Week 11 Flashcards
Digestive System
What is the opposite of dehydration synthesis?
hydrolysis
Does all chemical digestion consist of hydrolysis or dehydration reactions?
hydrolysis
Carbohydrates include (3)?
- sugars
- starch
- glycogen
Lipids include (3)
- triglycerides (fats and oils)
- phospholipids
- steroids (such as cholesterol, estrogen, and testosterone)
_____________ are proteins that help speed up metabolism, or the chemical reactions in our bodies
Enzymes
The (4) Digestive System Functions
- ingestion
- digestion
- absorption
- defecation
Where does the chemical breakdown
of protein begins?
Stomach
What does the stomach deliver to the
small intestine?
Chyme
What is the name of the internal folds of
the mucosa present when the stomach is
empty?
Rugae
What are the (7) structures of the stomach mucosa?
▪ Simple columnar epithelium dotted by
gastric pits that lead to gastric glands
▪ Mucous cells
▪ Mucous neck cells
▪ Chief cells
▪ Parietal cells
▪ Enteroendocrine cells
▪ Gastric glands
What are (4) important macro molecules?
- proteins
- carbohydrates
- lipids
- nucleic acids
What do mucous cells produce?
bicarbonate-rich alkaline mucus
The digestive tract consists of what (6) parts?
- mouth
- pharynx
- esophagus
- stomach
- small intestine
- large intestine.
What are the accessory (6) organs of the digestive system?
- teeth
- tongue
- salivary glands
- liver
- gallbladder
- pancreas
What are the (3) functions of rugae?
- increase surface area for digestion
- can expand the stomach to accommodate a large meal
- tightly compressing the food for churning
What glands are both endocrine and exocrine?
gastric glands
What is the simple columnar epithelium of the mucous of the stomach dotted by?
gastric pits
Columnar epithelial cells are AKA?
mucous cells
What are the (4) sections of the stomach in order?
- cardia
- fundus
- body
- pylorus
What are the (3) layers of the muscularis externa of the stomach?
- longitudinal layer
- circular layer
- oblique layer
What part of the digestive tract has 3 layers of muscle?
the stomach
What secrets mucous that is thin, watery, and slightly acidic?
The mucous neck cells
What secretes mucus that is thick and basic in acidity?
The surface epithelium
What do chief cells produce?
protein-digesting enzymes (pepsinogens)
Parietal cells produce (2)?
hydrochloric acid and intrinsic factor
What activates pepsinogen into pepsin?
hydrochloric acid
Enteroendocrine cells produce?
the hormone gastrin
What is needed for vitamin B12 absorption in the small intestine?
Intrinsic factor
what are the (3) subdivision of the small intestine in order?
▪ Duodenum
▪ Jejunum
▪ Ileum
In our gastric juice, there is (5) things present?
- hydrochloric acid
- pepsin/pepsinogen
- water
- mucous
- intrinsic factor
What type of digestion is mostly happening in the small intestine?
Chemical digestion
The duodenum receives what (3) things?
- chyme
- pancreatic juice
- bile
Most digestion and nutrient absorption occurs in which part of the small intestine?
jejunum
What (2) things produce enzymes for the small intestine?
- pancreas
- intestinal cells
What are the (4) structural modifications of the small intestine that increase surface area for food absorption?
- microvilli
- villi
- circular folds (plicae circulares)
- increased length
Where is the site where most absorption happens in the small intestine that has fingerlike projections?
villi
What are the tiny projections of the plasma membrane (that create a brush border appearance) from the small intestine called?
microvilli
What are the deep folds of mucosa and submucosa of the small intestine called?
Circular folds (plicae circulares)
Between the bases of the villi in the small intestine, there are numerous pores that open into tubular glands called?
intestinal crypts
In the small intestine, most absorbed nutrients pass into the blood capillaries, but most lipids are picked up by?
the lacteals
What are the (6) parts in order of the large intestine?
- cecum
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
- rectum
What type of cells produce alkaline mucus to lubricate the passage of feces in the large intestine?
goblet cells
What is it called when the muscularis externa layer is reduced to three bands of muscle in the large intestine?
taeniae coli
The teniae coli in the large intestine cause the wall to pucker into pocketlike sacs called?
haustra
The liver produces?
bile
The gallbladder stores?
bile
What are the (3) ducts of the liver?
- the common bile duct
- the cystic duct
- the pancreatic duct?
the bile duct is the same as?
the common bile duct
the bile duct joins the duct of the
pancreas and forms an expanded chamber called?
the hepatopancreatic ampulla and sphincter
During digestion, the contraction which duct reopens and then goes back to the common bile duct?
cystic duct
What is the movement of foods from one region of the digestive system to another referred to as?
Propulsion
What are (2) muscular movements of propulsion?
- Peristalsis
- Segmentation
alternating waves of contraction and
relaxation that squeezes food along the GI tract is what type of propulsion?
Peristalsis
What is the movement of materials back and forth to foster mixing in the small intestine called?
Segmentation
Is segmentation and peristalsis mechanical or chemical digestion?
Mechanical
What type of digestion is just rearranging molecules so they are more spread out?
Mechanical
Before food enters the blood, where does it have to enter first?
mucosal cells
What are carbohydrates are broken down into?
monosaccharides
What are proteins are broken down into?
amino acids
What are fats broken down to (2)?
- fatty acids
- glycerol
What are (3) disaccharides?
- Lactose
- Maltose
- Sucrose
What breaks down disaccharides?
Brush border enzymes
Lactose after using lactase turns into (2)?
- galactose
- glucose
Maltose after using maltase turns into?
- Glucose
Sucrose after using sucrase turns into (2)?
- Glucose
- Fructose
What enzyme initiates carbohydrate digestion?
Amylase
What breaks up large polypeptides from protein?
Trypsin
What separates the proteins chains?
Pepsin
Bile does what kind of digestion?
Mechanical digestion
unemulsified fat is separated by?
Bile salts
Waves of peristalsis occur from ________ to __________ forcing food past the pyloric sphincter
- fundus
- pylorus
The pylorus meters out what substance into the small intestine?
chyme (3 mL at a time)
What is it called when peristaltic waves close the pyloric sphincter, forcing content back into the stomach
Retropulsion
The stomach empties in how many hours?
4-6 hrs
What (2) factors causes the release of the
hormone gastrin?
- presence of food
- rising pH
What does gastrin cause the stomach glands to produce (3)?
- Protein-digesting enzymes
- Mucus
- Hydrochloric acid
What plays the major role in the digestion of fats, proteins, and carbohydrates as well as neutralizes acidic chyme?
Pancreatic enzymes
Which enzyme neutralizes acidic chyme?
pancreatic enzymes
Pancreatic juice has a rich supply of?
bicarbonate
(4) pancreatic enzymes?
- Pancreatic amylase
- trypsin
- Carboxypeptidase
- lipase
Release of pancreatic juice is stimulated by what (2) things?
▪ Vagus nerve
▪ Hormones
What (2) hormones stimulate the release of pancreatic juice?
- secretin
- cholecystokinin (CCK)
How are lipids absorbed?
diffusion
What hormone causes hepato-pancreatic sphincter to relax?
Cholecystokinin (CCK)
What hormone causes the liver to secrete more bile?
Secretin
What hormone causes weak contractions of the gallbladder?
vagus nerve
Which of the following forms of stimulation would cause the gallbladder to secrete bile (2)?
- Vagus nerve
- Cholecystokinin (CCK)
At the end of digestion, most substances are absorbed by what kind of transport
through cell membranes?
Active transport
Where is the destination of the building blocks?
Liver
How do the building blocks get transported to the liver?
- hepatic portal vein
- lymph
What is absorbed in the large intestine?
vitamins K and B
Is vitamin K and B broken down by stomach or from good bacteria?
Good bacteria - They digest fiber that the body can’t
Haustral contractions are most seen where?
The large intestine
is the peristalsis in the large intestine sluggish or fast?
Sluggish
Mass movements from large intestines are slow, powerful movements
that occur how many times per day?
3 to 4 times per day
Defecation occurs with relaxation of which sphincter?
voluntary (external) anal sphincter
Foods are oxidized and transformed into what?
Adenosine triphosphate ATP
Are calories the same as kilocalories?
Yes
What are (3) functions of nutrients?
- growth
- maintenance
- repair
What are (4) major nutrients?
- carbohydrates
- lipids
- proteins
- water
What are (2) minor nutrients?
- vitamins
- minerals
Are nucleic acids major nutrients?
No
(2) categories of metabolism?
- catabolism
- anabolism
What category of substances are broken down to simpler substances where energy is released?
catabolism
What is our body’s first choice for making energy (ATP)?
Glucose
excessively high levels of glucose
in the blood is referred to as?
hyperglycemia
low levels of glucose in the blood is referred to as?
hypoglycemia
Carbohydrate Metabolism in order (3)?
- glycolysis
- krebs cycle
- electron transport chain
What part of the carbohydrate metabolism harvests the most ATP?
Electron transport chain
What part of carbohydrate metabolism occurs in the cytosol?
glycolysis
What part of carbohydrate metabolism
splits glucose into two pyruvate molecules?
glycolysis
Fats are important for (4)?
- insulating the body
- protecting organs
- building some cell structures (membranes & myelin sheaths)
- Excess dietary fat is stored in subcutaneous tissue (in adipose tissue)
Excessive fat breakdown causes blood to becom?
acidic
What is a product of amino acid breakdown?
Ammonia
when ammonia and carbon dioxide mix together, they produce?
Urea
What organ degrades hormones?
Liver
What does the liver produce?
- cholesterol
- blood proteins (albumin and clotting proteins)
- bile (gallbladder stores bile)
What acids are produced by the body when it breaks down fat for energy?
Ketones
If we have high blood sugar, what happens?
Glycogenesis
Stored glycogen converted to glucose is referred to as?
Glucogenolysis
Amino acids and fats converted to glucose is referred to as?
Gluconeogenesis
What (2) things are picked up by the liver?
Fats and fatty acids
What are the (2) Functions of cholesterol?
- structural basis of steroid hormones and vitamin D
- Building block of plasma membranes
Where is most cholesterol produced?
Liver (85%)
Can cholesterol and fatty acids freely circulate in the blood?
No
Do LDLs or HDLs transport cholesterol to body cells?
LDLs
Do LDLs or HDLs transport cholesterol from body cells to the liver?
HDLs
The alimentary canal is a continuous, hollow tube present by which week of development?
5th week
Teething begins around what age?
6 months
Occurs when small, bulging sacs or pouches form on the inner wall of the intestine is referred to as?
diverticulosis
What are the 3 ducts of the liver in order?
1st. Right and left hepatic ducts
2nd common hepatic duct
3rd cystic duct
When chyme entering the duodenum, what (2) hormones are secreted?
- Cholecystokinin (CCK)
- Secretin
What (2) hormones travel to the pancreas, and causes the secretion of enzyme-rich pancreatic juice?
- Cholecystokinin (CCK)
- Secretin
What hormone causes the gallbladder to secrete stored bile?
Cholecystokinin (CCK)
What causes the release of pancreatic juice in gallbladder and pancreas?
Vagus nerve
In Krebs Cycle, what waste product is being produced?
CO2
