Chapter 24 - Digestive System Flashcards

1
Q

(2) groups of organs compose digestive system

A

**Gastrointestinal (GI) tract **

Accessory digestive organs

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2
Q

Gastrointestinal (GI) tract

A

mouth, most of pharynx, esophagus, stomach, small intestine & large intestine

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3
Q

Accessory digestive organs

A

teeth, tongue, salivary glands, liver, gallbladder & pancreas

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4
Q

(6) functions of digestive system

A

ingestion

secretion of water, acid, buffers & enzymes into lumen

mixing & propulsion

digestion (mechanical & chemical)

absorption

defecation

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5
Q

(4) LAYERS of GI Tract

A

Mucosa

Submucosa

Muscularis

Serosa

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6
Q

Mucosa - inner lining

A

**epithelium - **protection, secretion & absorption

**lamina propria - **CT with blood & lymphatic vessels & MALT

**muscularis mucosae - **thin layer of folded smooth muscle

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7
Q

Submucosa

A

CT binding mucosa to muscularis

contains many blood & lymphatic vessels

**submucosal plexus - **network of neurons

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8
Q

Muscularis

A

voluntary skeletal muscle in pharynx, mouth, upper 2/3 of esophagus & anal sphincter

involuntary smooth muscle elsewhere

arranged in **inner circular fibers **& **outer longitudinal fibers **

**myenteric plexus **between muscle layers

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9
Q

Serosa

A

outermost covering of organs suspended in abdominopelvic cavity

also called visceral peritoneum

esophagus lacks serosa - has **adventitia **

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10
Q

Neural Innervation (2)

A

Enteric Nervous system

Autonomic nervous system

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11
Q

enteric nervous sytem

A

intrinsic set of nerves - “brain of gut”

neurons extending from esophagus to anus

(2) plexuses
- **myenteric **(GI tract motility)

**- submucosal **(controlling secretions)

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12
Q

Autonomic Nervous system

A

extrinsic set of nerves

**Parasympathetic **stimulation - increases secretion & activity by stimulating ENS

**Sympathetic **stimulation - decreases secretion & activity by inhibiting ENS

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13
Q

Peritoneum

divided into? (2)

A

largest serous membrane of body

**parietal - **lines wall of cavity

visceral (aka serosa) - covers organs

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14
Q

(5) major peritoneal folds

A

greater omentum

falciform ligament

lesser omentum

mesentery

mesocolon

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15
Q

Oral Cavity

formed by?

A

cheeks, hard & soft palates & tongue

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16
Q

Oral cavity proper

A

space from gums & teeth to fauces (opening between oral cavity & oropharynx)

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17
Q

(3) pairs of major salivary glands secrete most of saliva

A

parotid

submandibular

sublingual

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18
Q

Salivation controlled by?

parasympathetic stimulation

sympathetic stimulation

A

ANS

parasympathetic stimulation - promotes secretion

sympathetic stimulation - decreases salivation

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19
Q

Teeth - (3) major regions

A

crown

root

neck

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20
Q

Dentin of crown covered by ___

A

enamel

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21
Q

2 sets of teeth

A

deciduous (baby teeth)

permanent teeth

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22
Q

Mechanical Digestion in mouth

A

chewing

tongue, teeth, saliva

forms bolus

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23
Q

Chemical Digestion

A

**salivary amylase - **secreted by salivary glands acts on starches

inactived by stomach acid

**lingual lipase - **secreted by lingual glands of tongue acts on triglycerides

activated in acidic environment of stomach

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24
Q

Pharynx

(3) parts

A

food passes from mouth into pharynx

**nasopharynx **- respiration

**oropharynx - **digestive & respiratory

**laryngopharynx - **digestive & respiratory

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25
Esophagus
secretes mucous, transports food - no enzymes produced, no absorption
26
Esophagus 1) mucosa 2) submucosa 3) muscularis 4) adventitia
1) protection against wear & tear 2) --- 3) divided into third superior - skeletal middle - skeletal & smooth inferior - smooth 2 sphincters
27
(2) sphincters in esophagus muscularis
**Upper esophageal sphincter (UES) -** regulates movement into esophagus **Lower esophageal sphincter (LES) - **regulates movement into stomach
28
Swallowing involves (3) (3) stages
mouth, pharynx, esophagus **voluntary - **bolus → oropharynx **pharyngeal - **pharynx → esophagus **esophageal - **esophagus → stomach
29
Stomach (4) main regions
**cardia** **fundus** **body ** **pyloric part **- pyloric antrum, pyloric canal, pylorus
30
Stomach mucosa
gastric glands open into gastric pits (3) types of **exocrine** gland cells - mucous neck cells, parietal cells, chief cells (pepsinogen & gastric lipase) **G cell - **endocrine cell - secretes gastrin
31
Muscularis of Stomach
additional 3rd inner oblique layer
32
Serosa
part of visceral peritoneum
33
Mechanical Digestion
mixing waves - creates **chyme**
34
Chemical Digestion - gastric juice parietal & chief cells
digestion of **salivary amylase ** inactivated by acidic **gastric juice **- activates **lingual lipase** (digest triglycerides into FAs & diglycerides) **Parietal cells- **secrete HCl (kills microbes & denatures proteins) **pepsin **secreted by chief cells (digests proteins) **gastric lipase **splits triglycerides into FAs & monoglycerides
35
Pancreas
lies posterior to greater curvature of stomach pancreatic juice secreted into pancreatic duct & accessory duct to small intestine
36
pancreatic duct joins __ \_\_\_ __ and enters ___ at ___ \_\_\_
common bile duct duodenum hepatopancreatic ampulla
37
Histology of Pancreas
99% of cells are **acini** - exocrine - secrete pancreatic juice 1% of cells are **pancreatic islets (Islets of Langerhans) ** - endocrine - secretes hormones glucagon, insulin, somatostatin, pancreatic polypeptide
38
Liver composed of (3)
heaviest gland of body 1) hepatocytes 2) bile canaliculi 3) hepatic sinusoids
39
1) hepatocytes
major functional cells of liver secrete **bile**
40
**2) bile canaliculi ** exits liver as?
ducts between hepatocytes that collect bile common hepatic duct → cystic duct from gallbladder → common bile duct
41
Hepatic Sinusoids
highly permeable blood capillaries recieving oxygenated blood from **hepatic artery **& deoxygenated blood from **hepatic portal vein**
42
Gallbladder contraction of smooth muscle fibers eject contents of gall bladder into ?
cystic duct
43
Functions of Gallbladder
store & concentrate bile produced by liver until it is needed in small intestine
44
**Hepatic Blood Flow** liver recieves blood from:
**hepatic artery **carrying oxygenated blood **hepatic portal vein **carries deoxygenated blood
45
Small Intestine (3) regions
duodenum jejunum ileum
46
Mucosa of Small Intestine
absorptive cells goblet cells intestinal glands paneth cells enteroendocrine cells
47
Submucosa of Small intestine
dudenal glands secrete alkaline mucus
48
Duodenum
recieves stomach contents, pancreatic juice & bile neutralize stomach acid, emulsifies fats, pepsin inactivated by pH increase, pancreatic enzymes
49
Jejunum
most digestion & nutrient absorption occur here
50
Ileum
has **peyers patch** - clusters of lymphatic nodules ends at **ileocecal junction **with large intestine
51
Special structural features of small intestine
**circular folds -** permanent ridge of mucosa & submucosa causes chyme to spiral **Villi **- contains arteriole, venule, capillary & lacteal **Microvilli - **projections of absorptive cells
52
Brush Border Enzymes
inserted into plasma membrane of absorptive cells
53
Mechanical Digestion governed by? segmentations
myenteric plexus localized mixing contractions mix chyme & bring it in contact with mucosa for absorption
54
Chemical Digestion 1) carbohydrates 2) proteins
1) pancreatic **amylase** **a-dextrinase, sucrase, lactase, maltase** in brush border 2) **trypsin, chymotrypsin, carboxypeptidase & elastase **from pancreas **aminopeptidase & dipeptidase **in brush border
55
Lipid Digestion emulsification by __ \_\_ increases surface area
triglyceride digestion bile salts **amphipathic** - hydophobic & hydrophilic regions
56
Nucleic Acids
**ribonuclease & deoxyribonuclease **in pancreatic juice **nucleosidases & phosphatases **in brush border
57
Absorption of: ## Footnote **1) Monosaccharides** **2) Amino acids**
1) facilitated diffusion or active transport 2) active transport
58
Large Intestine (4) major regions
cecum rectum colon anal canal
59
Large Intestine ## Footnote **ileocecal sphincter **
**ileocecal sphincter - **between small & large intestine
60
Colon divided into (4)
ascending, transverse, descending & sigmoid
61
opening of **anal canal (anus) **guarded by **?**
**internal anal sphincter** of smooth muscle & **external anal sphincter** of skeletal muscle
62
Anatomy of large intestine
**Mucosa** - mostly absorptive & goblet cells no circular folds or villi has microvilli **Submucosa** **Muscularis** - longitudinal muscle modified to form **teniae coli** forms **baustria - **pouches
63
**Large Intestine **begins as __ & __ in lower right corner
cecum & appendix
64
Digestion of Large Intestine 1) **mechanical digestion** 2) **chemical digestion**
1) haustral churning peristalsis mass peristalsis 2) bacterial action, no enzymes
65
Anatomy of **Anal Canal** anal columns hemorrhoids
**anal columns - **longitudinal ridges seperated by mucus secreting anal sinuses **hemorrhoids - **permanently distended veins
66
Defecation
stretching of rectum **intrinsic defecation reflex** via myenteric plexus → muscularis contracts & internal sphincter relaxs **parasympathetic defecation reflex **via spinal cord stretching of rectum → sensory signals to spinal cord →splanchnic nerves return signals
67
**Defecation **occurs only if ?
**external anal sphincter **is voluntarily relaxed
68
abdominal contractions **increase **abdominal pressure as...
**levator ani **lifts **anal canal **upwards feces will fall away
69