Digestion and parasitism Flashcards

1
Q

what enzyme breaks down triglycerides

A

lipase

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2
Q

what does lipase break down triglycerides into

A

glycerol and 3 fatty acids

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3
Q

enzyme that breaks down starch

A

amylase

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4
Q

the enzyme that breaks down sucrose

A

sucrase

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5
Q

enzymes that break down dipeptides into amino acids

A

dipeptidase

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6
Q

enzymes that break down polypeptides into dipeptides

A

proteases

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7
Q

endopeptidase

A

they cut in the middle of a polypeptide

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8
Q

exopeptidases

A

they cut at the terminal ends of the polypeptide

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9
Q

describe digestion in the buccal cavity

A

the food is broken down into small pieces in the mouth by the chewing action of the teeth (mastication)
it is then moistened by saliva

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10
Q

what does saliva consist of

A

water
mineral salts
lysozyme
salivary amylase
mucus

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11
Q

functions of mucus in digestion

A

acts as a lubricant

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12
Q

functions of lysozyme in digestion

A

it kills bacteria that may be present in the food

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13
Q

functions of mineral salts in saliva

A

they maintain the slightly alkali conditions

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14
Q

functions of salivary amylase

A

Hydrolyses starch to maltose

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15
Q

after digestion in the buccal cavity, what term is given to the food

A

bolus

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16
Q

peristalsis

A

a series of rhythmic contractions that move the bolus to the stomach

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17
Q

describe the series of muscle activities that occur during peristalsis to propel the bolus along the gut

A

the circular muscles behind the food contract and the longitudinal muscles relax

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18
Q

the name of the ridges on the stomach and their functions

A

rugae
they help with the mechanical breakdown of the food (churning)

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19
Q

how many layers of thick muscle does the stomach have, name them and is their collective function

A

three
longitudinal muscle
circular muscle
oblique muscle layer
they allow the stomach to contract and relax to grind the bolus

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20
Q

the function of the cardiac sphincter

A

it relaxes at the upper end of the stomach, allowing food to enter the stomach

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21
Q

the function of the pyloric sphincter

A

relaxes to allow food to exit the stomach into the duodenum

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22
Q

can the stomach stretch

A

yes

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23
Q

functions of the mucus released from goblet cells of the stomach

A

it protects the stomach wall from enzymes and acid

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24
Q

name three substances that the stomach absorbs

A

water
salts
alcohol
aspirin

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25
Q

which part of the stomach secretes gastric juice

A

it is secreted by glands in the mucosa of the stomach wall

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26
Q

which cells release HCl acid in the stomach
what are the functions of the HCl released

A

oxyntic cells
it kills most bacteria in the food swallowed
provides optimum ph for enzymes in the stomach
it activates pepsinogen

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27
Q

average ph of the stomach

A

1-2

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28
Q

the enzyme found in the gastric juice

A

pepsin

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29
Q

which cells release pepsin

A

chief cells

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30
Q

pepsin is released as inactive……… by chief cells

A

pepsinogen

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31
Q

which organ produces bile
where is bile stored

A

the liver
in the gall bladder

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32
Q

functions of bile

A

emulsifies lipids into small droplets(this increases the surface area, which in turn increases the rate of digestion)

aids in neutralizing the stomach acid as it enters the duodenum with food from the stomach

33
Q

which type of glands in the pancreas secretes pancreatic juice

A

exocrine gland

34
Q

the function of amylase and lipase

A

amylase hydrolyses starch into maltose

hydrolyses lipids into fatty acids and glycerol

35
Q

is the duodenum alkaline or acidic

A

alkaline

36
Q

Functions of the Brunner’s gland in the submucosa of the duodenum

A

it secretes mucus for lubrication and protection of the intestinal walls

it secretes alkaline juices which help to maintain the optimum ph for the functioning of the enzymes in this area

37
Q

in which part of the duodenum is the carbohydrate and protein digestion completed

A

in the membrane of the epithelial cells of the mucosa

38
Q

name two enzymes found in the duodenum and their functions

A

maltase: hydrolyses maltose into two glucose molecules
dipeptidases: hydrolyses dipeptides into amino acids

39
Q

pepsin

A

an endopeptidase secreted by gastric glands in the stomach as inactive pepsinogen

40
Q

trypsin

A

an endopeptidase secreted by the pancreas as inactive trypsinogen.

41
Q

trypsin is activated by

A

enterokinase

42
Q

name five things that the pancreas is composed of

A

sodium hydrogen carbonate
endopeptidases
exopeptidases
amylase
lipase

43
Q

the function of the sodium hydrogen carbonate in the pancreas

A

raises the pH to alkaline levels, thereby neutralizing stomach acid. this provides optimum conditions for pancreatic enzymes

44
Q

describe the process of chemical digestion of lipids

A

bile is added to lipids via the bile duct to emulsify the lipids into small droplets

the emulsified lipids get hydrolyzed by lipase from the pancreas, to form fatty acids and glycerol

45
Q

adaptations of the ileum for absorption

A

the lining of the ileum is folded to increase the surface area for absorption

the surface of the villi found on the surface of the ileum is made of specialized epithelial cells with projections called microvilli. these also help to increase the surface area for absorption

epithelial cells of villi are made of many mitochondria that aid active transport of substances

46
Q

describe the process of absorption of water-soluble vitamins

A

they pass through the epithelial membrane via facilitated diffusion through transport proteins and dissolve in the plasma

47
Q

describe the process of absorption of fatty acids and glycerol in the ileum

A

they diffuse into the SER in the epithelial cells via the epithelial membranes.

they then recombine into triglycerides and are packaged into vesicles along with cholesterols and phospholipids

the triglycerides enter the lacteals, which are the center of the villus

they are then transported to the subclavian vein through the lymphatic system
they enter the blood system at the thoracic duct.

48
Q

during absorption in the ileum, glucose, and amino acids are transported via the ………………… ……………………….vein to the ……………………………

A

hepatic portal
liver

49
Q

how are glucose and other monosaccharides absorbed in the ileum

A

they are absorbed into the epithelial cells by co-transport with sodium ions and then into the capillaries by facilitated diffusion.
Sodium ions are actively pumped out of the epithelial cells into the capillaries during this process.

50
Q

adaptions of the ileum to aid absorption

A

they have epithelial cells with microvilli to increase the surface area of the ileum for the absorption of molecules

they have goblet cells to secrete mucus

51
Q

after deamination, what happens to the remaining C H and O

A

they are converted to carbohydrates
they are also used in respiration

52
Q

what happens to the fatty acids(lipids) absorbed during absorption

A

they are used to produce phospholipids in cell membranes, to synthesize hormones

excess lipids are stored as fat

53
Q

the function of the glucose absorbed by the ileum

A

used in aerobic respiration

excess glucose is converted to glycogen or fat and stored in the liver

54
Q

the large intestines are divided into four main sections, name them

A

caecum
appendix
colon
rectum

55
Q

the function of the colon

A

absorption of the remaining water and mineral salts

the absorb vitamins like folic acid, secreted by microorganisms living in the colon

56
Q

why do carnivores have a short gut

A

because they feed on meat, which is high in proteins. and proteins are easily digested

57
Q

the dentition of a dog is designed for …………………. the prey, …………………….. and ……………….. meat off the bones and …………………… bones

A

gripping
cutting and tearing
crushing

58
Q

types of teeth in carnivores, their shape(structure) and their functions

A

incisors: they are small and shaped like chisels and are sharp. they are used to snip meat off bones and to cut lumps of meat up

canines: they are very long and sharp. they are used to impale and grip the prey, and to tear meat.

carnassial teeth: when the dog is eating, they fit together like a pair of scissors, sniping meat off the bone and also crushing bones

premolars and molars: they have strongly pointed cusps for cutting and tearing meat

59
Q

the carnassial teeth

A

the last upper premolar and the first lower molar

60
Q

types of teeth in carnivores, their shapes (structure), and function

A

incisors: they are small but are shaped like chisels and sharp. they are used to snip meat off bones and to cut lumps of meat up

canines: they are very long and sharp. they are used to impale and grip the prey to tear the meat

carnassial teeth: they fit together like a pair of scissors, snipping meat off bones and also crushing bones.

molars and premolars: they have strongly pointed cusps for cutting and tearing meat

61
Q

what is the dentition of herbivores designed for

A

for cutting off the grass from the plant when grazing
grinding the grass efficiently to smash the cellulose cell walls
thus releasing the digestible plant cell contents

62
Q

diastema

A

a space between the horny pad and the upper premolars

63
Q

function of the incisors in herbivores

A

they bite against the horny pad on the upper jaw. This enables the vegetation to be snipped off the plants during feeding

64
Q

the function of the diastema, and the advantage it grants the herbivore

A

it is filled with extra grass during feeding so that they can stop feeding until the grass is chewed and swallowed

this enables the herbivore to look around frequently to watch for predators

65
Q

is the diastema found in carnivores

A

no
it is a characteristic of herbivores

66
Q

how is the circular grinding motion of herbivores obtained, and what is the importance of this

A

through the horizontal movement of the lower jaws during chewing

this effectively breaks open the cellulose walls of plant cells

67
Q

the teeth of herbivores can grow throughout their lifespan, why is this

A

because the root cavities of their premolars and molars remain open throughout their lives. this means a good blood supply is maintained to the teeth, and it can therefore grow throughout their lives

68
Q

structure and function of the premolars and molars of herbivores

A

they are strengthened with ridges of cement which help to prevent the edges of the teeth from being chipped away by abrasive food

69
Q

why are herbivore guts longer than carnivore guts

A

because the cellulose cells walls in the food of herbivores need more time and enzyme action to be broken down

more space is required to accommodate bulkier plant material

70
Q

name an organism with a monogastric digestive system

A

humans

71
Q

name three animals with the ruminant digestive system

A

cow
sheep
goat

72
Q

the stomachs of sheep and cows are divided into ………….. chambers

name the chambers

A

4

rumen
reticulum
omasum
abomasum

73
Q

how do mammals break down cellulose cells walls in their food

A

they have cellulase-secreting bacteria that break down cellulose in plant cell walls

74
Q

do mammals contain cellulases

A

nope

75
Q

products of fermentation and their functions

A

beta glucose and large quantities of fatty acids

they form a major energy source for the animal

76
Q

describe the process of digestion in ruminants

A

mutualistic bacteria are mainly found in the rumen and reticulum. after chewing, the food is passed into the rumen

from the rumen, the food passes into the smaller reticulum. the food is then regurgitated from the reticulum into the buccal cavity for chewing of the cud

when the food is re-swallowed, it is channeled into the omasum

in the omasum, the food is churned about. It is then passed to the abomasum which produces the typical acid and secretions of all mammalian stomachs

any bacteria that enter the abomasum are killed by acid secretions and digested.

the food then goes into the intestines where the products of digestion can be absorbed

77
Q

which chamber of the stomach is known as the true stomach

A

the abomasum

78
Q

why is food churned in the omasum

A

to allow for further bacterial fermentation