Ultimate Review Guide: Cumulative Exam, Urinary and Reproductive

Functions of the Urinary System

• regulation of blood volume

• regulation of chemical makeup of blood (filtration, secretion, reabsorption)

• acid-base balance

• detoxification

Functions of the Kidneys

• Urine production

• Regulation

• Hormone production

Hormones produced by the kidneys

• Renin

• Erythropoietin

• Vitamin D (calcitriol)

Function of renin

regulation of blood pressure

• part of renin-angiotensin-aldosterone system

Function of erythropoietin

production of red blood cells, targets red bone marrow

Function of Vitamin D (calcitriol)

increase blood calcium

Minor calyces meet up and form _____ _____

major calyces

Number of major calyces in each kidney

3-4

The major calyx drains into the

major calyx

The functional unit of the kidneys are known as

nephrons

Components of nephrons

• renal corpuscle

• renal tubules

Components of renal corpuscle

• glomerulus

• Bowman’s capsule

Function of the renal corpuscle

filtration

Components of the renal tubules

• Proximal and distal convoluted tubules

• Loop of Henle

• Collecting duct

Functions of the renal tubules

• reabsorption, secretion, excretion

• concentration

Diseases that occur in the glomerulus will affect

filtration

Function of macula densa cells

monitor concentration of filter (osmolarity)

These presence of these molecules indicate abnormality in filtration in the glomerulus

• proteins

• high glucose

• red blood cells (RBCs) in males

• white blood cells (WBCs) in elevated amounts

• lipids

Percentage of blood filtered when it enters the glomerulus is

20%

Renal blood flow (RBF) volume

1200 mL

Renal blood flow (RBF) represents __% of cardiac output

20%

Renal plasma flow (RPF) volume

660 mL

This percentage of renal plasma flow (RPF) is filtered

20%

Renal plasma flow (RPF) filtration site

glomerulus

Filtration fraction

GFR / RPF

glomerular filtration rate / renal plasma flow

Normal glomerular filtration rate (GFR)

125 mL / min

What influences glomerular filtration rate (GFR)

salt intake

Primary site of reabsorption in nephron

proximal convoluted tubules

Primary function of proximal convoluted tubules

reabsorption

Percentage of sodium absorbed by the proximal tubules

~70%

Percentage of glucose, amino acids, and other organic molecules absorbed by the proximal tubules

~100%

Percentage of bicarbonate absorbed by the proximal tubules

~90%

Function of Loop of Henle

• establishes a concentration gradient

• reabsorption of water, sodium, and chloride

What is reabsorbed at the loop of Henle

water, sodium, and chloride

What part of the Loop of Henle is impermeable to water

thick ascending loop

What part of the Loop of Henle is capable of absorbing water

thin descending loop

Which of the following best describes secretion

Concentration movement of solutes from blood to tubules

If glomerular filtration rate (GFR) is too high, that means the levels of sodiums are _____ because there is little time for sodium reabsorption

higher

If glomerular filtration rate (GFR) is too low, that means the levels of sodiums are _____ because there is more time for sodium reabsorption

lower

Function of distal convoluted tubules

• secretion

• selective reabsorption

Primary site of secretion in nephron

distal convoluted tubules

The hormones that target the distal convoluted tubules are

aldosterone (primary) and atrial natriuretic factor (ANF)

Function of aldosterone in distal convoluted tubules

sodium reabsorption (which leads to higher blood pressure)

Function of ANF in distal convoluted tubules

sodium excretion (which lowers blood pressure)

Examples of things secreted by the distal convoluted tubules

• drugs

• acids

• ions

• toxins

The distal convoluted tubules selectively reabsorb these

water, sodium, and calcium

Function of collecting ducts

• Urine concentration

• Adjusts blood and urine osmolarity

• Transports urine down

Urine from the collecting duct flows down to the

renal pelvis

The presence of this hormone in the collecting ducts allows for water to pass through the tubule walls

antidiuretic hormone (ADH)

Function of antidiuretic hormone (ADH)

• water retention

• regulation of blood pressure

• decrease blood sodium

Production location of antidiuretic hormone (ADH)

supraoptic nuclei of the hypothalamus

Storage location of antidiuretic hormone (ADH)

posterior pituitary gland

Transport maximum

The maximal rate of reabsorption of a substance in the kidney tubules

What happens when GFR exceeds transport maximum?

carrier proteins become saturated, leading filtered substance to spill into urine

Example of GFR exceeding transport maximum

diabetics: little to no production of insulin leads to high blood glucose, leading the filtrate glucose rate to be higher than transport maximum

Renal Threshold

the idea that if plasma levels of a given substance rise above normal, it will become eventually become physically impossible to filter it, leading the substance to appear in urine

Renal Threshold for plasma glucose

180 mg/dL

Renal Threshold for plasma amino acids

65 mg/dL

Renal clearance

the clearance of a substance is the volume of plasma from which that substance is completely cleared by the kidneys per minute

Renal clearance is used to measure

GFR

Formula for renal clearance

C = (U x V / P )

clearance = urine concentration * urine flow rate / plasma concentration

Function of renin-angiotensin-aldosterone system

maintenance of blood volume and pressure

Dysfunction of the renin-angiotensin-aldosterone system is rooted can lead to

hypertension

The primary active hormone in the renin-angiotensin-aldosterone system is

angiotensin II

Stimulus that causes the release of renin

• drop of blood pressure

• stimulation of sympathetic nerve fibers

Function of angiotensin II in renin-angiotensin-aldosterone system

potent vasoconstriction, which increases BP