the urinary system
DESCRIPTION
The urinary system. 7.4. From the Heart to the Pelvis. Aorta renal arteries kidneys. Kidney: fist-shaped, about 0.5 kg. Can hold as much as 25% of body’s blood. . Wastes are filtered from blood by kidneys and conducted to the urinary bladder by ureters . - PowerPoint PPT PresentationTRANSCRIPT
THE URINARY SYSTEM7.4
From the Heart to the Pelvis
Aorta renal arteries kidneys.
Kidney: fist-shaped, about 0.5 kg.
Can hold as much as 25% of body’s blood.
Wastes are filtered from blood by kidneys and conducted to the urinary bladder by ureters.
Urinary sphincter: muscle located at base of bladder acting as a valve. Voluntary emptying
When bladder stretches, sends signal to brain. 200 mL: small signal sent 400 mL: more stretch receptor activated 600 mL: voluntary control is lost.
Sphincter relaxes, urine enters urethra, and is voided.
General Kidney Structure Cortex: outer layer Medulla: inner layer Renal pelvis: joins kidney to ureter.
Nephrons Nephron: slender tubules
About one million in each kidney Renal artery afferent arterioles
nephrons efferent arterioles peritubular capillaries (net of capillaries that wrap around kidney tubules.
Glomerulus: capillary bed from afferent arterioles. Surrounded by funnel-like part of nephron:
Bowman’s Capsule In the cortex of the kidney.
Bowman’s Capsule Where fluids (from blood) to be processed
into urine enter the kidney. Capsule tapers into thin tubule: proximal
tubule. Proximal tubule loop of Henle (descends
into the medulla of the kidney) distal tubule (last segment of nephron) collecting ducts.
Collecting duct: collects urine from many nephrons merge in kidney pelvis.
urine
blood
filtration
tubular reabsorption and secretion
General Functioning
of the Kidney
“refreshed” blood
Organs of the
Urinary
System
kidneys
ureters
urinary bladder
urethra
vein
artery
afferent
arteriole
efferent arteriol
eglomerulus
peritubular
capillaries
Bowman’s capsule
proximal convoluted tubuledistal convoluted tubule
loop of
Henle
collecting duct
renal cortex
renal medulla
Each kidney contains over 1 million nephrons and thousands of collecting ducts
Collecting duct
Loop of Henle
PCT
DCTGlomerulus
Glomerular
Filtration
afferent arteriole
glomerulus
efferent
arteriole
Bowman’s capsule
Filters blood; proteins can’t pass through
With help from your textbook, define the following terms:
Ureters Urethra Cortex Medulla Renal pelvis Nephron Afferent arterioles Glomerulus Efferent arterioles Peritubular capillaries Bowman’s capsule Proximal tubule Loop of Henle Distal tubule Collecting duct
Summary
Seatwork/Homework Page 348, #1,2,3,4