I Cards (Digestive System) | Unit C

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mouth

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Tags and Description

Biology

12th

GI Tract Parts (definitions + functions), Important Enzymes

99 Terms

1

mouth

aka oral cavity, contains tongue, teeth, hard and soft palate, uvula, and salivary glands. opens to throat

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2

teeth

masticates food via cutting, tearing, and grinding. 32 permanent ones.

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3

salivary glands

produces saliva via ducts (exocrine system) to moisten food. contains salivary amylase (ptyalin), bicarbonate ions (HCO3-), and mucins

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4

parotid gland

salivary gland, found near front of the ears

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5

submandibular gland

salivary gland, found deep in floor of mouth

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6

sublingual gland

salivary gland, found beneath the tongue

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7

salivary amylase/ptyalin

hydrolyzes starch into maltose. produced by salivary glands

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8

bicarbonate ions (HCO3-) for salivary glands

buffer, keeps pH between 6.5-7.5. produced by salivary glands

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9

mucins in mouth

lubricates bolus. produced by salivary glands

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10

bolus

soft ball of food, composed of food and saliva

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11

tongue

contains receptors for taste, composes a bolus for swallowing

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12

skeletal muscles

muscles you can control and contract quickly, performs wide range of movements and function

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13

soft palate

posterior of roof of mouth. closes nasopharynx to prevent food from entering nasal cavity, uvula hangs from here

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14

hard palate

anterior of roof of mouth, bony + hard

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15

nasopharynx

upper part of pharynx (throat) behind nose, connects nasal passages to rest of respiratory system

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16

uvula

when hit by bolus, triggers swallowing reflex

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17

pharynx (throat)

funnel-shaped pathway, leads to esophagus (into stomach) and trachea (to lungs)

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18

swallowing reflex

food → bolus → tongue + hard palate moves → pharynx → soft palate closes → epiglottis flips down → esophagus and peristalsis → cardiac sphincter relaxes and tightens

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19

epiglottis

flap which covers glottis. prevents food from entering lungs

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20

glottis

trachea opening

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21

trachea

airway that leads to lungs

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22

esophagus

muscle tube, dorsal to trachea, unflattens and squeezes rhythmically to pass bolus to stomach via peristalsis

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23

peristalsis

involuntary, triggered contraction and relaxation of muscles, forming a wave down a tube

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24

cardiac sphincter

close to heart, relaxes to allow bolus into stomach and tightens to prevent contents from coming back up

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25

sphincter

ring of muscle

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26

pyloric sphincter

relaxes to allow small amount of chyme to enter small intestine

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27

stomach

thick, muscular j-shaped sac responsible with storing food for up to 4 hours, secreting substances to dissolve and degrade food, and controlling rate of food entering small intestine

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28

rugae

folded inner surface of stomach, allows expansion for food. composed of columnar epithelium

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29

columnar epitheleium

column-shaped cells, covers end of esophagus to beginning of rectum

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30

gastric pits

divisions of columnar epithelium, leads to gastric glands

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31

gastric glands

produces gastric juice, composed of g-cells, chief cells, mucous cells, and parietal cells

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32

g-cells

secretes gastrin

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33

gastrin

stimulates secretion of gastric acid/HCl

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34

gastric acid/HCl

degrades food, kills food-borne bacteria, activates pepsinogen to pepsin

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35

chief cells

secretes pepsinogen

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36

pepsinogen

inactive enzyme, becomes pepsin when exposed to gastric acid/HCl

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37

pepsin

hydrolyzes proteins into smaller chunks at tyrosine and phenylalanine

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38

mucous neck cell

secretes mucin-containing mucus

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39

mucins in stomach

buffer for gastric acid/HCl, prevents stomach wall from digesting itself (no ulcers!)

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40

parietal cell

secretes gastric acid/HCl. → actives pepsinogen

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41

gastric juice

produced by gastric glands, 2L per day. contains water, mucus, HCl, and pepsin

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42

does not require digestion

vitamins, minerals (elements), water, and cellulose

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43

chyme

thick green semiliquid composed of semi-digested food and gastric juices

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44

pancreas

contains exocrine and endocrine cells

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45

pancreas exocrine cells

secretes pancreatic juices into pancreatic duct into duodenum

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46

pancreas endocrine cells

produces hormones like insulin and glucagon into blood

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47

pancreatic juice contains

P ancreatic Juice

L ipase

A mylase

N uclease

T rypsin

S odium Bicarbonate

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48

bicarbonate ions (HCO3-) for pancreatic juice

buffer, neutralizes acidic chyme to keep pH of duodenum 8-9

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49

pancreatic amylase

digests starch

starch + H2O → (amylase, hydrolysis) → maltose

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50

trypsin

active form of trypsinogen, digests proteins

proteins + H2O → (trypsin) → peptides

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51

lipase

catalyzes breakdown of lipids into fatty acids and glycerol molecules

fat droplets + H2O → (lipase) → glycerol and 3 fatty acids

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52

bile salts

works with lipase to emulsify lipids

lipids + H2O → (bile salts) → fat droplets

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53

pancreatic nuclease

acts in small intestine, degrades nucleic acids into nucleotides

nucleic acid + H2O → (pancreatic nuclease) → nucleotides

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54

pancreatic islets/islets of Langerhans

composes endocrine section of pancreas. secretes insulin and glucagon (hormones)

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55

insulin

released after eating, when blood glucose level is high. decreases concentration of glucose in blood via cell stimulation to take up and metabolize glucose

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56

glycogen

polysaccharide. the stored version of monosaccharides, liver and muscles stimulated by insulin to promotes fat buildup, inhibiting their use as energy source

“bank for a rainy day”

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57

glucagon

stimulates breakdown of glycogen into glucose for release into blood

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58

what is the body sugar level based on?

the opposing action of insulin (storing of monosaccharides) and glucagon (breaking apart of glycogen)

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59

diabetes mellitus/type 1 (early onset) diabetes

insulin deficiency, treated with insulin injections

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60

type 2 (maturity onset) diabetes

pancreas makes enough insulin, but body cells don’t respond due to receptor protein problem. treated with weight loss, exercise, medication (Glucophage or Metformin), and/or insulin

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61

pancreatic ‘burnout’

can be triggered by obesity

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62

small intestine

receives Chyme (stomach), Bile (liver), and Pancreatic secretions (pancreas). mechanically breaks down chyme, absorbs nutrients, and transports waste to large intestine. its epithelial cells packed with mitochondria

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63

duodenum

small intestine start. bile and pancreatic juices are secreted into here.

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64

jejunum

small intestine middle. secretes digestive enzymes

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65

ileum

small intestine longest and final section. joins cecum to ileocecal valve.

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66

cecum

‘pouch’ that forms start of large intestine/colon.

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67

ileocecal valve

sphincter, at junction of ileum and colon. allows waste to enter colon.

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68

mucosa

moist inner lining of some organs and body cavities

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69

villi

finger-like projections in the small intestine mucosa. greatly increases absorption surface area. contains capillary network and lymph vessel/lacteal

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70

capillary networks

found in villi. absorbs vitamins (A, C) and minerals (Na, Ca) from waste

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71

lymph vessel/lacteal

found in villi. absorbs fat and fat-soluble vitamins taken from waste

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72

absorption

occurs when food molecules brush through microvilli/brush border. passage of nutrient molecules from GI tract into bloodstream via mesenteric veins

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73

microvilli/brush border

micro projections on villi surface, greatly increases absorption and secretion surface area,

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74

mesenteric vein

drains blood from the large intestine, carries nutrient molecules

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75

vitamins (A, C) and minerals (Na, Ca) and GI tract

moves through unaltered, absorbed through mucosa into capillaries

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76

intestinal juice

I ntestinal nuclease

M altases

P eptidases

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77

peptidases

completes protein digestion

peptide + H2O → (peptidases) → amino acids

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78

maltases

completes maltose digestion

maltose + H2O → (maltase) glucose + glucose

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79

intestinal nuclease

completes nucleic acid digestion

nucleotides + H2O → (nuclease) → nitrogenous base + monosaccharide + phosphate group

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80

amino acids (protein), monosaccharides (carbs), and nucleotides (nucleic acids)

facilitated/active transport into epithelial cells of small intestine. diffuses into blood capillaries in villi

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81

triglycerides (lipids)

diffuses across lipid bilayer into villi since fat-soluble. glycerol and fatty acids → epithelial cell ER → triglyceride → chylomicron → lacteals

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82

chylomicron

rich in triglycerides. enters villi lacteal

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83

gastrin

gastrointestinal hormone. stimulated by chyme, increases stomach mobility and gastric juices in stomach

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84

secretin

gastrointestinal hormone. stimulated by HCl, increases pancreatic juices and stomach mobility, reduces gastric juices. produced and used by duodenum

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85

Cholecystokinin (CCK)

gastrointestinal hormone. stimulated by proteins and lipids. produced by duodenum, stimulates gall bladder to release bile

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86

hepatic portal vein (organ→vein→organ)

receives blood from venules from villi of small intestine, transports to liver

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87

liver

consists of 2 lobes, receives blood from small intestine

detoxifies/destroys

  • poisonous substances in blood

  • old red and white blood cells

produces

  • plasma proteins (contributes to tonicity)

  • urea

stores

  • glycogen

  • iron and fat-soluble vitamins A, D, E, K

regulates

  • blood cholesterol (cholesterol → bile)

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88

urea

waste product of protein breakdown, produced by liver.

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89

gall bladder

small, muscular, bulb-like structure under liver’s right lobe. stores bile. induced by CCK to release bile

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90

bile duct

carries bile from gall bladder to duodenum

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91

bile

emulsifies fat to smaller droplets for lipase to act. made in liver, stored in gallbladder

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92

large intestine/colon

extends from ileocecal valve to anus. absorbs water, salts, and bile to be recycled/used, compacts feces, houses beneficial bacteria

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93

Escherichia coli (E. coli)

beneficial bacteria, housed in the colon/large intestine. produces vitamins and helps break down plant matter

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94

rectum

terminal portion of large intestine, stores feces

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95

distension

enlargement/ballooning of rectum. causes anus to relax

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96

feces

waste. composed of water, fibre, dead GI cells (friction), bacteria

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97

cecum

bottom of ascending colon. ‘blind’ pouch

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98

appendix

small finger-like pouch connected to cecum, believed to play a role in immunity

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99

anus

composed of internal and external sphincters, relaxes to allow feces to leave body. tightens to collect feces in rectum

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