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Flashcards by sarahderveeuw, updated more than 1 year ago
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Created by sarahderveeuw
almost 9 years ago
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| Question | Answer |
| Why do we require amino acids? | We have amino acids that we can't always make, we therefore consume these amino acids; Phenylalanine and Threonine But sometimes we do it in excess |
| How are excess amino acids removed from the body? | Excess amino acids can be used for energy. Only problem is this creates ammonia in a process called deamnination. Seeing as ammonia is toxic, it needs to leave the body through means of excretion |
| What is excretion? | The removal of metabolic waste (not solid waste like egestion) from the body The kidney is the main organ of excretion |
| What are the functions of the Kidney? | • The key organ for regulated removal of water and soluble substances to maintain volume and composition of body fluids o Excretion of toxic waste substances generated in metabolism (urea, Most excretion aims at removing nitrogen, and that nitrogen comes from proteins that we have digested. We don’t get rid of all the amino acid, we just deaminize them and use the break down, uric acid, urobilinogen) or ingested (drugs, toxins etc.) o Ion (Na+, K+, Ca+ etc.)/water balance (osmolarity) o pH regulation of body fluids (hydrogen ion is what determines acidity) o Maintenance of blood pressure (by keeping extracellular fluid volume and composition within physiological range). If your blood pressure is not high enough, you won’t have enough oxygenated blood. o Hormone production: erythropoietin (EPO) for red blood cell production (can be taken as a drug that will cause bone marrow cells to divide) , renin (blood pressure regulator). o Controls levels of Ca2+ by regulating vitamin D synthesis. |
| What other organs are involved in excretion? | Organs in excretion (getting rid of byproducts from chemical reactions) - Skin excretes water and salts in perspiration - Lungs excrete carbon dioxide as a gas - Liver excretes bile pigments in bile - Kidneys excrete nitrogenous wastes in urine |
| Anatomy of the Kidney (Systems Level) | |
| Different types of excretion for different organisms | - Ammoniotelic – fish make ammonia - Ureotelic – humans’ convert ammonia to urea, less toxic, so can use less water - Ureotelic – birds, insects, reptiles, make uric acid (solid) and use less water than if you would need to make urea |
| Anatomy of Kidney (Organ Level) | |
| General Functions of the Kidney (BI305) | - removal of soluble nautral wastes - removal of small, soluble, toxin molecules eg drugs - regulate water content - regulate salt balance - regulate blood pressure and volume |
| Blood supply to the kidney | - Outside bit, renal cortex - Renal artery (takes blood in) - Renal vein (takes blood out) - Ureter which takes the urine out - (Anything Renal is kidney) |
| Blood supply to the nephrons | |
| Nephron Anatomy | |
| Nephron Structural Inforamtion | The nephron is the functional unit of the kidney responsible for the formation of urine. There are millions of nephrons per kidney Consist of small tubes (tubules) and associated small blood vessels. Fluid formed by filtration of blood enters the tubules and its content is modified by transport processes to and from the tubule lumen. The resulting fluid leaving the tubules via collecting ducts is urine. The different parts of the nephron perform distinct functions |
| Functional overview of a Nephron | |
| Function of a Nephron | Each kidney filters ~1000 Litres of blood a day to produce ~500 ml urine. With about 4L of blood each litre passes through nephrons about 500 times a day. 99.9% of the filtered fluid is reabsorbed. Most of the urea is not. Usually, all of the glucose is reabsorbed. The process of urine formation is termed DIURESIS. |
| The Four functions of the Nephron (BI305) | Four Functions of the Nephron Ultrafilration (1) – straining of the liquid part of the blood Blood goes from the artery into the afferent areteriole 180 litres of filtrate passes through the glomerulus a day, meaning 45 times for the blood Problem is that if we use up this much water we would constantly be losing water in the body – THUS reabsorption Reabsorption (2) – of glucose and sodium that go back into the blood Absolutely no glucose goes to the bladder (unless diabetes, where we can’t store glucose in the form of glycogen) Lose about 1.8 liters of water a day (which is a lot in consider everything that is being filtered – 180 liters) Reabsorption is urea (44%) Glucose (100%) and water Most of the substances are reaorbed in the proximal convoluted tubule through trans-epithelial pathways (through the specific cell) By the end of the proximal convoluted tubule, glucose should be fully absoorbed Volume reduction (3) Loop of Henle, starts with the descending limb starts in the cortext and ends in the medulla o As the loop enter the medulla the surroundi |
| The Glomerulus (Anatomy) | |
| Glomelular Substructure (The Glomerular Capillary) | |
| Better understanding of the stuctural hierarchy of the Glomerulus | |
| Ultrafiltration (1) | o Blood goes from the artery into the afferent areteriole o 180 litres of filtrate passes through the glomerulus a day, meaning 45 times for the blood o Problem is that if we use up this much water we would constantly be losing water in the body – THUS reabsorption |
| Ultrafiltration process (Glomerulus) | Golmerulus is the starting point for a single nephron Pressure is high enough in the glomerulus to push 20% of the fluid into a "cup-like-sac"; BOWMAN'S CAPSULE (now fluid is not called blood anymore as redblood cells don't get filtered, it's called filtrate - urea, water, smaller ions) |
| Net Filtration Pressure of the Glomerulus | |
| Glomelurar Filtration Rate and what affects it | |
| GFR and The Macula Densa | |
| Reabsorption (Proximal Convoluted Tubule) | "The tube near the beginning" one of two convoluted tubules Where osmorgegulation takes place, Reabsorb water Mainly organic solutes in the filtrate are reabsorbed such as glucose and amino acids Some water, potassium and sodium that you're going to want later |
| Reabsorption in the Loop of Henle | Most reabsorption occurs here, and at this point the loop of henle is located within the innter medulla of the kidney (Everything before this was in the cortex our outer medulla) Extracts most of the water we need from the filtrate as it travels down into the medulla Membrane is highly permeable to water soNa and Cl leaves through difusion as ir goes down to thebottom of the loop The ascending end of the tubule however needs to use pumps to pump out ions, seeing as filtrate ion concentration is much lower than exterior medulla salt concentration Inner medulla (bottom of loop) is therefore More hypertonic (super salty) and outer medulla is just hypertonic |
| Reabsorption and Volume reduction in the Distal Convoluted Tubule | Reabsorption of sodium, potassium, chlorine and other ions. and some water Regulation of Na, K, and Ca (pumps and hormones regulate this reabsorption process) a |
| By the end of the proximal Convoluted tube | Glucose is fully absorbed filtrate volume is reduced to 25% and remains isotonic ~ 75% of Na+ is reabsorbed, Cl- (charge balance, channel proteins) H2O (osmosis) |
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