Digestive System Flashcards
Digestive system
Aka gastrointestinal system
Responsible for changing food and nutrients into waste
Digestive enzymes are chemicals that break down food and nutrients into smaller forms so that the body can absorb them
Ingestion
The process of taking in food, chewing, and dissolving it in the mouth
This forms a soft ball (bolus) in preparation for digestion
This process utilizes the structures of the lips, teeth, face muscles, saliva, tongue and pharynx
Digestion
When the bolus enters the stomach it goes through two different digestion processes
First process is Mechanical:
Three layers of smooth muscle within the stomach wall enable the stomach to contract in many directions mashing the food
Second process is chemical:
The brain sends messages to the gastric glands in the stomach wall stimulating them to secrete gastric juices i.e pepsin
Absorption
Glucose and amino acids are absorbed by active transport after combining with a carrier molecule
These nutrients enter the blood through the capillaries in the villi and are transported to the liver
Fatty acids and monoglycerides are absorbed into the epithelial cells of the intestinal lining
There they are reassembled into triglycerides and then pass into the villi
Elimination
The removal of indigestible foods and other waste materials referred to as feces from the body
When feces arrive at the rectum, defaecation is stimulated through peristalsis
This process takes several hours depending on the quality of food and health of the digestive tract
What are the functions of the digestive system in order?
Ingestion
Digestion
Absorption
Elimination
What are the 4 primary organs of the digestive system?
Mouth
Stomach
Small intestines
Large intestines
Mouth
Mastication and deglution
Food enters the system at the mouth and is chewed by the teeth to break it up into smaller amounts so that it can be swallowed and digested
The salivary glands produce saliva which contain enzymes that start to break down the food
The food is then swallowed and moves down into the oesophagus (throat)
The epiglottis is a small flap of tissue that covers the trachea (windpipe) to prevent food from entering and going into the lungs
Stomach
Gastric digestion
The stomach is located in the left upper quadrant of the abdominal cavity
It is a food reservoir in the first major site of digestion
Digestive glands in the stomach produce pepsin and hydrochloric acid which turn the food into a semi liquid called chyme
Food leaves the stomach and enters into the small intestine
Small intestines
The small intestine is a coild, 20 foot long tube consisting of three parts
1 Duodenum
2 jejunum
3 ileum
About 90% of absorption of nutrients occurs in the small intestine (mostly ileum)
Villi which line the intestines and contain capillaries absorb the nutrients
The remaining 10% takes place in the large intestine and in the stomach
Peristaltic movements are what move the food through the small intestine
The walls of the intestine contract and relax to create segmental waves that push the food through intestines

Large intestines
The large intestine (aka bowel) extends from the small intestine to the anus
It joins the small intestine at the ileocecal valve - this valve closes after food has passed through it to prevent back up of material from the bowel
The appendix (in the right lower quadrant of abdomen) - is attached to the cecum
The appendix is believed to serve no purpose in the digestive system but problems arrive if it becomes inflamed or infected
The large intestine starts at the right lower quadrant, runs superiorly (ascending colon) crosses the abdominal cavity as the (transverse colon) and then runs inferiorly down the left side of the abdominal cavity as the (descending colon)
In the medial lower abdomen it becomes the rectum which leads to the external opening called the anus
Food is stored in the large intestine until it is expelled by defecation
Defaecation is controlled by two sphincters
the internal sphincter is controlled by the autonomic nervous system as is the rest of the digestive system ( this means the individual has no conscious control)
The external sphincter is controlled by the somatic nervous system and is under voluntary control
What are the accessory organs of digestion?
Liver
Gallbladder
Pancreas
liver
Lying in the upper right side of the abdomen, just under the diaphragm, lies the liver the largest and one of the most complex visceral organs in the body
Located below the diaphragm in the right upper quadrant of the abdomen under the ribs
The liver is capable of numerous complex and diverse actions, which include:
Secretes bile, which is important in the digestion of fat
Converts excess glucose into glycogen and stores it then when glucose is needed it releases glucose into the blood
Stores iron and certain vitamins
Converts excess amino acids to fatty acids and urea
Cholesterol and vitamin D is synthesized and stored in the liver
Performs many important functions in the metabolism of proteins, fats, and carbohydrates
Manufactures many of the plasma proteins found in the blood (clotting factor)
Breaks down bacteria and filters worn out red blood cells
Gallbladder
Pear-shaped organ of the digestive system
Situated under the liver and interior to the duo denum
Bile (a watery fluid which consists of salts and pigments) is produced by the liver and sent to the gallbladder through the Bile ducts
The gallbladder stores and concentrates bile ready for transport to the duodenum via the cystic and bile ducts
When digestion is complete bile is extracted by the ileum and also the large intestine and returned to the liver
Pancreas
A large elongated gland in the abdomen below the stomach with its head nestled in the curve of the duodenum
The pancreas is both exocrine (digestive system) and an endocrine (endocrine system) gland
It’s endocrine portion secretes the hormones insulin and glucagon
It’s exocrine parts secretes pancreatic juices, an alkaline fluid containing a number of digestive enzymes that chemically digest proteins, lipids and carbohydrates
In general, secretion of digestive juices is stimulated by the presence of chyme and by hormones
Food is slowly digested as it moves along through the digestive tract
Carbohydrate digestion begins in the mouth, where salivary amylase breaks down starches to dextrin and maltose
The enzymes trypsin, amylase, and lipase are secreted by the pancreas
tryspin breaks down proteins, amylase breaks down starch and lipase breaks down fats
Anorexia, nausea and vomiting
These are physiological responses that are common to many digestive disorders
They are protective responses to the extent that they signal the presence of disease and in the case of vomiting, remove toxic substances from the system
Anorexia
Represents a loss of appetite
Nausea
An unpleasant sensation often accompanied by pallor, sweating and rapid heartbeat
Vomiting (emesis)
 The sudden and forceful oral expulsion of the contents of the stomach
Esophageal reflux disease
The term reflux refers to backward or return movement
Refers to the backward movement of stomach contents into the esophagus, a condition that causes heartburn
Caused by a weak or incompetent lower esophagus sphincter that allows reflux to occur
Most common 30 to 60 minutes after eating and is worse if lying down or bending at the waste
This condition is usually treated with anti-acids
the person is advised not to over eat, to avoid tight clothing at the waist and not to lie down after a meal
Gastritis
This refers to inflammation of the mucosa of the stomach
Acute gastritis: is usually caused by local irritant such as bacteria, alcohol, caffeine and aspirin
May cause vomiting and possibly bleeding
Chronic gastritis: an ongoing problem usually resulting from alcohol abuse, cigarette smoking or chronic use of anti-inflammatory medication (NSAIDS)
Ulcers
Peptic ulcer is a term used to describe ulcerative disorders that occur in the upper digestive tract (stomach and small intestine) The area exposed to acid pepsin secretions
This causes pain and discomfort which is described as burning, gnawing or cramp like and often occurs when the stomach is empty
The pain is relieved by food or anti-acids
Complications include bleeding and perforation ( a hole that develops)
Irritable bowel syndrome
A disorder characterized by recurrent intestinal symptoms not explained by structural abnormalities
Persistent or recurrent abdominal pain, gas, alternating diarrhoea and constipation over a period of more than three months
Usually recommended that the client avoid fatty and gassy foods, alcohol, caffeine, stressful situations
Inflammatory bowel disease
The two related inflammatory bowel diseases are ulcerative colitis and Crohn’s disease 
Both produce inflammation of the ball without any known cause and both tend to occur in families
CROHN’S DISEASE
can affect any area of the digestive tract from the mouth to the anus
40% of cases the lesions are in the small intestine 30% they are in both the small and the large intestine
Consists of granulomatous lesions that are surrounded by normal appearing tissue
Symptoms are diarrhea, cramping pain, usually in the lower right quadrant, weight loss, fluid and electrolyte disorders and low-grade fever
The intestine may not be able to absorb nutrients and deficiencies may occur
There often periods when symptoms decrease and then flare up
ULCERATIVE COLITIS
Inflammation of the colon only
Main symptom is diarrhoea which may occur many times a day
Other symptoms; lack of appetite, weakness and fatigue
Symptoms may fluctuate (decrease and flare up)
Appendicitis
Common
Mostly Occurs in children or young adults but can occur at any age
The appendix becomes inflamed, swollen and gangrenous and eventually perforates (opens or bursts) if not treated
Cause is unknown -
Thought to be related to obstruction by hardened fecal matter
Sudden onset pain in the abdominal area and nausea
After a few hours, the pain becomes localized to the right lower quadrant which may be tender to the touch, low grade fever
Treatment: immediate surgical removal of appendix
If not removed, complications may occur & can be life threatening
Diarrhea
Excessive frequent passage of stool
Can be acute or chronic
Diarrhea that lasts less than 4 days is usually caused by stomach flu or other common illness and clear up on its own
Diarrhea that lasts more than 3 or 4 weeks is usually caused by inflammatory conditions
Constipation
Infrequent passage of stools
Can occur as a primary problem or a problem associated with another condition
Causes: inadequate fibre in the diet, inadequate fluid intake, inactivity or bedrest, failure to respond to the urge to defecate, haemorrhoids
Some medications may cause constipation (i.e painkillers, anti- acid medications)
Celiac disease
Intolerance to gluten
Gluten is a protein found in grains such as wheat, rye, oats, and barley
Symptoms: diarrhea, bloating, flatulence, abdominal pain
Intake of gluten may cause weakness, muscle wasting and fatigue due to lack of absorption of nutrients
Hemorrhoids
Swollen, tortuous veins in the rectum or anus
May be internal or external
Symptoms: itching and bleeding
The blood is bright red
Causes: straining during defecation, dampness, standing for long periods of time
Allergies
Allergies to foods and additives are common
Know the ingredients contained in the products as some clients may have life-threatening allergies
Cancer
Can be found at any location in the digestive system, from the esophagus to the intestines, to the rectum
Chemical digestion takes place in the
Duodenum
Difference between mechanical and chemical
Mechanical means something has to work to mix the food (aka mouth)
And chemical is the enzymes breaking things down - chemical reaction
Semisolid fluid that enters the small intensities
Chyme
This structure controls food travelling to the lower section of digestive tract and is situated at the end of the stomach
Help keep food moving in one direction
Sphincters
Travel of food in the digestive system
mouth, esophagus, stomach, small intestine, large intestine, rectum and anus
Lower part of the esophagus cardiac sphincter does what?
Relaxes to allow food to enter into the stomach
Maltase
Converts maltose into glucose
Invertase
Converts sugar into glucose
Erepsin
Converts peptones into amino acids
What is the cardiac sphincter
The cardia is the first part of the stomach, which is connected to the esophagus. It contains the cardiac sphincter, which is a thin ring of muscle that helps to prevent stomach contents from going back up into the esophagus.
