| Term | Definition |
|---|
| Urinary system function | maintain normal blood components and extract & remove waste products from the blood |
| Anatomy of the kidney | ventral to first few lumbar vertebrae; In dorsal abdomen, one on each side of the aorta; Left one is more caudal; Look for fat storage around the kidney, if none - starvation |
| Hilus | concave area around the kidney; where blood vessels, nerves & ureter enter & leave |
| Capsule | Tough, fibrous outer covering of the kidney; At necropsy it should peel off easily--if doesnt this means there was repeated kidney infections |
| Cortex | Outer layer of kidney tissue just under the capsule; looks grandular due to presence of the glomeruli |
| Medulla | Beneath cortex; lined or striated looking due to collecting ducts |
| Renal pelvis | Funnel shaped part of the hilus where urine collects before entering the ureter |
| Renal Artery | Short, has a blood pressure that is 70% that of the aorta. Enters the kidney & becomes the arcuate arteries, then that becomes the afferent arteriole, then it becomes the glomerus. |
| Ureter | Tube that carries urine from kidney to the bladder; somtimes can be ectopic. |
| Ectopic Ureter | Ureter does not connect from kidney to bladder, but to kidney to urethra. |
| Bladder | Hollow expandable organ, smooth muscle |
| Trigone | Area in the bladder where the two ureters come in and where the urethra comes out. |
| Urethra | Smooth muscle tube used for urine to exit the body. |
| Kegals | Exercises you do to strenghten the pelvic muscles to help treat incontinence. |
| Nephron | Basic function unit of the kidney; Approx. 1 million in each kidney; A tube used for collecting waste from the body and converting it to urine; We are only using about 1/4 of them at any time. |
| Glomerulus | Tuft of capillaries located in the cortex; Afferent arteriole coming in, efferent arteriole coming out. Leak/filter out electrolytes, antibiotics and poisons--end up in bowmans capsule |
| Proximal Convoluted Tubule (PCT) | Longest section of the nephron; found in the cortex; reabsorbs many things the body wants to conserve (Na, Cl, H2O, glucose) |
| Loop of Henle | U-shaped tube with a descending limb that is thin-walled, and a ascending limb which is thick walled. Extends into the medulla; contains most concentrated solution in its lowest area. Responsible for the concentration of urine. |
| Distal Convoluted Tubule (DCT) | Not as twisted as PCT. Last part of nephron; found in cortex. |
| Collecting Ducts | Many nephrons dump their wastes into each collecting ducts. Straight (give striations to the medulla). Pass through the medulla to reach the pelvis. |
| Interstitial Space | Area around the tubules and the blood vessels in the kidney. Area where things that are conserved get removed from the filtrate within the tube. |
| Blood Filtered at the Glomerulus | Blood filtered here has Water, small molecules like electrolytes (Na, Cl, K, H), Glucose, amino acids, urea & creatinine are filtered out. Any molecules will be filtered into Bowman's capsule. Large molecules wont be filtered (blood cells, protein, fat, antibodies) |
| Amount of Filtration depends on: | 1.Blood flow to the kidneys (dehydration decreases it). 2. Blood pressure (low in shock, anesthesia, surgery) |
| Blood going to kidney | 90% goes to glomeruli. 10% nourishes the kidney. Total blood volume of animal is filtered every 5 minutes. |
| Filtrate | Substances filtered at glomerulus into Bowmans capsule |
| Urine formed | For every 1 liter or urine formed approx. 180 liters of blood are filtered |
| Amount of Filtrate formed & urine produced | INCREASE filtrate, INCREASE blood pressure. DECREASE filtrate, DECREASE blood pressue. INCREASE filtrate, INCREASE blood volume. DECREASE filtrate, DECREASE blood volume. |
| Glomerular Filtration Rate | Speed at which filtrate is made at gomerulus. Affected by blood pressure and blood volume. |
| Clearance | The ability of a substance to be removed from the blood by the kidney & excreted into the urine. This substance must be filtered but not reabsorbed. EX: Creatinine (a measure of kidney function) |
| Urine is formed by: | Filtration (passive). Reabsorption (active & passive). Secretion (active) |
| Passive Transport | Type of transport where NO ENERGY IS USED. Water moves from areas of high water (low solute) to areas of low water (high solute). As water leaved the solute concentration increases (needed for urine concentration). |
| Active Transport | Type of transport that NEEDS ENERGY (ATP) and carrier molecules. Na and Cl pumps; glucose and amino acids tied to the Na pump. |
| Renal Threshold | Maximun amount of a substance in the blood that is filtered that can be reabsorbed. Threshold for glucose is 200 mg/dl. |
| Process of Urine formation | Filtrate in bowman's capsule comes from glomerus. PCT: Na/Cl is conserved & reabsorbed; bicarbonate, glucose, amino acids are reabsorbed here. H, K, NH3 excreted here, So fluid leaving PCT high in H,K,NH3, creatinine & urea. Loop of Henle: essential for the counter-current mechanism which is responsible for concentrating urine. Descending loop thin-walled & water diffuses out so the solute in the tube gets very concentrated at the bottom of the loop. The longer the loop of henle, the more concentrated the urine(can be seen in desert animals that need to conserve water. Ascending limb thick-walled; Na/Cl pump removes Na/Cl, but water cannot follow so the filtrate at the top of the loop is very dilute. DCT: reabsorbs water, secretes penicillin, H,K and ammonia. Collecting Ducts: water is reabsorbed into interstitial space and urine gets progressively more concentrated. |
| Diuresis | Increased urine production (polyuria) |
| Diuretic | Drugs that cause diuresis (alcohol, lasix) |
| Anti-Diuretic Hormone (ADH) | From the pituitary gland. Controls our bodies water for us. More is released if you are dehydrated, less is you are not. Lack of it with Diabetes Insipidus. |
| Diabetes Insipidus | Lack of ADH production. Make a lot of dilute urine. ADH made in pituitary body(part of brain). Nothing to do with sugar. |
| Renin | If blood pressure/volume decreased, receptors in afferent arteriole sense this and release this. This causes vasocontriction of the arteriole and increased blood pressure to the kidney. |
| Renin also activates... | Angiotensin..which causes the release of....Aldosterone (from the adrenal glands which encourages.....Na reabsorption & Water conservation (inorder to increase blood volume and blood pressure. |
| When energy (ATP) is used... | Lacid acid is often made. This makes body more acidic. Kidney helps body control the pH. Too acidic, more H secreted in PCT or DCT, or more HCO-3 reabsorbed in PCT. Too alkaline, less H secreted in PCT or DCT, or less HCO-3 is absorbed in PCT. |
| Urine pH | Usually acidic (cats, ferrets--carnivores) Mostly alkaline (cows, horses---herbivores). To lower pH use Methionine (vit. C). *Urine acidic, less chance for bladder infection. |
| Cystitis | inflammation/infection of the bladder. |
| Nephritis | inflammation/infection of the kidney. |
| Urolithiasis | Urinary stones or calculi |
| Pyelonephritis | inflammation/infection of the kidney and renal pelvis. |
| Azotemia | increase in nitrogenous waste in the blood. (BUN, creatinine). Typically 75% of all nephrons damaged. *Creatinine most important. |
| Uremia | Azotemia with other physical signs: uremic breath, acidosis, oral ulceration. |
| Isosthenuria | Very dilute urine, can be a permanent condtion. Typically 67% of nephrons damaged. |
| Micturition | Act of urinating. Involuntary control of the sphinter. |
| Erythropoietin | Hormone made in the kidney. Stimulates bone marrow to make more RBC's. If damaged can lead to anemia if animal does not make this. Athletes take this to increase RBCs (increase oxygen carrying capacity) |
| Blood Urea Nitrogen (BUN) | Blood Urea Nitrogen. If inreased either dehydrated or maybe kidney disease (for sure if creatinine increased also) |
| Creatinine | Normally found in blood, but if increased definite kidney disease. Most sensitive and important |
| PCT | 80% of water absorbed here. Also longest part of the nephron. |
Combine with other sets
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