Final - Urinary

Question 1

What are the components of the urinary system and their functions?

Answer 1

1. kidneys (conserve body fluids and electrolytes; remove metabolic wastes; endocrine functions)
2. ureters (transport urine from kidney to bladder)
3. bladder (store urine)
4. urethra (excretion of urine)

Question 2

Components of the kidney structure (4)

Answer 2

1. capsule of CT
2. cortex (has renal corpuscle)
3. medullary rays
4. medulla (mainly tubes) with pyramids

Question 3

What is a nephron?

Answer 3

functional unit of kidney (collects urine and secretes it)

Question 4

Describe the histology of the kidney capsule and its functions

Answer 4

1. outer layer fibroblasts and collagen
2. inner layer with myofibroblasts (contractibility aids in resisting volume pressure changes that vary with kidney function)

Question 5

Describe the anatomical structure of a nephron of the kidney (2 parts)

Answer 5

1. renal corpuscle (glomerulus with capillary tuft and Bowmans capsule)
2. tubular portion

Question 6

Describe the flow of filtrate from the glomerulus to the medullary collecting duct.

Answer 6

glomerulus-> proximal convoluted tubule -> proximal straight tubule -> thin loop Henle -> distal straight tubule -> distal convoluted tubule -> collecting tubule -> collecting ducts

Question 7

What is a renal corpuscle and where would you find it in a section of the kidney?

Answer 7

house fenestrated capillaries for blood filtration and is found in the cortex

Question 8

Describe Bowman’s capsule and explain podocyte relevance/function.

Answer 8

Fx: filtration

1. parietal layer - simple squamous epithelium
2. visceral layer - podocytes that create filtration slits

Question 9

How would you describe the histology of the capillaries in a renal corpuscle?

Answer 9

They are fenestrated/discontinuous and are larger, irregular, and more numerous than other capillaries for filtration

Question 10

What are the functions of mesangium?

Answer 10

1. phagocytosis (keep large proteins from blocking cells)
2. structural support
3. secreting

Question 11

Where do you find the mesangium?

Answer 11

in the glomerulus?

Question 12

What are the cell types associated with the mesangium?

Answer 12

1. mesangial cells: within basal lamina of the glomerulus
2. Lacis cells: along vascular pole

Question 13

Describe the function of the juxtaglomerular apparatus

Answer 13

senses blood volume and tubular fluid composition (endocrine)

Question 14

What is the purpose of the juxtaglomerular apparatus?

Answer 14

regulate blood pressure by activating renin-angiotensin-aldosterone system (RAAS)

Question 15

Describe RAAS

Answer 15

1. low blood volume
2. juxtaglomerular cells make renin (acid protease)
3. renin converts angiotensinogen -> antiotensin I
4. angiotensin I -> angiotensin II conversion by ACE on lung endothelial cells
5. angiotensin II stimulates release of aldosterone from adrenal glands to constrict blood vessels
6. aldosterone increases reabsorption of Na & H2O at collecting ducts

Question 16

Where would you find a lumen of a PCT in a kidney section?

Answer 16

cortex - star-shaped lumen with cubed cells

Question 17

Where would you find the lumens of the segments of Henle’s loop?

Answer 17

medulla

Question 18

Where would you find a lumen of the DCT?

Answer 18

in both the medulla and cortex… but mainly medulla - circular lumen that is simple cuboidal

Question 19

Collecting duct function

Answer 19

deals with water - how much to reuptake and how much to leave in the interstitial space (in medulla)

Question 20

Where does renal blood supply enter and exit the kidney, anatomically?

Answer 20

renal pelvis

Question 21

Beginning with the minor calyx and ending with the urinary bladder, which histological layers are present?

Answer 21

• all have transitional epithelium
• all have mucosa and muscularis (inner longitudinal + outer circular) with adventitia/serosa

Question 22

How would you describe the mucosa of the excretory regions?

Answer 22

transitional epithelium when stretched flat, when collapsed, dome-shaped

Question 23

Describe the muscularis of the excretory regions.

Answer 23

inner longitudinal and outer-circular

Question 24

What is the trigone in the urinary bladder?

Answer 24

triangular region with three openings has sympathetic, parasympathetic, and sensory fibers for nerve specialization

Question 25

For the urethra, compare the male and female urethra mucosal layers.

Answer 25

M: has glands (cowpers & glands of Littre) - urethra changes transitional -> stratified columnar -> stratified squamous)
F: has paraurethral glands (alkaline secretion) & more continuous (transfers to stratified squamous only at urethral opening)

Question 26

Would one expect to find striated muscle in the urethra?

Answer 26

Yes, because you can hold it in when going to the bathroom and flow rate

Question 27

Now that you have studied RAAS, explain what an ACE inhibitor is and why it is given to patients with hypertension?

Answer 27

In the lungs, ACE converts angiotensin I to II which then goes on to stimulate the release of aldosterone which increases the resorption of Na and H2O and leads to an increase in bp… by blocking ACE this conversion stops in the lungs and bp is not increased

Question 28

Now that you have seen the RAAS pathway, explain why having extra white adipose (being obese/overweight) is associated with higher risk of hypertension.

Answer 28

“white adipose tissue is the most abundant source of angiotensin after the liver” — leads to the activation of RAAS pathway and an increase in bp