Urinary System PDF

Urinary System Introduction 5 homeostatic functions 1. Regulated blood volume and blood pressure 2. Regulatutes plasma ion concentrations 3. Helps stabilize blood pH 4. Conserves valuable nutrients like glucose 5. Assists liver in detoxifyi...

Urinary System Introduction 5 homeostatic functions 1. Regulated blood volume and blood pressure 2. Regulatutes plasma ion concentrations 3. Helps stabilize blood pH 4. Conserves valuable nutrients like glucose 5. Assists liver in detoxifying poisons 6. Gluconeogenesis during exercise/flight or fight Kidneys look like beans in shape and color Both kidneys are retroperitoneal Each kidney is held in place and prostate by 3 external layers of connective tissue - Superficial to deep 1. Renal fascia- DICT which anchos each kidney to peritoneum and musculature of posterior abdominal wall 2. Adipose capsule- thickest layer which wedges each kidney in place and shields them from physical shock 3. Renal capsule - thin layer of DICT which covers exterior of each kidney to protect it from infection and physical trauma Kidney Kidney blood supply - Kidney receive 20-25% of total cardiac output - 1200 mL of blood flows through kidneys each minute - Kidneys receive blood through the renal artery Kidneys weigh 150g Helium are opening of medial surface of each kidney where renal artery, vein, nerves and ureters enter and exit Hilum opens into renal sinus which cavity is lined by renal capsule that is filled with urine drainage structures and adipose tissue 3 distinct regions 1. Renal cortex 2. Renal medulla 3. Renal pelvis Renal cortex and the renal medulla make up the urine forming portion of kidney Renal pelvis and its associated structure drain urine formed in cortex and medulla Renal corpuscle and renal tubule The renal corpuscle filters blood and consists of 2 parts 1. The glomerulus is a mass of fenestrated capillaries 2. An outer sheath of epithelial tissue known as bowman's capsule The renal tubule is known as pipes of nephron  1. Proximal convoluted tubule 2. Nephron loop- ascending/descending loop of henle 3. Distal convoluted tubule – collecting duct – papillary duct Types of nephrons There are 2 types 1. Cortical nephrons are primarily in the renal cortex which is outer - Peritubular capillaries supply blood to nephron loop 2. Juxtamedullary nephron has a long nephron loop deep in the renal medulla - Vasa recta surrounded the loop which arise from efferent arteriole Nephron Renal corpuscle filters the blood plasmas at the glomerulus in RBC and proteins not filtered Renal tubule modifies the filtrate Urine production 4 processes 1. Filtration at the glomerulus 2. Reabsorption back into the blood and body 3. Secretion and tubular stem and ultimately pee out 4. Excretion to pee stuff out Filtration at glomerulus Liquid components of the blood escape into bowman's capsule Glomerular capillaries are very leaky Podocytes with foot processes form the filtration structure Fenestrated capillaries are very leaky Proximal tubule Proximal tubule is made of SCEC with prominent microvilli - Microvilli project into tubule lumen to form brush border greatly increases the surface area Juxtaglomerular appratputs helps blood pressure in kidney Juxtaglomerular appratputs Juxtaglomerular appratputs composed of both macula densa and Juxtaglomerular cells to both regulate blood pressure and glomerular filtration rate 1. Hormone erythropoietin 2. Enzyme renin 3. Macula densa sense changes in flow Path of urine drainage Each renal pyramid tapers into a slender papilla Flow: PCT of loop of henle DCT to collect duct to papillary duct and then… 1. Each papilla borders on a cup shaped tube called a minor calyx which is where the first urine draining structure  2. 3 to 4 minor calyces drain into a larger urine drainage structure called major calyx 3. 2 to 3 major calyces drain into a large urine collecting chamber called the renal pelvis which leads to the ureter Micturition The discharge of urine involves voluntary and involuntary muscle Urine color Urinalysis is used to analyze urine composition as a diagnostic tool for detecting disease Urine color is formed by a yellow pigment Urochrome is a breakdown product of hemoglobin 1. Darker urine is more concentrated = less water 2. Lighter urine is less concentrated = more water Despite color urine should be translucent light is able to pass trough Cloudy urine may be a sign of infection or that too much protein is present