Digestive System

Question 1

what is digestion

Answer 1

animals must consume food for growth, repair and reproduction and to provide energy for normal functioning.

Question 2

parts of digestive system

Answer 2

1. gastrointestinal tract this is 9meter long path that food will take that goes from your mouth to your anus. includes the oesophagus, stomach and intestines
2. then there are the pancreas and gall bladder and liver which are essential for their secretion of special juices and enzymes
3. next are the enzymes, hormones, blood, nerves and bacteria that are all needed to coordinate the breakdown and delivery of food
4. finally, the mesentery, a large stretch of supportive tissue that keeps all your digestive organs in their place

Question 3

steps in digestion

Answer 3

1. ingestion
2. digestion
3. absorption
4. elimination/egestion

Question 4

Ingestion

Answer 4

eating with initial physical and chemical breakdown to swallow

Question 5

Digestion

Answer 5

Most of the gastrointestinal tract is to physically and chemically break down food in order for it to be small enough for absorption

Question 6

absorption

Answer 6

the movement from the G1 tract to the bloodstream to be used

Question 7

Eliminated/ Egestion

Answer 7

the undigested waste needs to be eliminated as faeces

Question 8

egestion

Answer 8

the discharge of undigested material form a cell in case of unicellular organism, and from the district tract (via the anus)

Question 9

Excretion

Answer 9

a process by which metabolic waste is eliminated form an organism. (via urine)

Question 10

Brain

Answer 10

the brain and the nervous system work together.
1. sensory and mental input
2. vagal activation of gastric motility and gastric juice secretion
3. Gastrin

Question 11

mechanical breakdown

Answer 11

food must be broken down into smaller pieces to allow it to be absorbed.

the first stage is chewing or churning. this increases the SA:V

Question 12

chemical digestion - enzymes

Answer 12

enzymes are secreted by various organs to catalyse, or speed up the breakdown of organic molecules into smaller units. occurs in the mouth, stomach and small intestine.

Question 13

Mouth

Answer 13

salivary glands secrete amylase ( a carbohydrate) which breaks starch down into sugar molecules.

mucus helps saliva slid down the gullet.

Question 14

swallowing

Answer 14

the chewed up food is called a bolus.

it is swallowed and moved down the esophagus

smooth muscles contract behind the bolus to prevent it form begin squeezed into the mouth.

rhythmic waves of contraction work to propel the food into the stomach. called peristalsis

Question 15

Stomach

Answer 15

the bolus enters the stomach from the esophagus and exits into the small intestine through the valve called the pyloric sphincter

gastric enzymes are secreted. pepsin is a gastric enzyme that breaks proteins down into smaller peptide units.

Question 16

Stomach (mechanical)

Answer 16

the stomach contain three layers of muscle that churn the food

Question 17

small intestine

Answer 17

• pancreatic enzymes- secreted in the pancreas
• bile- produced in the liver and stored and secreted via the gall bladder
• glands in the wall produce various enzymes to break small peptides into amino acids.

Question 18

chemical digestion (enzymes form pancrease)

Answer 18

macromolecules are broken down into smaller subunits.

• peptides into amino acids using proteases
• carbohydrates into simple sugars using amylases

-fats into fatty acids using lipases

• and large DNA and RNA molecules using nucleases

Question 19

absorption- Intestine

Answer 19

after food is broken down into molecules it can be absorbed into the bloodstream.
occurs in the small intestine
small intestine covered in villi and they are covered in microvilli that create a greater surface area to volume ratio.

Question 20

large intestine

Answer 20

water is absorbed and the waste products are secreted as a faeces though the anus.