Unit 1 - AOS2 - Digestive system

Question 1

3 points that make a mammal

Answer 1

• Give birth to live young
• Have the ability to produce milk to feed to young
• have hair or fur

Question 2

Autotroph

Answer 2

Create their own energy through photosynthesis or chemosynthesis (plants at the bottom of the ocean)

Question 3

Heterotroph

Answer 3

Cannot create their own energy,
- Therefore, get their energy through consuming other autotrophs or heterotrophs

Question 4

Herbivore

Answer 4

Eat plants
- Therefore eat a lot of cellulose (carbohydrate that forms plant cell walls)
- e.g. horse

Question 5

Carnivore

Answer 5

Eat meat
- gut produces enzymes to break down protein (protease)
- e.g. dog

Question 6

Omnivore

Answer 6

Eat both plants and animals
- Share features from herbivores and carnivores
- e.g. humans

Question 7

Carbohydrates

Answer 7

• Is broken down to glucose and stored as polysaccharide and glycogen in liver and muscles of animals
• Glucose breaks down to produce ATP during cellular respiration

Question 8

Fats

Answer 8

• required for cell membrane, hormones and vitamin
• excess fat is stored under the skin tissue and surrounding organs

Question 9

Protein

Answer 9

• Required for protein synthesis
• Stored as amino acids

Question 10

essential amino acids

Answer 10

the 9 amino acids that humans cannot make
- Found in milk, effs and meat and cannot be stored.

Question 11

Vitamins

Answer 11

• Organic (made from carbon and/or hydrogen and oxygen)
• required to make particular enzymes

Question 12

Minerals

Answer 12

• inorganic
• Obtained through diet (calcium, potassium, iron, magnesium, sodium)

Question 13

Chemical digestion

Answer 13

uses enzymes which break down complex compounds into simple compounds

Question 14

the 3 main kinds of digestive enzymes

Answer 14

Amylase:
- Act on carbohydrates (e.g. starch -> glucose)

Protease:
- Act on proteins

Lipase:
- Act on lipids

Question 15

4 main roles of the digestive system

Answer 15

1. Ingestion - eating or drinking nutrients
2. Digestion - food is broken up mechanically or chemically.
3. Absorption - taking up digested molecules into the internal environment of the cells in the digestive tract.
4. Egestion - the removal of wastes from the body

Question 16

Chemical digestion

Answer 16

food is broken through the actions of enzymes and is converted into a substance suitable for absorption.

Question 17

what are secretory epithelial cells & name them

Answer 17

• these cells are distributed through the digestive system depending on their function
• A combination of these cells makes up the tissues found within our digestive system
• Mucous cells
• G cells
• Parietal cells
• Chief cells
• Goblet cells

Question 18

Mucous cells

Answer 18

secrete and alkaline mucus that protects the epithelium against shear stress and acid.

Question 19

G cells

Answer 19

secrete gastrin which stimulates acid secretion

Question 20

Parietal cells

Answer 20

secrete hydrochloric acid

Question 21

Chief cells

Answer 21

secrete protease’s (enzymes that break down protein)

Question 22

Goblet cells

Answer 22

secrete a mucous that protects the stomach lining from the acid

Question 23

Name the layers of the tissues in the intestinal wall

Answer 23

1. Muscular layer - Outer layer (longitudinal layer)
   - Inner layer (circular layer)
2. Submucosa
3. Mucosa - muscularis mucosa
   - Lamina propria
   - Epithelium
4. Villi (small intestine)
5. Microvilli (small intestine)

Question 24

Mucosa

Answer 24

Inner most layer of the muscle wall (intestinal wall)
- Epithelium
- Lamina propria (underlying loose connective tissue layer)
- Muscularis mucosa (thin layer of smooth muscle)

Question 25

Submucosa

Answer 25

Is the thick layer of loose connective tissue that surrounds the mucosa - Contains blood vessels, lymphatic vessels and nerves.

Question 26

Muscularis externa

Answer 26

- smooth muscles responsible for movements of the digestive tract. - Inner and outer layer

Question 27

Villi

Answer 27

Tiny, finger-like projections that protrude from the epithelial lining of the intestinal wall. - create a large SA:V ratio - Contains Micro villi (tiny hair-like structures)

Question 28

Function of the digestive system

Answer 28

responsible for the digestion of food and the absorption of nutrients.

Question 29

Length of the digestive system

Answer 29

~30 feet (9m)

Question 30

the 3 things the mouth contains that help with digestive

Answer 30

**1. Salivary glands** - produces water, mucus, and amylase - 3 major glands (sublingual, submandibular, parotid) **2. Teeth** - Form of mechanical digestion - Food is broken down into smaller pieces and mixed with saliva Incisors: used for cutting and cropping Canines: Used to hold and tear food Premolars and molars: used for grinding and chewing **3. Tongue** - Pushes the food to the teeth and to the back of the throat

Question 31

Type of teeth Herbivores have

Answer 31

- Incisors to cur food (these are often only on the lower haw) - Large ridged molars to grind food

Question 32

Type of teeth carnivores have

Answer 32

- Small incisors - Large and sharp canines to tear meat off bones

Question 33

Type of teeth omnivores have

Answer 33

- Molars that roll and crush a variety of foods

Question 34

Bolus

Answer 34

lump/ball of food

Question 35

Esophagus

Answer 35

Muscular tube that connects the pharynx to the stomach

Question 36

Peristalsis

Answer 36

Muscles contractions that occur in the esophagus, that moves the bolus into the stomach

Question 37

Stomach

Answer 37

Organ that releases acids and enzymes to digest your food - Completes both mechanical and chemical digestion - muscles twist and churn to mix food with acids and enzymes (mechanical digestion) - Hydrochloric acid (HCI) and pepsin break down the food

Question 38

coats the lining of the stomach to prevent acids and enzymes from self-digestion

Answer 38

Mucus

Question 39

Chyme

Answer 39

soupy fluid of partially digested food that exits the stomach into the small intestine

Question 40

Small intestine

Answer 40

location where nutrients are absorbed into the blood stream - Duodenum - Jejunum - Ileum

Question 41

Duodenum

Answer 41

- Acid in chyme is neutralized by bicarbonate - Gall bladder (mixes bile with the chyme to aid breakdown of fats) and pancreas (mixes various enzymes to breakdown lipids, proteins, carbs and nucleic acids.

Question 42

Jejunum

Answer 42

Location here most nutrients are absorbed into the blood streams - Villi and Microvilli

Question 43

Ileum

Answer 43

Absorbs various vitamins and remaining nutrients from the chyme

Question 44

Large intestine structure and function

Answer 44

**Structure** 1. Ascending colon 2. Transverse colon 3. Descending colon 4. Rectum 5. Anus **Function** - Extracts moisture from the chyme prior to removal from the body (diarrhea and constipation) - Home to helpful bacteria - Rectum: stores feces until elimination - Anus: ring of muscles

Question 45

Accessory organs definition

Answer 45

An organ that helps with digestion but is not part of the digestive tract

Question 46

Pancreas

Answer 46

- Releases bicarbonate to neutralize the acid from the stomach - Releases enzymes to further brake down peptides into amino acids and carbs into smaller sugars

Question 47

Liver

Answer 47

- Processes the nutrients absorbed from the small intestine - Also detoxifies potentially harmful chemicals - Storage of excess carbs from glycogen

Question 48

Gall bladder

Answer 48

- releases bile into small intestine - Bile breaks down large fat droplets into smaller droplets (mechanical digestion --> emulsification) - Along side this using chemical digestion enzymes break down fat droplets into glycerol and fatty acids - Aids in neutralising stomach acids