Digestive System Flashcards
Gastrointestinal Tract Definition
tube that extends from mouth to anus
GI Tract Components
mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus
GI Tract - Peristalsis
This process pushes things through the tube, smooth muscle contracts and moves the things along its path
GI Tract Digestion Definition
process of breaking down food into small fragments
GI Tract Mechanical Digestion
Physically taking the food and making it smaller with teeth
GI Tract Chemical Digestion
You use chemicals in the body to break food down on a more molecular level
GI Tract Absorption Definition
water and food molecules passthrough to GI lymphatics and blood vessels
GI Tract Waste Definiton
Eliminating the rest of food that the body cannot digest
Accessory Digestive Organs
not part of GItract, but assist with digestion
* tongue, teeth, salivary glands, liver,gallbladder, pancreas
Abdominopelvic Cavity lined by
Peritoneum
Parietal Peritoneum location
Lines abdominal wall
Visceral Peritoneum location
covers abdominal organs
Digestive System control by…
autonomic nervous system (This is involuntary so it must be Autonomic)
Parasympathetic definition
in general, it stimulates or increases activity of GI tract(REST AND DIGEST)
Sympathetic Definition
in general, it inhibit or decrease activity of GI tract
Oral Cavity lined with?
Nonkeratinized Stratified Squamos Epithelium
How many Incisors
2
How many Canines
1
How many Premolars
2
How many Molars
3
Kids; How many Incisors
2
Kids; How many Canine
1
Kids; How many Premolars
0
Kids; How many Molars
1
Tongue Information
Skeletal muscle covered with stratified squamos epithelium
Motor: Cranial Nerve XII, Taste. Sensory: Texture, CN V
Upper part of the oral cavity?
Palae
Hard Palate
Anterior 2/3 of palate, bony
Soft Palate
Posterior 1/3
Formed from skeletal muscle
Function of soft palate and uvula
Used to close off nasopharynx when we swallow
3 pairs of salivary glands?
Parotid, Submandibular, and Sublingual Glands
Salivary Glands function?
Help secrete salvia
Function of Saliva (1-3)
Dissolves food molecules so they can be tasted
Moistens food, aids into compacting it into bolus (BalL)
Cleanses mouth
Function of Salvia (4-5)
Chemical digestion of carbohydrates (with salivary amylase)
Lysozyme and Antibodies in saliva inhibit bacterial growth in the mouth
Pharynx Definition
“Throat”
Muscular tube that connects nasal cavity and mouth, to larynx and esophagus
Pharynx Function
This skeletal muscle helps us “voluntarily” propel stuff from the mouth into the esophagus (voluntary swallowing)
What conducts both food and air?
Oropharynx and Laryngopharynx
How many layers in the walls
4 Layers, or Tunics
Mucosa
Innermost Tunic
Epithelium
Lamina Propria (Areolar CT)
Muscularis Mucosae (Thin layer of smooth muscle)
Submucosa
Connective Tissue
Contains major blood vessels
Muscularis
typically contains 2 layers of smooth muscle:
1) inner circular layer
2) outer longitudinal layer
* Responsibleforperistalsis: alternate waves of contraction and relaxation
Serosa or Adventita
outermost layer
- serosa= visceral peritoneum + areolar CT
- adventitia= areolar CT only
Esophagus Function
Propel food into the stomach
Esophagus Gross Anatomy
muscular tube that connects pharynx to stomach
Esophagus Histology
- -mucosa:nonkeratinized stratified squamous epithelium
- -muscularis: 2 layers of muscle
- upper 1/3: skeletal muscle(Voluntary for swallowing)
- middle 1/3: skeletal + smooth * lower 1/3: smooth muscle only
Stomach Function
churns food (Mechanical digetion) and mixes it with gastric juice (Chemical Digestion) to break it down into chyme(sounds like kyme)
Stomach Gross Anatomy
- connects to esophagus and duodenum
- - located in the upper left part of the abdomen
Stomach Histology(1)
- -mucosahassimple columnar epithelium
- mucosacontainsgastric pits
- branching off of gastric pits aregastric glands:
- -muscularis: has three (3) layers of smooth muscle, not two!
Stomach Histology (2)
- innermost oblique, inner circular, outer longitudinallayers (You want three layers because of all the churning that occurs in the Stomach)
What is gastric juice?
Acids an enzymes that are secreted that are used to break down food.
Small Intestine Functions
1) finishes the chemical digestion process
2) absorbs most (90%) of all of the nutrients
Small Intestine; Duodenum
receives chyme from stomach
* receives bile and pancreatic enzymes throughduodenal papilla
Small Intestine; Jejunum
3/5 of remaining small intestine
HUGE surface area. The more surface area you have, the more absorption that can occur.
Small Intestine; Ileum
○ Last 2/5 of the small intestine
○ Still some folds, but also contains immune function
Remember the MALT stuff
Small Intestine Histology
mucosahassimple columnar epithelium w/ goblet cells
- small intestine containscircular folds (plicae circulares):
- folds of mucosa and submocosa
Small Intestine Functions
1) increase surface area of small intestine through which nutrients can be absorbed
2) slow the chyme down and allow it to mix with intestinal juices, allowing time for full nutrient absorption (“Act as speed bumps”)
- - on circular folds arevilli
Small Intestine Function (2)
help increase surface area (along with the microvillous border on the mucosa), and provide a greater distance for materials to be ingested and absorbed
* in center of each villus are blood vessels and alacteal
Lacteal is something that absorbs dietary fat.
Large Intestine Function
- Absorption of water and electrolytes
2. Storage of undigested material (feces) until it can be expelled from the body
Large Intestine Segments
1Cecum: connects to ileum
* lower right part of abdomen
*vermiform appendix (Looks like a little worm on the donor)
2)ascending colon: right side of body
3)transverse colon: runs from the right to left side of body
4)descending colon: left side of body
5)sigmoid colon: in pelvic cavity, S-shaped
6)rectum and anal canal: terminal portion of large intestine
Large Intestine Histology
- -mucosahassimple columnar epithelium w/ goblet cells
- -muscularis: 2 layers of smooth muscle
- outer longitudinal layerconsists ofteniae coli
- *haustra
Liver Function
1) produces and secretes bile (an agent that helps with fat/lipid digestion)
2) it processes the products of digestion (including ingested alcohol and drugs)
Liver Anatomy
- right
- left
- quadrate (Next to Gallblader)
- caudate (Next To Vena Cava)
Liver Histology
– central vein
– Portal triad: (Three things at every corner)
o Branch of hepatic portal vein (Has bigger opening in middle)
o Branch of hepatic artery (Has thicker walls)
o Branch of bile duct (Has a cuboidal epithelium)
Liver Blood Flow
Goes from Triad to Central Vein, brining blood high in oxygen, Artery
Vein is bringing nutrients
Liver Bile Production
Bile goes toward the Triad
Gallbladder
- underneath liver
- -function:it stores bile secreted by liver
Pancreas
– behind stomach
–Acinar Cells
* secretepancreatic juice (Bases and Enzymes)
* pancreatic juice leaves via apancreatic duct
Biliary Apparatus
a network of “tubes” that transport bile and pancreatic juices TO theduodenum!
Common Hepatic Duct Formation
rightandleft hepatic ducts(from liver) unite
What has a cystic duct
Gallbladder
What forms common bile duct?
Cystic duct and common hepatic duct, connects with pancreatic duct
Next step of common bile duct
common bile duct opens into duodenum at the duodenal papilla
* here, bile and pancreatic juices are secreted!
Arterial Supply to Abdominal GI Tract
from branches of:
1) celiac trunk(Stomach and something else)
2) superior mesenteric artery(GI Tract)
3) inferior mesenteric artery(Large Intenstine)
Venous Drainage in Abdominal GI Tract (1)
- -hepatic portal system: veins that drain blood from GI tract directly TO liver
- 4 main 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
- 4 main veins:
Venous Drainage in Abdominal GI Tract (2)
- blood from hepatic portal vein is processed by the liver cells (hepatocytes)
- once processed, blood leaves theliver via hepatic veins and into the inferior vena cava
