Chapter 14 Digestive Flashcards
- Trace the path of food through the alimentary canal
mouth (oral cavity) > pharynx > esophagus > stomach > small intestine > large intestine
- What are the four layers of the wall of the digestive tract from innermost to outtermost
-mucosa (surface epithelium)
-submucosa
-muscularis externa (muscle layer)
-serosa (visceral layer peritoneum)
What are the hormones produced by the stomach?
What hormones are produced in the duodendrum?
Which one is in both?
Stomach:
-Gastrin
-Histamine
Duodendrum:
-Intestinal gastrin
-Secretin
-Gastric inhibitory peptide (GIP)
-Cholecystokinin (CCK)
Both:
-Somatostatin
- What are the accessory digestive organs? (5)
What do they do?
-teeth and tongue - break down food
-salivary glands - breaks down food
-liver -makes bile
-gallbladder - stores bile
-pancreas - has enzymes that break down all food
- What are the six main activities of the digestive system process?
- Ingestion - voluntary, food into mouth
- Propulsion - food going from 1 organ to the next (peristalsis)
- Food breakdown (mechanical) - food physically breaks down
- Food breakdown (digestion) - food chemically breaks down by enzymes
- Absorption - nutrients go to the blood stream or lymph
- defacation - elimination of indigestable feces
What are the digestive enzymes for carbohydrates?
proteins?
fats?
nucleic acids?
Carbohydrates :
Maltose - malt sugar
Lactose - milk sugar
Sucrose - table sugar
Proteins - amino acids (intermediatly polypeptides)
Fats/lipids - fatty acids and glycerol
Nucleic acid - pancreas helps digest them
- Describe the circulation of blood within the digestive system and hepatic portal system
Hepatic portal vein drains digestive organs and delivers this blood to the liver to be detoxified before entering circulation
-the livers needs will be met first.
- Describe the effects of aging on the
digestive system
-muscular wall loses tone, causing constipation
-saliva and digestive enzymes decrease, slowing digestion
-taste and smell diminish
-loss of teeth
-less peristalis
-weakened gag reflex
-liver shrinks and less detoxification happens
What is the homeostatic relationship between the digestive system and other body systems ?
- Provides cells nutrients for energy - fuel, growth, and repair
- What is energy balance in the body?
What is energy intake?
What is energy output?
What happens when this energy is unbalanced?
Energy balance = relationship between energy in and energy out
Energy intake is food + drink
Energy output is heat + work + energy storage.
- 60% loss is heat includes the energy we immediately lose as heat (about 60 percent of the total),
-plus energy for work and storage
-When energy intake and output are equal, weight is stable.
-When they are not, we either gain or lose weight.
What is basal metabolic rate (BMR) ?
What is its primary and secondary influences?
What is total metabolic rate (TMR) ?
How much is used for body heat and how much goes to make ATP?
Basal Metabolic Rate (BMR) - is the amount of calories the body uses at rest
Primary influencer: thyroxine (in thyroid gland
Secondary influences: age, gender, strong emotions, and body surface area
Total Metabolic Rate (TMR) - ) is all the calories you spend in a day
* 60 percent of food energy released is given off as heat;
*40 percent is available to make ATP or build body molecules;
What is the role of the liver? (3)
-Makes bile
-Stores fat (Glycogen)
-Detoxes drugs and alcohol
Most plant proteins are __________ amino acids.
Why?
Animal products are __________ amino acids.
Why?
incomplete
they lack one or more essential amino acids. Although they can be combined (such as beans and rice) to become complete.
complete
because they have all the essential amino acids required by the body in 1 product.
What is the innermost layer of the alimentary canal that lines the lumen.
Mucosa
Shaped like a worm, the appendix projects inferiorly from which region of the large intestine?
Cecum
The smooth lining of the stomach is dotted with millions of deep __________ which lead into ____________ that secrete ___________ after the hormone __________ is released by stomach cells.
Gastric pits
Gastric glands
Gastric juice
Gastrin
Along which segment of the alimentary canal does most of the absorption of digested foods occur?
Small intestine - jejunum
What is the innermost layer of the alimentary canal that lines the lumen.
Mucosa
Chief cells of the gastric glands secrete __________
The gastric glands, when stimulated by gastrin, make which 3 protein digesting enzymes?
What other enzyme is made in the stomach for milk protein?
pepsinogen
-pepsinogen
-mucus
-hydrochloric acid
-rennin
True or false: the large intestine has numerous goblet cells in its mucosa
true
What organ produces enzymes capable of digesting all categories of digestible foods?
Pancreas
Select the correct order for the three segments of the small intestine as chyme flows through them from the stomach to the large intestine. (3)
What does each part do?
- Duodenum - most busy, most breakdown
5% of small intestine - jejunum - absorption of nutrients and water
40% of small intestine - ileum - important vitamins absorbed
60% of small intestine
True or false: bile contains enzymes
How does this help digestion?
False - bile has salts that emulsify (break down) fats
Breaking down big pieces to smaller fat globules have more surface area for fat digesting enzymes to destroy
The fingerlike projections of the small intestine mucosa, which are so important in nutrient absorption, are the __________
Villi
What is the major source of fuel for making ATP in most body cells?
Glucose AKA blood sugar
Which process in the liver refers to the formation of glycogen?
Glycogenesis
Which areas of the alimentary canal break down food both physically and chemically? (3)
-Mouth
-Stomach
-Small intestine
True or false: the alimentary canal forms a continuous muscular tube that starts at the mouth and ends at the anus.
True
What does metabolism mean?
What does catabolism mean?
What does anabolism mean?
Metabolism - any chemical reactions at the cellular level
Catabolism - breaking down molecules
Anabolism - building up molecules
What is the preferred form of cell fuel?
These substances are brown down into _________
What do cells need this fuel for?
Carbohydrate
glucose (blood sugar)
making ATP (energy)
Proteins make up _______ of cells. They are broken down into ____________.
What do cells do with with this substance?
most
amino acids
-build proteins: both for their own use and for export
What is the role of the liver when it comes too blood glucose homeostasis?
High blood glucose levels: glycogenesis
-Stores glycogen (excess glucose)
Falling blood glucose levels:
-option 1:Releases glucose from glycogen (glycogenolysis)
-option 2: Makes new glucose from fat or amino acids (gluconeogenesis).
how are fatty acids, fats, and cholesterol transported to cells?
How are they transported for disposal in the liver?
Which is considered more healthy?
-insoluble in water so cannot use bloodstream
-the low-density lipoproteins, or LDLs, transport them to body cells
High density lipoproteins
A ratio with high HDLs and low LDLs because your getting rid of cholesterol
In which region of the alimentary canal does protein digestion begin?
In which region does carbohydrate digestion begin?
Stomach
Mouth
Why does the stomach epithelium secrete alkaline mucous?
Why does it secrete intrinsic factor?
protects the stomach wall from being digested.
needed for intestinal absorption of vitamin B12.
What are the two main functions of the large intestine?
What is the valve called that joined the small and large intestine?
-Water and vitamin absorption
-remove waste
Ileocecal valve
Mary has a dry mouth—very little saliva is being secreted. Digestion of which type of food will be affected (decreased) by this situation?
Starch (carbs)
Which organ is the only one that produces
enzymes capable of digesting all groups of food?
Where do the enzymes get released too?
pancreas
The duodenum
What is the proper order of the following
stages of food processing—defecation, absorption, digestion, ingestion?
Ingestion, digestion, absorption, and defecation
How do mechanical breakdown and digestion
differ from each other?
Mechanical breakdown breaks food down physically by squeezing and pummeling it.
Digestion uses enzymes to break the chemical bonds of the food molecules and release the nutrients
True or false: food in the GI tract is technically outside the body
True
True or false: the serosa visceral peritoneum is continuous with the parietal peritoneum which lines the abdominopelvoc cavity
True
True or false: the pharynx is made of skeletal muscle
True
What are the nerve plexuses inside the alimentary canal?
What nervous system are they from?
What do they help do?
Submucosal
Myenteric
Autonomic parasympathetic nervous system
Submucosal = secretions
Myenteric = Movement
Where does food enter the stomach from the esophagus?
Where does food leave the stomach for the small intestine?
Cardioesophageal sphincter
Pyloric sphincter
How big is the stomach?
How much can a full stomach contain?
How does a stomach look when it’s empty?
-15-25cm in length
-diameter and volume depend on how much food it contains
A full stomach can hold up to 4lites (1gallon) of food
It collapses in on itself
The stomach is a temporary __________ and the first site for food ____________
Storage tank
Breakdown
What is chyme?
Digested food in the stomach that’s a heavy like cream
Nearly all nutrient absorption happens in the ____________
Small intestine
What are the 3 things you will find on the small intestine walls?
Why do we have them?
Circular folds- folds that form a corkscrew slide and make chyme travel slowly so it can be absorbed
Villi - fingerlike projections on circular folds that absorb nutrients
Microvilli (brush border) - fuzziness on villi that have enzymes to finish digestion
To increase surface area for absorption
What is the pathway of the large intestine ? (7)
What does the large intestine do? (2)
What are the subdivisions of the large intestine? (5)
What is found in the large intestine?
Cecum > ascending colon > transverse colon > descending colon > sigmoid colon > rectum > anal canal
-Drys out indigestible food by absorbing its water
-eliminate feces
-cecum
-appendix
-colon
-rectum
-anal canal
Goblet cells - make alkaline mucous to lubricate feces passageway
Which part of your anus has smooth muscle?
Which part of your anus has skeletal muscle?
Internal anal sphincter
External anal sphincter
What is peristalsis movement along the tract?
What is segmental movement along the tract?
Contraction of smooth muscle squeezing food along the digestive tract (most used)
Alternating contractions mix food along the tract by moving backward and forward
True or false: food absorption occurs in the mouth
False - only in the small intestine
The __________ secures the tongue to the floor of the mouth.
The __________ is the bone attached to the tongue.
Lingual frenulum
Hyoid bone
What is the mucosa layer made of in the esophagus?
What is the mucosa layer made of in the rest of the GI tract?
Stratified squamous epithelial
Simple columnar epithelial
In which of the 4 layers of the alimentary canal would you find blood vessels, nerve endings, MALT, and lymphatic vessels?
Submucosa
The _________ layer of the alimentary canal has a longitudinal muscle layer and a circular muscle layer
Muscularis externa
Why do microvilli, villi, and circular folds decrease towards the end of the small intestine, and peyers patches (lymphatic tissue) increase?
Because the remaining undigested food has large amounts of bacteria which must be prevented from entering the bloodstream
What is a haustra ?
What is a rugae?
Large intestine pocketlike sacs of muscle bands
Folds in the stomach
True or false: gravity plays no part in the transport of food once it has left the mouth
True
What is in feces?
-undigested food residue
-mucus
-bacteria
-just enough water for passage
How many essential amino acids are there?
Can our body make them?
20
No we have to get them through our diet
How is blood glucose kept in homeostasis by the pancreas?
High blood sugar level:
-sensed by beta cells
-pancreas releases insulin to blood
- liver and body cells store glucose as glycogen
Low blood sugar level:
-pancreas releases glucagon
-glycogen breaks down into glucose
What are the 4 regions of the stomach from too top to bottom?
Most digestive activity happens in the ________ region of the stomach.
-cardia
-fundus
-body
-pyloric
Pyloric
True or false: the walls of the alimentary canal are made of the same 4 tissue layers
True - mucosa, Submucosa, muscularis externa, serosa
The outter most serosa layer is half a serous membrane pair, called the ______________. It lines the outside of the ____________. It is continuous with the ______________ which lines the inside of the _____________ cavity. Between them is the ___________ filled with serous fluid. The ________ is a membrane extension holding digestive organs in place and housing nerves, blood vessels, and lymphatic vessels.
Visceral peritoneum
Organs
Parietal peritoneum
Abdominopelvic
Peritoneal cavity
Mesentary
Chief cells make the enzyme___________ which is inactive, unless mixed with ___________ made by ____________ will turn it into __________. We need this enzyme to digest ___________.
Pepsinogen
Hydrochloric acid
Parietal cells
Pepsin
Protein
In the stomach, what is the third layer of the muscularis external called?
Is it on the outside or inside of the stomach?
Why do we have it?
Oblique layer
Inside
To mix and pummel food for mechanical digestion (physically breaking it down)
True or false: physical and chemical digestion occurs in the stomach
True
What protects the lining of the stomach?
What protects the small intestine from the hydrochloric acid from the stomach?
-Bicarbonate rich alkaline mucus from neck cells
-pancreatic juice neutralizes hydrochloric acid
What are all the valves as they move along the digestive tract
Cardioesophageal > pyloric > ileocecal > internal anal sphincter > external anal sphincter
Where do all the enzymes come from in the duodenum?
Small intestine cells
Pancreas enzymes from pancreatic ducts
Liver Bile from the bile duct
True or false: the pancreatic and bile duct join together at the duodenum and enter together
True
What are all the capillaries in each villi?
-Blood capillary
- lymph capillaries
- lacteal (fat absorbing lymphatic capillary)
Why is the appendix a potential trouble spot?
Because bacteria can accumulate and multiply there leading to inflammation (appendicitis)
True or false: some villi are present in the large intestine
False - only goblet cells
What is the pancreas exocrine function?
What is the pancreas endocrine function?
Secreting enzymes into the duodenum that breaks down all food and alkaline fluid to neutralize the acidic chyme
Makes hormones insulin and glucagon to keep blood sugar homeostasis
correctly match the gastric gland cell with its secretion.
Cheif cell -
Neck cell -
Parietal cell -
Enteroendocrine cell -
Cheif cell - Pepsinogen (inactive pepsin)
Neck cell - mucus
Parietal cell - Hydrochloric acid and instrinsic factor
Enteroendocrine cell - gastrin
What carries excess cholesterol from body cells to the liver?
High-density lipoprotein (HDL)
What organ manufactures and stores most of the body’s glycogen as a ready source of glucose?
liver
What is amylase?
What is Pancreatic lipase?
enzyme that breaks down carbohydrates
pancreas enzyme breaks down fats into fatty acids and glycerol. It works with bile, which is produced by the liver, to digest fat.
True or false: segmentation is an example of mechanical breakdown
True- it physically mixes the food
How does fiber benefit us?
It has no nutritional value but helps move food along the tract by strengthening mass movement contractions and softening stool
How do we digest carbohydrates? (6)
-Starch
-salivary amylase
-Pancreaatic amylase
-brush border (small intestine) enzyme break down lactose maltose and sucrose
1. Lactose > galactose and glucose
2. Maltose > glucose
3. Sucrose > glucose and fructose
-Glucose, galactose and fructose > villi > capillary > hepatic portal vein > liver
How do we digest protein? (5)
-Protein
-Stomach pepsin
-Pancreatic enzymes trypsin, chymotypsin, and carboxypeptidase turn large polypeptides into small polypeptides
-Brush border enzymes in the small intestine (aminopeptidase, carboxypeptidase, and dipeptidase) turn small polypeptides into amino acids
-Amino acids enter capillary in the villi and go to the hepatic portal vein to the liver
What happens in the digestion of fat? (6)
- Unemulsified fat injested
- Mouth and stomach use lingual and gastric lipases
- Fats emulsified by bile salts from liver
- Pancreas uses lipase in small intestine
- Fat breaks into monoglycerides and fatty acids or glycerol and fatty acids
- Fatty acids and monoglycerides enter through villi lacteals to lymph thoracic duct to systemic circulation, and glycerol/fatty acids go to the hepatic portal vein to liver
What is another name for the serosa layer?
Visceral peritoneum
These 2 substances when they reach the small intestine are only partially digested: _________ and ________
These 2 substances haven’t been digested at all up until the small intestine: _________ and __________
Protein and carbs
Fats and nucleic acid
Which 2 hormones influence the release of pancreatic juice and bile?
CCK and secretin
Where does the absorption of water occur?
All along the small intestine
What are mass movements?
Powerful waves in the large intestine that push feces to the rectum
What are carbs, fat, and protein used for in the body?
Carbs = make ATP (energy)
Fat = cell membranes, myelin sheaths, insulate the body with a fatty cushion
Protein = building cells
