Exam 4: Digestive System Flashcards Preview

Anatomy A-215 > Exam 4: Digestive System > Flashcards

Flashcards in Exam 4: Digestive System Deck (58):
1

Gastrointestinal (GI) Tract

-tube that extends from mouth to anus
-mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus

2

Functions of GI Tract

-digestion
-absorption
-elimination of wastes

3

Digestion

-process of breaking down food into small fragments
-2 types mechanical and chemical

4

Mechanical Digestion

-using forces/physically breaking down food
-Ex: stomach mechanically digests by muscle contraction

5

Chemical Digestion

-uses enzymes (proteins) that speed up a chemical reaction
-Ex: stomach chemically digests with gastric juices

6

Absorption

-water and food molecules pass through to GI lymphatics and blood vessels
-most nutrients absorbed in blood vessels

7

Lacteals

-absorb lipids and lipid soluble vitamins in small intestine (A, D, E, K)

8

Accessory Digestive Organs

-not part of GI tract but assist with digestion
-tongue, teeth, salivary glans, liver, gallbladder, pancreas

9

Peritoneum

-serous membrane that lines the abdominal cavity
-parietal lines abdominal wall
-visceral covers abdominal organs
-peritoneal cavity is the space between the two, serous fluid secreted here

10

Parasympathetic Innervation

-in general, it stimulates or increases activity of GI tract

11

Sympathetic Innervation

-in general, it inhibits or decreases activity of GI tract

12

Oral Cavity

-continuous posteriorly with oropharynx
-nonkeratinized stratified squamous epithelium
-upper part of the oral cavity: palate

13

Hard Palate

-anterior 2/3 of palate, bony

14

Soft Palate

-posterior 1/3 of palate, formed from skeletal muscle

15

Uvula

-dangling muscle off soft palate

16

Extra Credit Names

-Osmosis Jones and Drix

17

Function of Soft Palate and Uvula

-close off opening to nasopharynx when you swallow
-these muscles move and that's why milk goes up your nose

18

Teeth

-20 deciduous (baby) teeth replaced by 32 permanent teeth

19

Tongue

-big skeletal muscle
-covered with stratified squamous epithelium
-function: perceives taste and mechanical digestion

20

Salivary Glands

-3 pairs
-secrete saliva composed of water, mucus, amylase (digests carbs), lysozyme (antibacterial agent) and antibodies
-functions: dissolves food molecules so they can be tasted, moistens food and turns it into bolus, chemically digests carbs, cleanses mouth, lysozyme and antibodies inhibit bacterial growth

21

Pharynx

-throat
-muscular tube that connects nasal cavity and mouth, to larynx and esophagus
-function: propel food and drink to esophagus and air to larynx
-only the oropharynx and laryngopharynx conduct both food and air

22

GI Tract Layers

-4 layers, tunics
-mucosa, submucosa, muscularis, adventita/serosa

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Mucuosa

-innermost tunic
-esophagus has nonkeratinized stratified squamous epithelium
-stomach to anal canal has simple columnar epithelium
-areolar CT

24

Muscularis Mucosae

-thin layer of smooth muscle

25

Submucosa

-connective tissue
-contains major blood vessels

26

Muscularis

-typically contains 2 layers of smooth muscle:
-exception: stomach (3 layers)
-inner circular layer
-outer longitudinal layer
-responsible for peristalsis: alternate waves of contraction and relaxation

27

Serosa or Adventitia

- outermost layer
-serosa = visceral peritoneum + areolar CT
-adventitia = areolar CT only

28

Esophagus Gross Anatomy

-muscular tube that connects pharynx to stomach
-function:propel food to stomach

29

Esophagus Histology

-mucosa: nonkeratinized stratified squamous epithelium
-muscularis: 2 layers of muscle
-upper 1/3: skeletal muscle
-middle 1/3: skeletal + smooth
-lower 1/3: smooth muscle only

30

Reflux Esophagitis

-heartburn
-stomach contents back flow (reflux) into esophagus causing burning pain
-risk factors: overweight, smoking, large meals before bedtime

31

Stomach Gross Anatomy

-connects to esophagus and duodenum
-upper left quadrant
-main function: uses mechanical and chemical digestion to turn bolus into chyme

32

Stomach Histology

-mucosa has simple columnar epithelium
-mucosa contains gastric pits
-branching off of gastric pits are gastric glands
- muscularis: has three (3) layers of smooth muscle: innermost oblique, inner circular, outer longitudinal
-3 layers blend bolus with gastric juice turning the bolus into chyme

33

Gastric Glands

-cells that secrete gastric juice (acidic, contains HCl)

34

What prevents gastric juices from eating away at stomach itself?

-cells secrete layer of mucus-protective lining
-epithelium constantly regenerating

35

Peptic Ulcer

-erosion of wall of stomach or duodenum
-"balance" between acidic juices and mucosa repair thrown off so acid eats away at lining
-most causes are due to infection (helicobacter pylori)

36

Small Intestine Gross Anatomy

-functions: finishes chemical digestion process
-absorbs most (90%) of nutrients
-3 specific segments

37

Duodenum

-connects to stomach
-receives chyme from stomach
-receives bile and pancreatic enzymes through duodenal papilla

38

Jejunum

-middle part
-connects to duodenum and ileum

39

Ileum

-connects to cecum of large intestine
-majority of last part of chemicals get secreted and interact with chyme

40

Small Intestine Histology

-mucosa has simple columnar epithelium w/ goblet cells
-small intestine contains circular folds (plicae circulares): folds of mucosa AND submucosa!
-functions: act like speed bumps to slow down chyme, increase surface area for absorption
-on circular folds are villi

41

Villi

-folds of the MUCOSA only!
-function: increase surface area
-in center of each villus are blood vessels and a lacteal

42

Lacteal

-lymphatic capillary
-absorbs lipids and lipid soluble vitamins (A, D, E, K)

43

Large Intestine Gross Anatomy

-functions: most absorption of water and electrolytes (Na+, K+) and stores feces until they can be expelled from body
-different segments: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum and anal canal

44

Cecum

-sac that connects to ileum
-lower right part of abdomen
-vermiform appendix attaches here

45

Rectum and Anal Canal

-terminal portion of large intestine
-feces leaves anal canal through anus

46

Large Intestine Histology

- mucosa has simple columnar epithelium w/ goblet cells
-muscularis: 2 layers of smooth muscle: outer longitudinal layer consists of teniae coli
-haustra

47

Teniae Coli

-3 thin bands of smooth muscle that bunch large intestine into sacs called haustra

48

Colorectal Cancer

-most arise from polyps from mucosa
-not all polyps are cancerous
-blood in stool early warning sign
-colonoscopy to examine colon

49

Liver

-upper right part of abdomen
-functions: produce and secrete bile, processes products of digestion

50

Gallbladder

-underneath liver
-function: stores and concentrates bile

51

Gallstones

-condensations of bile material into stones
-first form in gallbladder
-painful if travel through billary apparatus
-4 F's risk factors: female, fat, fertile (had at least one child), forty's (or older)

52

Pancreas

-behind stomach
-acinar cells

53

Acinar Cells

-secreate pancreatic juice: contains digestive enzymes, alkaline, neutralizes acidic chyme
-pancreatic juice leaves via a pancreatic duct

54

Billary Apparatus

-a network of "tubes" that transport bile and pancreatic juices TO the duodenum!

55

Arterial Blood Supply to Abdominal GI Tract

-from branches of:
1) celiac trunk
2) superior mesenteric artery
3) inferior mesenteric artery

56

Venous Drainage of Blood from Abdominal GI Tract

-hepatic portal system: veins that drain blood from GI tract directly to liver, transports blood low in oxygen but high in nutrients to be processed
-4 mein veins.
1. Superior Mesenteric vein
2. Splenic vein
3. Inferior Mesenteric vein
4. Hepatic portal vein - receives blood from 1,2, and 3, and goes directly to the liver

57

Blood from Hepatic Portal vein

-processed by liver cells (hepatocytes)
-also get oxygenated blood from hepatic arteries
-once processed, blood leaves the liver via hepatic veins and into the inferior vena cava

58

Ducts of Billary Apparatus

-right and left hepatic ducts (from liver) unite to form the common hepatic duct
-gallbladder has a cystic duct
-cystic duct and common hepatic duct unite, forming common bile duct, it connects with pancreatic duct
-common bile duct opens into duodenum at the duodenal papilla: here, bile and pancreatic juices are secreted!