Urinary System

Question 1

Where are the structures of the urinary system located?

Answer 1

abdominopelvic cavity

Question 2

What are the four structures of the urinary system

Answer 2

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

Question 3

What is the main function of the kidneys

Answer 3

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

Question 4

What is the main function of the ureters:

Answer 4

Allows flow of urine into the bladder

Question 5

What is the main function of the bladder

Answer 5

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

Question 6

What is the main function of the urethra

Answer 6

allows urine to flow out of the body

Question 7

What are the excretory functions of the kidneys?

Answer 7

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

Question 8

What are the synthetic functions of the kidneys?

Answer 8

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

Question 9

Describe the process of excretion of waste

Answer 9

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

Question 10

Describe water body balance

Answer 10

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

Question 11

Describe Electrolyte balance

Answer 11

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.

Question 12

Describe blood pressure regulation

Answer 12

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

Question 13

Describe regulation of pH

Answer 13

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

Question 14

Describe the regulation of erythropoiesis

Answer 14

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

Question 15

Describe vitamin D synthesis

Answer 15

The final step of Vitamin D synthesis occurs in the kidneys

Question 16

Describe production of glucose

Answer 16

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.

Question 17

What are the three layers of the kidney?

Answer 17

The capsule
The renal cortex
The medulla

Question 18

Describe the capsule

Answer 18

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.

Question 19

Why is the renal capsule granular?

Answer 19

Due to nephrons

Question 20

Describe the medulla

Answer 20

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

Question 21

What % of the cardiac output do kidneys receive?

Answer 21

20%

Question 22

How do the kidneys make urine?

Answer 22

By filtering blood’s plasma

Question 23

What is the glomerular filtration rate (GFR)?

Answer 23

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

Question 24

Where does filtration occur?

Answer 24

In the glomerular capillaries

Question 25

Describe nephrons

Answer 25

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

Question 26

Where are the nephrons located?

Answer 26

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

Question 27

What do the nephrons located in the renal cortex do?

Answer 27

filter, reabsorb and secrete

Question 28

What do juxtamedullary nephrons do?

Answer 28

concentrate the urine by regulating water excretion.

Question 29

What type of transportation do nephrons use?

Answer 29

Active and passive (reabsorb the nutrients in urine)

And active to pump waste products into the renal tubes

Question 30

What are nephrons composed of?

Answer 30

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

Question 31

What are collecting tubules?

Answer 31

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

Question 32

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

Answer 32

1. Glomerular filtration
2. Reabsorption
3. section

Question 33

Describe the Glomerular filtration barrier

Answer 33

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

Question 34

Describe the Proximal convoluted tubule

Answer 34

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

Question 35

Describe the Descending Loop of Henle (reabsorption)

Answer 35

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.

Question 36

Describe the ascending loops of Henle

Answer 36

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.

Question 37

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

Answer 37

Dilute

Question 38

Describe the Distal convoluted tubule

Answer 38

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)

Question 39

Describe the collecting duct

Answer 39

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.

Question 40

Describe the ureters

Answer 40

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

Question 41

What does the ureters consist of?

Answer 41

Transitional epithelial mucosa
Smooth muscle muscularis
Fibrous connective tissue adventitia

Question 42

Describe the bladder

Answer 42

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).

Question 43

Describe the the urethra

Answer 43

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.