lecture 19

Question 0

Fold of kerckring

Answer 0

the first absorptive surface of the small intestine mucosa, well developed in the duodenum and jejunum protrudes into the lumen and increase absorption by 3 folds

Question 1

structures involved in increasing the surface area in the GI tract

Answer 1

folds of kerckring, villi, and microvilli

Question 2

villi

Answer 2

located on the epithelial surface of the small intestine all the way down to the ileocecal value, present on the folding of kerckring and increase absorption by 10 folds

Question 3

microvili

Answer 3

each intestinal epithelial cell on each villus has a brush boarder containing characteristic consisting of many microvilli

Question 4

central lacteal

Answer 4

stucture in the villus involved in the absorption of lymph

Question 9

pinocytic vesicles

Answer 9

are vesicles that pinch off in the portion of infold in the enterocytes membrane forming vesicle of absorbed fluids that have been entrapped

Question 10

Transcellular transport

Answer 10

this is transport require the movement of molecule through the cell from passing through apical membrane and basalateral membrane. and this usually require energy.

Question 11

water is transport entirely by —– give example

Answer 11

simple diffusion moving from high concentration to lower concentration of water example when chyme is diluted enough water absorbed though the intestinal mucosa into the blood and the reverse can occur when there is an hyperosmotic solution in the small intestine (chyme)

Question 12

The absorption of sodium ion is by

Answer 12

carrier mediated transport ( primary active transport) in the gallbladder and renal tubules

Question 13

transport of Na+

Answer 13

the transport of Na is done through primary active transport from the epithelial cells through the basal and side walls of the cell into paracellular spaces.

Question 14

with the transportation of na into the paracellular the drag of other ion occurs

Answer 14

Chloride ions.

Question 15

the function of Aldosterone in the intestinal tract is the same as the effect of aldosterone in the

Answer 15

renal tubules, where in both case it serves to conserve NaCl and water.

Question 16

how do the absorption of Na cause the reabsorption of water

Answer 16

with the primary active transport of Na into the Paracellular space, the osmotic gradient changes between the cell and the paracellular space which leads to the movement of water from a area of high concentration to an area of low concentration. ( simple diffusion)

Question 17

Absorption of Chloride ions in the duodenum and jejunum

Answer 17

is mainly by diffusion due to electrical gradient to follow Na because the epithelial cells has become electronegative due to the movement of Na and the paracellular space has become electropositive

Question 18

Ion are usually absorbed in what part of the intestine

Answer 18

the upper part of the intestine duodenum and jejunum

Question 19

absorption of calcium

Answer 19

this is usually by active transport and the parathyroid hormone is important in its reabsorption by activating vitamin D which enhances the absorption of ca

Question 20

the two forms of pinocytosis

Answer 20

fluid endocytosis and receptor mediated endocytosis

Question 21

receptor mediated endocytosis

Answer 21

the molecule comes in contact with protein at the membrane of the cell, this result in the invagination of the cell into pinocytic vesicles

Question 22

fluid endocytosis

Answer 22

it is the nonspecific invagination of specific molecule into the cell. it is a type of pinocytosis

Question 23

paracellular tansport

Answer 23

the transport of molecules through intercellular space and between the cells. this is important in the renal physiology ( kidneys)

Question 24

the absorption of bicarbonate ( active absorption of bicarbonate)

Answer 24

this is in a indirect way, when na is absorbed moderate amount of H ion is secreted into the lumen this thus combine with bicarbonate to form carbonic acid which then dissociate to h20 and co2, co2 is taking to the lung

Question 25

Transport of glucose

Answer 25

this is by secondary active transport apical part then facilitated diffusion at the basolateral membrane into the paracellular space and into the blood

Question 26

the first stage of glucose transport

Answer 26

there is a active transport of na the basolateral membrane of the intestinal cell into the blood causing the decrease of Na

Question 27

second stage of transporting glucose

Answer 27

the na that has been transported to the lumen binds with transport protein that also bind to the glucose ( GLUT) in this case thus transporting glucose and Na into the cells

Question 28

the transport protein that carries out the transport of Glucose into the cells

Answer 28

is a co-transport protein.

Question 29

absorption of fructose

Answer 29

it uses facilitated diffusion all through and does not us na - co-transport mechanism.

Question 30

absorption of galactose and animo acid

Answer 30

the same as glucose is absorbed

Question 31

the absorption of fats

Answer 31

the end product of fat which is fatty acid and monoglyceride dissolve in the bile mycelles, the mycelles are highly charge so they are soluble in chyme, the free fatty acid diffuse from the mycells into the epithelia cell were they are also soluble. then are taken up by the SER to form chylomicron released at the base of the cell to the lymph duct and into the blood.

Question 32

the bacteria in the colon are important for

Answer 32

forming vitamin K and vitamin B12

Question 33

vitamin k is important for

Answer 33

blood coagulation.