Digestive System Flashcards
1
Q
Consists of a complex set of organs, glands, and ducts that work together to function for ingestion, digestion, absorption, and elimination.
A
Digestive system
2
Q
What are the functions of the digestive system?
A
- Ingestion (and mastication)
- Mechanical Breakdown
- Propulsion (and mixing)
- Digestion (and secretion)
- Absorption
- Defecation/Elimination
3
Q
Consumption/taking food into the digestive tract via the mouth
A
ingestion
4
Q
Where food is chewed and churned
A
mechanical breakdown
5
Q
chewing
A
mastication
5
Q
- Swallowing
- movement of food through the digestive tract
A
propulsion
5
Q
Swallowing
A
propulsion
6
Q
- breakdown of large organic molecules into smaller molecules that can be absorbed
- Enzymes secreted by the digestive organs will allow breakdown of the complex food molecules to their chemical building blocks
A
digestion
7
Q
- Chemical building blocks will be absorbed and it will become nourishment for the body
- movement of molecules out of the digestive tract into the blood or lymphatic system
A
absorption
8
Q
- removal of undigested material and other waste products as feces
- Insoluble substances will be eliminated
A
elimination/defecation
9
Q
The digestive system is consisted by what
A
- digestive/Gastrointestinal tract (G.I. Tract)
- Accessory organs
10
Q
A continuous muscular tube that winds from the mouth down to the anus
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digestive/Gastrointestinal tract (G.I. Tract)
11
Q
- Functions to produce secretions
- Allows breakdown of food for absorption and nourishment
A
Accessory organs
12
Q
What are the layers of the digestive tract?
A
- Mucosa
- Submucosa
- Muscularis
- Serosa
13
Q
- innermost tunic
- consist of three layers
A
Mucosa
14
Q
three layers of mucosa
A
- mucous epithelium
- lamina propria
- muscularis mucosae
15
Q
Rich in mucus secreting cells; protects digestive organs from being digested by enzymes working within the cavity
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mucous epithelium/simple columnar epithelium
16
Q
Absorbs the end products of digestion; protects against pathogens
A
lamina propria
17
Q
Muscular mucosa; contains smooth muscles for motility especially for the small intestine
A
Muscularis Mucosae
18
Q
- lies outside the mucosa
- thick layer of loose connective tissue containing nerves, blood vessels, and small glands
A
Submucosa
19
Q
Where most blood vessels, lymphatic vessels, and nerve fibers are located (submucosa)
A
Areolar Tissue
20
Q
enables the organs to recoil or go back to its normal state after distention (submucosa)
A
Elastic Fibers
21
Q
- Muscularis Externa; Muscular layer
- Responsible for peristalsis; functions for movement of food as it travels into the digestive tract of the body
A
muscularis
22
Q
Found in the inner part of muscularis
A
circular smooth muscle
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found in the outer part of muscularis
longitudinal smooth muscle
24
- Outermost Layer
- Considered to be the visceral peritoneum; acts for protection of the external covering of the organs in the digestive tract
- consists of connective tissue layer (adventitia)
Serosa
25
- the connective tissue layer of regions of digestive tract not covered by peritoneum
- when the outer layer of the digestive tract is derived from adjacent connective tissue.
adventitia
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Walls of the abdominal cavity and abdominal organs are associated with a serous membrane. What is this serious membrane called?
peritoneum
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serous membrane that covers the organs
visceral peritoneum
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Serous membrane that lines the wall of the abdominal cavity
parietal peritoneum
29
potentially life threatening inflammation of the peritoneal membrane
peritonitis
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- Functions to hold many of the digestive organs in the abdominal cavity in place
- Fat-like structure that is attached to the intestine allowing for stability and to connect to other organs in the digestive tract
- Provides route for blood vessels, lymphatic vessels, and nerves to reach the digestive tract
Mesentery
31
- It is bounded by the lips and cheeks and contains the teeth, tongue, and palate.
- Functions mainly for mastication/mechanical digestion;
oral cavity
32
Point where the food is introduced to the mouth and churned down into smaller pieces with the assistance of the oral cavity structures
mastication
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No enzymes and chemical substances involved in digestion the food; happens physically
mechanical digestion
34
for Crushing or tearing of food
teeth
35
Used to move food around the mouth
tongue
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Surface to help grind/mash food
hard palate
37
Prevents food from going up to the nasal cavity
Soft Palate/ Uvula
38
- Secretion of saliva; softens and lubricates food
- Contains salivary amylase which helps break down carbohydrates into glucose
Salivary gland
39
the different salivary glands
- Parotid Gland (Biggest salivary gland)
- Submandibular Gland (Wharton gland)
- Sublingual Gland
40
The teeth and saliva work together to break down food into what?
a bolus
41
Connects the mouth to esophagus
consists of Nasopharynx, Oropharynx, Laryngopharynx
pharynx
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are responsible to act as a passageway of food
The Oropharynx and Laryngopharynx
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- Located in the posterior walls of the oropharynx and the laryngopharynx
- Assist the passage of food
- force the food from the pharynx by pushing it down to the esophagus
Pharyngeal Constrictor Muscle
44
- Also known as the gullet
- plays an important role for swallowing, which transports food from pharynx to stomach
- A muscular tube about 25 cm (10 inches) long and is collapsed when not involved in food propulsion
- lined with moist stratified epithelium that extends from pharynx to stomach
- The upper ⅔ of it contains skeletal muscle in its wall, while the lower ⅓ contains smooth muscle in its wall
- numerous mucous glands produce thick, lubricating mucus that coats itss inner surface
esophagus
45
Allows relaxation and distention of the esophagus; bolus can easily pass through the structure
Wave of Relaxation
46
The force that makes the bolus move; makes the area constricted from behind the bolus, so that it can easily move the bolus towards the succeeding part of the esophagus
Wave of Contraction
47
- located on the posterior aspect of the esophagus
- areas of thickened muscle that acts as a lid and keeps food from passing from one part of the tract to another.
Sphincters
48
Located in the proximal portion
Upper Esophageal Sphincter
49
Located distally; Cardiac Sphincter; joins the cardiac orifice of the stomach; stomach = structure that receives the bolus from the esophagus
Lower Esophageal Sphincter
50
Process of propulsion; swallowing
Deglutition
51
What are the phases of Swallowing:
Voluntary Phase
Pharyngeal Phase
Esophageal Phase
52
Bolus of food (yellow) is pushed by the tongue against the palates and posteriorly towards the oropharynx.
Voluntary Phase
53
- Respiration is momentarily inhibited;
Soft palate rises closing the nasopharynx to prevent food going towards the nasal cavity. The pharynx and larynx are elevated.
- Successive constriction of the pharyngeal constrictors from superior to inferior forces the bolus through the pharynx into the esophagus. Folds will expand to close the passage of the larynx.
Pharyngeal phase
54
- Epiglottis bent down over the larynx opening by the force of bolus pressing against it.
- Bolus is moved by peristaltic (peristalsis) contractions of the esophagus towards the stomach.
Esophageal Phase
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- From the esophagus, the bolus moves towards it where chemical digestion will occur.
- Houses food(bolus) for mixing with the different secretions in order to become a semifluid mixture called chyme
stomach
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four regions of the stomach
Cardiac Part
Fundus
Body
Pyloric Part
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- Where esophagus opens into;
- Where bolus is received and passed into the stomach.
Cardiac Part
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Most superior portion of the stomach
Fundus
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- Inferior to the fundus
- Largest area of the stomach.
- Two curves:
1. Greater Curvature - Convex Lateral
2. Lesser curvature - concave medial.
Body
60
gastric folds allow mucosa and submucosa to stretch; disappears when the stomach is filled.
Rugae
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Where chyme travels to go into the small intestine particularly the duodenum.
Pyloric Part
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thick ring of smooth muscle allows chyme to be pushed down.
pyloric sphincter
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secretions from the gastric glands include:
Hydrochloric Acid
Pepsin
Mucus
Intrinsic Factor
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kills microorganism/bacteria, activates pepsin
Hydrochloric Acid
65
Digests protein ; Breaks covalent bonds of protein to form smaller peptide chains.
pepsinogen
66
Binds to vitamin B 12 (important in DNA synthesis and RBC production) synthesis to aid in absorption
Intrinsic factor
67
found in mucous cells; lubricates and protects stomach lining from acidic chyme and pepsin.
Mucus
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REGULATION OF STOMACH SECRETIONS
1. Cephalic Phase – anticipatory stage
2. Gastric Phase – greatest gastric secretion
3. Intestinal Phase – inhibitory stage
69
HORMONES INVOLVED IN GASTRIC SECRETIONS
- Gastrin
- Secretin
- Cholecystokinin
70
- produced in the gastric glands
- increases gastric secretion
Gastrin
71
- produced in the duodenum
- decreases gastric secretion
- increases pancreatic and bile
Secretin
72
- produced in the duodenum;
- decreases gastric secretions
- strongly decreases gastric motility
- increases gallbladder contraction
- increases pancreatic enzyme secretion
Cholecystokinin
73
- also referred as “small bowel”
- Part of the GI tract where most of the absorption of nutrients takes place.
Small intestine
74
THREE MODIFICATIONS THAT INCREASE SURFACE AREA OF SMALL INTESTINES
1. Circular Folds
2. Villi
3. Microvilli
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FOUR INTESTINAL CELL TYPES
1. Absorptive Cells
2. Goblet Cells
3. Granular Cells
4. Endocrine Cells
76
cluster of lymphatic nodes located in the ileum that help protect the
intestinal tract from harmful pathogens
Peyer's patches
77
- Consists of the cecum, colon, rectum, and the anal canal.
- About 1.5 meters long
- Primary purpose is absorption of excess water and excretion of waste products (feces)
- Nerves in the lining of the rectum senses the expansion and tells the body when it’s time to expel the waste (defecation reflex)
large intestine
78
- The beginning of the large intestine, is a dilated, pouch-like structure that hangs slightly below the ileocecal opening.
- Location: Right lower quadrant of the abdomen near the iliac fossa.
Cecum
79
Extends superiorly from the cecum to the right colic flexure, near the liver where it turns to the left.
Ascending colon
80
- The longest and most movable part of the large intestine.
- Extends from the right colic flexure to the left colic flexure near the spleen, where the colon turns inferiorly.
- It is suspended by a fold of peritoneum and sags in the middle below the stomach.
transverse colon
81
Extends from the left colic flexure to the pelvis where it becomes the sigmoid colon.
descending colon
82
At the brim of the pelvis, the descending colon makes an s-shaped curve part
called
sigmoid colon.
83
Straight muscular tube that begins at the termination of the sigmoid colon and ends the anal canal.
rectum
84
The last 2-3cm of the digestive tract is the anal canal which begins at the end of the rectum and ends at the anus.
* Internal anal sphincter – superior end (smooth muscle)
* External anal sphincter – inferior end (skeletal muscle)
ANAL CANAL, ANUS
85
- Largest internal organ of the body and weighs about 3 pounds.
- Location: Right upper quadrant of the abdomen, tucked against the inferior surface of the diaphragm.
- Has two major lobes: right lobe and left lobe (separated by the falciform ligament)
- Smaller lobes located on the inferior portion: caudate and quadrate lobe
- Main function: Processes nutrients and detoxifies harmful substances from the blood.
liver
86
- Largest internal organ of the body and weighs about 3 pounds.
- Location: Right upper quadrant of the abdomen, tucked against the inferior surface of the diaphragm.
- Has two major lobes: right lobe and left lobe (separated by the falciform ligament)
- Smaller lobes located on the inferior portion: caudate and quadrate lobe
- Main function: Processes nutrients and detoxifies harmful substances from the blood.
87
specific functions of liver
1. Digestion – bile neutralizes stomach acid and emulsifies fats, which facilitates fat digestion
2. Excretion – bile contains excretory products such as cholesterol, fats, and bile pigments that result from hemoglobin breakdown
3. Nutrient Storage - Liver cells remove sugar from the blood and store it in the form of glycogen; they also store fat, vitamins (A, B12, D, E, and K), copper,
and iron.
4. Nutrient conversion - Liver cells convert some nutrients into others; for example, amino acids can be converted to lipids or glucose
5. Detoxification - Liver cells remove ammonia from the blood and convert it to urea, which is eliminated in the urine; other substances are detoxified and
secreted in the bile or excreted in the urine.
6. Synthesis of new molecules - The liver synthesizes blood proteins, such as albumin, fibrinogen, globulins, and clotting factors.
88
- Location: Retroperitoneal, posterior to the stomach in the inferior part of the left upper quadrant.
- Has a head, body and tail.
- Islets of Langerhans –endocrine part of the pancreas in charge of producing the glucagon and insulin.
- Acini – exocrine part of the pancreas which produce digestive enzymes (pancreatic juice)
- Major function: Hormone Release and Control of Pancreatic Secretions
pancreas
89
COMPOSITION OF THE PANCREATIC JUICES
- Water
- Bicarbonate Ions
- Pancreatic Enzymes:
1. Trypsin (digests protein)
2. Amylase (digests starch)
3. Lipase (digests lipid)
4. Nucleases (digests nucleic acid)
