Digestive System (lecture) Flashcards
What is the function of the digestive system?
- Ingestion
- Digestion
- Absorption
- Elimination
What is the purpose of ingestion and digestion?
Break down food to absorbable units. E.g. proteins to amino acids
What are accessory organs of the digestive system?
- liver
- pancreas
- gall bladder
Describe the oral cavity
- NKSSET -> protects from abrasion
- contains tongue -> skeletal muscle
- contains salivary glands -> produce saliva
What are the three types of salivary gland?
- parotid
- sublingual
- submandibular
What is the function of saliva?
- Lysozyme -> kills bacteria
- Lubricate food
- Amylase -> breaks down starch
How many teeth do humans have?
20 deciduous (baby)
32 permanent
What are the different types of permanent teeth?
- 8 incisors=cut/bite
- 4 canines=tear
- 8 bicuspids (premolars)=chew
- 12 molars=chew
- last set are wisdom teeth
- impacted wisdom teeth are removed
What is peristalsis?
Rhythmic wave, one-directional movement
Describe the esophagus
- NKSSET
- Adventitia (no serosa)
- Muscularis externa:
- skeletal muscle: top 1/3
- transition: middle 1/3
- smooth muscle: bottom 1/3
What is esophageal hiatus?
Hole in the diaphragm esophagus goes through
What is the function of the stomach?
- store food
- mechanical digestion
- chemical digestion
- low pH to kill bacteria
Pyloric sphincter
controls what enters the GI tract
Cardiac sphincter
“false sphincter”
Rugae
folds of the stomach (allows stomach to stretch)
What is gastric ulcer?
- ET necrosis revealing CT
- Sx: N/V, hematochezia, hematemesis, dyspnea
- Tx: antibiotics and antacids
What is hiatal hernia?
- elastic fibers of the esophagus weaken
- Sx: acid reflux,
- Tx: medication, minor surgery
Structures of the small intestine
Duodenum
Jejunum
Ileum
Duodenum functions
- neutralize stomach acid through bicarbonate from the pancreas
- receives secretions from the pancreas, liver, and gallbladder
- bile from the liver and gall bladder
- bicarbonate and digestive enzymes from the pancreas
- secretions from the sphincter of Oddi
Jejunum functions
site for majority of absorption
Ileum functions
majority of absorption
- lots of blood vessels and lymphocytes
Large intestine functions
- store feces
- absorb water
- lots of bacteria
Taenia Coli functions
- ribbons of muscle along the large intestine that facilitate peristalsis and help form structures known as Haustra which aid in water and electrolyte absorption
Cecum structures
Ileocecal Valve
- controls flow of digested material between the SI and LI
Appendix
- contains lots of bacteria
Name the structures of the Large intestine
Cecum
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
Sigmoid colon functions
- store feces
- Levator Ani muscle -> allows control of bowel movement
What is appendicitis?
- Inflammation of the appendix that closes off opening from the overproliferation of bacteria
- can progress to burst appendix, which releases bacteria into peritoneal fluid (peritonitis)
What is diverticulitis?
Pouches on the outsides of colon (diverticulum) that can become inflamed.
What is colitis?
umbrella term that is used to describe diseases that cause colon inflammation
Colon cancer
- polyps
- becoming number one cause of cancer deaths
Dx: 1) colonoscopy -> Biopsy
2) Stool sample
Liver functions
- makes bile to emulsify fat (breaks up into smaller pieces)
- breaks down toxins and drugs
- removes and destroys old RBCs
- makes all blood proteins (except antibodies)
What is the falciform ligament; liver?
Thin, crescent-shaped sheet of connective tissue that attaches part of the liver to the anterior abdominal wall and the diaphragm
Describe the pathway of bile
- From L & R lobe of liver (combine to common hepatic duct)
- Gallbladder (store bile). -> cystic duct
- Common bile duct -> released into duodenum
What are gallstones?
- Concentrated bile that forms stones.
- prevention: male < 30 yo
What is jaundice?
- yellowing of skin, mucus membranes, and sclera due to excess buildup of bilirubin, a yellowish compound that is the byproduct of blood breaking down. It is also a component of bile.
- common in newborns because the liver is unable to keep up with blood breakdown
- Tx: phototherapy
What is cirrhosis?
- Scar tissue formed on the liver
Sx: jaundice
Tx: liver transplant
