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Flashcards in Urinary System Deck (43)
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1

Where are the structures of the urinary system located?

abdominopelvic cavity

2

What are the four structures of the urinary system

(two) kidneys:
(two) ureters:
(one) bladder
(one urethra

3

What is the main function of the kidneys

The kidneys (made of adipose tissue) form urine, regulate blood volume, electrolyte homeostasis and production of hormones like erythropoietin

4

What is the main function of the ureters:

Allows flow of urine into the bladder

5

What is the main function of the bladder

To store bladder. The contraction and relaxation occurs from smooth muscle contraction

6

What is the main function of the urethra

allows urine to flow out of the body

7

What are the excretory functions of the kidneys?

Regulation of pH
Regulation of blood pressure
Water and electrolyte balance
Excretion of waste products

8

What are the synthetic functions of the kidneys?

Vitamin D synthesis
Release of renin
Regulation of erythropoiesis
Production of glucose

9

Describe the process of excretion of waste

The kidney excrete urea, uric acid, creatinine or hormone metabolites. Hydrophilic drugs are easily excreted while hydrophobic drugs are normally attached to proteins and required metabolism by the liver

10

Describe water body balance

If input > output then body water (amount of water in tissue) will increase
If input < output then body water will decrease.

11

Describe Electrolyte balance

If input > output then body electrolyte will increase
If input < output then body electrolyte will decrease.
Note: NA+ is key and regulates almost all excretory processes in the kidney. It is also used for regulation of blood pressure.

12

Describe blood pressure regulation

This occurs via the RAAS by adjusting the;
Na+ excretion (electrolyte)
H2O output (blood volume)
Vasoconstriction (angll)

13

Describe regulation of pH

Kidneys regulate;
• H+ excretion,
• HCO3- excretion
• And HCO3- synthesis

14

Describe the regulation of erythropoiesis

Erythropoiesis relates to RBC production. produced by interstitial cells within the peritubular capillary bed of the renal cortex (kidney)

15

Describe vitamin D synthesis

The final step of Vitamin D synthesis occurs in the kidneys

16

Describe production of glucose

The kidneys convert lactate, glycerol and certain aa into glucose. It is usually the liver that is the most glucose producing but the kidneys can also produce up to 50% of the required glucose.

17

What are the three layers of the kidney?

The capsule
The renal cortex
The medulla

18

Describe the capsule

The capsule has three components; renal fascia, Perennial fat capsule
Renal capsule.
In the capsule there is the hilum where blood vessels and nerves enter and exit the kidney. This is also where the ureters exits to transport urine.

19

Why is the renal capsule granular?

Due to nephrons

20

Describe the medulla

The medulla has pyramids (renal pyramids) which point toward the ureter on the outside of the kidney.

21

What % of the cardiac output do kidneys receive?

20%

22

How do the kidneys make urine?

By filtering blood's plasma

23

What is the glomerular filtration rate (GFR)?

The rate at which filtrate is formed by nephrons from this 600mL of plasma

24

Where does filtration occur?

In the glomerular capillaries

25

Describe nephrons

The nephron is the functional unit of the kidney. This is where the blood enters the kidney and urine is produced.

26

Where are the nephrons located?

They are located in the renal cortex (80%) and the rest are in the medulla. The ones located in the medulla are called juxtamedullary nephrons

27

What do the nephrons located in the renal cortex do?

filter, reabsorb and secrete

28

What do juxtamedullary nephrons do?

concentrate the urine by regulating water excretion.

29

What type of transportation do nephrons use?

Active and passive (reabsorb the nutrients in urine)
And active to pump waste products into the renal tubes

30

What are nephrons composed of?

• Bowmans’s capsule (glomerular capsule)
• Proximal convoluted tubule (PCT)
• Loop of Henle
• Distal convoluted tubule (DCT)

31

What are collecting tubules?

Multiple DCT’s merge together to form collecting tubules that eventually combine to form collecting ducts

32

What is the excretory function of kidneys (urine) is due to a balance of?

1. Glomerular filtration
2. Reabsorption
3. section

33

Describe the Glomerular filtration barrier

The glomerular barrier ensures that RBCs are not filtered (glomerular capillaries).
It also filters large proteins and plasma

34

Describe the Proximal convoluted tubule

The proximal convoluted tubule secretes and reabsorbs. There is lots of mitochondria so active transport occurs. 100% of nutrients is reabsorbed through Na+ dependent transport (glucose, aa)
There is also active secretion oh H+ organic acids and bases

35

Describe the Descending Loop of Henle (reabsorption)

The descending loop has few mitochondria hence no active transport. Selective permeability to water allows for only water movement out of the descending, thin part of loop.

36

Describe the ascending loops of Henle

lots of mitochondria, lots of active transport). No water reabsorption occurs here
Descending part of Loop re-absorbs water and the ascending part of loop reabsorbs ions but overall more ions than water is reabsorbed across the entire loop.

37

Is the fluid more dilute or concentrated when exiting the loops?

Dilute

38

Describe the Distal convoluted tubule

Water, Na+, Ca++, Cl reabsorbed here but the amount is dependent on the presence of;
• Parathyroid hormone (increases Ca+=)
• Aldosterone (increases Na+ absorption and K+ secretion)
• Anti Diuretic hormone (increases water absorption)

39

Describe the collecting duct

The water reabsorption depends on ADH levels.
• High levels of ADH = all water is reabsorbed and we get low volume, concentrated urine
• Low levels of ADH = less water is reabsorbed and we get high volume of dilute urine.

40

Describe the ureters

convey urine from kidneys to the bladder. They are located in the retroperitoneal cavity

41

What does the ureters consist of?

Transitional epithelial mucosa
Smooth muscle muscularis
Fibrous connective tissue adventitia

42

Describe the bladder

Located in retroperitoneal cavity
Smooth muscle contraction causes urination (micturition). Micturition involved stretching of bladder, integration of CNS signal to increase parasympathetic output to contract the smooth muscle and relax the external urinary sphincter (skeletal muscle under voluntary control).

43

Describe the the urethra

The urethra's function is the provide a conduit for urine to exit. In females, the urethra is located anterior to vagina. In males, the urethra comes through the middle of the prostate gland, penis.