Nephron Function and Blood Filtration

Juxtaglomerular apparatus

(Deep nephron) Function is to regulate blood pressure and the filtration rate of glomerulus.

Nephrons

- Smallest structure of kidney and carry out all functions of the system. - Nephrons extract water and solutes from blood as necessary to maintain homeostasis. - Urine is manufactured here.

Purpose of tubular reabsorption and tubular secretion

-To maintain balance & pH levels. - Goes up and down twice to get the most out of reabsorption and secretion.

Function of ascending and descending limbs of loop of hence.

Ascending: Further water absorption Descending: Reabsorption of sodium and chloride ions.

Main Functions of Nephrons

Blood Pressure, pH, Nutrients

Function of glomerulus

Blood is delivered here, main function is filtration.

Explain effects of aldosterone

Controls sodium/potassium pumps

Function of papillary duct

Delivery or urine to minor calyx

Where does secretion take place in nephron?

Distal convoluted tubule. Nephron pumps waste into nascent urine.

Explain Blood colloid osmotic pressure

Draws water out of filtrate and into plasma opposing filtration.

List 3 main activities necessary for urine formation.

Filtration, Reabsorption, Secretion

Renal Nerves

Follow arteries to each nephron. They assist in; adjusting rates of urine formation by changing blood flow and blood pressure, stimulate the release of renin.

Where does filtration take place in nephron?

Glomerulus

Function of Loop of Henle (Nephron Loop)

Holds ascending limp turns into descending limb.

Explain glomerular filtration and ANS

Hormones control blood volume, and the ANS changes local blood pressure by vessel constriction or dilation to keep NFP near 10mm Hg.

Explain effects of parathyroid hormone on reabsorption.

Increases Ca2+ reabsorption at DCT (distal convoluted tubule).

Where does reabsorption take place in nephron?

Nephron loop, descending limb & ascending limp.

Explain glomerular Net filtration pressure

Net pressure (NFP) across the glomerular capillaries.

Function of Proximal & Distal Convoluted Tubules

Proximal Tubule: Reabsorption of water, ions and all organic nutrients. Distal Tubule: Secretion of ions.

Blood Flow through Kidneys.

Renal artery -> Segmental Artery -> Interlobar artery -> Arcuate Artery -> Cortical Radiate Arteries -> Afferent arterioles -> Nephrons (Glomerulus, Efferent Arterioles, Peritubular capillaries) -> Venules -> Cortical Radiate Veins -> Arcuate Veins -> Interlobar veins -> Renal Vein.

Explain capsular hydrostatic pressure

Results from resistance of filtration present in the nephron that must be pushed toward renal pelvis.

Cellular mechanisms behind tubular reabsorption.

Thick ascending limp is impermeable for water but permeable to Na+ tubular liquid becomes hyper osmotic distal tubule +collecting duct, reabsorption is dependent on hormones according to the body needs regulated.

Function of collecting duct

Variable reabsorption of water and reabsorption or secretion of sodium potassium, hydrogen and bicarbonate ions.

Explain effects antidiuretic hormone

Without ADH water does not leave collecting duct = dilute urine.

Explain glomerular filtration and Hydrostatic Pressures

is the blood pressure in the glomerular capillaries pushing fluid out.