Digestive Flashcards
What are the two group of the digestive system?
Alimentary canal and Accessory organs
What are the four functions of the digestive system?
- Take in food
- Break it down and absorb nutrients into bloodstream
- Rid the body of indigestible remains
The Alimentary canal (or GI tract) runs from where to where?
Mouth to anus
What does the alimentary canal do?
- Digests food: breaks it down into smaller fragments
- Absorbs fragments into bloodstream through lining
What organs make up the alimentary canal?
mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus
Which organs make up the accessory organs?
Teeth, Tongue, Gallbladder, and Digestive glands
What is the function of salivary glands?
produce secretions that help breakdown foodstuffs
Which 2 organs secrete substances to aid in digestion?
Liver and Pancreas
How many parts are there to the small intestine? What are their names and locations?
3: Duodenum, Jejunem, and Ileum
Duodenum: shortest, connects to the stomach before connecting to the jejunem
Jejunem: connects duodenum and ileum
Ileum: longest, connects to colon
TRUE OR FALSE:
There are 3 portions that make up the large intestine
FALSE
There are 4: Ascending, Transverse, Descending, and Sigmoid colon
How many actions/stages are involved in food processing? What are they?
6
In order: Ingestion, Propulsion, Mechanical Breakdown, Digestion, Absorption, & Defecation
What’s Ingestion?
eating; entry of food into the alimentary canal through the mouth
Define Propulsion
the movement of food through the alimentary canal
What two processes are included in Propulsion?
Swallowing & Peristalsis
Explain Swallowing and Peristalsis
Swallowing: voluntary movement of food from the mouth to stomach via the pharynx and esophagus
Peristalsis: involuntary; sequential, alternating waves of contraction and relaxation of alimentary canal smooth muscle; propel food through intestines
What’s Mechanical Breakdown?
the mechanical breakdown of food via mastication and segmentation
What actions occur in mechanical digestion?
chewing, mixing food with saliva, churning food in stomach
Define Segmentation
Localized contractions of (usually) the small intestine that mixes food with digestive juices; food is moved forward then back, mixes food and breaks it down mechanically, absorption
What does Digestion involve?
The breakdown of complex food molecules into chemical building blocks (ex: protein –> amino acids)
Whats the step after Digestion and what is it?
Absorption; nutrients are absorbed through the lumen of the alimentary canal and into the blood (or lymph)
TRUE OR FALSE
Defecation is the elimination of excess nutrients
FALSE
Defecation is the elimination of indigestible substances via the anus in the form of feces
What is the Peritoneum? Name the 2 types and their locations
The Peritoneum consists of the serous membranes that line the abdominal cavity.
1. Visceral - membrane on external surface of most digestive organs
2. Parietal - membrane that lines the body wall
What is the fluid-filled space called between 2 peritoneums?
Peritoneal cavity
What is the double layer of peritoneum that holds organs in place?
Mesentery
What is the function of the mesentery? (3)
- Hold organs in place
- Site of fat storage
- Provides route for circulatory vessels, lymphatics and nerves
Describe the Difference between Peritoneal organs and retroperitoneal organs
Peritoneal organs are organs that have kept their mesentery while retroperitoneal organs are located behind the peritoneum.
Which organ is NOT retroperitoneal?
A. Duodenum
B. Large Intestine
C. Pancreas
D. Liver
D. Liver; the liver is considered peritoneal as it’s located in the peritoneal cavity
What are secondarily retroperitoneal organs?
Organs initially formed within peritoneum but become retroperitoneal; fuse to posterior abdominal wall
What are intraperitoneal organs?
organs located within the peritoneum
TRUE OR FALSE
The mesentery attaches to the posterior abdominal wall
TRUE
The gut tube is suspended by…
A. Retroperitoneum
B. Mesentery
C. Parietal peritoneum
D. Visceral peritoneum
B. Mesentery
What are the names of the two mesenteries? Their functions?
Greater omentum - a “fatty apron” of peritoneum
Lesser omentum - attaches to lesser curvature of stomach
All digestive organs have the same four basic layers (tunics):
Mucosa, Submucosa, Muscularis externa, and Serosa
What is the mucosa and how many layers does it have?
Mucosa is a tunic layer that lines the lumen and has 3 sublayers: Epithelium, Lamina propria, and Muscularis mucosae
What are the functions of these (the mucosa) layers?
Functions can perform one or all three:
- Secrete mucous, digestive enzymes, and hormones
- Absorbs end products of digestion
- Protects against infectious disease
Describe the Epithelium layer
- Simple columnar and mucous-secreting cells in most of tract
- Secretes mucous
- May secrete enzymes and hormones
What is the purpose of mucous?
Ease food passage and protect digestive organs from enzymes
TRUE OR FALSE
Simple squamous epithelium is found in the Mouth, esophagus, and anus
FALSE
Stratified squamous epithelium is found here
Describe the Lamina Propria layer
- Loose areolar CT
- Rich supply of capillaries
- Contain lymphoid follicles
Describe the Muscularis Mucosae layer
Smooth muscle that produces local movements of mucosa
Describe the Submucosa layer
- areolar CT
- submucosal nerve plexus
- abundant in elastic tissue
- blood and lymphatic vessels
Describe the Muscularis externa layer
Layer responsible for segmentation and peristalsis. Contains inner and outer layer
Describe the Serosa layer
Contains mesothelium
