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The Kidney. David, Sterling, Chelsea & Yuki. Structure. The Beautiful Structure of the KIDNEY. Nephrons. For remembrance purposes; “Zac Nephrons”. What are Nephrons? Nephrons are tiny tubules within the kidney that produce filtrate from the blood and remove waste products as urine.
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The Kidney David, Sterling, Chelsea & Yuki
Structure The Beautiful Structure of the KIDNEY.
Nephrons For remembrance purposes; “Zac Nephrons” What are Nephrons? • Nephrons are tiny tubules within the kidney that produce filtrate from the blood and remove waste products as urine. How do Nephrons work? • In glomerulus capsules, small particles and fluid are filtered out of the blood stream. • These particles are captured in the Bowman’s capsule surrounding the glomerulus. • These solutes then travel down the proximal convoluted tubule, there the body reabsorbs important nutrients and vitamins that have been caught in the filtrate. • It then travels into the loop of Henle. In the descending tube, water leaves the tubule by osmosis to be reabsorbed back into the body and in the ascending tube salts are removed but only by active transport. • In the distal convoluted tubule, secretion process takes place as the tubule absorbs ammonia, uric acid, etc. • These concentrated solutes are then filtered into the renal pelvis structure, which then funnels them into the ureter.
The Kidneys responds to several different changes in the environment including Water balance Blood pressure pH of blood Kidneys and Homeostasis
Water balance ADH allows water to pass through the walls of the collecting ducts Osmoreceptors in the hypothalamus sense the sodium concentration, when it is high, more ADH is secreted, when it is low less ADH is secreted. This causes a negative feedback that brings the sodium concentration and water level back to normal.
Water Balance at Work Stimulus – Drink water Sodium concentration drops Osmoreceptors notice a drop in sodium Less ADH is released The nephron reabsorbs all the sodium and some water The water is expelled as waste leaving the blood with normal sodium levels
Blood Pressure Cells in the afferent arteriole sense change in pressure (called juxtaglomerular cells) These cells then release an enzyme called renin, which breaks angiotensinogen into Angiotensin I then Angiotensin II Angiotensin II causes blood vessels to contract Also makes the adrenal glands produce aldosterone Aldosterone stimulates more sodium reabsorbtion, water is also reabsorbed with the sodium this allows for more blood volume in the veins, without this mechanism, giving blood would be impossible.
- optimal pH: 7.3-7.5 pH outside of 6.8-7.8 causes death different foods, different pH (most of them do not have ph=7.4) - cellular respiration produces CO2, CO2 moves through cell membranes, then enters the bloodstream CO2(aq) + H2O(l) H2CO3(aq) H2CO3(aq) H+(aq) + HCO3-(aq)---ACIDIC - [H+] controls the pH level - Buffer systems, along with respiratory system and kidneys, maintain acid-base balance by CHEMICAL EQUILIBRIUM Buffer System in Human Body
--- H2CO3(aq) & HCO3-(aq) 1). Bicarbonate Buffers Forward rnx Reverse rnx in blood plasma H+(aq) + HCO3-(aq) H2CO3(aq) reversible, at equilibrium (no net change in []) if: Acidic OR [H+] ↑--- forward rnx dominates, [H2CO3]↑, [HCO3-]↓ -- H2CO3 breaks down into CO2 and H2O, is exhaled out by lungs Basic OR [H+] ↓--- reverse rnx dominates, [H2CO3]↓, [HCO3-]↑ --H2CO3 ionizes to produce more H+ ions quantify by Henderson-Hasselbalch equation: pH =pKa + log [ HCO3-] / [CO2]
The Role of Kidney (in bicarbonate buffer system) • Restoration of Buffer (H2CO3-) • CO2 in peritubular capillaries and tubule lumen enters kidney tubule cells by active transport to produce H2CO3- and H+ • H2CO3- travels back into the bloodstream Diagram 2). Phosphate Buffers • in internal fluid of cells • H2PO4-(aq) H+(aq) + HPO42-(aq) 3). Protein Buffers e.g. Hemoglobin can acts as hydrogen ion receptor/ donor depending on the blood pH level Abnormal pH Level • Acidosis---abnormally low pH, acidic • Alkalosis---abnormally high pH, basic
Dialysis • Alternative “kidney” to people with end stage kidney failure (lost 80%-95% of kidney function) • Has most of the functions of a normal kidney: eliminates urea, excessive salt and water, other waste products, maintain a moderate level of ions (K+, Na+, H2CO3+, etc.) • Unable to produce hormones, such as renin (an enzyme that triggers the release of aldosterone from pituitary gland) or activate vitamin D Video
Hemodialysis Usually done in hospitals A tubes is bridged between an artery and a vein to transfer blood
Peritoneal Dialysis • Blood is cleaned inside of the body • Can be done almost anywhere, patients can perform most daily activities • A plastic tube, catheter, is inserted into the abdominal membrane • Dialysate slowly fills up the abdomen • Wastes and extra fluid in the blood diffuses into the solution Usually in 4 hrs- • Used dialysate, along the wastes, exits the body through catheter
Kidney Diseases Acute Kidney Failure Kidney Failures that developed over a short time of period. Usually there are no severe damage done to the kidney itself. Chronic Kidney Disease When one suffers from gradual and usually permanent loss of kidney function over time. This happens gradually over time, usually months to years.
Acute Kidney Failure Pre-renal Problems affecting the flow of blood before it reaches the kidneys Post-renal Problems affecting the movement of urine out of the kidneys Renal Problems with the kidney itself that prevent proper filtration of blood or production of urine
Chronic Kidney Diseases • Chronic kidney disease is a growing health problem in the United States. A report by the Centers for Disease Control (CDC) determined that 16.8% of all adults above the age of 20 years have chronic kidney disease. • Although chronic kidney disease sometimes results from primary diseases of the kidneys themselves, the major causes are diabetes and high blood pressure
Kidney Diseases Symtoms ACUTE KIDNEY FAILURE CHRONIC KIDNEY DISEASES Decreased urine production Body swelling Confusion Fatigue Nausea, vomiting Diarrhea Metallic taste in the mouth • Metallic taste in the mouth • Fatigue • Loss of Appetite • Increase in urine production • Swelling Legs • Shortness of Breath • Chest pain • Decrease in sexual interest
Kidney Transplant ADVANTAGES DISADVANTAGES • No annoying life- term treatments • Works just like your old ones~! • Safe, procedure is 85% successful • Immune Response of the recipient • Donor Kidney is often identified at foreign and the receiver’s immune system may attack to destroy the transplanted kidney