the control of blood water potential Flashcards
what does osmoregulation mean
-maintaining water potential of the blood restricted limits
which organs have major roles in osmoregulation
-hypothalemus and pituitary gland
what do the kidneys do in osmoregulation
-filter the blood ( ultrafiltration)
-selectivley reabsorb substances like glucose , amino acids and water
-urea, excess ions are left to form urine
whats the functional unit of the kidneys called
nephron
-there are about 1mil in each kidney
what does the cortex of each kidney contain
glomerulus
renal capsule
proximal convoluted tubule
distal convoluted table of each nephron
where does ultrafiltration occur
-between the glomerulus and the renal capsule of each nephron
-results in the formation of the glomerular filtrate
-each glomerulus is supplied with blood by an afferent arteriole ,branched form the renal artery
describe the process of ultra filtration
-high blood pressure forces glomerelous filtrate out such as glucose and amino acids
-through endothelial cells of the glomerelous that act as pores that allow proteins out but blood cells in
-through the basement membrane ( that acts as a main fine filter that allow small substances through)
what causes the high blood pressure in the glomerulus
-the contraction of the left ventricle
-affernt arteriole is wider than the efferent arteriole
what do the capillaries have that is an advantage
-endothelial cells
-have pores between them , allowing plasma to pass through but hold back the blood cells
what and why are endothelial cells attracted do
-basement membrane
what does the basement membrane do
-acts as the main fine filter
-holds back large plasma proteins in the plasma allowing only small molecules like glucose , amino acids through ,and urea and water
-located on the glomerlous
where are the epithelial cells located
-the walls of the renal capsule and are called podocytes
what do the epithelial cells of the renal capsule do
-many feet like structures
-which extend to the basement membrane and allow filtrate to pass through rapidly
what does the glomerular filtrate contain
-small soluble components of blood
-glucose, amino acids , water , urea
REMAIN IN BLOOD CAPILARY
-blood cells
-large plasma proteins
what do the blood cells and large plasma proteins that remain in the blood capillary go to
enter the efferent arteriole
what does the efferent arteriole do
-filtered blood from the glomerulus to the rest of the kidney and back to the general circulation
-forms a capillary network around rest of each nephron into which substances from the filtrate are SELECTIVELY REABSORBED
In simple terms, the efferent arteriole is a blood vessel that carries blood away from the glomerulus (the network of tiny capillaries in the kidney). After the blood has been filtered in the glomerulus, the efferent arteriole transports the remaining blood (which still contains waste products, nutrients, and other substances) to the next part of the nephron and eventually back into the circulation.
what does the proximal convoluted tubule do
-filtered glucose and amino acids are completely reabsorbed back into the blood as filtrate passes through proximal convoluted tubule
what are the processes in reabsorption
-initialy by facilitated diffusion and active transport
-into the cells lining the PCT
-most of the time mineral and water is aso reabsorbed at the PCT
what does presence of glucose in urine mean
-diabetes diagnosis
-caarrier proteins are unable to reabsorb all filtered glucose by active transport
-as the blood glucose concentration is too high
Scientists investigated the relationship between the thickness of the kidney medulla of
different species of mammals and the concentration of their urine.
-as conc of urine increases, thickness of medulla increases why ?
1) thicker medulla means longer loop of henle
2)increase in sodium ion concentration in the medulla
3)so water potential gradient is maintained so more water reabsorbed from the loop by osmosis
Explain the shape of the curve in the loop of Henle in the graph.- ( loop of henle increases)
-conc rises in descending limb because sodium ions enter and water is lost ( due to the sodium and chlorine being actively diffused from the ascending limb whihc caused a decreased water potential in the medulla tissues )
-concentration falls in ascending limb because sodium ions actively removed
-but water remains in ascending limb because its walls are impermeable to water
