12a Abdomen Deep and the Digestive System Flashcards
(100 cards)
The anus has two sphincters
- Internal anal sphincter composed of smooth muscle (involuntary-parasympathetic control)
- External anal sphincter composed of skeletal muscle (voluntary)
These sphincters are closed except during defecation
Colon
Has distinct regions: ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, and sigmoid colon
The transverse and sigmoid portions are anchored via mesenteries called mesocolons
95% of water is absorbed in the large intestines by osmosis
Large Intestines (Teniae coli)
three bands of longitudinal smooth muscle in its muscularis
Large Intestines (Haustra)
pocketlike sacs caused by the tone of the teniae coli
-Slow segmenting movements that move the contents of the colon and sequentially contract as they are stimulated by distension
Large Intestines (Epiploic appendages)
fat-filled pouches of visceral peritoneum
Parts of Colon
Ascending Colon
Transverse Colon
Descending Colon
Sigmoid Colon-S Curve to the rectum
Rectum and anal canal
Cecum with appendix
Sac that receives waste from the small intestines and lies below the ileocecal valve
Contains a worm-like vermiform appendix (lymphatic tissue)
Presence of food in the stomach
Activates the gastrocolic reflex
Initiates peristalsis that forces contents toward the rectum
The Gallbladder
Thin-walled, green muscular sac on the ventral surface of the liver
Stores and concentrates bile by absorbing its water and ions
Releases bile via the cystic duct, which flows into the bile duct
Composition of Bile
A yellow-green, alkaline solution containing bile salts, bile pigments, cholesterol, neutral fats, phospholipids, and electrolytes
The chief bile pigment is bilirubin, a waste product of heme
Bile salts
cholesterol derivatives that:
Emulsify fat
Facilitate fat and cholesterol absorption
Help solubilize cholestero
Enterohepatic circulation
recycles bile salts
The chief bile pigment is
bilirubin, a waste product of heme
Hepatocytes’ functions include
- Production of bile
- Processing bloodborne nutrients
- Storage of fat-soluble vitamins
- Detoxification
Secreted bile flows between hepatocytes toward the bile ducts in the portal triads
Liver sinusoids
enlarged, leaky capillaries located between hepatic plates
Kupffer cells
hepatic macrophages found in liver sinusoids
Portal Triads
Hexagonal-shaped liver lobules are the structural and functional units of the liver
Composed of hepatocyte (liver cell) plates radiating outward from a central vein
Portal triads are found at each of the six corners of each liver lobule
Portal triads consist of a bile duct and
Hepatic artery – supplies oxygen-rich blood to the liver
Hepatic portal vein – carries venous blood with nutrients from digestive viscera
The ligamentum teres
Is a remnant of the fetal umbilical vein
Runs along the free edge of the falciform ligament
The falciform ligament
Separates the right and left lobes anteriorly
Suspends the liver from the diaphragm and anterior abdominal wall
Exocrine function
Secretes pancreatic enzymes
1. Trypsin- polypetides>peptides
2. Lipase- fat>fatty acids
3. Amylase- Carbohydrates>glucose
4. Nucleases –Nucleic acid>nucleotides
5. Carboxypeptidase- polypeptides>peptides
Acini (clusters of secretory cells) contain zymogen granules with digestive enzymes
Endocrine function
- Insulin –(Beta cells of Islets of Langerhans) decreases blood sugar by removing it from blood into cells
2. Glucagon- (Alpha cells)increases blood sugar by breaking down glycogen into glucose and fat.
Cystic Duct
connect the Gall bladder to the Common Hepatic Duct to form the Common Bile Duct
Main Pancreatic Duct
also known as the Duct of Wursung
Accessory Pancreatic Duct
Duct of Santorini