10.2 Anatomy and Function of Urinary System Part 2 Flashcards
What is the renal tubule?
receives filtrate from capillaries in the capsules and empties into the collecting ducts
What are the two main purposes of the blood vessels that surround the nephrons?
- carry arterial blood toward capillaries of the capsule for filtration
- carry filtered blood and reabsorbed substances away from the tubule
What type of arteriole does blood from the renal artery flow into?
afferent arteriole
What do afferent arterioles branch into?
branch into a ball of capillaries known as the glomerulus
Where does blood flow after the glomerulus?
efferent arterioles
What causes fluid to leak out of the glomerular capillaries?
constriction of the efferent arterioles
What is the glomerular basement membrane?
filter that fluid passes through
Where does fluid enter after glomerular basement membrane?
Bowman’s capsule
Where does the process of filtration occur?
afferent arterioles
efferent arterioles
glomerulus
Bowman’s capsule
What is the process of secretion?
movement of substances into the filtrate (normally active transport) that increases the rate at which they are removed from the plasma
Where does secretion occur?
along the tubule but mostly in the DCT and collecting duct
What is the purpose of concentration and dilution?
to ensure urine volume and osmolarity are appropriate
Where does the process of concentration and dilution occur?
distal nephron
What does the distal nephron include?
DCT and collecting ducts
What are the two hormones that are involved in concentration and dilution?
ADH
aldosterone
What effect does ADH have on concentration and dilution?
released when dehydrated; when fluid in bloodstream is low and solute concentration is high. used to prevent diuresis
What is diuresis?
water loss in the urine
What secretes ADH?
posterior pituitary
What effect does aldosterone have on concentration and dilution?
causes increased absorption of sodium in the distal nephron resulting in increased plasma osmolarity and water retention to raise blood pressure
What releases aldosterone?
adrenal cortexwhen blood pressure is low
How does ADH and aldosterone work together?
raise blood pressure; aldosterone causes sodium reabsorption to increase plasma osmolarity and ADH causes water reabsorption to increase plasma volume
