Digestive System Flashcards
Enumerate the 5 Functions of the Digestive System
- Ingestion and Mastication
- Propulsion and Mixing
- Digestion and Secretion
- Absorption
- Elimination
How long does a man can live without food and water?
3 to 7 days
How long does a man can live without food?
1 to 2 months
This is needed to sustain function and activity of body.
Food
Consumption of solid or liquid food usually through mouth
Ingestion
Also known as chewing, in which food is crushed and mixed with saliva to form a bolus for swallowing.
Mastication
Movement of food from one end of the digestive tract to the other. (one-way movement)
Propulsion
Movement of food back and forth in the digestive tract. (two-way movement)
Mixing
This is the serous membrane that lines the peritoneal cavity.
Peritoneum
This holds organs that hangs
Mesentery
The anatomy of the digestive system consists of?
- Digestive tract
- GI tract
- Associated organs
This aids in propulsion of food ; most organs contain these layers except stomach.
Tunics / Layers of the GI tract
From outer to inner layer, enumerate the Tunics / Layers of the GI tract.
- Serosa
- Muscularis (outer layer)
- Muscularis (inner)
- Submucosa
- Mucosa
What is the component of serosa?
Visceral peritoneum / adventitia
What is the component of outer muscularis?
Longitudinal smooth muscle
What is the component of inner muscularis?
Circular smooth muscle
What is the component of submucosa?
Plexus
What are the components of mucosa?
- Mucous epithelium
- Lamina propria
- Muscularis mucosae
This is a general term referring to serous membranes attached to abdominal organs.
Mesentery
A mesentery associated with the small intestine.
Mesentery proper
This connects the lesser curvature of the stomach to the liver and diaphragm
Lesser omentum
This connects the greater curvature of the stomach to the transverse colon and posterior body wall
Greater omentum
What are the 2 regions of the oral cavity?
- Space between lips/cheeks and mouth
- Oral cavity proper
These are important in the process of mastication (mechanical digestion)
Lips and Cheeks
A large muscular organ that occupies most of the oral cavity.
Tongue
This is also known as the mechanical digestion.
Mastication
This is also known as the chemical digestion.
Secretion of diff. chemicals
The tongue is connected at the posterior portion by a connective tissue, and this tissue is also known as?
Frenulum
The teeth of an adult is called what?
Secondary / permanent (32)
The childhood teeth is called what?
Primary / Deciduous (20)
From most central to most lateral, enumerate the 8 types of teeth present in our mouths.
- Central incisor
- lateral incisor
- Canine
- 1st pre-molar
- 2nd pre-molar
- 1st molar
- 2nd molar
- 3rd molar
The 3rd molar is also known as?
Wisdom tooth
This is formed by living cellular calcified tissue (dentin)
Bulk of tooth
Dentin is covered by ________ in the crown region
Enamel
What is the living cellular calcified tissue that forms the bulk of tooth?
Dentin
This contains pulp which consists of blood vessels
Pulp cavity
Each teeth is held in place within the pockets in the bone called _______.
Alveoli
Alveoli is covered by what?
Gingiva (gums)
This forms the roof of the oral cavity that separates the oral from nasal cavity.
Palate
Anterior part of the palate that contains the bone
Hard palate
Posterior part of the palate and contains skeletal muscle and connective tissue
Soft palate
This is the posterior extension of the soft palate ; “punching bag”
Uvula
This produces saliva and regulated primarily by Autonomic nervous system with parasympathetic stimulation.
Salivary glands
Forms a protective ring of lymphatic and nasal and oral cavities of pharynx
Tonsils
Tonsil that is near the internal opening of nasal cavity
Pharyngeal tonsil
Tonsil that is on the each side of posterior opening or nasal cavity
Palatine tonsil
Tonsil that is on the posterior surface of tongue
Lingual tonsil
Serous gland located just anterior to each ear ; its ducts enter through the 2nd upper molar
Parotid glands
Located below the mandible and produces more serous than mucous secretions
Submandibular glands
Smallest gland and produce mainly mucous secretions
Sublingual glands
How much saliva is produced daily?
0.5 - 1.5 L
Saliva is a mixture of 2 things:
- Serous (watery)
- Mucous fluids (contains mucin that is stimulated by sympathetic)
This breaks down starch
Salivary amylase
This process increases efficiency of digestion
Mastication
This connects the mouth to the esophagus.
Pharynx
3 parts of pharynx (from superior to inferior):
- Nasopharynx
- Oropharynx
- Hypopharynx (Laryngopharynx)
Part of pharynx that only serves as an air passageway
Nasopharynx
Part of pharynx that is the passageway of both food and air
Oropharynx
Part of pharynx that is mostly the passageway for food
Hypopharynx
Also known as swallowing
Deglutition
Made up of moist stratified squamous epithelium that extends from the pharynx to the stomach
Esophagus
The constriction of _________ allows food to go to the stomach.
Esophagus
How long is the esophagus?
25 cm long
What is the location of the esophagus?
Anterior to the vertebrae and posterior to the trachea
This wave of muscle moves ahead of the bolus which allows the digestive tract to expand
Wave of relaxation
This wave of muscle moves behind the bolus which propels it through the digestive tract
Wave of contraction
A phase wherein bolus of food is pushed by tongue against hard and soft palate
Voluntary phase
A phase wherein the soft palate is elevated, closing off the nasopharynx
Pharyngeal phase
This is a muscular hollow organ which temporarily stores ingested food and continue the process of mechanical digestion
Stomach
What type of tissue the stomach has?
Simple columnar epithelium
Has a J shape
Stomach
Features a lesser and greater curvature
Stomach
What are the four major regions of the stomach?
- Cardia
- Fundus
- Body
- Pylorus
This layer produces a churning action in the stomach
Muscularis layer
These are the folds in the stomach ; occurs when the person is hungry
Rugae
This is the opening of the stomach
Cardia
This is the superior part of stomach
Fundus
This is the largest part of the stomach
Body of the stomach
This is the inferior part of the stomach
Pylorus
This is the semifluid mixture of food and gastric secretions
Chyme
Stomach secretions (2L) of the gastric glands include four (4) substances:
- Hydrochloric Acid
- Pepsin
- Mucus
- Intrinsic factor
This substance from the gastric glands kill microorganism and activates the enzyme, pepsin (produced by parietal cells)
Hydrochloric acid
This substance from the gastric glands break covalent bond of proteins to form smaller peptide chains (chief cells)
Pepsin
This substance from the gastric glands lubricate the epithelial cells of the stomach wall
Mucus
This substance from the gastric glands bind with vitamin B12 and makes it more readily absorbed in the small intestine (also produced by parietal cells)
Intrinsic factor
CNS reflex occurs in?
Medulla oblongata
Local reflex occurs in?
Enteric plexus in the wall of GI tract
2 movements in the stomach:
- Mixing waves (weak contractions)
- Peristaltic waves (strong contractions)
Its major function is absorption of nutrient.
Small intestine
Smallest section of small intestine ; described as C-shaped located below the stomach that surrounds the pancreas
Duodenum
This part receives stomach chyme, pancreatic juice and bile from liver and gallbladder via duodenal ligament
Duodenum
2 hormones that are excreted by the duodenum:
- Cholecystokinin
- Secretin
This hormone from the duodenum stimulates pancreas to release enzymes in pancreatic juice and stimulates the gallbladder to release bile.
Cholecystokinin
This hormone regulates the environment within the duodenum.
Secretin
This marks the division between duodenum and the jejunum.
Suspensory muscle of duodenum
This is a part of the small intestine that is 2.5 m long which absorbs sugars, amino acids, and fatty acids.
Jejunum
This is the longest part of the small intestine wherein it absorbs any final nutrients, with major absorptive products being vitamin B12 and bile acids.
Ileum
These are small aggregates of lymphatic tissue found in the mucosa of the ileum
Peyer’s patches
The mucosa and submucosa form a series of __________ that runs perpendicular to the long axis of the digestive tract.
Circular folds
Tiny, fingerlike projections of the mucosa form numerous ________, which are 0.5-1.5 mm long
Villi
These are the numerous cytoplasmic extensions called the ________.
Microvilli
This is the largest internal organ and weighs about 1.36 kg
Liver
Weight of liver?
1.36 kg
This blood vessel takes oxygen rich blood to the liver
Hepatic artery
This blood vessel carries deoxygenated blood but rich in absorbed nutrients and other substances from the digestive tract, and delivers it to the liver
Hepatic portal vein
This blood vessel carries blood away from the liver and into the inferior vena cava
Hepatic vein
This organ processes nutrient and detoxifies harmful substances from the blood.
Liver
How much bile does the liver produce each day?
600 - 1000 L daily
This is a complex alkaline solution that contains bile salts, bile pigments, cholesterol, lipids, lipid soluble hormone, and lecithin (mixture of phospholipids)
Bile
This specific content of bile solubilizes ingested fat and fat-soluble vitamins, facilitating their digestion and absorption
Bile salts
This organ is retroperitoneal and posterior to the stomach.
Pancreas
Pancreas is composed of both ________ and _______ tissues.
Endocrine and Exocrine
This tissue of the pancreas is where pancreatic islets, or islets of Langerhans are arranged, and these islets produce the hormone insulin and glucagon.
Endocrine
What are the 2 hormones produced by the islets of Langerhans?
Glucagon and Insulin
This tissue of the pancreas is composed of acinar glands
Exocrine
These cells produce digestive enzymes that empties into the pancreatic duct.
Acini cells
TRUE or FALSE:
Pancreatic enzymes are important in digesting all major classes of foods.
TRUE
What are the 3 major protein digesting enzymes (proteolytic enzymes)?
- Trypsin
- Chymotrypsin
- Carboxypeptidase
This continues the polysaccharide digestion that began in the oral cavity.
Pancreatic amylase
This is a lipid-digesting enzyme
Lipase
These degrade DNA and RNA into nucleotides.
Nucleases
This organ extends from the ileocecal junction to the anus.
Large intestine
Chyme is converted into what?
Feces
This is the process of elimination of feces
Defecation
From the large intestine, these are small pouches of the peritoneum filled with fat.
Omental appendices
From the large intestine, these are saccules in the colon that gives it its segmented appearance.
Haustra
From the large intestine, these are small pouches of the peritoneum filled with fat and situated along the colon and upper part of the rectum.
Teniae coli
This is the proximal end of the large intestine
Cecum
Cecum is located in what quadrant of the abdomen?
Right lower quadrant
What is attached to the cecum?
Appendix
What are the 4 parts of the colon?
- Ascending colon
- Transverse colon
- Descending colon
- Sigmoid colon (terminal portion)
This is the terminal portion of the colon.
Sigmoid colon
Approximately 1.5-1.8 m long and can be divided into 4 parts
Colon
What is the mucosal lining of the colon?
Crypts
This contains many mucous-producing goblet cells
Crypts
Straight-muscular tube that begins in the termination of sigmoid colon and anal canal
Rectum
This is the last 2-3cm of digestive tract.
Anal canal
