Chapter 25- Digestive System Flashcards
6 different activities that the digestive system carries out:
- Ingestion
- Secretion
- Propulsion/Motility
- Mechanical & Chemical Digestion
- Absorption
- Elimination
Ingestion
Intake of food
Secretion
enzymes (pH)
Motility
The food that is being digested will be ____ from one part of the tract to the next. Most of this movement occurs because of involuntary muscle contractions along the length of the ___________ ______ This muscle contraction is termed ______
The food that is being digested will be MOVED from one part of the tract to the next. Most of this movement occurs because of involuntary muscle contractions along the length of the GASTROINTESTINAL TRACT. This muscle contraction is termed PERISTALSIS.
Mechanical Digestion
The physical breakdown of particles into smaller pieces
Chemical Digestion
The molecular breakdown of molecules into smaller ones.
Usually involves enzymes
Enzyme:
a substance that increases the rate of chemical reactions without changing themselves. Each enzyme will have its own ______ that it can work on, and will work best at _____ _____ and _____ ___
a substance that increases the rate of chemical reactions without changing themselves. Each enzyme will have its own SUBSTRATE that it can work on, and will work best at OPTIMAL TEMP and OPTIMAL pH.
Absorption
passage of digested food into the blood and lymphatics
Elimination
waste
Elimination: removal of undigested substances from the G.I. tract termed_______ This would include some water, foods that cannot be digested, foods that were digested but not absorbed, cells of the GI tract that were sloughed off, bacteria. The eliminated material is termed _____ or _____
removal of undigested substances from the G.I. tract termed DEFECATION. This would include some water, foods that cannot be digested, foods that were digested but not absorbed, cells of the GI tract that were sloughed off, bacteria. The eliminated material is termed FECES or STOOL.
2 main groups that the organs of digestive system can be divided into
The G.I. tract (alimentary tract) and the accessory structures
The G.I. tract (alimentary tract): these are the organs that the food ____ _____ ____
List the pathway
The G.I. tract (alimentary tract): these are the organs that the food actually passes through:
mouth–> pharynx–> esophagus–> stomach–> small intestine–> large intestine
Accessory structures:
aid in ______, but the food ___ ___ __ ____ ___
Exs:
aid in digestion, but the food does not go through them
Exs: teeth, tongue, salivary glands, liver, gall bladder, and pancreas.
Organs are surrounded by visceral peritoneum which is continuous with the parietal peritoneum. The connection between visceral and parietal is called the _________. Some organs are located retroperitoneal (including pancreas, duodenum, and part of the large intestines).
Organs are surrounded by visceral peritoneum which is continuous with the parietal peritoneum. The connection between visceral and parietal is called the MESENTERY. Some organs are located retroperitoneal (including pancreas, duodenum, and part of the large intestines).
Mouth- distance and time
Distance: a few inches
Time: a few seconds
The mouth is the opening to the digestive tract from ___ to _____
from lips to pharynx
Two compartments of the mouth
Vestibule and Oral cavity
Vestibule
area of mouth between the cheeks and the gums outside teeth
Oral cavity
lined by hard and soft palate superior, uvula posterior, teeth anterior
inside teeth
2 sets of teeth
The deciduous (20 teeth), followed by permanent (32 teeth)
The deciduous teeth enter thru gingiva beginning at _________ and is usually complete by age _______. The permanent teeth then begin entering at ________ and are complete by age _____________.
The deciduous teeth enter thru gingiva beginning at 6 months and is usually complete by age 2 yrs.. The permanent teeth then begin entering at 6 yrs and are complete by age 12
Accessory structures of the mouth
Teeth
Tongue
Salivary glands
4 different types of teeth, amount, and purpose
Incisors (8), bite/cut
Canines (4), tear
Premolars (8) and Molars (12), grind
Tongue - structure composed mostly of skeletal muscle. It is attached to the bottom of the mouth by the ______ _____. Functions:
Tongue - structure composed mostly of skeletal muscle. It is attached to the bottom of the mouth by the LINGUAL FRENULUM. Functions:
1. chewing / swallowing
2. taste
3. speech
Salivary glands: There are 3 major pairs of salivary glands which produce serous (watery) or mucus secretions. 1.Parotid Glands:_____of salivary glands, found anterior to the ears producing serous secretion. Secretions enter over the upper 2nd molar.
2. Submandibular glands: found under ____ producing primarily a _____secretion. Secretions enter adjacent to the lingual frenulum.
3. Sublingual glands: found under_____ producing more _____ ___. Numerous openings compared to the parotid and submandibular glands.
Salivary glands: There are 3 major pairs of salivary glands which produce serous (watery) or mucus secretions. 1.Parotid Glands: Largest of salivary glands, found anterior to the ears producing serous secretion. Secretions enter over the upper 2nd molar.
2. Submandibular glands: found under mandible producing primarily a serous secretion. Secretions enter adjacent to the lingual frenulum.
3. Sublingual glands: found under tongue producing more mucus secretion. Numerous openings compared to the parotid and submandibular glands.
Functions of the salivary glands: these 3 sets of exocrine glands will secrete ____ into the mouth. Secretion is under the control of the nervous system (parasympathetic primarily) releasing 1-1.5L a day.
Functions of the salivary glands: these 3 sets of exocrine glands will secrete SALIVA into the mouth. Secretion is under the control of the nervous system (parasympathetic primarily) releasing 1-1.5L a day.
Functions of the salivary glands:
- Taste
- Lubrication
- Antibacterial
- Digestion
Contents of saliva
- Water
- Lysozymes
- Mucin
- Enzymes
1.Mechanical Digestion: The _____ will move the food around the mouth, allowing it to mix with the saliva. Chewing , termed _______, due to the teeth will break up the food, increasing the surface area and therefore allowing for more digestive enzymes to come into contact with more of the food and also decreasing the size of the food so that it can be swallowed safely. Chewing is important because chemical digestion occurs on the surface of cells- vital to increase surface area.
1.Mechanical Digestion: The TONGUE will move the food around the mouth, allowing it to mix with the saliva. Chewing , termed MASTICATION, due to the teeth will break up the food, increasing the surface area and therefore allowing for more digestive enzymes to come into contact with more of the food and also decreasing the size of the food so that it can be swallowed safely. Chewing is important because chemical digestion occurs on the surface of cells- vital to increase surface area.
The result of the actions of the teeth and tongue is the formation of a soft rounded ball of food called a ____.
The result of the actions of the teeth and tongue is the formation of a soft rounded ball of food called a BOLUS. The bolus, with the help of the tongue, will be passed from the mouth into the pharynx.
What enzyme comes from saliva?
Salivary Amylase
Chemical Digestion: The mouth is the site for the beginning of the digestion of
________ by the enzyme, _______ _____. This enzyme is specialized to digest ___saccharides into ___saccharides. Only the monosaccharide form of the carbohydrate can actually enter the cell, so these disaccharides will need to be further digested in another part of the digestive system. Only 3-5% (____ ___) of the total CHO digestion occurs in the mouth.
Chemical Digestion: The mouth is the site for the beginning of the digestion of
CARBOHYDRATES by the enzyme, SALIVARY AMYLASE. This enzyme is specialized to digest polysaccharides into disaccharides. Only the monosaccharide form of the carbohydrate can actually enter the cell, so these disaccharides will need to be further digested in another part of the digestive system. Only 3-5% (very little) of the total CHO digestion occurs in the mouth.
The salivary amylase is produced primarily by which glands? (hint: serous secretion)
Parotid and Submandibular
Lingual lipase
Works at a pH of 5 and digests lipids
Summary (for mouth):
Ingestion-
Motility-
Mechanical Digestion-
Chemical Digestion-
Absorption-
Elimination-
Ingestion- yes! (mouth is only area for this)
Motility- mastication
Mechanical Digestion- mastication
Chemical Digestion- salivary amylase
Absorption- no
Elimination- no
Mastication is ____ and is important because..
Mastication is voluntary and is important because it increases the surface area, allowing enzymes to work better
Salivary amylase is made in the ____, but can function in other areas
mouth
The pharynx is from the ____ to the _____ and is the location of the ____
- from the uvula to the epiglottis
- location of the tonsils
Pharynx:
When the bolus is formed, ______ (swallowing) occurs pushing the bolus into the _____ and with the help of _______, the bolus continues into the esophagus. The _______ covers the larynx and prevents food/water from entering as the bolus passes
When the bolus is formed, DEGLUTITION (swallowing) occurs pushing the bolus into the PHARYNX and with the help of PERISTALSIS, the bolus continues into the esophagus. The EPIGLOTTIS covers the larynx and prevents food/water from entering as the bolus passes
The pharynx consists of 3 areas:
oro-
naso-
laryngo-
Summary (for pharynx):
Ingestion-
Motility-
Mechanical Digestion-
Chemical Digestion-
Absorption-
Elimination-
Ingestion- no
Motility- deglutination
Mechanical Digestion- deglutination
Chemical Digestion- continuation of salivary amylase (functions, but not produced)
Absorption- no
Elimination- no
____ in the pharynx (______) is the last time where things are voluntary
Motility in the pharynx (deglutination)
The esophagus is from the ____ to the ____
epiglottis to the stomach
The esophagus is located in the ______ of the thorax and contains the 4 tunicas common to the alimentary canal. However, it’s unique due to
The esophagus is located in the mediastinum of the thorax and contains the 4 tunicas common to the alimentary canal. However, it’s unique due to the tunica muscularis, which is made up of involuntary skeletal muscle
Esophagus:
As the bolus moves from the pharynx into the esophagus, it will pass through a _____ called the _____ _____ _____
As the bolus moves from the pharynx into the esophagus, it will pass through a SPHINCTER called the UPPER ESOPHAGEAL SPHINCTER
Sphincter: circular muscle that can constrict an opening regulating movement of digestive contents through the G.I. tract. Typically these are composed of ___________ and is _______
Sphincter: circular muscle that can constrict an opening regulating movement of digestive contents through the G.I. tract. Typically these are composed of smooth muscle and is involuntary
The esophagus will go through the ______, the large muscle that separates the thoracic cavity from the abdominal cavity, at an opening called the ________ _____. Sometimes this opening causes a weakness in the diaphragm and the portions of abdominal organs (like the lower esophagus and upper stomach) can protrude into the thoracic cavity, causing pain and discomfort. This pathology is called a _____ ____. The esophagus eventually narrows and the bolus will go through the LOWER ESOPHAGEAL SPHINCTER (_____ _____) into the stomach.
The esophagus will go through the DIAPHRAGM, the large muscle that separates the thoracic cavity from the abdominal cavity, at an opening called the ESOPHAGEAL HIATUS. Sometimes this opening causes a weakness in the diaphragm and the portions of abdominal organs (like the lower esophagus and upper stomach) can protrude into the thoracic cavity, causing pain and discomfort. This pathology is called a HIATAL HERNIA. The esophagus eventually narrows and the bolus will go through the LOWER ESOPHAGEAL SPHINCTER (CARDIAC SPHINCTER) into the stomach.
Peristalsis
Involuntary wave-like contractions of smooth muscle. In the G.I. tract, these contractions push digesting food forward.
Distance and time for esophagus
Distance: 8-10 inches
Time: few seconds
Summary (for esophagus):
Ingestion-
Motility-
Mechanical Digestion-
Chemical Digestion-
Absorption-
Elimination-
Ingestion- no
Motility- peristalsis
Mechanical Digestion- peristalsis
Chemical Digestion- salivary amylase (still functions)
Absorption- no
Elimination- no
Stomach:
- a ______ organ 6-10 inches in length located in the ____ _____ ____
- attached to other organs and body wall via an _____
Stomach:
- a J-shaped organ 6-10 inches in length located in the upper left quadrant
- attached to other organs and body wall via an OMENTUM.
The stomach has the 4 tunicas common to alimentary canal although the tunica muscularis is unique in that it
has 3 layers instead of the typical two: circular, longitudinal, and oblique
4 areas to the stomach
- _____ _____-surrounds ____ ____
- fundus-rounded portion
- body- large central portion
- _____- most inferior portion, right around the ____ _____
- cardiac region -surrounds cardiac sphincter
- fundus-rounded portion
- body- large central portion
- pylorus- most inferior portion, right around the PYLORIC SPHINCTER
The walls are not smooth but are arranged in large folds when the stomach is empty= ____ When empty the stomach is the size of a clenched fist holding approx. 50ml but can hold up to 4L when full.
Ex: Joey Chestnut
Rugae contain _____ _____and lead to gastric glands.
The walls are not smooth but are arranged in large folds when the stomach is empty= Rugae When empty the stomach is the size of a clenched fist holding approx. 50ml but can hold up to 4L when full.
Ex: Joey Chestnut
Rugae contain gastric pits and lead to gastric glands.
Distance and time for the stomach
Distance: 6 inches
Time: 2-6 hours
MECHANICAL DIGESTION (stomach): When the food enters the stomach, _____ ____ will push the bolus around, causing it to be mixed with the digestive enzymes of this organ. The bolus becomes more liquified and is called ____. Continue to have peristaltic waves which propels the food particles forward.
MECHANICAL DIGESTION: When the food enters the stomach, MIXING WAVES will push the bolus around, causing it to be mixed with the digestive enzymes of this organ. The bolus becomes more liquified and is called CHYME. Continue to have peristaltic waves which propels the food particles forward.
CHEMICAL DIGESTION (stomach): Unlike the mouth and other parts of the digestive system in which the pH is maintained around 6-8, the stomach pH is around __.. Total amount of secretions roughly__-___ L although influenced by the amount and type of food ingested.
This acidic pH is due to the secretion of HCL(hydrochloric acid) by the _____ ____ found in the stomach wall. This HCL will maintain an optimal pH for the enzymes of the stomach to work. It also offers some protection to the person by killing microbes that enter the body through the food that they ingest. Has a minor effect directly on digestion of food. Inactivates salivary amylase due to pH change.
CHEMICAL DIGESTION: Unlike the mouth and other parts of the digestive system in which the pH is maintained around 6-8, the stomach pH is around 2. Total amount of secretions roughly 2-3 L although influenced by the amount and type of food ingested.
This acidic pH is due to the secretion of HCL(hydrochloric acid) by the PARIETAL CELLS found in the stomach wall. This HCL will maintain an optimal pH for the enzymes of the stomach to work. It also offers some protection to the person by killing microbes that enter the body through the food that they ingest. Has a minor effect directly on the digestion of food. Inactivates salivary amylase due to pH change.
PEPSIN - an enzyme that is secreted into the stomach lumen by ____ ____
It is responsible for beginning the digestion of ______. Pepsin is secreted in inactive form = _______, and will be converted to pepsin in the presence of HCL.
PEPSIN - an enzyme that is secreted into the stomach lumen by CHIEF CELLS.
It is responsible for beginning the digestion of proteins. Pepsin is secreted in inactive form = PEPSINOGEN, and will be converted to pepsin in the presence of HCL.
MUCUS: alkaline substance that is produced by ____ ____ in stomach lining is also important in digestion. It moistens bolus and offers protection to lining of stomach.
MUCUS: alkaline substance that is produced by mucous cells in stomach lining is also important in digestion. It moistens bolus and offers protection to lining of stomach.
Gastrin and Histamine are
hormones produced by enteroendocrine cells
INTRINSIC FACTOR: a glycoprotein that is also secreted by ____ ___ that allows for the intestinal absorption of vit. B12, needed for the production of RBCs ( due to synthesis of DNA).
INTRINSIC FACTOR: a glycoprotein that is also secreted by parietal cells that allows for the intestinal absorption of vit. B12, needed for the production of RBCs ( due to synthesis of DNA).
The biggest problem for people who have their stomach removed is the lack of intrinsic factor, which may lead to _____, a decrease of red blood cells in the blood. This problem is solved by taking vit B12 exogenously.
The biggest problem for people who have their stomach removed is the lack of intrinsic factor, which may lead to ANEMIA, a decrease of red blood cells in the blood. This problem is solved by taking vit B12 exogenously.
3 phases to stomach digestion
- Cephalic phase
- Gastric phase
- Intestinal phase