The Urinary (renal) System Flashcards
(26 cards)
Functions of the kidneys
Regulate blood composition Regulate blood pressure Stimulate red blood cell production Maintain calcium levels Clean blood of toxic waste Vitamin D activation
Renal capsule
Fibrous connective tissue surrounding each kidney
Perirenal fat
Engulfs renal capsule and acts as cushioning
Renal fascia
Thin layer loose connective tissue
Anchors kidneys and surrounding adipose to abdominal wall
Cortex
Outer areas
Renal columns
Medulla
Inner area
Surrounds renal sinus
Ureter
Exits at the hilum
Connects to urinary bladder
Nephron
Functional unite if the kidney
Bowman’s capsule
Glomerulus
Glomerulus
Network of capillaries
Afferent arteriole
Blood enters glomerulus through
Efferent arteriole
Blood exits glomerulus through
3 main processes involved in the regulation of blood composition
Glomerular filtration
Tubular flitration
Tubular secretion
Glomerular filtration
Filtering of blood into tubule forming the primitive urine
Filter through glomerular capillaries and Bowman’s capsule
Then flows into PCT
Filter due to size, not blood composition
Tubular reabsorption
Absorption of substances needed by the body from the tubule to blood
Occurs at PCT
Active and passive transport
Influence blood and urine - depends on sodium, water ect
Tubular secretion
Secretion of substances to be eliminated from the body into the tubule from the blood
Occurs along DCT
Get rid of what didn’t fit through filtration or is unrecognised
Movement of harmful substances to nephron
Passive or active
Sodium reabsorption
PCT - reabsorbs 65% of filtered sodium
Loop of Henle - reabsorbs 25%
Distal tubule - reabsorbs 8%
Collecting duct - reabsorbs 2% in presence of aldosterone
Antidiuretic Hormone (ADH)
Secreted by posterior pituitary gland
Controls permeability of DCT walls and collecting duct
Osmoreceptors in hypothalamus snese sodium conc. change in blood
Negative feedback
ADH
Increase in ADH - increase permeability - decrease urine volume
Decrease in ADH - decrease in permeability - increase in urine volume
Renin secretion increases with
a decrease in blood pressure or sodium concentration
Aldosterone
Steroid hormone
Increases reabsorption of sodium from filtrate
Causes water to move back to blood by osmosis
Decreases urine volume
Tubular load
Total amount of a substance filtered into nephron each minute
Tubular maximum
max rate at which a substance can be reabsorbed
The process in which the kidney maintain blood pressure
low BP - Low sodium - high aldosterone - high sodium reabsorption - high water reabsorption - high blood volume - increase in blood pressure
Diuretics
Increase rate of urine formation (coffee)
Used to treat hypertension and cirrhosis of the liver
Lead to dehydration and electrolyte imbalances
