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Flashcards in Digestive System(A&P) Deck (75):
1

Divisions of the Digestive System

1) Alimentary Tract, Gastrointestinal Tract, Digestive Tract(tube like structure that extends from the mouth to the anus

2) Accessory Organs(Organs necessary for digestion but not part of the Gi tract(Salivary glands, liver, gall bladder, pancreas

2

Functions of the Digestive System(Ingestion)

-taking in food
-eating

3

Functions of the Digestive System(Digestion)

-breakdown of food we eat
-mechanical digestion: breaking large particles to small particles
-chemical digestion: breakdown of large molecules into small ones that can be absorbed

4

Functions of the Digestive System(Absorption)

-transfer of digested nutrients from the gi tract to the bloodstream

5

Functions of the Digestive System(Elimination)

-undigested material eliminated from tract; deformation

6

Functions of the Digestive System?

-Ingestion
-Digestion
-Absorption
-Elimination

7

Walls of the digestive tract(Innermost to outermost)

-Mucosa
-Sub Mucosa
-Muscle
-Serosa

8

Mucosa

-innnermost layer
-mucous membrane(goblet cells make mucous)
-protects underlying tissues
-many secretory gland
-ph of stomach=1-2 acidic

9

Muscle

-smooth muscle
most of gi tract has 2 layers:
-inner layer has fibers that are arranges in a circular pattern(contraction narrows the lumen)
-outer layer has fibers that are arranged in a longitudinal pattern(contractions make the gi tract shorter)
-combination of contractions of both muscle layers produce peristalsis
-stomach has an extra layer(total of 3 layers) to strengthen it and help with mixing food and digestive enzymes

10

Serosa

-visceral layer of the peritoneum is part of the wall of the gi tract
-esophagus is covered with fibrous connective tissue
-parietal layer lines the abdominal cavity

11

Peritoneal Membrane

-forms a large, flat, folded structure
-helps to anchor digestive organs
-contains: blood vessels, lymph vessels and nerves
-separates abdominal cavity into compartments which help to restrict the spread if infection
-membranes behind the digestive organs are the mesentery and mesocolon, membrane in front are the greater and lesser omentum

12

Mouth; Oral Cavity; Buccal Cavity(Function)

-ingestion
-mastication(chewing
mechanical digestion of food in smaller particles performed mainly by the teeth assisted with tongue, cheeks, lips, mixes food with saliva for lubrication
-saliva begins the chemical digestion of starch
-deglutition; swallowing, amount of food we swallow is bolus

13

Mouth; Oral Cavity; Buccal Cavity(Structure)

-naso cavity separated from oro-cavity by palate
-soft and hard palate
-uvula posterior margine of the soft palate
-gums/gingiva=ridges of mucosa that surrounds the base of each tooth
-maxillae=upper jaw
-mandible=lower jaw(only movable bone in skull

14

Mouth; Oral Cavity; Buccal Cavity(Accessory Structure)-Tongue

Tongue
-muscular organ that is anchored by the frenulum to the floor of the mouth
function: taste bud, help with chewing, swallowing, and speech
-sublingual capillary bed

15

Mouth; Oral Cavity; Buccal Cavity(Accessory Structure)-Salivary Glands

Salivary Glands
-three pairs: Parotid,Submandibular,Sublingual
Parotid
-anterior and inferior(largest
Submandibular
-near body of mandible
Sublingual
-under tongue
Function:
-secrete saliva
-moistens food
-helps with mastication and deglutition
-amylase converts starch to sugar

16

Mouth; Oral Cavity; Buccal Cavity(Accessory Structure)-Teeth

Teeth
-made of dentin(calcium based salt)
-crown projects above the gun and is covered w/ enamel
-root: under the gum line and anchors tooth in the jaw
-overcourse of lifetime a person will have 2 sets of teeth
-decidous teeth(baby teeth) 20 total
-permanent teeth(32 total)

17

Pharynx(throat)

-common passage way for resp and gi system
-deglutition: tongue pushes a bolus of food mixed with saliva into the pharynx
-uvula extension of the palate, doses the nasopharynx during swallowing
-epiglottis covers larynx during swallowing

18

Esophagus(Gullett)

-muscular tube about 10inces long
-moves food mixed with mucus by peristalsis into stomach
-travels through the esophageal hiatus in the diaphragm before it reaches the stomach

19

Stomach(Function)

-food storage
-churn
-digestion
-HCL: kills pathogen/most that reach stomach
-Pepsin: begins chemical digestion in stomach

20

Stomach(location)

-upper right quadrant

21

Stomach(Muscle Layers, spincters)

-J shaped organ
-2spincters
-cardiac sphincter(lower esophageal spinster) at entrance
-pyloric sphincter at the exit
Three layers of muscle
-circular, longitudinal, oblique(strengthens for mixing/churning)
-when empty it has folds called rugae

22

Regions

Fundus
-superior rounded edge of stomach
-part next to diaphragm
Body
-greater and lesser curvature
Pylorus
-next to pyloric spinster

23

Gastric Pits

-cells that produce secretions
-secretion of gastric pits are called gastric juices

24

Goblets Cells

-make mucus
-protects lining of stomach

25

Chief Cells

-make digestive enzymes(pepsin)
-begins chemical digestion of protein

26

Parietal Cells

-make HCL and intrinsic factor
-HCL- part of the first line of immune defense
-Intrinsic factor to absorb b12
-not enough b12 can cause pernicious anemia

27

Control of Stomach Activity(Nervous Control)

-vagus nerve
-parasympathetic nerve(Cr Never 10)
-promotes stimulates system

28

Control of Stomach Activity(Hormonal Control)

gastrin produced by G cells in stomach in response to:
-stomach distension
-presence of caffeine in stomach
-presence of partially digested protein in the stomach

29

Function of gastrin

-secretion of large amounts of gastric juice
-closure of the cardiac sphincter
-food leaves stomach as chyme(highly acidic) through pyloric sphincter and enters the small intestine

30

Small Intestine(Structure)

-longest part of the digestive tract
-20ft long and 1 inch in diameter
-lining is folded and it contains millions of finger like projections called villi
-villi increases surface area for absorption
-each villus contains blood capillaries and a lacteal
-lacteal is a lymph capillary
-lacteal: absorbs fat and fat soluble vitamins

31

Small Intestine(Divisions)(Duodenum)

-First 12 inches of small intestine
-C shaped
-receives chyme from stomach and digestive secretions from the liver and pancreas
-has many mucous secreting glands to protect it from acidic chyme
-most digestion and absorption takes place here

32

Small Intestine(Divisions)(Jejunum)

-8ft long
-some digestion and absorption takes place

33

Small Intestine(Divisions)(IIeum)

-12ft long
-ends at the ileocecal valve-valve btw ileum and cecum
-has peyers patches
-peyer patches: patches pf lymphatic tissue fluid found at distal end of ileum. prevent invasion of small intestine by normal flora from large intestine

34

Enzymes

secreted by small intestine

35

Lactase

enzyme that takes disaccharide(LACTOSE) and breaks down into two monosaccharides(GLACTOSE & GLUCOSE)

36

Sucrase

enzyme that takes disaccharide(Sucrose) and breaks down into two monosaccharides(FRUCTOSE & GLUCOSE)

37

Maltase

enzyme that takes disaccharide(MALTOSE) and breaks down into two monosaccharides(GLUCOSE & GLUCOSE)

38

Digestion in Small Intestine:
Enzymes secreted by the pancreas

Digestion in small intestine gets help by the pancreas:
-pancreatic amylase=acts on polysaccharide
-pancreatic lipase=acts on lipids
-pancreatic enzymes=trypsin and chymotrypsin acts on protein
-bile(emulsify fat) is secreted by the liver

39

Large Intestine(Structure)

-about 5ft long and 2.5inches in diameter
-begins at the ileocecal valve and ends at the anus
-walls from a series of pouches with creases(tinea coli)

40

Seven Subdivision of the Large Intestine:

1.Cecum
2.Ascending Colon
3.Transverse Colon
4.Descending Colon
5.Sigmoid Colon
6.Rectum
7.Anal Canal

41

1. Cecum

-receives material from the ileum
-attached to cecum is vermiform appendix

42

2.Ascending Colon

-located on the right side of the abdominal cavity
-extends from the cecum to the hepatic flexure

43

3.Transverse Colon

-extends across the abdomen from the hepatic flexure to the splenic flexure

44

4.Descending Colon

-located on the left side of the abdomen
-extends from the splenic flexure to the sigmoid flexure

45

5.Sigmoid Colon

-starts at the sigmoid flexure and empties into the rectum
-S shaped segment which bends posteriorly

46

6.Rectum

-last 15cm of large intestine
-stores fecal matter

47

7.Anal Canal

-last portion of the rectum
-contains two sphincter
internal anal sphincter(involuntary)
external anal spinster(voluntary)

48

Large Intestine(Function)

-absorption of water
-absorption of bile salts
normal flora in the large intesting produce:
-vit K
-biotin
-vit b12
-stores waste
-defacation

49

Pathway of Food

-Mouth(tongue, teeth, saliva(chemical digestion of starch in mouth)
-Pharynx-orophrynx-laryngopharnx-uvula-epiglottis
-Esophagus
-Stomach-mechanical and chemical digestion, cardiac sphincter and pyloric sphincter
-Small Intestine-Duodenum,Jejunum,Illium
-Large Intestine-cecum,ascend colon,transverse colon,descending colon,sigmoid rectum
-Anus-internal anal sphincter and external anal sphincter

50

Pancreas
(Accessory Digestive organ)

-located posterior to the stomach in the upper L quadrant
Produces pancreatic enzymes:
-Pancreatic amylase
-Pancreatic Lipase
-Proteolytic Enzymes(Trypsin-Chymotrypsin)
-produces sodium bicarbonate(alkaline-substance)
-Neutralize Chyme

51

Liver
(Accessory Digestive organ)

-larget gland located in RUQ
-two lobes right and left
-right lobe is larger
-left extends across the abdomen
-recieves blod from the gi tract and spleen by the hepatic portal vein

52

Liver(Functions)
(Accessory Digestive organ)

-stores glycogen, vitaminsADEK,Bcomplex, and iron(rbc removed by the spleen)
-synthesis of plasma proteins(albumin and clotting factors(prothrombin/fibrinigen))
-albumin=osmotic pressure, return of fluid from tissue to blood stream
-destroys old rbcs
-detoxifies harmful substances
-modifies lipids to enhance their use by cells
-synthesis of urea
-synthesis of bile
bile
-bile is needd for digestion of lipids
-bile(bile salts) emulsify fat
-emulsify means to break up into small droplets
-bile is a green secretion

53

Bile

-systhesis by the liver
-bile is needd for digestion of lipids
-bile(bile salts) emulsify fat
-emulsify means to break up into small droplets
-bile is a green secretion

54

Gall Bladder
(Accessory Digestive organ)

-muscular sac/pouch on the the inferior surface of the liver which stores bile
-bile ismade by the liver and flows into the hepatic ducts
-travels via cyctic duct to the gall bladder
-gall bladder absorbs water from concentrate bile
-chyme enters the duodenum, the gall bladder contracts and sends bile through the cyctic duct to the common bile duct to the duodenum

55

Enzymes and their actions

-enzymes and protein catalysts that speed the reaction invovled in digestion
-all digestion reactions are catabolic(breakdown)
-hydrolysis=type of chemical reaction that digestion reactions belong to, splitting apart using water

56

Amylase

-Produced by: Salivary Glands, Pancreas
-Location of action: Mouth, Duodenum
-Acts on: Starch or CHO and turns into disachccride

57

Pepsin

-Produced by: chief cells in stomach
-Location of action: stomach
-Acts on: protein-peptide

58

HCL

-Produced by: parietal cells in stomach
-Location of action: stomach
-Acts on: protein

59

Bile

-Produced by: Liver
-Location of action: Duodenum
-Acts on: Emulsifies fat

60

Lipase

-Produced by: Pancreas
-Location of action: Duodenum
-Acts on: lipids--->faty acids and glycerol

61

Tripsin/Chymotrypsin

-Produced by: Pancreas
-Location of action: Duodenum
-Acts on: Protein---> peptides

62

Sucrase,Maltase,Lactase

-Produced by: Duodenum
-Location of action: Duodenum
-Acts on: Disaccharides--->Monosacccharides

63

Peptidases

-Produced by: Duodenum
-Location: Duodenum
-Acts on: Peptides----->amino acids

64

Carbohydrate Digestion(digestive process)

-starts in the mouth with salivary amylase
-continues in the small intestine w/
-pancreatic amylase and
-lactase: digest lactose into glucose and galactose
-maltase: digest maltose into 2 glucose molecules
-sucrase: digest sucrose into glucose and fructose
-end product of starch=carbohydrate
-digestion is monosaccaride

65

Protein Digestion(digestive process)

-starts in the stomach with HCL and pepsin
-continues in the small intestine with trypsin and chymotrypsin
-from the pancreas and peptidases secreted by the small intestine
-end product of protein digestion is amino acid

66

Fat Digestion(digestive process)

-starts in small intestines
-bile(bile salts) emulsify fat
-lipase from the pancreas digests into fatty acids and glycerol
-end product of fat digestion is fatty acids and glycerol

67

Nervous Control

-parasympathetic stimulation(vagus nerve) increase the production of digestive secretions and increase motility of the Gi Tract

parasympathetic stimulation occurs due to:
-sight and smell of food
-stomach distention
-stretching causes smooth muscle to contract
-presence of food in stomach stretches smooth muscle wall causing it to contract activating parasympathetic stimulation

-sympathetic stimulation leads to a decrease in production of digestive secretions and decreases motility of the Gi tract

68

Hormonal Control
(Gastrin secreted by g cells in the stomach)

-in response to stomach distention, presence of caffeine in stomach, presence of partially digested protein in the stomach
-function of gastrin: secretion of large amounts of gastric juice, and closure of cardiac sphincter

69

Hormonal Control
(Small intestine Secretes 3 Hormones)
GIP=Gastric Inhibitory Peptide

--secreted when chyme enters small intestine
-inhibits the secretion of gastric juices and decreases gastric motility
-stimulates the release of insulin

70

Hormonal Control
(Small intestine Secretes 3 Hormones)
Secretin

-secreted when chyme enters the small intestinge
-function of secretin; decrease gastric secretions
-stimulate the release of water and bicarbonate from the pancreas
-stimulate the release of bile from the liver

71

Hormonal Control
(Small intestine Secretes 3 Hormones)
Cholecyctokinin

-cck is secreted when fat enters the small intestine
Function of cck
-stimulate the release of digestive enzymes from the pancreas
-stimulates the release of bile from the gallbladder
-inhibits gastric emptying

72

Small Intestine(absorption)

-absorption of digested starch, protein, lipids
-villi increase surface for absorption
-peristalsis causes movement
-villi has blood capillary(monosaccharide/aminoacids) and lacteal capillary(fattyacid/glycerol)

73

Large Intestine(absorption)

-absorption of water, vitamins, and minerals
-most of what is absorbed is water
-vitamin k in large intestine absorbed
-minerals

74

Defecation

-a spinal reflex initiated by the presence of fecal matter in the rectum
-internal anal sphincter(involuntary)
-external anal sphincter(voluntrary)
-both must relax in orer for defecation to take place

75

Effects of Aging on Digestive System:

-decrease sense of taste and appetite
-decrease in secretions of the Gi system
-decrease in peristalsis which leads to an increase in constipation
-decreased production of intrinsic factor may lead to pernicious anemia
-decreased muscle tone of the cardiac sphincter leads to an increase in GERD/pylosis