Renal Physiology Flashcards
functional units of kidney;
that has approximately _
nephrons;
1 - 1.5 million
responsible primarily for removal of waste products and reabsorption of nutrients; with make up approximately _ of nephrons
Cortical nephrons; 85%
Cortical nephrons are situated primarily in the _
cortex of the kidney
Their primary function is concentration of the urine. This extend deep into the _ of the kidney
Juxtamedullary nephrons; medulla
nephrons clear waste products selectively from the blood and simultaneously to maintain the body’s essential _ and _ balances
water and electrolyte
renal functions:
renal blood flow,
glomerular filtration,
tubular reabsorption,
tubular secretion
supplies blood to the kidney
renal artery
The human kidneys receive approximately _ of the blood pumped through the heart at all times.
25%
blood pathway in the kidney
afferent arteriole -> glomerulus -> efferent arteriole -> peritubular cappilaries -> vasa recta
what is bigger between afferent and efferent arteriole
afferent
providing for the im- mediate reabsorption of essential substances from the fluid
proximal convoluted tubule
final adjustment of the urinary composition
distal convoluted tubule
located adjacent to the ascending and descending loops of Henle in juxtamedullary nephrons
vasa recta
When dealing with kidney sizes that vary greatly from the average _ of body surface
1.73 m2
the total renal blood flow is approximately _, and the total renal plasma flow ranges from _
1200 mL/min; 600 to 700 mL/min
The glomerulus consists of a coil of approximately _ capillary lobes, the walls of which are referred to as the _
eight; glomerular filtration barrier
glomerulus is located within _, which forms the beginning of the renal tubule
Bowman’s capsule
a nonselective filter of plasma substances with molecular weights less than 70,000, several factors influence the actual filtration process
glomerulus
Plasma filtrate must pass through three glomerular filtration barrier cellular layers:
the capillary wall membrane,
the basement membrane (basal lamina),
the visceral epithelium of Bowman’s capsule
Cellular Structure of the Glomerulus
The endothelial cells of the capillary wall differ from those in other capillaries by containing pores and are referred to as _.
fenestrated
Epithelial cells of the inner lining of Bowman’s capsule that contain foot-like processes
podocytes
an autoregulatory mechanism within the _ maintains the glomerular blood pressure at a relatively constant rate regardless of fluctuations in systemic blood pressure
juxtaglomerular apparatus
_ regulates the flow of blood to and within the glomerulus. The system responds to changes in blood pressure and plasma sodium content that are monitored by the juxtaglomerular apparatus, which consists of the juxtaglomerular cells in the afferent arteriole and the _ of the distal convoluted tubule
renin-angiotensin-aldosterone system; macula densa
an enzyme pro- duced by the juxtaglomerular cells
renin
RAAS system activation
renin - substrate angiotensinogen - hormone angiotensin I - angiotensin-converting enzyme (ACE) - angiotensin II
converts angiotensin I to angiotensin II in alveoli of the lungs
angiotensin-converting enzyme (ACE)
Angiotensin II cor- rects renal blood flow in the following ways:
- vasodilation of afferent & constriction of efferent
- reabsorption of sodium and water in the proximal convoluted tubules
- aldosterone release by adrenal cortex
- ADH release by hypothalamus
sodium-retaining hormone
aldosterone
the substance to be reabsorbed must com bine with a carrier protein contained in the membranes of the renal tubular epithelial cells
active transport
is the movement of molecules across a membrane as a result of differences in their concentration or electrical potential on opposite sides of the membrane
Passive transport
Passive reabsorption of water takes place in all parts of the nephron except the _, the walls of which are impermeable to water.
ascending loop of Henle
plasma concentration at which active transport stops
renal threshold
For glucose, the plasma renal threshold is
160 to 180 mg/dL
adh is also known as
vasopressin
↑Body Hydration = _ ADH = ↑Urine Volume
↓ADH
eliminating waste products not filtered by the glomerulus and regulating the acid–base balance in the body through the se- cretion of hydrogen ions
tubular secretion
major site for removal of these nonfiltered substances
proximal convoluted tubule
The buffering capacity of the blood depends on _ ions
bicarbonate (HCO3–)
