Digestive System II Flashcards
Describe the location of the stomach and where it gets its vasculature?
- Intraperitoneal
- In LUQ (left upper quadrant)
- Vasculature from the celiac trunk
How does the stomach contribute to digestion?
- Mechanical breakdown
- mixing and churning via segmentation (contractions of muscular wall)
- Chemically/enzymatically
- secreted acids and enzymes
Mixed bolus and gastric juices is called:
Chyme - viscous, acidic, soupy mixture
What mesentery is associated with the greater curvature of the stomach?
Greater omentum = forms “apron”
What is the greater omentum?
What is found here?
Mesentery from the greater curvature of the stomach to the transverse colon
- Protective layer
- Blood, nerves and lymphoid tissue
- Lipid deposition for temp control
- Immunological function
- Moves easily = follows infection within the perotineum
Why is the upper portion of the stomach given the term “cardiac”
Close to heart
Shares dermatome with heart = sensory implications (eg heartburn)
What are the four major parts of the stomach as mentioned in lecture?
- Fundus
- Cardia
- Pyloric Canal (Pylorus)
- Body
What type of epithelium makes up the stomach? And why?
Simple Columnar Epithelium - absorption
What are the three layers of smooth muscle in the stomach?
- Inner oblique
- middle circular
- outer longitudinal
What are the folds within the stomach called? What is their purpose?
Rugae
- Allow stomach to stretch
The surface of the Rugae is called the ______ and is where we would find:
The surface of the Rugae is called the Gastric Pit and is where we would find:
- Stem cells
- 1 cell layer of Simple Columnar Epithelium
Each gastric pit is associated with ______ which produce the HCl and enzymes
Each gastric pit is associated with Gastric glands (many) which produce the HCl and enzymes
Label the Rugae:
- Gastric pit
- Mucosa
- Muscularis
- Submucosa
- Gastric Gland
- Serosa
What are the 5 Gastric Gland secretory cells mentioned in lecture?
- Surface Mucous Cell
- mucous
- Mucous Neck Cell
- mucous
- Parietal Cell
- HCl
- Chief Cell
- pepsin, lipase
- Neuroendocrine cell
- gastrin
What is the difference between the mucous produced by the surface mucous cells and the mucous produced by the mucous neck cells?
- Surface mucous cell:
- Thick alkaline mucous
- Mucous Neck Cell
- Higher water content
Which gastric gland-secretory cells secrete HCl?
Parietal Cells
Which Gastric gland - secretory cell secretes pepsin and lipase?
Chief cell
What is important about the type of enzymes produced by chief and parietal cells?
Chief cells secrete pre-enzymatic enzymes. Not able to digest until they mix with the mucous within the mucous neck cell = activates enzymes/acid
PROTECTION - prevents digestion of “self”
What hormone is released by the neuroendocrine cell in the gastric gland?
Gastrin - stimulates chief and parietal cells
What are the three parts of the small intestine?
- Duodenum
- associated with stomach, liver and pancreas
- Final digestion
- Jejunum
- Most absorption
- ileum
- Remaining absorption
What is present in the small intestine that makes it especially good at absorption? (3)
- Circular folds called plicae circulares
- villi
- microvilli
The small intestine is mostly ______ (location) with the exception of the duodenum
The small intestine is mostly intraperitoneal (location) with the exception of the duodenum
The small intestine extends from the ______ of the stomach to the ______ (beg of L. intestine) and is found in _______ quadrant(s)
The small intestine extends from the pyloric orifice* of the stomach to the *ileocecal valve (beg of L. intestine) and is found in all 4 quadrant(s)
The duodenum receives ____ from the stomach and secretions of the _____ and _____ via the ______
The duodenum receives chyme from the stomach and secretions of the pancreas and gallbladder via the gall bladder
What occurs in the duodenum?
Digestion of fat, proteins and sugars
What is the vasculature of the duodenum?
Anastomosis of the celiac and SMA (superior mesenteric a.) branches
recall: anastomosis = connection/joining between vessels
Which structure provides protection for the small intestine against the acidity of the chyme? How?
Brunner’s Glands
- Provide abundant alkaline mucous to neutralize the acidity of the chyme
- Pancreatic buffers contribute to neutralization
Where are Brunner’s glands found?
In the submucosal layer (connective tissue layer of duodenum)
What does chyme in the duodenum stimulate?
Stimulates mucosa to produce hormones (secretin and cholecystokinin -CCK) to relax sphincter = release pancreatic juice and bile
What is bile?
Where is it stored?
Bile is a byproduct of liver filtration that aids in the digestion of lipids (when combined with salt)
stored in the Gallbladder
Bile and pancreatic juices enter the Duodenum through the:
Hepatopancreatic ampulla
What does the pancreas produce? (ie what is found in the pancreatic juices entering the duodenum)
Enzymes that aid in the digestion of fats, proteins and carbs + bicarbonate buffer
Describe the position of the pancreas
(in relation to stomach, duodenum and spleen; _____perittoneal, and quadrant)
Pancreas is
- posterior to the stomach
- between the duodenum and spleen
- Retroperitoneal
- upper quadrants
What is the vasculature of the pancreas?
Anastomosis of celiac and SMA branches (superior mesenteric a)
What is secreted by the pancreas?
- Digestive enzymes
- trypsin, chymotrypsin (protein)
- pancreatic amylase (carbs)
- pancreatic lipase (fats)
- Bicarbonate buffer
- neutralizes acidic chyme
- establishes alkaline pH for pancreatic digestive enzymes
Where does the pancreas drain into (vein)
Splenic vein
Head of the pancreas is associated with the _____ and the tail with the ______
Head of the pancreas is associated with the duodenum and the tail with the spleen
What are the endocrine secretions of the pancreas? Where are they released from?
Hormones:
- glucagon (from alpha cells)
- insulin (from beta cells)
- Somatostatin (from delta cells)
- Islets of langerhans - associated with vasculature
The connective tissue of the pancreas that is NOT islets of langerhans and that drains into ducts is called?
Pancreatic acini (acinus sing.)
What is the exocrine secretion from the pancreas?
From Pancreatic acini
- Water, ions and digestive enzymes
- buffers (sodium bicarbonate)
How does the pancreas prevent enzymes from eating through epithelium?
Centroacinar cells - secrete bicarbonate buffer and regulate pre-enzyme release from acinar cells