Steam flowing through a long, thin-walled pipe maintains the pipe wall at a uniform temperature of 500 K. The pipe is covered with an insulation blanket comprised of two different materials, A and B. The interface between the two materials may be assumed to have an infinite contact resistance, and the entire outer surface is exposed to air for which T 300 K and h 25 W/m2 K. (a) Sketch the thermal circuit of the system. Label (using the preceding symbols) all pertinent nodes and resistances. (b) For the prescribed conditions, what is the total heat loss from the pipe? What are the outer surface temperatures Ts,2(A) and Ts,2(B)?
Urinary System Kidneys filter to get rid of metabolic wastes other than CO2 as urine Components | Kidneys (2) { Each has drainage tube coming off called ureter | Ureters { Empty into urinary bladder | Urinary bladder { Storage tank | Urethra *no accessory structures in urinary system- only these structures! Functions | Fluid filtration { Passage of fluid across filtration membrane Functions | Fluid filtration | Regulate blood volume { Liquid component of blood, plasma, how much goes into urine { The only determine bloodo volume Functions | Fluid filtration | Regulate blood volume | Maintains salt/ water balance { By using water Functions | Fluid filtration | Regulate blood volume | Maintains salt/ water balance | Maintains acid/ base balance { Related to the 3 bullets above Functions | Fluid filtration | Regulate blood volume | Maintains salt/water balance | Maintains acid/base balance | Gluconeogenesis { Kidneys are a site ofgluconeogenesis Functions | Fluid filtration | Regulate blood volume | Maintains salt/water balance | Maintains acid/base balance | Gluconeogenesis | Renin production { Kidneys produce renin { Renin is a chemical that will control activity of kidneys Functions | Fluid filtration | Regulate blood volume | Maintains salt/water balance | Maintains acid/base balance | Gluconeogenesis | Renin production | Erythropoietin production { Regulates cellular portion of blood Functions | Fluid filtration | Regulate blood volume | Maintains salt/water balance | Maintains acid/base balance | Gluconeogenesis | Renin production | Erythropoietin production | Activates vitamin D Kidney Structure: how its made up | Capsule: Very thin outer layer | Cortex: The outer region | Medulla: The central region | Pelvis: the flattened portion within the kidney that is connected to ureter | Pyramids: triangular shaped sections; looked striped in pic | Columns: extension of cortex between pyramids | form thisyces: minor calyces merge to Hilum= the indentation on side | Minor calyces: where pyramids empty Supportive Layers | Renal capsule { Supporting layer that holds kidney all together | Adipose capsule { Adipose tissue that envelopes kidneys; a cushion for protection, insulator so don’t lose heat *Kidneys are outside | Renal fascia peritoneal cavity= { Anchoring structure to retroperitoneal hold kidneys to read abdominal wall Nephron (the functional and structural unit of kidney) | Glomerulus { A capillary bed with blood vessels; fenestrated so leaks plasma { Under higher pressure than any other bed in body | Renal tubule { glomerulus and collects plasma: sphere that surrounds { capsule, twistsuted tubule: closest to bowman's { ascending limbscan be divided into descending and { Distal convoluted tubule | Collecting ducts { A single collection duct can attach to multiple renal tubules | Renal corpuscle { The glomerulus and bowman's capsule Types of nephrons | Cortical { Most of the nephrons (85%) { Means that most of nephron is in the cortex and only a small part of loop of Henle goes into medulla { Next to the medulla { Most of the loop of Henle is *switching between types in medulla, and is longer/ of nephron used changes deepner the concentration of urine { 15% of nephrons formed!! Nephron Vasculature (blood vessels) | Afferent arteriole { Takes blood TO the glomerulus | Efferent arteriole { Takes blood AWAY from glomerulus | Glomerulus { Specialized capillary bed | Peritubular capillaries { Regular capillary bed around tubule | Vasa recta { peritubular capillaries that surround the tubule in a Juxtamedullary capillary Juxtaglomerular Apparatus | Modification where distal convoluted tubule runs against afferent arteriole { muscle where cells enlarge and gain ability to secrete reninà called juxtaglomerular cells | mechanoreceptors to detect changes in blood pressure { Distal convoluted tubule cells that function asa densa cells chemoreceptors to detect concentration of filtrate Filtration Membrane | Fenestrated epithelium { Holes to leak plasma { Surrounded by a basement membrane | Podocytes { Green thing in pic { Cells that have extensions called pedicels { Create filtration slits so that we don’t lose too much | Basement membrane { Will not allow large things like proteins to pass through These three things { Also creates an electrically selective together all create a membrane filtration membrane The process of urine production begins with filtration in glomerulus, filtrate passes through and good stuff is reabsorbed, in case some stuff that we want to get rid of didn’t get filtered they are secreted by the tubule FILTRATE DOES NOT = URINE, IT BECOMES URINE by taking things out and adding to Filtration Pressures | Glomerular hydrostatic pressure { Pressure of blood inside glomerulus | Colloid osmotic pressure of intracapsular space { Pulls fluid out of circulation into tubule | Colloid osmotic pressure of glomerular blood { A resistance { Large stuff draws fluid back in | Capsular hydrostatic pressure { Pushes fluid back in Renal blood flow (RBF) Glomerular filtration rate(GFR)= volume of filtrate produced each minute; combined of all nephrons in both kidneys *look at changes in afferent and efferent arterioles
