Slide Set 7: Urinary System Flashcards Preview

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Flashcards in Slide Set 7: Urinary System Deck (173)
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1

What is the most important function of kidneys?

homeostatic regulation of:
- water
- ion content of the blood
= electrolyte balance.

2

The kidneys maintain normal blood concentrations of ions and water by balancing intake of those substances with their excretion in the urine, obeying the principle of ________

mass balance

3

Kidney function can be divided into 6 major categories:

1. Regulation of extracellular fluid volume and blood pressure.
2. Regulation of osmolarity.
3. Maintenance of ion balance.
4. Homeostatic regulation of pH
5. Excretion of wastes.
6. Production of hormones

4

How is regulation of extracellular fluid volume and blood pressure achieved?

When extracellular fluid volume decreases, blood pressure also decreases.

If ECF volume and blood pressure fall too low, the body cannot maintain adequate blood flow to the brain and other essential organs.

The kidneys work in an integrated fashion with the cardiovascular system to ensure that blood pressure and tissue perfusion remain within an acceptable range.

5

How is regulation of osmolarity achieved?

The body integrates kidney function with behavioural drives, such as thirst, to maintain blood osmolarity at a value close to 290 mOsM.

6

How is maintenance of ion balance achieved?

The kidneys keep concentrations of key ions within a normal range by balancing dietary intake with urinary loss.

Sodium (Na+) is the major ion involved in the regulation of extracellular fluid volume and osmolarity. Potassium (K + ) and calcium (Ca2 + ) concentrations are also closely regulated.

7

What is the major ion involved in the regulation of extracellular volume and osmolarity?

Sodium (Na+) is the major ion involved in the regulation of extracellular fluid volume and osmolarity.

8

How is homeostatic regulation of pH. achieved?

The pH of plasma is normally kept within a narrow range.
If extracellular fluid becomes too acidic, the kidneys remove H+ and conserve bicarbonate ions (HCO3-), which act as a buffer. Conversely, when extracellular fluid becomes too alkaline, the kidneys remove HCO3- and conserve H+. The kidneys play a significant role in pH homeostasis, but they do not correct pH disturbances as rapidly as the lungs do.

9

What happens if the ECF becomes too acidic?

the kidneys remove H+ and conserve bicarbonate ions (HCO3-), which act as a buffer.

10

What happens if the ECF becomes too alkaline?

the kidneys remove HCO3- and conserve H+.

11

Which one is faster in terms of ph correction: kidneys or lungs?

lungs

12

How is excretion of wastes achieved?

The kidneys remove metabolic waste products and foreign substances, such as drugs and environmental toxins.
Metabolic wastes include creatinine from muscle metabolism and the nitrogenous wastes urea and uric acid.
A metabolite of hemoglobin called urobilinogen gives urine its characteristic yellow color.

Hormones are another endogenous substance the kidneys clear from the blood. Examples of foreign substances that the kidneys actively remove include the articial sweetener saccharin and the anion benzoate, part of the preservative potassium benzoate, which you ingest each time you drink a diet soda drink.

13

What gives the yellow color to urine?

A metabolite of hemoglobin called urobilinogen gives urine its characteristic yellow color.

14

How is production of hormones achieved?

Although the kidneys are not endocrine glands, they play important roles in three endocrine pathways.

Kidney cells synthesize erythropoietin, the cytokine/hormone that regulates red blood cell synthesis.

They also release renin, an enzyme that regulates the production of hormones involved in sodium balance and blood pressure homeostasis.

Renal enzymes help convert vitamin D3 into a hormone that regulates Ca2+ balance.

15

Give examples of kidney enzymes

erythropoietin - RBC production

renin - sodium balance and blood pressure homeostasis

renal enzymes - convert vitamin D3 into a hormone that regulates Ca2+ balance.

16

Explain urine production and the route it takes for excretion

1. water and solutes move from plasma into the hollow tubules (nephrons) that make up the bulk of the paired kidneys.
2. modify the composition of the fluid as it passes through.
3. The modified fluid leaves the kidney and passes into a hollow tube called a ureter. There are two ureters, one leading from each kidney to the urinary bladder.
4. The bladder expands and fills with urine until, by reflex action, it contracts and expels urine through a single tube, the urethra.

17

What is micturition?

is the process by which urine is excreted - urination

18

A cross section through a kidney shows that the interior is arranged in two layers:

an outer cortex and inner medulla

19

The layers of kidneys are formed by the organized arrangement of microscopic tubules called _______.

nephrons

20

What is the functional unit of kidneys?

The nephron is the functional unit of the kidney

21

Each nephron has two components:

–Vascular component
–Tubular component

22

From nephrons the urine travels to the ______ which can be thought of as the start of the urinary plumbing, then to the ureter

calyx

23

Vascular elements of kidney and the order

afferent arteriole --> glomerulus --> efferent arteriole
--> peritubular capillaries --> vasa recta (capillaries that dip into the medulla) --> renal capillaries --> venules
--> small veins --> renal vein

24

What is the function of the renal portal system?

First to filter fluid out of the blood and into the lumen of the nephron at the glomerular capillaries, then to reabsorb fluid from the tubule back into the blood at the peritubular capillaries.

25

Tubular elements of kidneys and the order

Nephron --> Bowman’s capsule + glomerulus -->renal corpuscle --> proximal tubule --> loop of Henle --> descending limb --> ascending limb --> distal tubule --> collecting duct ---> medulla ---> cortex --> renal pelvis (urine) --> ureter

26

The nephron begins with a hollow, ball-like structure called __________ that surrounds the glomerulus

Bowman’s capsule

27

The combination of glomerulus and
Bowman’s capsule is called the___________.

renal corpuscle

28

The loop of Henle is divided into two:

descending limb
ascending limb

29

a hairpin-shaped segment that dips down toward the medulla and then back up

The loop of Henle

30

the final part of the ascending limb of the loop of Henle passes between the afferent and efferent arterioles. is region is known as the ______

juxtaglomerular apparatus