Digestive System Flashcards
What are the main parts of the digestive system?
The mouth
The pharynx
The esophagus
The stomach
The small intestine
The large intestine
What are the accessory parts of the digestive system?
Teeth
The Tongue
The Salivary glands
The Pancreas
The Liver
The Gallbladder
What is the main function of the mouth? What is the main function of the esophagus?
The mouth begins mechanical digestion and the esophagus brings food to the stomach
What is the main function of the Stomach?
It uses enzymes to break down food
What is the main function of the small intestine?
It continues to breakdown food with enzymes but it also absorbs nutrients into the bloodstream
What is the main function of the salivary glands?
They produce an enzyme that begins food digestion via saliva
What is the main function of the pancreas?
The pancreas produces numerous enzymes that enter into the small intestine to digest foods
What is the main function of the liver?
It produces bile which helps to break down fats and filters all the blood from the DS
What is the main function of the gallbladder?
It stores bile (we could live without it)
What is the main function of the Large intestine?
It removes solid wastes, it reabsorbs water into the bloodstream, it houses bacteria that produce vitamin k for blood clotting
What makes up the exit to the digestive system?
The rectum (inner anal canal) and anus
What are the four major layers of the digestive tract?
The mucosa
The submucosa
The muscularis externa
The serosa
What’s special about the mucosa layer of the SI?
The mucosa of the small intestine make up folds called plicae (increased surface area = increased absorption)
What is the Submuscosa?
It contains large blood vessels and lymphatics
It also contains several sensory neurons, parasympathetic ganglia, and sympathetic postganglionic fibers
What is the Muscularis Externa?
It is the layer that contains smooth muscle
It is innervated by myenteric plexus
What is the function of the serosa? (Digestive system)
It helps to anchor the digestive system to mesenteries
What is it called when food gets moved through the digestive system?
Peristalsis
What is it called when material is churned fragmented while moving through the DS?
Segmentation
What are mesenteries?
They are fused double sheets of peritoneal membrane that help stabilize position of organs and blood vessels
What are the structures to know in the Oral cavity?
Tongue
Uvula
Palatoglossal arches
Salivary glands
Teeth
What is ankyloglossia?
It’s the result of a very short lingual frenulum
What are the three sections of the tongue?
The body, the root, and the dorsum (where the taste buds are contained)
What are the two types of muscles on the tongue?
Intrinsic tongue muscles (fine movement) and Extrinsic tongue movement (gross movement)
What are the three pairs of salivary glands? What do they produce?
The parotid
The sublingual
The submandibular
They all produce salivary amylase
What are the types of teeth?
There are four incisors per jaw
There are two cuspids (canine) per jaw
Four bicuspids (premolars) per jaw
Four to six molars per jaw
What are the three parts of a tooth?
The Crown (made of enamel, consists of dentine, consists of pulp with is highly vascularized)
The Neck
The Root (Consists of artery, vein, nerve)
What are the three phases of swallowing?
The Buccal phase (The tongue pushes food to the oropharynx)
The Pharyngeal phase (The epiglottis covers the glottis and you swallow)
The Esophageal phase (the upper esophageal sphincter opens and bolus begins moving down)
What are the sections of the stomach?
The lesser curvature
The greater curvature
The Cardia (entrance)
The Fundus
The Body
The Gastric Rugae
The Pylorus (exit)
What are the three types of muscles found on the stomach?
Circular, longitudinal, and oblique muscles
What types of cells are located in the stomach?
Mucous surface cells- produce lots of mucous to protect stomach lining
Mucous neck cells- produce mucous to lubricate food entering the stomach
Gastric pits & glands
What are the types of gastric pits?
Parietal cells- secrete intrinsic factor (absorbs vitamin b12) and HCl (kills microorganisms)
Chief cells- secrete pepsinogen (turns into pepsin via HCl)
Enteroendocrine cells- cells of stomach that produce hormones. G cells produce gastrin which activates the parietal cells
How big is the small intestine?
About 20 ft long and 1-2 inches in diameter
What are the three sections of the small intestine?
Duodenum (receives digestive enzymes from pancreas and bile from the liver/gallbladder)
Jejunum (most digestion and absorption occurs here) (8 feet)
Ileum (12 feet)
What happens when acidic chyme enters the duodenum?
Buffers are used to maintain a normal small intestine pH of about 7 or 8
What are inside the small intestine that increase surface area?
Plicae (which contain villi)
What is contained inside a villus and what is their function?
A villus contains capillaries (which absorbs digested nutrients) and a lacteal (where large lipids go)
What are intestinal crypts?
They stay at the base of the villi and produce new epithelial cells
It also contains enteroendocrine cells that produce intestinal hormones including CCK and Secretin
What is Secretin?
It causes the liver to begin making bile and causes the pancreas to release buffers into the duodenum
What is CCK (Cholecystokinin)?
Causes the pancreas to release digestive enzymes into duodenum and it causes the gallbladder to release stored bile
How big is the large intestine?
It’s about five feet long and 3 inches wide
What are the six parts of the large intestine?
Cecum
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
What is the cecum?
It connects the ileum to the LI
The ileocecal valve regulates movement of material between the sections
What is attached to the cecum?
The (vermiform) appendix
What are the parts of the rectum?
The anal canal
The anal columns
And the anus
What makes the liver special?
It’s the largest visceral organ of the body
It has a large blood reservoir
It’s involved in metabolic regulation, hematological regulation, bile production
Where does the hepatic portal system take all blood in the DS?
The liver
What happens to the blood that passes through the liver?
Phagocytic cells remove bad erythrocytes
Liver cells also synthesize plasma proteins for blood clotting
What does bile do?
It emulsifies fat
What separates the two sections of the liver?
The falciform ligament
What is the liver divided into?
Lobules
The center of each liver lobule contains a vein from what?
The hepatic portal system
What are the phagocytic cells in the liver called?
Kupffer cells
What is involved in collecting and disposing of bile in the gallbladder?
The cystic duct
