amylase- continues the digestion of carbohydrates

Question 13

Types of Lipases

Answer 13

Liquid digesting enzymes
- pancreatic lipase breakdown, triglycerides into fatty acids and glycerol
- cholesterol lipase , removes a fatty acid from a steroid cholesterol
- a third lipase , acts on phospholipids, and breaks them down into glycerol and fatty acids

Question 14

Liver and gall bladder

Answer 14

Liver makes bile that is stored in the gallbladder

Bile: a combination of bile pigments and salts that physically break down fats to increase SA for lipase to act

Arrival of fat containing chyme in the duodenum stimulates the gallbladder to contract

Question 15

Absorption of monosaccharides

Answer 15

Absorbed by active transport into cells of the intestinal villi and then to blood

Passed to liver where all are converted to glucose
Circulated from liver to body cells

Question 16

Absorption of amino acids

Answer 16

Active transport
- villi to blood
- liver to body cells

Question 17

Absorption of glycerol and fatty acids

Answer 17

Absorbed by diffusion into cells of the villi

• inside cells they are reassembled and coated with proteins to make them water soluble
• absorbed by lymph vessels
• once in blood the protein coat is removed and the lipase hydrolyzes the fat into glycerol and fatty acids

Question 18

Absorption of glycerol and fatty acids

Answer 18

Diffusion into cells of villi
- fats are reassembled and coated with protein to make them water soluble

• absorbed into lymph vessels
• once in blood the coating is removed and the lipas hydrolyzes the fat into glycer and fatty acids

Question 19

Absorption of nucleic acids

Answer 19

Broken down further and absorbed by active transport into the blood

Question 20

Large intestine

Answer 20

Absorbs water, minerals and vitamins
A undigested is chyme is further broken down by anaerobic bacteria
- these bacteria also produce vitamin b12 and k

Question 21

Celluslose

Answer 21

Make up plant walls
- indigestible
- forms bulk of feces
- bulk sends message to brain about bowel movement

Question 22

Rectum and Anus

Answer 22

Last 20cm of the large intestine
Rectum stores feces and has three fold that allow gas but no solid
The opening of the anus has 2 sphincters
- one is under control
- one is controlled with nervous system
- feces leaves through peristalsis