unit 8 Digestive Anatomy Flashcards
What are the two major functions of the digestive system?
Digestion and absorption
Define digestion.
Breaking down ingested food into smaller pieces
Define absorption.
Taking small pieces into the body to convert them into cellular energy or use them as building blocks
What are the two types of digestion?
- Mechanical digestion
- Chemical digestion
Where does mechanical digestion primarily occur?
In the oral cavity and stomach
What is chemical digestion?
The breakdown of food using chemical reactions, including enzymes
What happens to macromolecules after digestion?
They are absorbed into the body as simple sugars, amino acids, fatty acids, and monoglycerides
What is the role of absorptive cells?
To facilitate the entry of nutrients into the bloodstream
Where do fatty acids and monoglycerides enter before the bloodstream?
The lymphatic system
What is the oral cavity’s role in digestion?
The first place where food is mechanically and chemically digested
What are the types of teeth involved in mechanical digestion?
- Incisors
- Canines
- Premolars
- Molars
What are deciduous teeth?
The first set of baby teeth that erupt around six months of age
What is the total number of adult permanent teeth?
Thirty-two
What is the function of saliva in digestion?
Moistens and chemically breaks down food
What enzyme in saliva begins carbohydrate digestion?
Amylase
What structure separates the nasal cavity from the oral cavity?
Hard palate
What is the role of the uvula during swallowing?
Blocks passage of food into the nasopharynx
What is the pharynx?
The throat of the digestive tract
What are the three regions of the pharynx?
- Nasopharynx
- Oropharynx
- Laryngopharynx
What type of epithelium is found in the oropharynx and laryngopharynx?
Stratified squamous epithelium
What is peristalsis?
Alternating contractions of muscle layers in the esophagus to propel food forward
What are the two sphincters associated with the esophagus?
- Upper esophageal sphincter
- Lower esophageal sphincter (gastroesophageal sphincter)
What are the four regions of the stomach?
- Cardiac region
- Fundus
- Body
- Pylorus
What is the function of the cardiac region of the stomach?
Where food enters the stomach
What is chyme?
The paste formed from food in the stomach after mechanical digestion
What enables the stomach to perform mechanical digestion?
An additional third muscular layer known as the oblique layer
What is the role of the pyloric sphincter?
Controls the movement of chyme into the small intestine
What is the function of the ileocecal valve?
Controls the flow of material from the small intestine to the large intestine
What are teniae coli?
Muscular bands that help in the peristalsis of the large intestine
What are haustra?
Pouches formed by the teniae coli in the large intestine
What are the major accessory organs involved in digestion?
- Salivary glands
- Liver
- Pancreas
- Gallbladder
What is the function of the liver?
Processes nutrients from the digestive tract
What is the role of the pancreas in digestion?
Produces enzymes that aid in the digestion of carbohydrates, proteins, and fats
What are the mesenteries?
Folds of peritoneum that support and stabilize the digestive organs
Differentiate between intraperitoneal and retroperitoneal locations.
Intraperitoneal structures are surrounded by peritoneum, while retroperitoneal structures are located behind it
What is chyme?
A paste formed by the mixing of food with gastric juices in the stomach
Chyme is created by the mechanical action of the stomach and the chemical action of digestive enzymes.
What is the function of the pylorus in the digestive system?
To move chyme forward within the digestive tract using peristaltic waves
The pyloric sphincter regulates the passage of chyme into the small intestine.
What happens to the stomach when there is no food present?
It collapses to about the size of a fist
The stomach is ‘J’ shaped with a lesser curvature facing the liver and a greater curvature facing the spleen.
What are rugae?
Interior folds of the stomach that allow it to expand
Rugae enable the stomach to accommodate varying amounts of food.
What are the three regions of the small intestine?
- Duodenum
- Jejunum
- Ileum
The small intestine is 7 to 13 feet long and completes chemical digestion and nutrient absorption.
What is the primary function of the duodenum?
Neutralize acidic chyme and facilitate fat digestion
The duodenum receives bile and pancreatic juices to aid in digestion.
What critical role does bile play in digestion?
Emulsifies large fat drops into small droplets
This process allows lipase to break down fats into monoglycerides and fatty acids.
Where does most absorption occur in the small intestine?
In the jejunum
The jejunum has a large surface area due to its unique folding.
What is the primary function of the ileum?
To reclaim bile salts and absorb nutrients
The ileocecal valve regulates the passage of chyme into the large intestine.
What vitamins are absorbed in the large intestine?
- Vitamin K
- Vitamin B
Intestinal microorganisms produce these vitamins.
What are the seven regions of the large intestine?
- Cecum
- Ascending colon
- Transverse colon
- Descending colon
- Sigmoid colon
- Rectum
- Anal canal
The large intestine is shorter but wider than the small intestine.
What is the function of the appendix?
Houses symbiotic bacteria and helps maintain the microbiome
The appendix can become inflamed and may need to be surgically removed if it bursts.
What are the internal and external sphincters’ roles in defecation?
They regulate the release of feces from the anal canal
The internal sphincter is smooth muscle, while the external sphincter is skeletal muscle.
What structures are unique to the large intestine?
- Tenia coli
- Haustra
- Epiploic appendages
Tenia coli are muscle bands that create pouches (haustra) in the colon.
What is the role of the liver in digestion?
Produces bile that aids in fat digestion
Bile travels through ducts to reach the duodenum.
What does the gallbladder do?
Stores and concentrates excess bile
The gallbladder releases bile when fatty foods are consumed.
What is the primary function of the pancreas?
Releases enzyme and bicarbonate-rich juice for digestion
This juice mixes with bile in the hepatopancreatic ampulla before entering the duodenum.
What is the peritoneum?
Serosa surrounding most digestive organs
The visceral peritoneum attaches to organs, while the parietal peritoneum faces the cavity walls.
What is mesentery?
A double layer of serosa that supports blood vessels and nerves to the digestive tract
It helps anchor intraperitoneal organs.
What is the greater omentum?
A mesentery sheet that hangs over digestive organs
It functions to keep intraperitoneal organs in place.
Where does carbohydrate chemical digestion first occur?
In the oral cavity
Salivary amylase begins the breakdown of carbohydrates.
What macromolecule first starts being chemically digested in the stomach?
Proteins
The stomach’s acidic environment activates pepsinogen to pepsin, which digests proteins.
Where in the digestive tract does the most mechanical digestion occur?
In the stomach
The churning action of the stomach breaks down food into smaller pieces.
What is the function of the large intestines?
To absorb water and store fecal matter
It converts liquid chyme into solid waste.
What does NEC stand for in the context of neonatal health?
Necrotizing enterocolitis
NEC is a serious gastrointestinal problem that mostly affects premature infants.
What study is referenced in relation to NEC in the NICU?
NICU NEC (WGS) study
This study focuses on the microbiome and its relationship with NEC in neonatal intensive care settings.
What microbe appears to be more abundant in children with NEC?
Klebsiella
Klebsiella is a genus of bacteria known to cause infections in humans, particularly in immunocompromised individuals.
What is one way to investigate if a microbe causes a disease?
Conduct an experiment to observe changes in disease outcomes upon introducing or removing the microbe
This could involve animal models or controlled clinical trials.
Do we know for sure that the identified microbes caused the NEC?
No, causation has not been definitively established
While correlations exist, further research is needed to confirm causation.
What key observation was made regarding gut bacteria in relation to NEC?
Increased gut bacterial replication precedes the onset of NEC
This suggests that bacterial overgrowth may play a role in the development of the condition.
What did you learn about the digestive system through this activity?
The digestive system’s microbiome can significantly impact health outcomes
Understanding the microbiome helps in comprehending diseases like NEC.
What public databases related to the digestive system can you search for?
MicrobiomeDB
MicrobiomeDB is a platform for integrating and analyzing microbiome experiments.
Was it easy to find a database related to the digestive system?
Varies; some may find it easy while others may not
Accessibility can depend on familiarity with research tools.
Describe a dataset you encountered in your research.
Observations may include types of microbes and their abundance
Even without full understanding, datasets typically contain structured information on microbial populations.
What hypothesis could a database related to the digestive system help investigate?
The relationship between specific gut microbes and gastrointestinal diseases
This could lead to insights on disease prevention or treatment.
What disease related to the digestive system could be researched?
Celiac disease
Celiac disease is an autoimmune disorder triggered by ingestion of gluten in genetically predisposed individuals.
