Digestive System Flashcards
What is the alimentary canal?
hollow tube structures of the digestive systems accessory structures
Teeth, tongue, salivary glands, liver, gallbladder, bile ducts, pancreas
What are nutrients required?
Carbohydrates
Proteins
Lipids
Vitamins
Minerals
What are the goals of the digestive system?
To digest food into smaller molecules
Absorb smaller molecules into the blood
What is mechanical digestion?
Physical breakdown of food into smaller pieces
Forms more surface area for contact with digestion enzymes
What is chemical digestion?
Splitting complex, non absorbable food molecules to smaller absorbable molecules (hydrolysis)
Enzymes that speed up reactions and enable digestion to occur
What are the glands of the mouth?
The parotid gland
The submandibular gland
The sublingual gland
What is the physiology of digestion in the mouth?
Does mechanical and chemical digestion
Mastication
Amylase partially digests carbs
Mucus mixes with food to make it easier to swallow
Produces a bolus
What is the pharynx composed of?
Nasopharynx
Oropharynx
Laryngopharynx
Epiglottis
What is the esophagus?
A tube that does through the diaphragm to connect to the stomach
What is deglutition?
Swallowing, which involves 4 cranial nerves
What is peristalsis?
Wavelike contractions to move the bolus down
What is the stomach made of?
Has 3 layers of smooth muscle in its walls going in different direction
The lining has rugae for more surface area
What do mucus cells do?
Produce alkaline mucous
What do endocrine cells do?
Produce gastrin
What do parietal cells do?
Produce hydrochloride acid and intrinsic factors
What do chief cells do?
Produce pepsinogen and gastric lipase
What do regenerative cells do?
They are stem cells to replace other cells
How does the liver work?
Has 4 loves arranged in hepatic lobules
Hepatocytes produce bile which help in chemical digestion
Bile is released in the hepatic ductules leading to hepatic duct
How does the bilary passageway work?
The common bile duct is a tube common to the hepatic, cystic and pancreatic duct
Hepatopancreatic sphincter controls the opening of the duct
What does the gallbladder do?
Collects the overflow of bile and concentrates it
What does the pancreas do?
Secrets bicarbonate ions and enzymes for carbs, lipids and protein digestion
What is the small intestine composed of?
The duodenum, jejunum, and ileum
What does secretin do in the small intestine?
Released from endocrine cells of the duodenum responding to acetic chyme
What does cholecystokinin do?
Secreted by endocrine cells of the duodenum responding to presence of lipids
What is segmentation in the small intestine?
Ensures all contents of the small intestine contacts the vili for absorption
What does peristalsis in the small intestine do?
It further moves the contents through the jejunum and ileum to the ileocecal valve
What is the colon?
Part of the large intestine
Composed of the cecum, ascending, transverse, descending, and sigmoid colon and rectum
What is the anus?
Part of the large intestine
Contains 2 sphincter muscles (internal and external)
What does the hepatic portal vein do?
Drains nutrient rich blood from capillaries in villi and carries it to capillary beds in the liver
What do the lacteals do?
They absorb fatty acids and glycerides
Join the bloodstream at the subclavian veins and eventually the liver
What are the functions of digestive system?
Ingestion
Digestion
Absorption
Defecation
