Exam 4: Digestive System Flashcards Preview

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

Gastrointestinal (GI) Tract

A
  • tube that extends from mouth to anus

- mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus

2
Q

Functions of GI Tract

A
  • digestion
  • absorption
  • elimination of wastes
3
Q

Digestion

A
  • process of breaking down food into small fragments

- 2 types mechanical and chemical

4
Q

Mechanical Digestion

A
  • using forces/physically breaking down food

- Ex: stomach mechanically digests by muscle contraction

5
Q

Chemical Digestion

A
  • uses enzymes (proteins) that speed up a chemical reaction

- Ex: stomach chemically digests with gastric juices

6
Q

Absorption

A
  • water and food molecules pass through to GI lymphatics and blood vessels
  • most nutrients absorbed in blood vessels
7
Q

Lacteals

A

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

8
Q

Accessory Digestive Organs

A
  • not part of GI tract but assist with digestion

- tongue, teeth, salivary glans, liver, gallbladder, pancreas

9
Q

Peritoneum

A
  • 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
Q

Parasympathetic Innervation

A

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

11
Q

Sympathetic Innervation

A

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

12
Q

Oral Cavity

A
  • continuous posteriorly with oropharynx
  • nonkeratinized stratified squamous epithelium
  • upper part of the oral cavity: palate
13
Q

Hard Palate

A

-anterior 2/3 of palate, bony

14
Q

Soft Palate

A

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

15
Q

Uvula

A

-dangling muscle off soft palate

16
Q

Extra Credit Names

A

-Osmosis Jones and Drix

17
Q

Function of Soft Palate and Uvula

A
  • close off opening to nasopharynx when you swallow

- these muscles move and that’s why milk goes up your nose

18
Q

Teeth

A

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

19
Q

Tongue

A
  • big skeletal muscle
  • covered with stratified squamous epithelium
  • function: perceives taste and mechanical digestion
20
Q

Salivary Glands

A
  • 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
Q

Pharynx

A
  • 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
Q

GI Tract Layers

A
  • 4 layers, tunics

- mucosa, submucosa, muscularis, adventita/serosa

23
Q

Mucuosa

A
  • innermost tunic
  • esophagus has nonkeratinized stratified squamous epithelium
  • stomach to anal canal has simple columnar epithelium
  • areolar CT
24
Q

Muscularis Mucosae

A

-thin layer of smooth muscle

25
Q

Submucosa

A
  • connective tissue

- contains major blood vessels

26
Q

Muscularis

A
  • 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
Q

Serosa or Adventitia

A
  • outermost layer
  • serosa = visceral peritoneum + areolar CT
  • adventitia = areolar CT only
28
Q

Esophagus Gross Anatomy

A
  • muscular tube that connects pharynx to stomach

- function:propel food to stomach

29
Q

Esophagus Histology

A
  • 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
Q

Reflux Esophagitis

A
  • heartburn
  • stomach contents back flow (reflux) into esophagus causing burning pain
  • risk factors: overweight, smoking, large meals before bedtime
31
Q

Stomach Gross Anatomy

A
  • connects to esophagus and duodenum
  • upper left quadrant
  • main function: uses mechanical and chemical digestion to turn bolus into chyme
32
Q

Stomach Histology

A
  • 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
Q

Gastric Glands

A

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

34
Q

What prevents gastric juices from eating away at stomach itself?

A
  • cells secrete layer of mucus-protective lining

- epithelium constantly regenerating

35
Q

Peptic Ulcer

A
  • 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
Q

Small Intestine Gross Anatomy

A
  • functions: finishes chemical digestion process
  • absorbs most (90%) of nutrients
  • 3 specific segments
37
Q

Duodenum

A
  • connects to stomach
  • receives chyme from stomach
  • receives bile and pancreatic enzymes through duodenal papilla
38
Q

Jejunum

A
  • middle part

- connects to duodenum and ileum

39
Q

Ileum

A
  • connects to cecum of large intestine

- majority of last part of chemicals get secreted and interact with chyme

40
Q

Small Intestine Histology

A
  • 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
Q

Villi

A
  • folds of the MUCOSA only!
  • function: increase surface area
  • in center of each villus are blood vessels and a lacteal
42
Q

Lacteal

A
  • lymphatic capillary

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

43
Q

Large Intestine Gross Anatomy

A
  • 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
Q

Cecum

A
  • sac that connects to ileum
  • lower right part of abdomen
  • vermiform appendix attaches here
45
Q

Rectum and Anal Canal

A
  • terminal portion of large intestine

- feces leaves anal canal through anus

46
Q

Large Intestine Histology

A
  • mucosa has simple columnar epithelium w/ goblet cells
  • muscularis: 2 layers of smooth muscle: outer longitudinal layer consists of teniae coli
  • haustra
47
Q

Teniae Coli

A

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

48
Q

Colorectal Cancer

A
  • most arise from polyps from mucosa
  • not all polyps are cancerous
  • blood in stool early warning sign
  • colonoscopy to examine colon
49
Q

Liver

A
  • upper right part of abdomen

- functions: produce and secrete bile, processes products of digestion

50
Q

Gallbladder

A
  • underneath liver

- function: stores and concentrates bile

51
Q

Gallstones

A
  • 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
Q

Pancreas

A
  • behind stomach

- acinar cells

53
Q

Acinar Cells

A
  • secreate pancreatic juice: contains digestive enzymes, alkaline, neutralizes acidic chyme
  • pancreatic juice leaves via a pancreatic duct
54
Q

Billary Apparatus

A

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

55
Q

Arterial Blood Supply to Abdominal GI Tract

A
  • from branches of:
    1) celiac trunk
    2) superior mesenteric artery
    3) inferior mesenteric artery
56
Q

Venous Drainage of Blood from Abdominal GI Tract

A
  • 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
Q

Blood from Hepatic Portal vein

A
  • 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
Q

Ducts of Billary Apparatus

A
  • 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!