Terminology
The process in which substances enter the nephron
What is secretion?
What feature of the membrane is more likely to make the membrane selectively permeable?
The presence of protein channels which help transport substances
What is the function of parietal cells?
The production of HCl
What does the small intestine and the nephron have in common?
A large surface area.
The process in which substances leave the nephron
What is reabsorption?
What is the driving force which pushes the filtrate into the nephron from the capillaries?
What is pressure?
What is the role of CO2 during the formation of HCl?
CO2 combines with H2O to make H2CO3 which eventually breaks down into H+ and HCO3-
Why does so much reabsorption occur in the small intestine?
The proteins have already been digested in the stomach. The fat has been digested in the small intestine. The remnants of the food are now ready to be reabsorbed by the body to use for processes such as cellular respiration.
A unit for measuring the concentration of substances
What is osmolarity?
What is the mechanism which pushes food down the digestive tract?
What is peristalsis?
What is the role of histamine during hydrochloric acid production?
It stimulates the production of hydrochloric acid by binding to a receptor site on the cell membrane
What can cause an overgrowth of bacteria in the small intestine?
Insufficient hydrochloric acid production by the stomach. Too little HCl can allow more bacteria to enter the small intestine.
A transmembrane protein which transports water
What are aquaporins?
Why is the shape of a nephron so convoluted (many turns and changes in direction)?
What is an increase in surface area or what is the maximizing of the surface area/volume ratio?
Antihistamine (found proton pump inhibitor medication to treat stomach problems from too much HCl production) is known to get in the way of hydrochloric acid production. How does this work?
Antihistamines get in the way of histamines binding to the receptor site. Therefore less HCl is able to be produced.
Why can bacteria be beneficial in the small intestine?
Although there are enzymes to digest proteins and fats, the bacteria can tackle the digestion of substances which otherwise couldn't be broken down.
Term used for membranes which allow certain substances to pass but not others
What is selectively permeable?
Why is active transport still beneficial during the formation of urine?
The active transport of ions such as Na+, Cl- increases the osmolarity outside of the neuron, which encourages the reabsorption of water. Also, the reabsorption of bicarbonate (HCO3 - ) or the secretion of H+ could help maintain a healthy pH.
Vitamin B12 is needed in adequate amounts for good health and comes from food. However there is a catch. Vitamin B12 is bound to a protein during the early stages of digestion. How could an insufficient HCl production lead to a vitamin B12 deficiency?
HCl activates pepsinogen into pepsin which then leads to protein digestion. The HCl can separate the protein binding to B12. If the B12 and the protein are not separated, we can't absorb the B12 later in the digestion process.
Why is peristalsis less stronger in the small intestine?
The small intestine plays a major role in the reabsorption of nutrients. It takes time for this reabsorption process to occur to maximize the benefits.