The Urinary System Flashcards
Identify the components of the urinary system and discuss their functions.
KIDNEYS - Filter blood and regulate body fluid volume
URETER - Kidney -> Bladder. Thick walled and narrow. Peristaltic contractions.
BLADDER - Reservoir for storing urine, 250-300ml. Serous and muscular layers with an inner mucous coat.
URETHRA - Bladder -> Exterior.
List the functions of the kidney.
Regulate body fluid volume Osmolality (electrolyte balance) Formation of urine Excretion of metabolic waste products and toxins Acid-base balance Production of hormones e.g EPO Activation of vit D
Describe the gross anatomy of the kidney.
Has a cortex, medulla, hilum and renal sinus with many nephrons.
Trace the path of blood flow through the kidney.
Glomerulus -> Near proximal tubule -> Loop of henlé -> Distal tubule -> Collecting duct.
Draw a labelled diagram and describe the structure of the nephron.
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List the components and describe characteristics of the filtration membrane.
The filtration membrane has to be crossed by all of the fluid entering the nephron to get into the bowmans capsule. It filters out large proteins and other large molecules such as red blood cells.
It consists of three layers: Epithelium of the capillaries, glomerular basement membrane and the outer epithelium consisting of podicytes
Explain the process involved in the formation of urine.
The glomerulus first filters out the plasma from the blood. Then as the plasma makes its way through the nephron reabsorption of all the useful things occurs such as water and glucose. What is left then goes into the collecting duct which filters into the ureters and the bladder to be expelled.
Discuss the role of the kidney in water and electrolyte balance.
The kidney maintains the balance of all the electrolytes in the body by excreting them if the levels get too high but otherwise reabsorbing them. Controlled by hormones such as aldosterone which stimulates sodium reabsorption, ANP which increases sodium excretion
Discuss the role of the kidney in long term control of blood pressure.
The kidney controls the rate of excretion of water from the body and therefore the blood volume. By increasing or decreasing the amount of water excreted it can increase or decrease blood pressure. ADH causes an increase in water reabsorption when BP is low.
Discuss the role of the kidney in the maintenance of acid-base balance.
The kidney excretes H+ and reabsorbs HCO3-
METABOLIC ACIDOCIS
When the body produces excessive amounts of acid or the kidneys are not removing enough acid from the body.
METABOLIC ALKALOSIS
When blood pH is elevated beyond normal range 7.35-7.45. Can be die to decreased H+ conc, leading to increased bicarbonate, or as a direct result to increased bicarbonate.
Discuss the process of micturition and explain how it is controlled.
Stretch receptors in the bladder activated by the detrouser muscle -> sensory afferent fibres in pelvic nerve relay to sacral region of spinal chord -> Interneurones relay message -> Thalamus -> Cerebral cortex -> Parasympathetic efferent fibre in pelvic nerve -> post-ganglionox neurone -> Stimulates detrouser muscle to contract -> Voluntary relaxation of external urethral sphincter -> Micturition
Describe the composition and appearance of urine and appreciate how these may vary under different conditions.
Haematuria - blood in urine
Proteinuria - protein in urine
Urines odour comes from bacteria breaking urea down into ammonia
Explain the consequences of renal failure and consider possible treatments.
High BP, Hyperkalemia, Anemia, Shallow complexion, Peripheral neuropathy, Metastaltic calcification, Itching skin, Ureamic toxins, Na+ and H2O retention and metabolic acidosis.
Treatments: Haemodialysis, peritoneal dialysis or transplant
