Chapter 48-The Digestive System Flashcards Preview

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Flashcards in Chapter 48-The Digestive System Deck (40):
1

4 phases of animal nutrition

1. Ingestion
2. Digestion-break down large molecules into smaller monomers
3. Absorption-absorb monomers, water, salts form digestive tract into body
4. Elimination-of undigested material

2

Types of digestive systems

Intracellular-single celled organisms
Extracellular-within digestive cavity
-Gastrovascular cavity-cnidarians and flatworms, only one opening

3

who has the most primitive complete digestive tract

-nematodes

4

Order of general digestive characteristics

ingested food=stored or physical fragmentation
-chemical digestion next
-products pass through guts epithelial linging into the blood
-wastes excreted from anus

5

Chemical digestion

digestion by a specific enzyme that cleaves a sspecific bond

6

Physical Digestion

any digestion that does not involve specific enzymes

7

Tubular tract of vertebrates consists of

-mouth and pharynx-ingestion
-esophagus-delivers food to stomach
-stomach-preliminary digestion
-small intestine-digestion and absorption
-large intestine-absorption of water and minerals
-cloaca or rectum-elimination

8

Layers of gastrointestinal tract

-mucosa-innermost surface (lined with epithelium)
-submucosa-connective tissue
-muscularis-circular and longitudinal smooth muscle layers
-serosa-outermost

9

Birds have what to break up food

two chambered stomach
-gizzard-muscular chamber that uses ingested pebbles to pulverize food

10

Carnivores have what type of teeth

pointed teeth that lack flat grinding surfaces

11

Herbivores have what type of teeth

large flat teeth suited for grinding cellulose walls

12

Humans have what type of teeth

carnivore teeth up front and herbivore teeth in the back

13

what is salivation controlled by

nervous system

14

Epiglottis

closes off the respiratory tract, blocks off larynx

15

Bolus

food from mouth ready to be swallowed

16

peristalsis

rhythmic one direction waves on contraction that push the bolus through the esophagus to the stomach

17

3 types of secretory cells in stomach

mucus-secreting cells-mucus protects stomach lining
-parietal cells-secrete HCL and intrinsic factor, makes stomach pH about 2
-chief cells-secrete pepsinogen which is converted to pepsin within stomach by HCL activity

18

what type of digestion does stomach do

physical-low pH helps denature food proteins
-absorption of some water

19

Chyme

mixture of partially digested food and gastric juice in stoach

20

small intestine

very long
-digests chyme from stomach
-digestive enzymes and bicarbonate from pancreas secreted into here with bile form liver and galbladder

21

small intestine consists of?

Duodenum-first section, most digestive enzymes enter, much digestion
-Jejunum-digestion in first part, absorption elsewhere
-Ileum-some absorption, form feces, many bactery

22

epithelial wall of small intestine?

covered with villi, which are covered with microvilli

23

Pancreas

exocrine and endocrine gland
-Exocrine function-pancreatic fluid with enzymes is secreted into the duodenum through pancreatic duct

24

Pancreatic enzymes

trypsin and chymotrypsin-proteins into smaller polypeptides
-pancreateic amylase-polysaccharides into shorter sugars
-Lipase-fats into free fatty acids and monoglycerides
-bicarbonate neutralizes acidic chyme

25

Liver

bodys largest internal organ
-secretes bile-involved with physical digestion of lipids

26

Gallbladder

stores and concentrates bile from liver

27

Absorption in small intestine

Jejunum
-amino acids and monosaccharides are transported through epithelial cells to blood
-fatty acids and monoglycerides diffuse into epithelial cells

28

Large intestine

Much shorter than small intestine
-no digestion
-reabsorbs water, remaining electrolytes, vitamin k

29

Feces composition

-60-75% water
-40-25% undigested material, salts, bacteria

30

Ruminants

Four chambered stomach
-cellulose degrading microbes

31

Rumination

Contents of stomach are regurgitated and chewed

32

What regulates gastrointestinal activiteis

nervous and endocrine systems

33

What does the nervous system do for digestion

stimulates salivary and gastric secretions in response to sight, smellm and consumption of food

34

Liver

chemically modifies the substance absorbed from the digestive tract before they reach the rest of the body
--ex. alcohol

35

Insulin

Liver regulated
-stimulates removal of excess blood glucose by liver and skeletal muscles (converted and stored as glycogen)

36

Glycogenolysis

glucagon stimulates liver to break down glycogen to release glucose into blood

37

Gluconeogenesis

liver converts other molecules into glucose if fasting continues

38

Basal Metabolic Rate

Minimal amount of energy consumed under defined resting conditions

39

Leptin

peptide hormone
-key to appetite control
-produced by adipose tissue in response to eating, receptor located in hypothalamus

40

Essential nutrients

animals are unable to manufacture these for themselves
-vitamins (vitamin c)
-amino acids-9 required
-long chain unsaturated fatty acids
-minerals