Urinary

Question 1

Roles of Urinary system

Answer 1

• Cleansing the blood
• regulation of pH
• Regulation of Blood pressure (nephron)
• Regulating the concentration of blood Solutes
• Determins the concentration of RBC (epo production) (nephron)
• Final synthesis of vitamin D (converting calcidiol to calcitriol) (nephron)

Question 2

Symptoms from Kidney disfunction

Answer 2

Weakness
Lethargy
shortness of breath
anemia
widespread edema (swelling)
Metabolic acidosis
rising K+ levels
heart arrhythmias
etc...

Question 3

What other system controls the urinary system

Answer 3

nervous- failure will result in Incontinence

Question 4

The kidneys receive ____% of RESTING cardiac output

Answer 4

20-25%

they are extremely well vascularized

Question 5

What part of the Endocrine system is on top of the kidney. What is it’s role?

Answer 5

• The Adrenal Gland
• Adrenal cortex = produces aldosterone to stimulate sodium reabsorption
• Adrenal Medulla = release catecholamines (epinephrine and norepinephrine)

Question 6

Renal Column Role

Answer 6

• connective tissue
• separate the renal pyramids
• divides kidney into 6-8 lobes
• supportive framework for vessels that entre and exit cortex

Question 7

Renal Pyramid Role

Answer 7

• bundles of collecting ducts

- transport urine from nephrons to calyces for excretion

Question 8

What makes the kidney lobes

Answer 8

Pyramids and renal columns

Question 9

renal hilum role

Answer 9

-entry and exit point

-

Question 10

Renal Pelvis Placement and role

Answer 10

• Emerges from hilum

- formed from major and minor calyxes in kidney

Question 11

Renal Arteries and veins

Answer 11

• Renal arteries from descending aorta through hilum to bring blood
• Renal veins return cleansed blood through hilum into inferior vena cava

Question 12

Nephrons: role, anatomy, and types

Answer 12

• functional units
• balance the plasma to homeostatic set points and excrete potential toxins
• afferent arterioles supply blood through glomerulus capillaries
• Glomerular/ Bowman’s Capsule receives filtrate
• Cortical nephrons: short loop of Henle that barely leaves cortex
• Juxtamedullary nephrons: long loop of Henle that goes into Medulla

Question 13

Renal Corpuscle

Answer 13

-Bowman’s capsule + Glomerulus = renal corpuscle

Question 14

Bowman’s Capsule

Answer 14

-Continuous sophisticated tubule with proximal end that surrounds the glomerulus and receives filtrate

Question 15

Order of flow through a cortical nephron

Answer 15

-Glomerular (Bowman’s) capsule
-Proximal convoluted tubule
-Descending limb of the nephron loop
-Ascending limb of the nephron loop
-Distal convoluted tubule
(drains into collecting duct)

Question 16

After passing through the renal corpuscle the capillaries form ……
Which then…..

Answer 16

• a second arteriole , efferent arteriole
• forms capillary network around distal portions of nephron tubule (Peritubular capillaries and Vasa recta) -> then returns blood (mostly water and solutes) to venous system

Question 17

Why is the Renal Cortex easy to distinguish? What is found there?

Answer 17

• It is lighter in colour then the rest of the kidney

- Renal Corpuscles, Proximal convoluted tubules, and distal convoluted tubules

Question 18

3 steps/ principals of nephron

Answer 18

Filtration
reabsorption
secretion

Question 19

What factors allow substances to cross into the nephron

Answer 19

• fenestrations : prevent filtration of blood cells or large proteins (but allow most other things)
• Electric Charge: proteins associated with the pores are negatively charged, so they repel negatively charged substances and allow positively charged substances
• Therefore no blood cells or large proteins should be in urine and there is a slight positive charge (Na+, K+)

Question 20

Loop of Henle, function and Anatomy

Answer 20

Descending: initially thick, then thin
Ascending: initially thin, then thick
Thick part of loop: simple cuboidal epithelium
This part of loop: Simple Squamous epithelium
-allows varying permeabilities for solutes and water

Question 21

Convoluted tubule. Why named that? Role? Anatomy?

Answer 21

• progressively widening path
• simple cuboidal cells form it with prominent Microvilli on Luminal Surface, forming Brush Border
• this structure is key to reabsorb solutes (Na+, Cl-, glucose, etc.)

Question 22

Distal convoluted tubule

Answer 22

• simple cuboidal epithelium
• Shorter & Less active then Proximal Convoluted Tubule in absorption and secretion -> fewer microvilli on apical surface and no brush border

Question 23

Where are the Macula Densa cells. What is their role?

Answer 23

Juxtaglomerular apparatus

• release paracrine signals (w/ ATP) as a response to Na+ in fluid
• Regulate renin release
• -> Renin takes A.As off of angiotensinogen to make angiotensin I

Question 24

Where are juxtaglomerular cells? What do they do?

Answer 24

in juxtaglomerular apparatus
-is a modified smooth muscle cell lining the afferent arteriole that can contract or relax in response to ATP or Adenosine
-

Question 25

Steps of the Nephron

Answer 25

1) GFR increases 2) Flow through tubule increases 3) flow past macula densa increases 4) Paracrine from macula densa to afferent arteriolr 5)Afferent arteriole constricts -Resistance in afferent arteriole -Hydrostatic Pressure in glomerulus decreases GFR decreases

Question 26

What is it called when filtrate osmolarity is too high? How does the system react?

Answer 26

Hyperosmotic -juxtaglomerular cells contract, decreasing GFR, so less plasma is filtered, leading to less using formation and greater fluid retention (ultimately will decrease blood osmolarity toward physiological norm.

Question 27

What happens when osmolarity of filtrate is too low? How does the body react?

Answer 27

juxtaglomerular cells will relax | -increases GFR and increasing loss of water to the urine, causing blood osmolarity to rise to norm

Question 28

Angiotensinogen-> Angiotensin I-> Angiotensin II

Answer 28

- Made from renin breaking A.As off of Angiotensinogen - Angiotensin I is not active until converted to Angiotensin II by angiotensin converting enzyme - Angiotensin II is a vasoconstrictor that increases blood pressure - Angiotensin II also stimulates aldosterone hormone release

Question 29

Aldosterone: where released from, and role

Answer 29

-released from Adrenal cortex -stimulates Na+ reabsorption by kidney (resulting in water retention and Increased blood pressure)

Question 30

Natriuretic hormones

Answer 30

- peptides that stimulate kidneys to excrete Na+ - inhibit aldosterone release-> inhibiting Na+ recovery in collecting duct - also inhibit ADH release-> less water being recovered in the collecting ducts

Question 31

Collecting Ducts

Answer 31

-Continuous with nephron (but not part of it) -Collects filtrate from multiple nephrons for modification -will merge with other collecting ducts and they head towards Medulla Forming ~30 terminal ducts -terminal ducts empty at Papilla -lined with simple squamous epithelium with ADH receptors -have aqua porin channel proteins in membranes

Question 32

Aqua Porin Channel proteins in collecting duct allow for:?

Answer 32

water to readily pass from duct lumen through the cells and into the interstitial spaces to be recovered by vasa recta allows for recovery of lots of water back into blood -in absence of ADH channels aren't inserted into membrane, so water can't be reabsorbed, so it is excreted as dilute urine

Question 33

How do different urine molecules/ ions move from cell membranes?

Answer 33

- Na+ : active transport - Anion reabsorption: electrochemical gradient - Water moves by osmosis (following solute reabsorption) - other solutes increase as amount of fluid in Lumen decreases - permeable solutes by diffusion

Question 34

volume of flitrate formed by both kidneys per minute is called:

Answer 34

Glomerular Filtration rate

Question 35

How much blood does the heart pump at rest What is the rate of kidney filtration how much filtrate a day How much urine a day

Answer 35

~5L blood per minute About 1 L will enter kidneys for filtration therefore ~125mL/min filtrate produced in men and 105mL filtrate/min in women This becomes about 180L/day in men 150L/day in women >95% is reabsorbed to circulation therefore 1-2 L of urine per day

Question 36

what influences Glomerular filration rate

Answer 36

Hydrostatic pressure and colloid osmotic pressure on either side of the capillary membrane of the glomerulus Filtration occurs as pressure forces fluid and solutes through a semipermeable barrier with the solute movement constrained by particle size

Question 37

Hypdrostatic pressure

Answer 37

Influences glomerular filtration rate is the pressure produced by a fluid against a surface If you have a fluid on both sides of a barrier, both fluids exert a pressure in opposing directions ->Net fluid movement will be in the direction of the lower pressure

Question 38

Osmosis

Answer 38

Osmosis is the movement of water across a membrane (that is impermeable to a solute in the solution) •This creates osmotic pressure, which will exist until the solute concentration is the same on both sides of a semipermeable membrane •As long as solute concentration differs across the membrane, water will be pulled to the higher solute concentration

Question 39

Glomerular hydrostatic pressure EXCEEDING capsular (luminal) hydrostatic pressure will cause? How is this related to osmotic pressure?

Answer 39

Glomerular filtration-> also needs to take into account osmotic pressure •Typically much higher in the glomerular capillary (blood colloid osmotic pressure)