Digestive System Flashcards
What are the 3 chief functions of the digestive system
Digestion: breakdown of food
Absorption: transfer of nutrients from digestive tract into the blood or lymph
Elimination: eliminate undigested waste material
What is the digestive tract
A continuous passageway beginning at the mouth and terminating at the anus
What is the function of the accessory organs in the digestive tract
Organs necessary for the digestive process but are not a direct part of the digestive tract
What are the accessory organs of the digestive tract
Salivary glands
Liver
Gallbladder
Pancreas
Thin two layered serous, epithelial membrane that lines the abdominopelvic cavity and covers most of the organs within the cavity
Peritoneum
Parietal layer of the peritoneum lines what
Lines the abdominopelvic cavity; outer layer
The visceral layer of the peritoneum covers the
Organs
What is parietal space
Cavity between the 2 membrane layers and contains serous fluid
What is the functions of the peritoneum
Supports and binds the organs
Carrie’s blood vessels, lymphatic vessels and nerves
There are 4 subdivisions of the peritoneum which are
Mesentery
Mesocolon
Greater omentum
Lesser omentum
The mesentery is fan shaped and extends from the posterior abdominal wall to the small intestines. What does it house?
Houses blood vessels and nerves between the layers that supply the intestine
The mesocolon extends from?
The posterior abdominal wall to the colon
Greater omentum is large, contains much fat and hangs like an apron over the front of the intestine. It extends from?
The lower portion of stomach and colon (transverse) like a loop
The lesser omentum is a small membrane that extends between the
Stomach and the liver
What are the four layers of the digestive tract wall (from inside to outside)
Mucosa
Submucosa
Smooth muscle
Serous membrane
What is the function of the mucosa
Secretion, protection and absorption
What is the function of the submucosa
-Regulation of digestive function
-intestinal cell nourishment
-removal of absorbed nutrients
Function of smooth muscle
Motility; moves food through the GI tract
Serous membrane function
Protection
Support
Separation between organs
What is a lumen
Hollow space within the “tube” of the digestive tract
There are 2 types of muscular contractions important in the digestive process which are
Peristalsis and segmentation
What propels the tube contents rapidly
Peristalsis
Mixes the contents (food with digestive juices) and propels them slowly
Segmentation
The mouth aka oral cavity processes food by what 4 things
Ingestion
Mastication
Mixing with saliva
Deglutition
What is deglutition
Movement of food towards throat to be swallowed
Salivary amylase does what
Initiates starch digestion
What is the function of the tongue
Aids in chewing, swallowing and speech
Surface covered in tastebuds
The pharynx is aka the
Throat
3 divisions of the pharynx are
Oropharynx
Nasopharynx
Laryngopharynx
A bolus of food is moved into the pharynx where ______ forces it into the esophagus
Reflex swallowing
What raises to prevent food and liquid from entering the nasal cavity
Solar palate and uvula
The opening to the larynx/trachea is guarded by the
Epiglottis
Swallowed food enters into the
Esophagus
The esophagus is a muscular tube about 10 inches long, no digestion occurs here instead food is
Lubricated with mucus
The esophagus passes through ______ of the diaphragm to join stomach
Esophageal hiatus
Inner oblique muscle layer of the stomach aids in
Grinding food and mixing it with digestive juices
What are the structures of the stomach
Greater curvature
Lesser curvature
Fundus
Body
Pylorus
The sphincters of the stomach
Lower esophageal sphincter (LES)
Pyloric
What is a sphincter
A muscular ring that regulates the size of an opening
(Two sphincters at each end of the stomach)
The lower esophageal sphincter (LES) is located where? What does it control
Located between the esophagus and the stomach
-controls the passage of food from the esophagus into the stomach
LES is aka the
Cardiac sphincter
The pyloric sphincter is located where? What does it regulate
Located between the distal end of the stomach and the small intestine
-regulates the passage of food from stomach into the duodenum
What is the stomachs function
To store food, regulate movement of food into the small intestine (digestive organ) and churn
When the stomach is empty the lining forms many folds called
Rugae
(As stomach expands these folds disappear)
The stomach secretes substances to form gastric juice. What are the 2 digestive juices
Hydrochloric acid
Pepsin
Hydrochloric acid does what
Prepares proteins for digestion and activates pepsin; also destroys foreign organisms
Pepsin (enzyme) digests
Proteins
Stomach delivers what to the small intestine
Chyme
What is the longest part of the digestive tract
The small intestine (10ft in length)
What are the 3 subdivisions of the small intestine
Duodenum (1st 10 inches)
Jejunum
Ileum
Almost all digestion and absorption of food occurs in the
Small intestine
Functions of the small intestine
Secretion
Motility
Digestion
Absorption
Mucus is secreted in the small intestine in order to
Protect the small intestine from the highly acidic content coming from stomach
Motility, segmentation occurs to ensure food is thoroughly mixed with digestive tissues and it is regulated to ensure
Proximal segments contract before the distal segments
Enzymes are secreted that continue digestion of
Proteins and carbohydrates
Subdivisions of the large intestine include (10)
Cecum
Ileocecal valve
Appendix
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
Anal canal
Anus
The cecum is the
First part of the large intestine; it is a small pouch
The ileocecal valve is a sphincter between the ileum of the small intestine and the cecum; it prevents
Food from travelling backward into the small intestine
The vermiform appendix (appendix) is attached to the cecum; it is a small blind tube containing
Lymphoid tissue
The ascending colon is the second portion of the large intestine; it extends upward along the
Right side of the abdomen towards the liver
The transverse colon bends and extends across the abdomen. It bends sharply and extends downwards forming the
Descending colon
Sigmoid colon is the lower part of the colon that bends posteriorly in an “s” shape and continues downwards; empties into the
Rectum
Undigested food enter the ____ and leaves to the outside of the body through the anus
Anal canal
Functions of the large intestine (6)
Secretes mucus
Water is reabsorbed
Stores and eliminates undigested food
Vitamin K and some B complex vitamins are generated
Peristalsis
Defecation
The accessory organs release secretions through ducts into digestive tract. What are the accessory organs
Salivary glands
Liver; releases bile, emulsifies fat
Gallbladder
Pancreas
What are the 3 pairs of salivary glands
Parotid
Submandibular
Sublingual
Functions of the salivary glands
Secrete saliva
Moistens food
Facilitates mastication and deglutition
Helps keep teeth and mouth clean
What is the largest accessory organ
Liver
The liver is located in the upper right portion of the abdominal cavity under the diaphragm. It is supplied with blood through what 2 things
Portal vein: rich in digestive end products
Hepatic artery: high in oxygen
The main digestive function of the liver is to
Emulsify fat
-the liver synthesizes bile, which is necessary for fat digestion
Bike exits the liver by the common hepatic duct which merges with the _____ to form the _____
Cystic duct (from gallbladder); to form the common bile duct > duodenum
What are some of the function of the liver
Manufactures bile
Controls blood glucose levels
Modifies fat
Stores some vitamins, iron
Forms blood plasma proteins
Destroys old RBC’s
Synthesizes urea
Detoxifies harmful substances
The gallbladder is a muscular sac located in the inferior surface of the liver. It stores
Bile
When chyme enters the duodenum the ______ contracts, the hepatopancreatic sphincter opens and what flows into the duodenum
The gallbladder contracts; bile flows into the duodenum
The pancreas is a long endocrine gland that extends from the duodenum to the spleen. It produces?
Insulin and glucagon hormones
The pancreas releases what 3 things
Enzymes that digest food (amylase, trypsin, lipases)
Water to dilute food
Bicarbonate ions (to neutralize the acidic chyme arriving from the stomach)
Enzymes are protein molecules that act as
Catalysts, speeding up chemical reactions
What is the role of water in the digestive system (3)
Used in the chemical process of digestion (hydrolysis)
Produces digestive juices
Dilutes food
How many litres of water is secreted into the digestive tract daily
7L
Absorption is the process of moving nutrients from the GI tract into the
Blood or lymph nodes
Most absorption takes place in the
Small intestine
Absorption; Fats take an indirect route to the blood, since they are absorbed into
Lacteals; and travel through the lymphatic system to the blood
What vitamins are produced by bacteria in the colon and they are absorbed from the large intestine along with some water
Vitamin K and some B vitamins
Nerves in digestive system are located in
Submucosa and between muscle layers of organ walls (enteric nervous system- ENS)
What typically stimulates digestion
Parasympathetic
What typically inhibits digestion
Sympathetic system
Nervous and hormonal mechanism control of digestion main goal is to optimize
The processes of digestion and absorption
What stimulates the secretion of saliva and the release of gastric juices
Sensory stimuli
Bolus in stomach stimulates release of
Gastrin into blood
** promotes stomach secretions and motility
When chyme enters the duodenum hormones known as ____ are released in duodenum that stimulates what and inhibits what
Gastric-inhibitory peptide (GIP)
Stimulate intestinal activity inhibits stomach activity
Gastric inhibitory peptide (GIP) stimulates
Insulin release from pancreas
A number of hormones function to regulate appetite, what initiates hunger
Ghrelin
What is anorexia
Chronic loss of appetite
-possible emotional or social favotrs
What is anorexia nervosa
Psychological disorder
Starving one self
What is bulimia
Binge purge syndrome
Eating disorders stress the body; what can result
Lack of estrogen produced in women
Loss of bone (osteoporosis)
Degeneration of myocardium
4 sources of digestive problems
Mechanical
Nervous
Chemical
Hormonal
What is peritonitis
Inflammation of the peritoneum following infection of an organ covered by peritoneum
(Ex of causative factors ruptured appendix, perforated ulcer, penetrating wound)
Mumps is a contagious viral infection of what salivary gland
Parotid
What is cirrhosis
Chronic disease where active liver cells are replaced by scar tissue (alcoholic type is most common)
Hepatitis is what inflammation
Liver inflammation
Cholelithiasis is aka
Gallstones
What is pancreatitis
Destruction of pancreas by its own secretion
