Functions of the Gastrointestinal Systems of animals (MOUTH + STOMACH)

Question 1

What is digestion?

Answer 1

breakdown of large insoluble food compounds into smaller water-soluble components so that they can be absorbed into the blood plasma.

Question 2

What are the two types of digestion?

Answer 2

mechanical digestion
chemical digestion

Question 3

What is the process called in mammals where food is chewed?

Answer 3

mastication

Question 4

What is mechanical digestion?

Answer 4

• in mouth
• food is physically broken down

Question 5

What is chemical digestion?

Answer 5

• gastrointestinal tract
• digestive enzymes

Question 6

What is defecation?

Answer 6

release of feces through the anus.

Question 7

What does the digestive systems of animals depend on?

Answer 7

• diet
• habitat
• other physiological characteristics

Answer 8

• more complex in omnivores
• most complex in herbivores

Question 9

How is the digestion process controlled?

Answer 9

• autonomic nervous system
• hormonal control
• reflex mechanism

Question 10

What types of nerves stimulate digestion?

Answer 10

parasympathetic nerves

Question 11

What types of nerves inhibit digestion?

Answer 11

sympathetic nerves

Question 12

What is the function of short reflexes?

Answer 12

• provide digestive tract with extensive self control
• stimulatory effects on the digestive processes
• inhibitory short reflexes are important for relaxation of GI sphincters

Question 13

What is the function of long reflexes?

Answer 13

• originate within and outside the digestive tract
• involve long neural pathways between the central nervous system in the walls of the digestive tract.

Question 14

What is the secretion of saliva regulated by?

Answer 14

autonomic nervous system

Question 15

Explain the regulation of hunger.

Question 16

What is the hunger center regulated by?

Answer 16

“hungry blood”- low in glucose, amino acids, etc.
empty stomach which irrigates gastric mucosa mechanocereptors

Question 17

What is injection?

Answer 17

entry of food in the digestive system

Question 18

mechanical and chemical digestion

Answer 18

mastication and mixing

Question 19

absorbtion

Answer 19

nutrients are absorbed from the digestive system into the circulatory and lymphatic system

Question 20

excretion

Answer 20

removal of undigested materials from the digestive tract through defecation

Question 21

What are the functions of the digestive system?

Answer 21

• feed intake and mechaical crushing
• secretory
• motility
• breakdown of nutrients (hydrolysis)
• resporption
• exretion
• protection
• endocrinic
• analytical

Question 22

What is peristasis?

Answer 22

wavelike motion

Question 23

mixing

Answer 23

mixing motion
- oral cavity and stomach
- mechanical digestion

Question 24

segmentation

Answer 24

• small intestine contractiona nd relaxing

Question 25

What are the two parts of the digestive system?

Answer 25

- gastrointestinal tract - accessory organs

Question 26

the oral cavity

Answer 26

- mechanical processing (teeth, tongue, palatal surfaces) - lubrication - initiation of swallowing reflex

Question 27

What is prehension?

Answer 27

- bringing food to the mouth - mechanisms vary with behaviour and diet

Question 28

What is mastication? What is it completed by? What muscle? What does it lead to?

Answer 28

- teeth, jaw, tongue, teeth - striated muscle - controlled voluntary - reduces size of particles (chewing) + moistenes (mixing with saliva)

Question 29

Explain salivary secretion. What is it secreted by? State the three types.

Answer 29

- saliva - salivary glands - 3 glands: parotid, mandibular, sublingual glands

Question 30

What does the type of saliva depend on?

Answer 30

- quantity and composition of saliva varies between species (food consistency)

Question 31

What are the functions of saliva?

Answer 31

- lubrication - antibacterial effect - enzymatic digestion - pH regulation - binding of tannins - providing urea for protein synthesis in the forestomachs - thermoregulation

Question 32

How are saliva secretions regulated?

Answer 32

- neural control (via sympathetic and parasympathetic nervous systems) - parasympathetic --> increase saliva secretions (Watery consistency) - sympathetic --> small volume of highly viscous saliva

Question 33

What does sympathetic stimulation result in?

Answer 33

- decreased production of saliva by acinar cells - increased protein secretion - decreased blood flow to glands

Question 34

What does parasympathetic stimulation result in?

Answer 34

- acinar cells increase the secretion of saliva - duct cells increase HCO3- secretion - co-transmitters result in increased blood flow to the salivary glands - contraction of myoepithelium to increase the rate of expulsion of saliva

Question 35

swallowing

Answer 35

- voluntary action -

Question 36

What is the function of the pharynx?

Answer 36

Seperate the respiratory and digestive systems.

Question 37

What is the esophagus?

Answer 37

- small muscle lines tube - muscle cells --> spincters - peristalsis (wave like contractions)

Question 38

Explain the physiology of the stomach.

Answer 38

monogastric stomach: cats and dogs - temporary food store - digestion of food -

Question 39

chyme

Answer 39

mixture of feed and digestive secretions

Question 40

glandular stomach

Answer 40

- cardiac - fundic - body - pyloric

Question 41

types of cells is the stomach

Answer 41

- chief cells: secrete pepsinogen - parietal cells: secrete HCL and intrinsic factor (glycoprotein) (helps vit B12 absorption) - mucin-rpoducing cells: secrete mucous and alkaline substances - endocrine cells: gastrin (stimulated parietal cells), ECL cells (histamine - reduces production of HCL)

Question 42

function of HCL

Answer 42

- lowers stomach ph - PEPSINOGEN --> PEPSIN - acidifies stomahc content - degrades conective tissue and muscle tissue - denaturation - kills microorganisms

Question 43

digestion enzymes

Answer 43

- amylase- carbohydrate digestion (resulting in disaccharides) - pepsin- protein digestion (results in peptides) - lipase- lipid digestion (results in fatty acids)

Question 44

what are the phases

Answer 44

- cephalic - gastric - intestinal phase

Question 45

cephalic phase

Answer 45

- sight, smell and taste food -> stimulate food digestion

Question 46

gastric phase

Answer 46

- distention of stomach (stretch-receptors) - chemoreceptors

Question 47

intestinal phase

Answer 47

- release of hormones - inhibit gastric function - (sensory stetch receptors are stimulated)

Question 48

rabit stomach

Answer 48

- always full - monogastric - no vomiting

Question 49

avian stomach

Answer 49

- crop: moistened - proventriculus: mixed with mucous and digestive juices - gizzard: mashed and ground (mascular walls and gravel)