Exam 4: Urinary System

What is the urinary system made up of?

two kidneys, two ureters, one urinary bladder, one urethra

What do the kidneys do?

filter blood of wastes and excrete them into fluid called urine

What is the functional unit of the urinary system?

the nephron: 1 million

What does the renal fascia do?

anchors to other structures

What does the adipose capsule do?

protects and anchors

What does the renal capsule do?

continuous with ureter

What is the order of connective tissue superficial to deep? 

renal fascia, adipose capsule, renal capsule

What is the renal hilum an entrance for?

renal artery, renal vein, ureter, nerves and lymphatics

What is the renal corpuscle made up of?

glomerulus and Bowmans capsule

What is the glomerulus?

mass of capillaries that is fed by the afferent arteriole & drains into the efferent arteriole

How much blood do the kidneys filter?

receive 20-25% of resting cardiac output

What do renal nerves primarily carry?

sympathetic outflow

What does the cortical nephron contain?

80-85% of nephrons

How is urine created?

glomerular filtration + secretion - reabsorption

What is glomerular filtration driven by?

blood pressure

How much water passes out of the glomerular capsule in a day?

150-180 liters

What is the glomerular filtration rate?

amount of filtrate formed by both kidneys each minute 

How do you calculate the glomerular filtration rate?

GBHP-CHP-BCOP= 10 mmHg

True or False: the kidneys maintain a constant GFR

True 

What is the average glomerular filtration rate for males?

125 mL/min

What is the average glomerular filtration rate for woman?

105 mL/min 

What is the glomerular filtration rate controlled by?

renal auto regulation, neural regulation, hormonal regulation

What are the 8 functions of the kidneys?

formation of wastes, composition of ionic compounds, regulation of blood pH, regulation of blood volume, regulation of blood pressure, regulation of blood osmolarity, regulation of glucose levels, production of hormones/vitamins

What is included in the formation of wastes?

ammonia, urea, uric acid, urobobin, creatinie

What is involved in the composition of ionic compounds?

regulation of K+, Na+, Cu+, Cl-

What is involved in the regulation of blood pH?

bicarbonate ions, H+ ions

How is the regulation of blood pressure regulated?

RASS system, renin released for increase in BP

What is the normal blood osmolarity?

300 milosmoles/liter

How much blood flows through the afferent arteriole?

180 liters of blood

Is the descending loop thin or thick?

thin

Where is water reabsorbed?

descending loop through aquaporins

Is the ascending loop thin or thick?

thick

True or False: There is water reabsorption in the ascending loop

false

how much reabsorption happens in the PCT?

65% of ions

True or False: There is 100% reabsorption of glucose in the PCT

true

How many ions are reabsorbed in the PCT and how many are secreted as urine?

99% reabsorbed, 1% urine

How many liters are secreted as urine?

1.8 liters

What percentage of ions are absorbed in the DCT?

15%

What are the reabsorption routes?

paracellular and transcellular reabsorption

What is paracellular reabsorption?

passive fluid leakage between cells

What is transcellular reabsorption?

directly through tubule cells

What does primary active transport us?

ATP

What does primary active transport do at rest?

accounts for 6% of total body ATP use

What is secondary active transport driven by?

ions electrochemical gradient

What percentage of water reabsorption is by obligatory reabsorption?

90%

What percentage of water reabsorption is by facultative reabsorption?

10%

What is facultative water reabsorption regulated by?

ADH

Where do you find macula densa cells?

in DCT

What do the macula densa cells do?

early warning system, monitor sodium (Na+)

If there is higher sodium, what happens to the afferent arteriole?

constriction

If there is lower sodium what happens to the afferent arteriole?

dilates

Where can you find JG cells?

walls of afferent arteriole

What does RASS stand for?

renin angiotensin aldosterone system

When does the RASS system kick on?

when there is low BP & BV

What does renin do?

raises BP

What is the response when the walls of afferent arteriole becomes less stretched?

renin is released in response

Where is renin released from?

JG cells

What happens when renin is released as a response to the walls of the afferent arteriole becoming stretched?

Angiotensinogen is released before angiotensin 1

Where is angiotensinogen synthesized from? 

hepatocytes

How does angiotensin 1 become angiotensin 2?

angiotensin converting enzyme comes from the lungs

What happens in response to angiotensin 2?

1. lower GFR - constriction of arterioles

2. increase reabsorption of sodium in the PCT = higher reabsorption of water

3. Aldosterone

Where is aldosterone released from? 

adrenal cortex

What happens when aldosterone is released?

1. act upon collecting duct

2. increase reabsorption of sodium and potassium

3. increase reabsorption of water

4. increase in BP & BV

What does ADH stand for?

antidiearitic hormone

What is ADH?

a vasopressin

Where does ADH come from?

posterior pituitary gland

What does ADH do?

regulates water absorption

Where does ADH act on?

late DCT and collecting duct

What are aquaporins? 

water channels 

If you are dehydrated what happens to urine and ADH?

lower urine output, higher ADH

What happens if you are over hydrated to urine and ADH?

higher urine output, lower ADH

Where do you find the juxtamedullary nephron?

in the medulla, long loop of henle

What percentage of contents are absorbed in the juxtmedullary nephron?

15%

What percentage of contents are reabsorbed in the cortical nephron?

85%, shorter

Where do you find the cortical nephron?

the renal cortex