Wk 10- The Renal System

What are the 4 pain organs/ tissues of the renal system? • K? x2 = active renal organs • Ur? x2 = urine > bladder • B? = ? storage • U? = ? disposal

The kidneys: Main functions ~ Removal of w? R? of fluids / e? Regulation ?h Maintain blood ? Control erythropoiesis ( ? blood cells)

The kidneys: 10-12 cm long Renal cortex = o? region kidneys , contains n? Renal medulla= inside kidneys, renal py? separated by renal c?

Kidneys: Kidneys remove w? and regulate composition of b? 1200 ml blood /? Represents 20-2?% cardiac output Path of blood in the kidney = A? artery in , E? artery out for filtration

The nephron: F? unit of the kidney Renal corpuscle = Glomerulus (ca? network) Glomerular capsule (Bo? capsule) Renal tubule = Tubes conveying fil?

The nephron: Each kidney has ?.25 million Nephrons Cortical nephrons = 80-??% of all nephrons Short nephron loops (loops of h?) Juxtamedullary nephrons = extend into the m? , long nephron loops

Nephrons: Contain capillary network of the gl? The capillaries are covered by Po? and Ped? cells Re? and secretion take place across t? walls

The Nephrons: What are the 3 nephron functions? • Glo? filtration = w? and solutes in plasma cross filter surface • T? re? = ??% water and useful solutes return to b? via peri tubular capillaries and vasa recta • T? secretion = secretion of wastes, t? and ions from peri tubular capillaries

Filtration: Filtration occurs in the renal Cor? across the filtration membrane Fenestrated ca? = very l? Pedicels of p? required to prevent larger sol? leaving the blood

Filtration: Fluid filtered / day Males = 1?0 l/ day Females = 1?0 l/ day 9?% reabsorbed into bloodstream 1-? L urine/ day

Regulation of filtration rate Glomerular filtration rate (—) = amount of filtrate produced by the kidneys every ? Maintained at 12? ml/min Kidneys regulate the vascular tone of the Afferent and efferent art? to maintain correct filtration pressure

Tubular reabsorption and secretion : Tubular reabsorption returns 9?% of w? and filtered sol? back to the bloodstream. Reabsorption can be passive or a? >= A?P Concentration ? allow diffusion of solutes Os? gradients allow diffusion of water molecules Solutes too big are secreted out of blood

Renal tubules There are ? Renal tubules They are Proximal convoluted tubule = epithelial cells with micro villi. Most ab? done here. Nephron loop / loop Henle = divided into descending and a? limbs Distal convoluted tubule = cells lack micro villi

Proximal convoluted tubule 6? % water, N-+ , K+ reabsorbed 100% of gl? and a? a?

Nephron loop/ loop Henle Tube loops down into m? 20% water reabsorbed Descending limb = ? Ascending limb = mostly solutes –+ ? and Cl-

Distal convoluted tubule Most remaining water absorbed via osmosis Reabsorption of –+? And C? and C-+? ADH? and aldosterone released to combat de? Collecting duct = final tube that can adjust u? volume and co? Reabsorbed the remaining water and solutes.

Urine: Urine is produced to maintain h? Waste products are removed whilst useful materials are re? 3 main organic waste products removed = 1. Urea= breakdown of a? a? 2. Cr? = produced during cr? phosphate 3. U? Acid = produced during nitro? base recycling