1.  cavity  not involved in digesting food  passageway leads to stomach  connection between nasal & oral cavities to larynx & esophagus

2. 1. nasopharynx- connects w/ nasal cavity 2. oropharynx- passageway food moving down & air moving into trachea 3. laryngopharynx- passageway to esophagus

5.  1 st stage: › voluntary › food chewed- mixed w/ saliva › rolled into mass by tongue- BOLUS- forced into pharynx

6.  food is prevented entrance to nasal cavity  epiglottis slaps shut over larynx to keep food from going down trachea  tongue seals off oral cavity  different muscle actions open esophagus & forces food down it

7. epiglottis trachea

8.  breathing momentarily inhibited  peristalsis transports food down into & through esophagus  choking occurs when food lodges in larynx  Heimleich maneuver can dislodge food

10.  straight tube  ~ 25 cm long  food passageway from pharynx to stomach  goes thru opening in diaphragm  contains mucous glands w/ secretions that moisten & lubricate inner lining

12.  wavelike motion propels food down tubular structures  contraction of muscle occur above food & relaxation below it

14.  hiatal hernia  acid reflux  Barrett’s esophagus

15.  Caution!

17.  j-shaped, pouched organ  ~ 1 L capacity  fxns: receives food from esophagus, mixes food w/ gastric juices, begins protein digestion, limited absorption, moves food into small intestines

19. 1. cardiac- 2. fundus- temp storage area 3. body- main part 4. pylorus- approaches small intestines

21.  inner lining contains gastric glands w/ 3 types secretory cells: A. mucous cells- secrete mucus w/ other secretions keeping stomach from digesting itself B. chief cells- secrete digestive enzymes- pepsinogen C. parietal cells- release HCl & intrinsic factors all these form GASTRIC JUICE (2-3 L/day)

24. inner lining= RUGAE- disappears when stomach is distended ulcer is open sore in the lining of stomach may be caused by presence of H pylori bacteria

25.  pepsinogen is released & when hits HCl forms PEPSIN which digests almost ALL types of protein  intrinsic factors aid in vitamin B 12 absorption in small intestines  mostly digestion occurs in stomach, but some absorption of water, salts, and drugs does occur

26. mechanical & chemical digestion begin here resulting in a semi-paste called CHYME rate at which this enters sm intestine depends of type of food liquids pass thru quickly fatty foods 3-6 hours proteins & carbs pass thru more quickly

27.  medulla oblongata- vomiting center  body prepares for the process by closing off nasal cavity, trachea, contraction of diaphragm, contraction of abdominal muscles, etc

28.  dual fxn- endocrine gland & digestive gland  closely associated w/ small intestine in the curve of duodenum  fxn: release pancreatic juice  juice contains enzymes that digest carbs, fats, nucleic acids, proteins

30.  PANCREATITIS- condition where there is a blockage in release of juice  essentially pancreas digests itself

33.  largest internal organ in body  inferior to diaphragm on right side of body (under ribs)  4 lobed organ (2)  connected to sm intestines by ducts  main fxn: manufacture bile salts

36.  imp role in carb metabolism › regulates glucose in bld  imp in lipid metabolism- converting subst into fats (bile salts)  imp in protein metabolism

37.  produce plasma proteins  destroy bacteria/old rbc & wbc

38.  produce enzymes that break down poisons that are harmful to body  stores certain vitamins/minerals needed by body  also stores poisons that can’t be broken down & excreted  activates vitamin D

40.  cirrhosis  hepatitis  cancer

41.  surrounds gallbladder- small, green sac embedded in liver  stores & concentrates bile

42.  gallstones  gallbladder attacks

43.  major digestive organ  ~ 21 feet long  3 subdivisions: A. duodenum- ~10” long (25cm) diameter: ~ 2” (5cm) C-shaped around the pancreas B. jejunum- ~ 8’ long greater diameter thicker walls, more vascularized

44. C. ileum- ~ 12’ long hard to distinguish between jejunum & ileum

45.  mesentery- thin membrane that suspends the portions of the intestines from walls  contains blood vessels, nerves, lymphatic vessels

47.  only processes small amount of food at a time so pyloric sphincter muscle considered gatekeeper  produces enzymes to digest food (w/ help of pancreatic enzymes & bile)

48.  enzymes secreted by mucosal cells break down proteins, carbs, fats  wall of intestine has many tiny projections called villi  microvilli project off the villi  the epithelial lining is replaced every 3 to 6 days  food absorption occurs thru these structures

50.  carries on mixing movements & peristalsis  chyme moves slowly; 3-10 hours  if wall becomes distended/irritated, a peristaltic rush pushes contents to large intestine so quickly that water, nutrients, & electrolytes aren’t absorbed - diarrhea

52.  ~ 5’ length  greater diameter than small int  fxns: 1. dry out indigestible food residue by absorbing water 2. eliminate residues from body as feces

53.  little or no digestive fxns  no secretions except mucus by goblet cells in wall › protects inner wall › binds fecal matter  normally absorbs water & electrolytes  many bacteria, intestinal flora, inhabit organ (100 trillion)  help break down substances that aren’t by our digestive system

54.  4 principle regions: 1. cecum- beginning; dilated pouchlike contains appendix (appendicitis) 2. colon- subdivided into 4 parts: a. ascending colon- right side b. transverse colon- across c. descending colon- left side d. sigmoid colon- s-shaped 3. rectum 4. anal canal

56.  mixing & peristalsis occurs but slower  2-3 mass movements happen per day  forces feces into lower 2 regions until eliminated  if feces stay in too long leads to constipation