Chapter 3 - Grastrointestinal Tract and Kidney Flashcards
An increase in ADH has what affect on the kidneys and on which structure?
It increases water absorption by the distal convoluted tubule.
What happens to the breakdown products of fat in the small intestine?
They are resynthesized into fats and packaged into chylomicrons that are transported to the lymph and eventually the tissues.
What contracts to prevent food regurgitation from the stomach?
gastroesophageal sphincter
In the lower stomach, what is secreted by endocrine cells?
gastrin
The thick ascending tube of the loop of Henle is mostly permeable to what molecule(s)?
Na+ and K+
What is the purpose of the glycoprotein, intrinsic factor?
It complexes with Vitamin B12 to be absorbed by the small intestine.
On average, how much urine is produced each day?
1-1.5 L
Which enzyme breaks down proteins?
protease
Which enzyme breaks down celluluse?
cellulase
In the stomach, what is secreted by surface cells?
mucus
What makes peristalsic action so quick?
the electrical continuity of gap junctions in the smooth muscle cells of the GI tract
The loop of Henle and collecting duct are located in which portion of the kidney?
medulla
What causes large intestinal reabsorption of water?
absorption of Na+ and Cl-
What is the functional unit of the kidney?
nephron
What is the major pigment in bile?
bilirubin
What do peptidases do?
They cleave peptide bonds, hydrolyzing proteins.
Where is bile stored?
gallbladder
What causes small intestinal reabsorption of water?
absorption of Na+ and glucose
What two compounds secreted from the small intestine act in the pancreas?
1) cholecystekinin (CCK)
2) secretin
What is the term for organisms that cannot change their internal ionic concentrations to meet that of their surrounding environment?
osmoregulators
What is one of the most powerful stimulants of HCl release that often causes ulcers?
histamine
What do the acini of the pancreas secrete to the small intestine?
bicarbonate
In the stomach, what is secreted by parietal cells?
HCl and instrinsic factor
The epithetial cells of the distal convoluted tubule are mostly permeable to what molecule(s)?
Na+
90% of GI digestion occurs where?
small intestine
The glomerulus and Bowman’s capsule are located in which portion of the kidney?
cortex
What compounds does the liver synthesize for digestion?
bile
What is the term for organisms that can change their internal ionic concentrations to meet that of their surrounding environment?
osmoconformers
The thin descending tube of the loop of Henle is mostly permeable to what molecule(s)?
H2O
What is the active form of pepsinogen and what class of enzyme is it? What stimulates its activation?
pepsin, a peptidase
HCl stimulates its activation.
What is the function of the glomerulus?
Filtration: It is a small capillary bed where blood from the heart is forced into the surrounding Bowman’s capsule, filtering out large molecules from the plasma.
In the stomach, what is the purpose of gastrin?
It stimulates the release of HCl and pepsinogen.
About how many liters of filtrate pass through the kidneys each day?
180 L
What are the three major nitrogenous waste products of metabolism?
1) ammonia
2) urea
3) uric acid
How does bicarbonate react in the small intestine?
It combines with H+ to produce carbonic acid, which dissociates into CO2 and H2O.
Where in the kidney does 65% of resbsorption and secretion occur?
proximal convoluted tubule
The thin ascending tube of the loop of Henle is mostly permeable to which molecule(s)?
urea
What structure transports urine from the kidneys to the bladder?
ureter
Where is glucose totally reabsorbed in the kidney?
proximal convoluted tubule
What is normal body pH?
7.4
What is the typical osmolarity of plasma and filtrate?
~300 milliosmols/L
In the stomach, what is secreted by chief cells?
pepsinogen
What is the typical mechanism for reabsorptive transport in the proximal convoluted tubule?
It typically uses symport activity, transporting bigger molecules along with Na+.
Which enzyme breaks down fats?
lipase
What is the compensatory response to metabolic acidosis?
hyperventilation
An increase in aldosterone has what effect on the kidneys and on which structure?
It increases Na+ absorption by the distal convoluted tubule.
In the stomach, what is the purpose of mucus?
It protects the lining of the stomach and lubricates the food.
What must be present in order for the small intestine to absorb glucose (this is a cotransporter)
Na+
What is the purpose of CCK in relation to fats?
In the presence of fats, it acts to constrict the gallbladder and relax the sphincter of Oddi, allowing bile to empty into the small intestine and emulsify those fats.
How many amino acids are essential?
9
Why can only certain animals digest cellulose from plants?
Their digestive systems contain microorganisms that make and secrete the necessary enzyme to break it down.
What macromolecules are digested starting in the mouth and by which enzyme?
starch and glycogen by salivary amylase
Which enzyme breaks down starch and glycogen?
amylase
