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Kidneys
- >Located on each sie of the vertebral column in the upper abdomen outside the peritoneal cavity
- >Major structures of kidney are medulla, cortex renal artery, renal vein, renal pyramid, renal calyx, renal pelvis, ureter, nephron
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Kidney infection
Cystitis - bladder infection
Pyelitis - inflammation of the renal pelvis
pyelonephritis - inflammation of renal parenchyma, calices and pelvis due to local bacterial infection
Uretitis - inflammation of ureter
Urethritis - Inflammation of urethra - caused by Ecoli or klebsiella, and some transmitted diseases including chlamydia, gonorrhea and ureplasma urealyticum infection
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blood supply in the kidneys
Renal artery branches off the abdoninal aorta and supplies blood to kidney
Renal vein - 99% of filtered blood is reabsorbed and circulated through renal vein back to general circulation and remaining 1% of filtered blood contains waste product is processed further by kidney.
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Cortex
Outer layer of kidney containing 1.3 millions of nephrons that begin urine production
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Medulla
Inner portion of kidney, made of renal pyramids and tuvular structures
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Nephron
The functional unit of the kidney
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Renal pyramid
Channels output to renal pelvis for excretion
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Renal pelvis
After proessing the formed urine is channelled to the pelvis
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Renal calyx
Channels formed urine from the pyramids to the pelvis
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Ureter
Tube that transport urine to the bladder
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Kidney functions
Maintain homeostasis by regulating volume and composition of blood
Eliminate wast products
Regulate blood volume and BP
Regulate plasma ion concentrations
Stabilise blood Ph
Activation of Vit D
Production of erythropoietin
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Erythropoietin
A hormone produced by the kidney that promotes the formation of red blood cells in the bone marrow
levels fall in chronic renal failure resulting in anaemia
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Vitamin D
Activation occurs in kidney
responsible for Ca absorption
Patients with chronic renal failure have infufficient vit D requires oral supplements
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Nephron
Functional unit of kidney
each kidney contains approx 1 million nephron
- main activities include:
- selective reabsorption
- selective secreation
- mechanical filtration
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Structure of nephron
Glomerulus are network of twisted caillaries which acts as a filter for the passage of protein and RBC free filtrate
Bowman's capsule surrounds the glomerulus and acts as a reservior fro the filtrate
Proximal convoluted tube are site of reabsorption of glucose, amino acids and electrolytes back to circulation
Loop of Henle U-shaped tubule located in mefulla and extending from proximal to distal convoluted tubule
Distal convoluted tube is the site of where filtrate enters the collection tubule
Collecting tubule release urine
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Urea an creatinine
Are Nitrogenous wastes resulting from the end products of protein metabolism and muscle activity
UREA - most abundant. Produced during aminao acid breakdown
CREATININE is produced as a breakdown of muscle tissue
plasma concentrations are indicative of changes in renal function
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Urine
Sterile, no bacteria
- >Nitrate in dipstick indicates bacterial metabolism
- >PH is slightly acidic
- >Specific gravity compares the concentration of urine with distilled water
- >Dilute urine has a low specific gravity due to excessive intake of water
- >Concentrated urine has a high specific gravity for example inadequate fluid intake.
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Ureters
- >Ureters is a long narrow fibro muscular tube 24-30cm that connects each kidney to the bladder. Urine that is formed within nephron flows into the ureter
- >Ureter originate at the lower portion of the renal pelvis and terminate in the trigone of the bladder wall
- >Movement of urine from the renal pelves through the ureters into the bladder is faciliated by peristalsis movement.
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Urinary bladder
- >Highly muscular orgain that can store up to 1L of urine.
- >Ligaments hold the bladder in its place
- >Contraction of the detrusor muscle and relaxation of the internal and external spincters com[resses the bladder to expels urine into the urethra
- >Trigone funnels ruine into the urethra
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Urination ( Micturition)
- >Storage and emptying funtions of bladder is controlled by the nervous system
- >Promotes contration of the bladder wall and relaxation o fthe internal bladder sphincter
- >voluntary control of urination is provided by muscles in teh external sphincter and pelvic floor which is controlled by nervous system
- >Micturination occurs when the external sphincter i srelaxed and the detrusor muscle contracts. Both of these are controlled by the nervous system.
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Urethra
The urethra is a muscular tube that frains urine form the body. 3-4 cm long in female, close to 20cm long in male.
- Its arises from the base of the bladder
- In males the prostate gland which lies just below the bladder surrounds the urethra
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Incontinence
Inability to voluntary control urination
- Causes:
- > Immaturity
- >nocturnal enuresis- night bed wetting
- >stress incontinence - childbirth can stretch and damage sphincter muscles
- >Damage to central nervous system, nerves or spinal cord to the bladder or external urethral spincter eg stroke
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Urinary tract infection ( UTI)
- >More common in women due to shortness of urethral and sits close to anus
- >Cause by E.coli
- >cause painful urination, frquency increases, loin pain and fever, smelly urine.
- >Untreated can spread to ureter to the kidney and this is known as Pyelonephritis
- >Pyelonephritis results if bacteria invade corted and medulla causing high fever, intense pain vomiting and diarrhoes, blood cells and pus in urine.
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