Week 9-10 LO4 Urinary System Class PDF

1 Introduction The urinary system removes waste products from the body, regulates the water and electrolytes balance. Shier, Butler & Lewis (2018)  2 Structur...

1 Introduction The urinary system removes waste products from the body, regulates the water and electrolytes balance. Shier, Butler & Lewis (2018)  2 Structures of the Urinary System 2 Kidneys 2 Ureters 1 Urinary bladder 1 Urethra Shier, Butler & Lewis (2018)  3 Kidney Kidney is reddish brown, bean-shaped organ with smooth surface. It is about 12 cm long, 6 cm wide, and 3 cm thick in adult. Kidneys filter the blood of our body: approximately 180 liters of blood filters through the kidneys every day, 1.5 liters leaving as urine Each kidney has about 1 million nephrons (Nephron is the functional unit of Kidney) Shier, Butler & Lewis (2018)  4 Location of the kidneys Located on posterior abdominal wall. (1) each side of vertebral column.(2) Behind the peritoneum (3) below the diaphragm (4) The upper and lower borders of the kidneys are generally at the level of the 12th thoracic and 3rd lumbar vertebrae. (5) Shier, Butler & Lewis (2018)  5 Behind the below the posterior abdominal each side of vertebral peritoneum diaphragm wall column  6 Kidney Structure Shier, Butler & Lewis (2018)  7 Kidney Structure Hilum: is a medial border where renal blood vessels and lymph vessels, and nerves enter the kidney. Shier, Butler & Lewis (2018) Kidney – Gross Anatomy Shier, Butler & Lewis (2018)  9 Kidney Structure o Renal Pelvis: It is a funnel shaped sac, located mostly inside the renal sinus. It directs the urine formed by the kidney toward the ureter. The pelvis is formed by the convergence of two or three tubes, called major calyces. o The major calyces are formed by the convergence of seven to twenty minor calyces Minor calyx: cup that nestles the papilla of each pyramid; collects its urine o Renal papilla: it is the apex of pyramid extends into each minor calyx. Shier, Butler & Lewis (2018)  Renal Pelvis 10 It is a funnel shaped sac, located mostly inside the renal sinus. The renal sinus is a fat-filled cavity in the middle of the kidney that cushions important parts. It directs the urine formed by the kidney toward the ureter. The pelvis is formed by the convergence of two or three tubes, called major calyces. o The major calyces are formed by the convergence of seven to twenty minor calyces Minor calyx: cup that nestles the papilla of each pyramid; collects its urine o Renal papilla: it is the apex of pyramid extends into each minor calyx.  11 Kidney Structure Cont… Renal capsule Is the outer fibrous membrane that surrounds the cortex. - It helps maintain the shape of the kidney, supports and protects the kidney. Renal capsule - Each Kidney has two regions: 1. Renal Cortex: an outer layer. 2. Renal Medulla: an inner layer. Shier, Butler & Lewis (2018)  12 Kidney Structure Renal cortex: - The outer region of the kidney, appears somewhat granular and it forms a shell around the medulla. - It dips into the medulla between the renal pyramids, forming renal columns. - Contains the Renal corpuscle (glomerulus and the glomerular capsule) and most of the renal tubules (proximal and distal convoluted tubules) of the nephron. Shier, Butler & Lewis (2018)  13 Kidney Structure Renal Medulla: - The inner region of the kidney - Is composed of renal pyramids and their apexes form the renal papillae. - The tissue of the medulla (pyramids) appears striated because it consists of microscopic tubules (the loops of Henle and collecting ducts) of the nephron. Shier, Butler & Lewis (2018)  14 Renal Blood Vessels Renal arteries: arise from abdominal Aorta to Kidneys Transport large volume of unfiltered blood with excretory products (urea, uric acid, alcohol, some drugs, excess ions) Nitrogenous wastes) to the kidney. Oxygenated O2 Renal vein: Kidneys to Vena cava Transport filtered blood, cleaned of waste products from kidney to vena cava Deoxygenated CO2 Shier, Butler & Lewis (2018)  15 Activity 1: Label the diagram 1. _____. 2. _____. 3. _____. 4. _____. 5. _____. 6. _____. 7. _____. 8. _____. 9. _____. 10. ____.  16 Urea Ammonia (NH3)is converted into urea by the liver. Urea is then transported in the blood to the kidneys where the urea is removed from the blood.  17 Kidneys Functions: Blood filtration and regulation of body fluids volume and composition (cleaning the blood ) Excretion and removal of wastes produced during protein metabolism like urea and uric acid. (They get rid of waste products from protein breakdown, like urea) Regulation of water balance – osmotic pressure of blood, interstitial fluid, lymph. (They help control how much water is in our body and blood) Regulation of pH: Excretion of hydrogen and bicarbonate ions to maintain constant PH. (They keep our blood at the right acidity level by managing certain ions) Regulation of calcium ions absorption by forming the active form of vitamin D. (They help make vitamin D active, which is important for calcium use) Regulation of blood pressure by secreting the enzyme renin. (They make a hormone that tells the body to produce more red blood cells) Secretion of erythropoietin, a hormone that stimulates the production of erythrocytes (RBCs), controlling the rate of RBC formation. Kidneys Functions: Shier, Butler & Lewis (2018)  19 Nephron - The nephron is known as the basic functional unit of the kidney since it is the location for urine formation. - Each kidney contains about 1 million of them. - Each nephron consists of a renal corpuscle and a renal tubules. - Nephrons are responsible for urine formation. Shier, Butler & Lewis (2018) Kidney – Microscopic Anatomy Shier, Butler & Lewis (2018)  21 Nephron structure: 1. Renal corpuscle is composed of the glomerulus (Bundle of Capillaries) and the glomerular capsule (Bowman’s capsule). 2. Renal tubules are composed of the following: (about 3 cm) i) Proximal convoluted tubule (PCT) ii) Loop of Henle iii) Distal convoluted tubule (DCT) – leading into a collecting tubule./ duct Shier, Butler & Lewis (2018)  22 Renal Corpuscle Renal Corpuscle= Glomerulus+ Glomerular Capsule (Bowman’s capsule ) Shier, Butler, Lewis; McGraw Hill, 2016  23 Functions of The Nephron Parts: Nephron Parts Functions Glomerulus (glomerular capillaries): The fluid filtration starts (Filtration of fluid and solutes from plasma). Glomerular capsule: Receives the fluid (filtrate) then directs the filtrate to the proximal convoluted tubule (PCT). Proximal tubules: Reabsorption of nutrients, all glucose, various ions and 2/3 of water. Directs the filtrate to the loop of Henle (descending limb). Loop of Henle (descending limb): Water reabsorption only. Directs the filtrate to the (ascending limb). Loop of Henle (ascending limb): Selective reabsorption of sodium, potassium and chloride. directs the filtrate to the DCT. Distal convoluted tubule: Secretion of hydrogen and potassium ions and medicine and alcohol. Directs the filtrate to the collecting duct. Collecting ducts: Water conservation. collecting and directing urine to the minor calyces through the papilla.