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Anatomy & Physiology Review I > Chapter 24 - The Digestive System > Flashcards

Chapter 24 - The Digestive System Flashcards

1
Q

What are the Organs of the Digestive System?

A

1- Mouth (Oral Cavity)
Contains Teeth and Tongue

2- Parotid Gland (Salivary Gland)

3-Sublingual Gland (Salivary Gland)

4- Submandibular Gland (Salivary Gland)

5- Pharynx

6- Esophagus

7- Liver

8- Gallbladder

9- Stomach

10- Pancreas

11- Duodenum

12- Jejunum

13- Ileum

14- Cecum

15- Appendix

16- Ascending Colon

17- Transverse Colon

18- Descending Colon

19- Sigmoid Colon

20- Rectum

21- Anal Canal

22- Anus

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2
Q

What are Named Portions of the GI Tract?

A

1- Esophagus
2- Stomach
3- Small Intestine
4- Large Intestine
5- Rectum

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3
Q

What are Accessory Structures of the GI Tract?

A

1- Teeth
2- Tongue
3- Salivary Glands (Parotid, Sublingual, Submandibular)
4- Liver
5- Gallbladder
6- Pancreas

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4
Q

What are the 6 Basic Processes in Digestion?

A

1- Ingestion
2- Secretion
3- Motility
4- Digestion
5- Absorption
6- Defecation

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5
Q

What are the Layers of the GI Tract?

A

From deep to superficial:

1- Mucosa:
Lumen
Epithelium (with Glands in Mucosa)
Lamina Propria (has MALT)
Muscularis Mucosae
Ducts of Glands outside GI Tract (Like from Pancreas)

2- Submucosa:
Glands in Submucosa
Submucosal Plexus (Plexus of Meissner)

3- Muscularis:
Circular Muscle
Longitudinal Muscle
Myenteric Plexus (Plexus of Auerbach)

4- Serosa:
Areolar Connective Tissue
Epithelium
Arteries
Nerves
Veins
Mesentery

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6
Q

What is Enteric Nervous System?

A

For Digestion:

1- Submucosal Plexus
2- Myenteric Plexus

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7
Q

What is ANS for Gut?

A

1- Parasympathetic:
Relaxed
Energy on food

2- Sympathetic:
Fight-or-flight
Energy on something else

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8
Q

What is GI Reflex Pathway?

A

GI Reflex Pathways regulate GI secretion and motility in response to stimuli within the GI Tract

1- Mucosal Epithelium send nerve impulse to ANS, CNS, and Enteric Nervous System

2- In Enteric Nervous System, Submucosal Plexus sends sensory nerve impulse to Myenteric Plexus and motor nerve impulse back to Mucosal Epithelium

3- In Enteric Nervous System, Myenteric Plexus sends motor nerve impulse to Longitudinal and Circular smooth muscle layers of Muscularis

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9
Q

What is Peritoneum?

A

Peritoneum:
Largest serous membrane in body

1- Lesser Omentum:
Posteroinferior to Liver
Posterosuperior to Stomach
Connects Liver and Stomach

2- Mesocolon:
Inferior to Pancreas and Stomach
Posterosuperior to Transverse Colon
Holds Pancreas to Transverse Colon

3- Mesentery:
Between Duodenum and Jejunum
Holds Duodenum to Jejunum

4- Greater Omentum:
Anterior to most GI Tract
Connected to Stomach and Transverse Colon

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10
Q

What is the Mouth?

A

Mouth:
Formed by Cheeks, Hard Palate, Soft Palate

1- Superior Labial Frenulum:
Attaches superior lip to gum

2- Gingivae:
Gums
Cover tooth sockets
Help anchor teeth

3- Hard Palate:
Bony
Forms most of the roof of the mouth

4- Soft Palate:
Muscular
Forms the rest of the mouth’s roof

5- Uvula:
Prevents swallowed food from entering Nasal Cavity

6- Fauces:
Opening between Oral Cavity and Oropharynx

7- Tongue:
Forms floor of mouth
Manipulates food for chewing and swallowing
Shapes food
Senses taste

8- Lingual Frenulum:
Limits movements of Tongue posteriorly

9- Inferior Labial Frenulum:
Attaches inferior lip to gum

10- Cheek:
Forms lateral wall of Oral Cavity

11- Molars:
3 Last teeth on each side (12 total)
Grind food

12- Premolars:
2 Teeth on each side (8 total)
Crush and grind food

13- Canines
1 Tooth on each side (4 total)
Tears food

14- Incisors:
4 Teeth up and down (8 total)
Cut food

15- Oral Vestibule:
Space between Cheeks, Lips, Gums, and Teeth

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11
Q

What are Salivary Glands?

A

Salivary Glands:
Outside mouth
Empty contents into ducts which deliver saliva to Oral Cavity

3 Pairs:
1- Parotids Glands
2- Submandibular Glands
3- Sublingual Glands

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12
Q

What is the Tongue?

A

Together with associated muscles, forms floor of Oral Cavity
Composed of skeletal muscle covered with mucous membrane
Participates in chewing, swallowing, and speech
Upper and Lateral surfaces on Tongue are covered with Papillae, some of which contain Taste Buds

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13
Q

What are Teeth?

A

Teeth:
Project into mouth and adapted for mechanical digestion

From Superficial to Deep:

a- Crown:

1- Enamel:
Made of calcium salts
Protects the tooth from wear and tear

2- Dentin:
Calcified connective tissue
Makes majority of tooth

b- Neck:

1- Gingival Sulcus

2- Gingiva

3- Pulp Cavity:
Contains Pulp (connective tissues containing nerves and blood vessels)

c- Root:

1- Pulp Cavity

2- Cementum:
Bone-like substance that attaches Root to Periodontal Ligament

3- Root Canal:
Extension of the Pulp Cavity that contains nerves and blood vessels

4- Alveolar Bone

5- Periodontal Ligament:
Helps anchor tooth to underlying bone

6- Apical Foramen:
Opening at base of a Root Canal through which blood vessels, Lymphatic vessels, and nerves enter the tooth

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14
Q

What is Mechanical Digestion in Mouth?

A

Chewing mixes food with saliva and forms Bolus which is easily swallowed

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15
Q

What is Chemical Digestion in Mouth?

A

Salivary Amylase converts polysaccharides to disaccharides

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16
Q

What does Cheek and Lips do?

A

Keep food between teeth

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17
Q

What does Salivary Glands do?

A

Secrete Saliva

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18
Q

What does Extrinsic Tongue Muscles do?

A

Move tongue from side to side and in and out

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19
Q

What does Intrinsic Tongue Muscles do?

A

Alter shape of tongue

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20
Q

What does Taste Buds do?

A

Serve as receptors for Gustation and presence of food in mouth

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21
Q

What does Lingual Glands do?

A

Secrete Lingual Lipase
Breaks down Triglycerides into fatty acids and Diglycerides

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22
Q

What does Teeth do?

A

Cut, tear, and pulverize food

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23
Q

What is Pharynx?

A

Pharynx:
Funnel-shaped tube that extends from Internal Nares to Esophagus posteriorly and to Larynx anteriorly

Composed of skeletal muscles and lined with mucous membrane

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24
Q

What is Esophagus?

A

Esophagus:
Collapsible, muscular tube that lies posterior to Trachea and connects Pharynx to Stomach

1- Lumen of Esophagus

2- Mucosa:
Nonkeratinized stratified squamous epithelium
Lamina Propria
Muscularis Mucosae

2- Submucosa

3- Muscularis:
Circular layer
Longitudinal layer

4- Adventitia

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25
Q

What is Deglutition?

A

1- Tongue shapes the chewed, lubricated food (Bolus) and moves it to the back of the mouth cavity

2- Tongue rises against the Palate and closes the Nasopharynx

3- Uvula and Palate seal off the Nasal Cavity

4- Epiglottis covers the Trachea
Breathing is temporarily interrupted

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26
Q

What is Stomach?

A

J-shaped enlargement of GI Tract
Esophagus goes to Stomach

1- Esophageal Sphincter
2- Cardia
3- Body
4- Pyloric Antrum
5- Pyloric Canal
6- Pyloric Sphincter
7- Pylorus
8- Duodenum

Fundus:
Top part of Stomach

Lesser Curvature:
Top part

Greater Curvature:
Bottom part

Serosa

Muscularis:
1- Longitudinal layer
2- Circular layer
3- Oblique layer

Rugae of Mucosa

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27
Q

What are the Functions of the Stomach?

A

1- Mixes saliva, food, and gastric juice to form Chyme
2- Serve as reservoir for food before release into Small Intestine
3- Secrete gastric juice, which contains HCL, Pepsin, Intrinsic Factor, and Gastric Lipase
4- Secretes Gastrin into blood

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28
Q

What are the Cells of the Stomach?

A

1- Surface Mucous Cell:
Secretes mucus

2- Mucous Neck Cell:
Secretes mucus

3- Parietal Cell:
Secretes HCL - Kills microbes in food, denatures proteins, converts Pepsinogen inti Pepsin
Secretes Intrinsic Factor - Needed for absorption of vitamin B12 for Erythropoiesis

4- Chief Cell:
Secretes Pepsinogen - Pepsin (activated form) breaks down proteins into peptides
Secretes Gastric Lipase - Splits Triglycerides into fatty acids and Monoglycerides

5- G Cell:
Secretes the hormone Gastrin - Stimulates Parietal Cells to secrete HCL and Chief Cells to secrete Pepsinogen, and increase motility of stomach, and relaxes Pyloric Sphincter

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29
Q

What is Pancreas?

A

Pancreas is a Gland that:
Lies posteriorly to Stomach
Produce enzymes that digest carbs, proteins, fats, and nucleic acids
Produces Sodium Bicarbonate which buffers Stomach Acid
Empties its contents into the Duodenum

Head
Body
Tail
Pancreatic Duct (Duct of Wirsung)
Common Bile Duct
Major Duodenal Papilla

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30
Q

What is Liver and Gallbladder?

A

Liver:
Makes Bile, which is important in the emulsification of fats

Right Lobe
Left Lobe
Right Hepatic Duct
Left Hepatic Duct
Common Hepatic Duct

Gallbladder:
Stores Bile until it is needed

Fundus
Body
Neck
Cystic Duct

Right and Left Hepatic Ducts merge into Common Hepatic Duct
Common Hepatic Duct and Cystic Duct merge into Common Bile Duct
Common Bile Duct merges with Pancreatic Duct into Hepatopancreatic Ampulla (Ampulla of Vater) and goes inot Duodenum

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31
Q

What is Histology of Liver?

A

Liver composed of:
Hepatocytes
Bile Canaliculi
Hepatic Sinusoids

1- Portal Triad:
Bile Duct
Branch of Hepatic Artery
Branch of Hepatic Portal Vein

2- Central Vein

3- Bile Canaliculi:
(Canals leading to Bile Duct from between Hepatic Laminae)

4- Hepatocytes

5- Hepatic Laminae:
(Rooms for Hepatocytes)

6- Hepatic Sinusoids:
(Between Hepatic Laminae)

7- Stellate Reticuloendothelial Cell (Kupffer Cell)

8- Connective Tissue

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32
Q

What is Blood Supply of the Liver?

A

1- Oxygenated blood from Hepatic Artery
Nutrient-rich deoxygenated blood form Hepatic Portal Vein

2- Hepatic Sinusoids

3- Central Vein

4- Hepatic Vein

5- Inferior Vena Cava

6- Right Atrium

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33
Q

What is Functions of Liver and Gallbladder?

A

1- Carbohydrate, lipid, and protein metabolism
2- Processing of drugs and hormones
3- Bilirubin excretion
4- Bile Salts synthesis
5- Storage
6- Phagocytosis
7- Vitamin D activation

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34
Q

What is Small Intestine?

A

Small Intestine:
Majority of Digestion and Absorption occurs in Small Intestine

Duodenum
Jejunum
Ileum

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35
Q

What is Functions of Small Intestine?

A

1- Segmentations mix Chyme with Digestive Juices and brings food into contact with Mucosa for Absorption
Peristalsis propels Chyme through Small Intestine

2- Completes Digestion of carbohydrates, proteins, lipids
Begins and completes digestion of nucleic acids

3- Absorbs about 90% of nutrients and water that pass through Digestive System

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36
Q

What is Circular Folds in Small Intestine?

A

Circular Folds:
Plicae Circulares
Increase surface area for digestion and absorption

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37
Q

What is Histology of Small Intestine?

A

1- Serosa

2- Muscularis:
Longitudinal layer
Myenteric Plexus
Circular layer

3- Submucosa:
Lymphatic vessel
Arteriole
Venule

4- Mucosa:
Muscularis Mucosae
Lamina Propria
Lymphatic Nodule
Paneth Cell
Opening of Intestinal Gland
Enteroendocrine Cell
Lacteal
Goblet Cell
Blood Capillaries
Villi
Absorptive Cell (with Microvilli)

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38
Q

What are Cells of Small Intestine?

A

1- Paneth Cell:
Secretes Lysozyme
Capable of Phagocytosis

2- Enteroendocrine Cell:
Secrete the hormone Secretin, Cholecystokinin (CCK), or GIP

3- Goblet Cell:
Secrete Mucus

4- Absorptive Cell:
Digests and absorbs nutrients

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39
Q

What is Intestinal Juice and Brush Border Enzymes?

A

Intestinal Juice:
Provides a vehicle for absorption of substances from Chyme as they come in contact with the Villi

Brush Border Enzymes:
Found on surfaces of the Microvilli of Absorptive Cells
Break down food products

40
Q

What is Mechanical Digestion in Small Intestine?

A

1- Segmentation:
Localized contractions

2- Peristalsis:
Propulsive contractions

41
Q

What is Chemical Digestion in Small Intestine?

A

Digestion of:
Carbs
Proteins
Lipids
Nucleic Acids

42
Q

What is Activity of Pancreas?

A

Deliver pancreatic juice into Duodenum via Pancreatic Duct to assist absorption

43
Q

What is Activity of Liver?

A

Produce Bile (Bile Salts) necessary for emulsification and absorption of lipids

44
Q

What is Activity of Gallbladder?

A

Store, concentrate, and deliver Bile into Duodenum via Common Bile Duct

45
Q

What is Activity of Small Intestine?

A

Major site of digestion and absorption of nutrients and water in GIT

46
Q

What is Activity of Mucosa/Submucosa’s Intestinal Glands?

A

Secrete intestinal juice to assist absorption

47
Q

What is Activity of Mucosa/Submucosa’s Absorptive Cells?

A

Digest and absorb nutrients

48
Q

What is Activity of Mucosa/Submucosa’s Goblet Cells?

A

Secrete Mucus

49
Q

What is Activity of Mucosa/Submucosa’s Enteroendocrine Cells?

A

Secrete:
1- Secretin
2- Cholecystokinin (CCK)
3- Glucose-Dependent Insulinotropic Peptide (GIP)

50
Q

What is Activity of Mucosa/Submucosa’s Paneth Cells?

A

Secrete Lysozyme (bacterial enzyme)
Phagocytosis

51
Q

What is Activity of Mucosa/Submucosa’s Duodenal Glands (Brunner’s Glands)?

A

Secrete alkaline fluid to buffer stomach acids and mucus for protection and lubrication

52
Q

What is Activity of Mucosa/Submucosa’s Circular Folds?

A

Folds of Mucosa and Submucosa that increase surface area for digestion and absorption

53
Q

What is Activity of Mucosa/Submucosa’s Villi?

A

Fingerlike projections of Mucosa that are sites of absorption of digested food
Increase surface area for digestion and absorption

54
Q

What is Activity of Mucosa/Submucosa’s Microvilli?

A

Microscopic, membrane-covered projections of Absorptive Epithelial Cells that contain Brush-Border Enzymes
Increase surface area for digestion and absorption

55
Q

What is Activity of Segmentation?

A

Type of Peristalsis
Alternating contractions of Circular smooth muscle fibers that produce segmentation and resegmentation of sections of Small Intestine
Mixes Chyme with Digestive Juices
Brings food into contact with Mucosa for absorption

56
Q

What is Activity of Migrating Motility Complex (MMC)?

A

Type of Peristalsis:
Waves of contractions and relaxation of Circular and Longitudinal Smooth muscle fibers passing the length of Small Intestine
Moves Chyme towards Ileocecal Sphincter

57
Q

What is Activity of Salivary Amylase?

A

Source:
Salivary Glands

Substrate:
Starches (polysaccharides)

Products:
Maltose (disaccharide)
Maltotriose (trisaccharide
Alpha-Dextrin

58
Q

What is Activity of Lingual Lipase?

A

Source:
Lingual Glands in Tongue

Substrate:
Triglycerides (fats and oils)
Other lipids

Products:
Fatty acids
Diglycerides

59
Q

What is Activity of Pepsin?

A

(Activated from Pepsinogen by Pepsin and HCL)

Source:
Stomach Chief Cells

Substrate:
Proteins

Products:
Peptides

60
Q

What is Activity of Gastric Lipase?

A

Source:
Stomach Chief Cells

Substrates:
Triglycerides

Products:
Fatty acids
Monoglycerides

61
Q

What is Activity of Pancreatic Amylase?

A

Source:
Pancreatic Acinar Cells

Substrates:
Starches (polysaccharides)

Products:
Maltose (disaccharide)
Maltotriose (trisaccharide)
Alpha-Dextrin

62
Q

What is Activity of Trypsin?

A

(Activated from Trypsinogen by Enterokinase)

Source:
Pancreatic Acinar Cells

Substrates:
Proteins

Products:
Peptides

63
Q

What is Activity of Chymotrypsin?

A

(Activated from Chymotrypsinogen by Trypsin)

Source:
Pancreatic Acinar Cells

Substrates:
Proteins

Products:
Peptides

64
Q

What is Activity of Elastase?

A

(Activated from Proelastase by Trypsin)

Source:
Pancreatic Acinar Cells

Substrates:
Proteins

Products:
Peptides

65
Q

What is Activity of Carboxypeptidase?

A

(Activated from Procarboxypeptidase by Trypsin
(Activated from Procarbcurypeptidase by Trypsin)

Source:
Pancreatic Acinar Cells

Substrates:
Amino acids at Carboxyl end of peptides

Products:
Amino acids
Peptides

66
Q

What is Activity of Pancreatic Lipase?

A

Source:
Pancreatic Acinar Cells

Substrates:
Triglycerides that have been emulsified by Bile Salts

Products:
Fatty acids
Monoglycerides

67
Q

What is Activity of Ribonuclease?

A

Source:
Pancreatic Acinar Cells

Substrates:
RNA

Products:
Nucleotides

68
Q

What is Activity of Deoxyrybonuclease?

A

Source:
Pancreatic Acinar Cells

Substrates:
DNA

Products:
Nucleotides

69
Q

What is Activity of Brush-Border Enzymes of Microvilli Alpha-Dextrinase?

A

Source:
SI

Substrate:
Alpha-Dextrin

Products:
Glucose

70
Q

What is Activity of Brush-Border Enzymes of Microvilli Maltase?

A

Source:
SI

Substrates:
Maltose

Products:
Glucose

71
Q

What is Activity of Brush-Border Enzymes of Microvilli Sucrase?

A

Source:
SI

Substrates:
Sucrose

Products:
Glucose
Fructose

72
Q

What is Activity of Brush-Border Enzymes of Microvilli Lactase?

A

Source:
SI

Substrates:
Lactose

Products:
Glucose
Galactose

73
Q

What is Activity of Brush-Border Enzymes of Microvilli Enterokinase?

A

Source:
SI

Substrates:
Trypsinogen

Products:
Trypsin

74
Q

What is Activity of Aminopeptidase?

A

Source:
SI

Substrates:
Amino acids at Amino ends of peptides

Products:
Amino Acids
Peptides

75
Q

What is Activity of Dipeptidase?

A

Source:
SI

Substrates:
Dipeptides

Products:
Amino Acids

76
Q

What is Activity of Nucleosidase and Phosphatase?

A

Source:
SI

Substrates:
Nucleotides

Products:
Nitrogenous Bases
Pentose
Phosphates

77
Q

What is Activity of Lacteal?

A

1- Micelle in Lumen of SI

2- Micelle broken into 2 parts:
Large-chain and short-chain fatty acids
Monoglycerides

3- Simple diffusion into Absorptive Cell of Villus:
Inside they become Triglyceride engulfed by Chylomicron

4- Chylomicron goes to Lacteal of a Villus

5- Go to Thoracic Duct

6- Go to junction of Left Internal Jugular and Left Subclavian Veins

78
Q

What is Anatomy of Large Intestine?

A

From Small Intestine’s Ileum:

1- Vermiform Appendix
Mesoappendix connecting Ileum and Vermiform Appendix

2- Cecum

3- Ileocecal Sphincter (Valve)

4- Ascending Colon:
Has Teniae Coli on it
All parts of Colon made of Haustra (bulbs of the colon)

5- Right Colic Flexure (Hepatic)

6- Transverse Colon

7- Left Colic Flexure (Splenic)

8- Descending Colon:
Has Omental Appendices on it

9- Sigmoid Colon

10- Rectum

11- Anal Canal:
External Anal Sphincter (voluntary)
Internal Anal Sphincter (involuntary)
Anal Column

12- Anus

79
Q

What is Functions of Colon?

A

Functions of Colon:

1- Haustral churning, Peristalsis, and Mass Peristalsis drive contents of Colon into Rectum

2- Bacteria in Colon converts proteins into amino acids, break down amino acids, and produce some B Vitamins

3- Absorption of some water, ions, and Vitamins

4- Formation of feces

5- Defecation

80
Q

What is Histology of Colon?

A

1- Serosa

2- Muscularis:
Longitudinal layer
Myenteric Plexus
Circular layer

3- Submucosa:
Venule
Arteriole
Lymphatic vessel

4- Mucosa:
Muscularis Mucosae
Lymphatic Nodules
Lamina Propria
Intestinal Glands
Goblet Cells
Absorptive Cells
Openings of Intestinal Glands

5- Lumen of Large Intestine

81
Q

What is Glands and Cell Types of Colon?

A

1- Goblet Cells:
Secrete Mucus

2- Absorptive Cells:
Has Microvilli
Absorb water

82
Q

What is Mechanical Digestion in Colon?

A

1- Haustral Churning:
Distention reaches a certain point and walls of the Haustra contract to squeeze contents onwards

2- Peristalsis:
Propulsive contractions

3- Mass Peristalsis:
Strong Peristaltic wave that begins in Transverse Colon and quickly drives the contents of the Colon into the Rectum

83
Q

What is Chemical Digestion in Colon?

A

The last stages of digestion occur through bacterial action:

Substances are further broken down by bacteria
Some vitamins are synthesized by bacterial action

84
Q

What is Absorption and Feces Formation?

A

1- Absorption:
Colon absorbs water, electrolytes, and some Vitamins

2- Feces:
Consist of water, inorganic salts, sloughed-off epithelial cells, bacteria, products of bacterial decomposition, and undigested portions of food

85
Q

What is Defecation Reflex?

A

Rectal wall distends and Stretch Receptors send sensory nerve impulses to the Sacral Spinal Cord

Motor impulses travel back to the Descending Colon, Sigmoid Colon, Rectum, and Anus

Longitudinal Rectal muscles contract and the Internal Anal Sphincter opens

86
Q

What is Activity and Function of Large Intestine’s Lumen?

A

Activity:
Bacterial activity

Function:
Breaks down undigested carbs, proteins, and amino acids into products that can be expelled in feces or absorbed and detoxified by Liver
Synthesize certain B Vitamins and Vitamin K

87
Q

What is Activity and Function of Large Intestine’s Mucosa?

A

Activity:
1- Secrete Mucus

2- Absorption

Function:
1- Lubricate Colon
Protects Mucosa

2- Water absorption solidifies feces and contributes to body’s water balance
Solutes absorbed include ions and some vitamins

88
Q

What is Activity and Function of Large Intestine’s Muscularis?

A

Activity:
1- Haustral Churning
2- Peristalsis
3- Mass Peristalsis
4- Defecation Reflex

Function:
1- Moves contents from Haustrum to Haustrum by muscular contractions
2- Moves contents along length of Colon by contractions of Circular and Longitudinal muscles
3- Forces contents into Sigmoid Colon and Rectum
4- Eliminates feces by contractions in Sigmoid Colon and Rectum

89
Q

What are the Phases of Digestion?

A

1- Cephalic Phase:
Stimulates Gastric secretions and motility

2- Gastric Phase:
Neural and hormonal mechanisms

3- Intestinal Phase:
Neural and hormonal mechanisms

90
Q

What is the Negative Feedback Loop for Gastric Juice pH and Gastric Motility?

A

1- Food enters Stomach

2- Increased pH of Gastric Juice
Increased distention of Stomach walls

3- Chemoreceptors and Stretch Receptors in Stomach detect pH increase and distention and send nerve impulses to Submucosal Plexus

4- Submucosal Plexus sends Parasympathetic nerve impulses to both Parietal Cells and Smooth Muscle in Stomach Walls

5- Parietal Cells secrete HCL, and Smooth Muscle contracts more vigorously

6- Increase in acidity of Stomach Chyme, mixing of Stomach contents, emptying of Stomach

91
Q

What is the Stimulus, Site of Secretion, and Actions of the Major Hormone Gastrin?

A

1- Stimulus:
Distention of Stomach, partially digested proteins and caffeine in Stomach, and high pH of Stomach Chyme stimulate Gastrin secretion by Enteroendocrine G Cells

2- Location:
Enteroendocrine G Cells located mainly in Mucosa of Pyloric Antrum of Stomach

3- Major Effects:
Promotes secretion of gastric juice
Increases gastric motility
Promotes growth of Gastric Mucosa

4- Minor Effects:
Constricts Lower Esophageal Sphincter
Relaxes Pyloric Sphincter

92
Q

What is the Stimulus, Site of Secretion, and Actions of the Major Hormone Secretin?

A

1- Stimulus:
Acidic Chyme (High H+ level) that enters Small Intestine stimulates secretion of Secretin by Enteroendocrine S Cells

2- Location:
Enteroendocrine S Cells in Mucosa of Duodenum

3- Major Effects:
Stimulates secretion of Pancreatic juice and Bile that are rich in Bicarbonate ions (HCO3)

4- Minor Effects:
Inhibits secretion of Gastric Juice
Promotes normal growth and maintenance of Pancreas
Enhances effects of CCK

93
Q

What is the Stimulus, Site of Secretion, and Actions of the Major Hormone Cholecystokinin (CCK)?

A

1- Stimulus:
Partially digested proteins (amino acids), Triglycerides, and fatty acids that enter the Small Intestine stimulate secretion of CCK by Enteroendocrine CCK Cells

2- Location:
Enteroendocrine CCK Cells in Mucosa of Small Intestine
Also released in Brain

3- Major Effects:
Stimulates secretion of Pancreatic Juice rich in Digestive Enzymes
Causes ejection of Bile from Gallbladder and Opening of Sphincter of the Hepatopancreatic Ampulla (Sphincter of Oddi)
Induces satiety

4- Minor Effects:
Inhibits Gastric emptying
Promotes normal growth and maintenance of Pancreas
Enhances effects of Secretin

94
Q

How does Aging affect Digestive System?

A

Aging results in:

1- Decreased secretory mechanisms and motility
2- Loos of strength and tone of digestive muscular tissue
3- Changes in Neurosecretory feedback
4- Diminished response to pain and internal sensations

95
Q

What are some Digestive System Disorders?

A

Tooth decay
Periodontal diseases
Ulcers
Diverticula
Tumors
Hepatitis
Anorexia Nervosa

Anatomy & Physiology Review I (30 decks)

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