Digestive system Flashcards
What are the 6 main functions of the digestive system
- Ingestion 2. Motility 3. Secretion 4. Digestion 5. Absorption 6. Defecation
Taking nutrients into the body
Ingestion
Voluntary and involuntary movement of materials
Motility
Production/ release of substances
Secretion
Mechanical and chemical breakdown of nutrients
Digestion
Transport of nutrients into blood/lymph
Absorption
Removal of wastes undigestible substances
Defecation
Mechanical digestion is breakdown from
large to small pieces
Chemical digestion is breakdown from
complex to simple molecules
What 6 things make up the GI tract
- Oral cavity 2. Pharynx 3. Esophagus 4. Stomach 5. Small intestine 6. Large intestine
What are the 6 accessory organs of the digestive system
- Teeth 2. tongue 3. salivary glands 4. liver 5. Galbladder 6. Pancreas
What are the 4 main layers of the GI tract wall (from inner most to outer most)
- Mucosa 2. submucosa 3. Muscularis 4. Serosa or Adventitia
The mucosa is comprised of
mucosal membrane
What is the primary tissue type of the mucosa
simple columnar epithelium
The tissue of the mucosa is specialized for
secretion and absorption
Some areas of the mucosa contain what tissue type
stratified squamous epithelium
Why do some areas of the mucosa contain strat. squamous epi.
to better withstand abrasion
What are the 5 layers of the GI tract wall
- Mucosa 2. Submucosa 3. Muscularis 4. Adventitia 5. Serosa
The submucosa is comprised of
areolar connective tissue
The submucosa layer contains what 4 things
- blood/ lymph vessels 2. nerves 3. glands 4. lymphatic tissues
The muscularis consists of layers of
smooth muscle fibers running in different directions
The muscularis layer is thickened in many places to form
sphincters
The muscularis aids in
mixing and movement of food through the GI tract
Mechanical breakdown and mixing associated with the muscularis layer
segmentation
What is the outermost layer of the GI tract wall in organs that are outside the peritoneal cavity
Adventitia
What is an example with an organ that would have adventitia
Esophagus
The adventitia is comprised of
areolar connective tissue
What is the outermost layer of the GI tract wall in organs that are inside the peritoneal cavity
Serosa
The serosa is also made of areolar connective tissue but
covered by the visceral peritoneum
What are the 3 serous membranes in the digestive system
- Parietal peritoneum 2. Visceral peritoneum 3. Peritoneal cavity
Serous membrane that lines the inner surface of the abdominal cavity walls
Parietal peritoneum
Serous membranes that reflects and covers surfaces of internal organs
Visceral peritoneum
Fluid-filled space between the visceral and parietal layers
Peritoneal cavity
Inflammation of the peritoneum
peritonitis
Extensions of the peritoneum that help support and attach GI tract to abdominal wall
Mesenteries
What are the 2 main mesenteries of the digestive system
- Greater omentum 2. Mesentery proper
Mesentery that anteriorly covers most abdominal organs
Greater omentum
Mesentery that suspends most of the small intestine to posterior abdominal wall
Mesentery proper
What is the entrance to the GI tract
Oral cavity
What are the 2 regions of the oral cavity
- Vestibule 2. Oral cavity proper
The oral cavity is primary involved with what type of digestion
mechanical digestion
Is the oral cavity involved with any chemical digestion
yes, some
How is the oral cavity involved in chemical digestion
the digestion of carbohydrates via salivary amylase
What is another chemical secreted with saliva other that salivary amylase
lingual lipase
Lingual lipase is activated in the
stomach to aid in fat break down
What are the 2 major regions of the tooth
- Crown 2. Root
What is our first set of teeth called
baby/deciduous teeth
How many teeth are in the 1st set
20
What is our second set of teeth called
adult/permanent teeth
What are the 4 types of teeth
- incisors 2. Canines 3. Premolars 4. Molars
How many incisors do we have
8
What is the primary function of incisors
biting
How many canines do we have
4
What is the primary function of canines
piercing/ tearing
How many premolars do we have
8
What is the main function of premolars and molars
grinding/ chewing
How many molars do we have
12
The salivary glands are ______ digestive structures
Accessory
The salivary glands are _____ glands
exocrine
What are the 3 sets of salivary glands
- Parotid glands 2. Submandibular gland 3. sublingual gland
The pharynx is a passage for
air and food
What are the 3 regions of the pharynx
- Nasopharynx 2. Oropharynx 3. Laryngopharynx
The oropharynx and laryngopharynx consist of what tissue
stratified squamous
The oropharynx and laryngopharynx contain skeletal muscle to aid in
deglutition (swallowing)
When food passes into the pharynx it is referred to as the
bolus
What are the 3 phases of deglutition
- Voluntary phase 2. Pharyngeal phase 3. Esophageal phase
Directs bolus toward the oropharynx
Voluntary phase
Tactile sensory receptors in pharynx detect bolus- stimulates elevation of the soft palate and uvula and elevation of larynx
Pharyngeal phase
Entry of bolus into esophagus stimulates peristalsis to propel food toward stomach (esophageal sphincters relax to allow passage
Esophageal phase
The esophagus
collapsible tubular passageway for food
The point where the esophagus passes through the diaphragm
esophageal hiatus
Point where the food enters the stomach from the esophagus
Cardia/cardiac orifice
The stomach is involved in what type of digestion
both mechanical and chemical digestion
The stomach chemically digests proteins via _____ and lipids via ______
proteins via pepsin and lipids via lipase
Ingested material spends how long in the stomach
2-6
Does much absorption happen in the stomach
No
When food exits the stomach it is referred to as
chyme
Rapid expulsion of gastric contents through the oral cavity
Emesis (vomiting)
Where is the vomiting center located in the brain
the medulla oblongata
The vomiting center stimulates what 4 things to happen when triggered
- increased HR 2. sweating 3. feeling of nausea 4. increased saliva production
After the vomiting center is stimulated what 3 things happen
- a deep inhale 2. closing of the glottis and nasal passageways 3. contraction of abdominal muscles
What is the longest portion of the digestive tract
the small intestine
What are the 3 regions of the small intestine
- Duodenum 2. Jejunum 3. Ileum
Where does most chemical digestion and absorption occur
The small intestine
Where are most accessory organ products secreted
The small intestine
What structures in the small intestine help to slow the flow of chyme
circular folds
What 2 things in the small intestine increase the surface area for absorption
Vili and Microvili
Finger-like projections of mucosa
Vili
extensions of plasma membrane of the Vili
microvili
Lymphatic capillaries within vili
Lacteals
What absorbs lipids and lipid-soluble substances in the small intestine
lacteals
What is produced in the small intestine to break down carbohydrates
Brush border enzymes
Brush border enzymes break down _____ into ______
disaccharides/trisaccharides into monosaccharides
The carbs that are broken down into simple monosaccharides are
absorbed into the blood
Proteins are broken down into ______ in the small intestine
amino acids
amino acids in the small intestine are absorbed into the
blood
Fats are broken down into _______ in the small intestine
monglycerides to fatty acids
Monglycerides and fatty acids are picked up by
lacteals
What are the 4 lobes of the liver
- Right lobe 2. left lobe 3. Quadrate lobe 4. Caudate lobe
The liver is an __________ organ of the digestive tract
accessory organ
What is the main function of the liver
produce and release bile into the duodenum
Yellow-green substance produced by the liver
Bile
What two substances found in bile emulsify fats
- Bile salts 2. lecithin
What is the function of the gallbladder
store and concentrate bile
Gallstones form as a result of too much
cholesterol
The pancreas is an ________ organ located behind the stomach
accessory
The endocrine function of the pancreas is owed to
islet cells
Islet cells produce
insulin and glucagon
The exocrine function of the pancreas is owed to
acinar cells
Acinar cells produce
pancreatic juice
What are the 6 substances in pancreatic juice
- Water 2. Bicarbonate 3. Pancreatic amylase 4. Pancreatic lipase 5. Proteases 6. Nucleases
Bicarbonate in pancreatic juice
neutralizes acidity of chyme
Pancreatic amylase in pancreatic juice aids in the digestion of
carbohydrates
Pancreatic lipase in pancreatic juice aids in the digestion of
lipase
Proteases digest
proteins
Nucleases digest
nucleic acids
What are the 4 sections of the large intestine
- Ascending colon 2. Transverse colon 3. Descending colon 4. Sigmoid colon
Chyme enters the large intestine via the
illocecal valve
The lining of the large intestine aids in the absorption of
water and electrolytes
The large intestine compacts chyme into __________ which is stored until elimination occurs
feces
The large intestine contains indigenous microbiota who’s function is
Produce vitamins and protection
What is the final product of the GI tract
feces
What are the 2 movements of the large intestine
- Peristalsis 2. Mass movements
Peristalsis is
sluggish
The large intestine engages in mass movements
2-3 times per-day to force feces toward the rectum
What two Reflexes are involved in the movements of the large intestine
- Gastocolic reflex 2. Defecation reflex
Reflex initiated by stomach distension that causes a mass movement
Gastrocolic reflex
Reflex that relaxes the internal anal sphincter
Defecation reflex
Nutrients consumed in large amounts
Macronutrients
What are the 3 macronutrients
- Carbohydrates 2. Proteins 3. Fats
Nutrients consumed in small amounts
Micronutrients