Urinary System Flashcards
Primary Function of Urinary System
Excretion-removal of organic waste products from bodily fluids
Elimination- discharge of these waste products into environment of body
Homeostatic regulation- regulates the volume and solute concentration of blood plasma
Secondary Functions of Urinary System
Regulates blood volume and blood pressure Regulates concentrations of Na+, K+, CI- Stabilizes blood pH Conserves valuable nutrients Detoxifies poisons or drug breakdown
Located on both sides of vertebral column between T12-L3 and produces urine
Kidneys
The tube or vessel that carries urine from kidneys to bladder
ureter
Carries urine to exterior of body
urethra
Kidney has 3 layers of connective tissue
renal capsule
adipose tissue
renal fascia
layered collagen fibers that cover outer surface of organ
renal capsule
thick layer of adipose tissue that surrounds renal capsule
adipose capsule
has a dense fibrous outer layer that attaches to kidney to surrounding structures
renal fascia
Kidney has 2 layers
Renal cortex
Renal medulla
superficial portion of kidney that contacts renal capsule
renal cortex
consists of 6-18 renal pyramids
renal medulla
a ________ consists of a _________ , the overlying area of the renal cortex and the adjacent tissue of renal column
renal lobe; renal pyramid
in the cortex of each ________ are tubular structures called nephrons
renal lobe
a ______ is the basic functional unit of a kidney
nephron
each kidney has ______ nephrons
1.25 million
kidneys receive _______ % of total cardiac output with 1200 ml of blood flowing through each minute
20-25%
A nephron has how many parts?
2
Renal Corpuscle
Renal Tubule
the glomerulus and bowman’s capsule are a part of?
renal corpuscle
the proximal convoluted tubule, Loop of Henle, distal convoluted tubule, collecting system are a part of what?
renal tubule
The Loop of Henle contains what?
Thin Descending Limb
Thick Ascending Limb
The Collecting System contains what?
Collecting Duct
Papillary Duct
_________ is approximately 50 intertwining capillaries and projects into bowman’s capsule
glomerulus
the site where filtration occurs
renal corpuscle
Blood pressure forces water from the blood vessel along with dissolved solutes (filtrate) into the ____________
capsular space
at __________, the capillaries are covered by epithelia tissue consisting of large cells called podocytes
bowman’s capsule
______ are large cells that have feet called ______
podocytes; pedicels
these contract/relax to control capillary diameter and blood flow rate
mesangial cells
Filtrate passes through small slits between ________ to get into __________
pedicels; capsular space
when filtrate enters the renal tubule is becomes…
tubular fluid (future urine)
filtration occuring in bowman’s capsule is caused by
hydrostatic blood pressure
What does hydrostatic blood pressure do?
forces water and solutes out of blood vessel by passing through pores into capsular space
where does re-absorption of nutrients take place?
along the proximal convoluted tubule
where does secretion of nutrients occur?
along the proximal convoluted tubule and distal convoluted tubule
what regulates the final volume of solute concentrate of the urine?
Loop of Henle and Conducting System
the most abundant organic waste, a byproduct generated by breakdown of amino acids by liver
urea
generated by breakdown of creatine phosphate a high energy molecule in skeletal muscle
creatinine
waste product generated by recycling nitrogenous bases of RNA molecules
uric acid
Renal tubule has 3 functions
- Reabsorbs useful organic substances (amino acids, proteins, glucose)
- Reabsorbs 90% of H20 filtrate
- Secretion of any waste in blood that has failed to enter into renal corpuscle
3 segments of Renal Tubule
Proximal Convoluted Tubule( PCT)
Loop Of Henle
Distal Convoluted Tubule (DCT)
reabsorbs H20 ions, and all organic nutrients
(PCT) Proximal Convoluted Tubule
“U” Shaped segment that seperates the PCT and DCT, divided into thick ascending limb and thin descending limb
Loop Of Henle
secretes ions, acids, drugs and toxins. Variable reabsorption of water, Na+ ions, and Ca+2 ions (under control of hormonal endocrine system)
(DCT) Distal Convoluted Tubule
reabsorption of water takes place here, but is impermeable to salts
Thin descending limb
reabsorption of Na+ and Cl ions (solutes) takes place here, but is impermeable to water
Thick ascending limb
consists of 2 ducts, which carries tubular fluid away from nephrons
Collecting System
_________ duct - variable reabsorption of water, reabsorption or secretion of Na+, K+, H+ and bicarbonate due to hormones
collecting
_________ duct- delivers urine to minor to minor caylx
papillary
2 Types of Nephrons
Cortical Nephrons
Juxtamedullary Nephrons
Cortical Nephron
85% of all nephrons located superficial to cortex short loop of henle smaller nephron numerous (performs most of reabsorption and secretions functions of kidneys)
Juxtamedullary Nephron
15% of all nephrons
long loop of henle
extend deep into medulla
has a vasa rectus
a long straight peritubular capillary that lies between loop of henle
vasa rectus
Steps of Renal Function (pg 12)
This is the short and sweet version
1) filtrate arrives at the glomerulus
2) in PCT ions and organics are removed from filtrate
3) in PCT and Loop of Henle water leaves tubular fluid
4) Na+ and Cl- transported out of thick ascending limb
5) solutes can be readjusted by reabsorption and secretion by active transport
6) DCT is impermeable to water unless ADH is secreted
7) Vasa recta absorbs water and solutes from tubular fluid
This is the first essential kidney function, because if this DOES NOT OCCUR the remaining mechanisms CANNOT OCCUR
Glomerular Filtration
Filtration in the glomerulus depends on adequate ________ flow and normal _______ pressures
blood; filtration
3 interacting levels of control used to stabilize Glomerular Filtration Rate
- Auto-regulation at local level
- Hormonal-regulation initiated by kidney
- Autonomic regulation primarliy by sympathetic nervous system
reduction of blood flow and reduction in glomerular blood pressure by dilation of afferent artery, glomerular capillaries, and constriction of efferent artery
auto-regulation
the walls of the afferent arteriole contain specialized smooth muscle cells called juxtaglomerular cells which produce renin.
Hormonal regulation initiated by kidney
hormone that regulates blood volume and blood pressure
renin
Hormones acting as Nephrons
ADH
PTH
CT
Aldosterone
hormone that causes water reabsorption
ADH
hormone that causes reabsorption of Calcium at nephron
PTH
hormone that causes secretion of Calcium at nephron
CT
hormone that causes sodium reabsorption and potasium and hydrogen
Aldosterone
___________ - low blood flow causes sympathetic system to react
Autonomic Regulation
reactions of autonomic regulation
constriction of venous vessels and reservoirs
increases cardiac output via HR
All increasee blood flow to the glomerulus which raises blood pressure
Counter Current Multiplication
reabsorbs water (thin) and solutes (thick) before they reach the DCT and collecting system creates a concentration gradient so water is absorbed passively
2 muscular tubes, about 12 inches long which link kidneys to the bladder
ureter
_______ penetrate the posterior wall of bladder without entering the peritoneal cavity
ureter
urine passes through the ______________ of the kidney to the __________ of the ureter
minor caylx; renal pelvis
_____________ are slit like openings that prevent backflow of urine
urethral openings
a muscular hollow organ that temporarily stores urine
bladder
the bladder is held in place by
middle umbilical ligament
lateral umbilical ligament
The bladder has folds called?
rugae
The ________ funnels urine into the urethra
trigone
The wall of the bladder has a contractile muscle called the??
detrusor muscle
what muscles forces urine into the urethra?
detrusor muscle
carries urine from the bladder to exterior of body
urethra
Male urethra
8 inches long
Prostatic urethra
Membranous urethra
Penile urethra
Female urethra
1-2 inches
micturation reflex
allows urination
micturation reflex stimulates 2 neurons
thalamus
parasympathetic fibers
the bladder stretching stimulates the thalamus
sends commands to relax external and internal urethral sphincters
parasympathetic fibers in spinal cord sends commands to
detrusor muscle so bladder contracts
urine volume excedeing 500ml
can force open internal urethral sphincter
