LECTURE 6: RENAL/URINARY SYSTEM

Question 1

What are the main functions of the urinary system?

Answer 1

1. Filter blood
2. Collect waste as urine
3. Transport urine to external environment

Question 2

What are the components of the urinary tract?

Answer 2

1. Kidneys (2)
2. Ureters (1 per kidney)
3. Urinary bladder
4. Urethra

Question 3

What is the position of the kidneys?

Answer 3

The right kidney is lower than the left.

Question 4

What is the hilum of the kidney?

Answer 4

The hilum is where structures enter and exit the kidney.

Question 5

What supplies blood to the kidney?

Answer 5

Renal artery (renal a.) supplies blood to the kidney.

Question 6

What are the main parts of kidney anatomy?

Answer 6

1. Cortex
2. Medulla
3. Renal pelvis
4. Renal sinus
5. Renal columns
6. Pyramids

Question 7

What are the renal functions?

Answer 7

1. Maintenance of extracellular volume & osmolarity
2. Endocrine functions
3. Excretion

Question 8

What ions are involved in the maintenance of extracellular volume?

Answer 8

Na+, K+, Ca2+, Cl-, HPO42-

Question 9

What is the renal vasculature pathway?

Answer 9

1. Renal a. → Segmental a. → Interlobar a. → Arcuate a. → Cortical radiate aa.
2. Afferent arterioles → Glomeruli → Efferent arterioles → Peritubular capillaries → Vasa recta → Peritubular venules → Cortical radiate vv. → Arcuate v. → Interlobar v. → Renal v. (to IVC)

Question 10

What is the difference between left and right renal veins?

Answer 10

The left renal v. is longer than the right and drains into the inferior vena cava (IVC). The right renal v. drains into the IVC directly.

Question 11

What is the pathway of urine conduction?

Answer 11

Collecting ducts of nephrons → Renal papillae → Minor calices → Major calices → Renal pelvis → Ureter

Question 12

What are the two types of control of renal function?

Answer 12

1. Intrinsic control
2. Extrinsic control

Question 13

What are the two types of nephrons?

Answer 13

1. Cortical nephrons
2. Juxtamedullary nephrons

Question 14

What is the primary site of filtration in the nephron?

Answer 14

Glomerulus

Question 15

What is the function of the proximal convoluted tubule (PCT)?

Answer 15

Reabsorption of salts, glucose, urea, and secretion of ammonia and bioactive substances.

Question 16

What is the function of the descending limb of the nephron loop?

Answer 16

The descending limb is permeable to water and reabsorbs water due to the hypertonic medulla.

Question 17

What is the function of the ascending limb of the nephron loop?

Answer 17

The ascending limb is impermeable to water and reabsorbs salts, maintaining the hypertonic medulla.

Question 18

What are the functions of intercalated cells in the distal convoluted tubule?

Answer 18

Intercalated cells regulate pH by secreting H+ and reabsorbing HCO3-.

Question 19

What do principal cells in the distal convoluted tubule do?

Answer 19

Principal cells reabsorb Na+ and H2O, stimulated by aldosterone and vasopressin.

Question 20

What is the juxtaglomerular apparatus?

Answer 20

The juxtaglomerular apparatus includes the macula densa and afferent arteriole, regulating renal blood flow and GFR.

Question 21

What do juxtaglomerular cells secrete?

Answer 21

Juxtaglomerular cells secrete renin, which increases blood pressure.

Question 22

How do diuretics work?

Answer 22

Diuretics increase tubular secretion of water or decrease tubular reabsorption of water.

Question 23

What is a common use for diuretics?

Answer 23

Diuretics are commonly used to treat hypertension by reducing blood volume via diuresis.

Question 24

How does caffeine affect renal function?

Answer 24

Caffeine increases GFR, proportional to blood pressure.

Question 25

How does alcohol affect urine production?

Answer 25

Alcohol inhibits ADH production, reducing water reabsorption and increasing urine output.

Question 26

At which point in the urinary system does filtrate become urine?

Answer 26

Filtrate becomes urine when it reaches the collecting duct. ## Footnote The collecting duct is where further reabsorption of water and ions occurs, and the fluid that remains is ultimately excreted as urine.

Question 27

What are the learning objectives related to the urinary system?

Answer 27

1. Describe the gross anatomical features of the ureters, urinary bladder, and urethra. 2. Describe the blood supply of the bladder. 3. Explain the process of micturition and the innervation of the structures involved. 4. Discuss the autonomic inputs of the inferior hypogastric plexus and the structures it supplies.

Question 28

What are the three parts of the ureters?

Answer 28

1. Abdominal part: Located in the abdomen. 2. Pelvic part: Located in the pelvis. 3. Intramural part: Passes through the wall of the bladder.

Question 29

What is the primary blood supply to the pelvic structures?

Answer 29

The internal iliac artery is the primary source of blood supply to the pelvic structures.

Question 30

What arteries supply the urinary bladder?

Answer 30

The urinary bladder is supplied by the superior vesical arteries and inferior vesical arteries.

Question 31

What is the function of the detrusor muscle?

Answer 31

The detrusor muscle is responsible for contracting the bladder to expel urine.

Question 32

What are rugae in the urinary bladder?

Answer 32

Rugae are folds in the bladder's inner lining that allow it to expand as it fills.

Question 33

What structures are involved in the vascular supply of the bladder?

Answer 33

Blood is supplied to the bladder by the superior and inferior vesical arteries, and the vesical plexus is involved in its innervation.

Question 34

What is the trigone of the bladder?

Answer 34

The trigone is a triangular area on the floor of the bladder formed by the ureteric orifices and the internal urethral orifice.

Question 35

What controls the release of urine from the bladder?

Answer 35

The internal urethral sphincter controls the release of urine from the bladder and is under autonomic control.

Question 36

What allows for voluntary control over urination?

Answer 36

The external urethral sphincter, which is under somatic control, allows for voluntary control over urination.

Question 37

What is the inferior hypogastric plexus?

Answer 37

The inferior hypogastric plexus is a complex network of nerves supplying the pelvic organs.

Question 38

What type of input does the inferior hypogastric plexus receive?

Answer 38

Parasympathetic input comes from the pelvic splanchnic nerves (S2-S4), and sympathetic input comes from the sacral splanchnic nerves and sacral sympathetic ganglia.

Question 39

What role does the vesical plexus play?

Answer 39

The vesical plexus plays a key role in the micturition reflex, which is the process of urination.

Question 40

What triggers the micturition reflex?

Answer 40

The reflex is triggered when the bladder fills to approximately 200 mL.

Question 41

What happens during parasympathetic stimulation in micturition?

Answer 41

Parasympathetic stimulation causes the detrusor muscle to contract.

Question 42

What happens during sympathetic stimulation in micturition?

Answer 42

Sympathetic stimulation causes the internal urethral sphincter to relax.

Question 43

What is the role of somatomotor stimulation in urination?

Answer 43

Somatomotor stimulation causes the external urethral sphincter to relax, allowing for voluntary control of urination.

Question 44

Where is the urinary bladder located?

Answer 44

The bladder is located in the subperitoneal or extraperitoneal space.

Question 45

What is the structure of the urethra in females?

Answer 45

The urethra is 4-5 cm long in females and has a tripartite structure: 1. Prostatic part, 2. Membranous part, 3. Spongy (penile) part.

Question 46

Where is the external urethral meatus located in females?

Answer 46

In females, the external urethral meatus is located between the glans clitoris and the vaginal orifice.

Question 47

What type of information is transmitted to the inferior hypogastric plexus through the pelvic splanchnic nerves?

Answer 47

The pelvic splanchnic nerves carry parasympathetic fibers. ## Footnote These fibers contribute to the autonomic regulation of the pelvic organs, including the urinary bladder and other structures involved in micturition.