Urinary System A and P II

Main job of the system?

Filter blood to make urine

What do kidneys do

filter

What do the ureters do?

carry urine

What does the bladder do

store urine

What does the urethra do?

Relase urine

Where are the urinary system organs located

retroperitoneal

Important Kidney functions?

1. Balance chemicals

2. Control pH

3. Control blood pressure

4. Make hormones

5. Remove drugs and hormones

How does the urinary system control pH?

Acid-base balance, adjust H+ and bicarbonate (HCO3)

How does the urinary system control blood pressure?

Release or keep water, release renin (increase BP)

What does the hormone EPO and Calcitrol do?

EPO: makes red blood cells, Calcitrol: absorb calcium

Hilum of Kidney

entry and exit for blood vessel and ureter

layers around kidney

1. Fibrous capsule: protective layer, inner

2. Perinephric fat: cushion and support

3. Renal Fascia: holds kidney in place

4. Paranepheric fat: outer cushion

Renal cortex is located

outer

Renal medulla is located

inner

Renal Pyramid

structures within the renal medulla that contain nephron loops and collecting ducts, involved in urine formation.

Renal papilla

the tip of the renal pyramid that drains urine into the minor calyx.

Renal lobe

functional unit to make urine, cortex + medulla +collum

Renal collum

cortex tissue between pyramids

Renal sinus made of and does what?

made up of minor and major calyx and pelvis, open space for urine drainage

The minor calyx drains one

pyramid/medulla

Renal pelvis is merged

major calyces and mergers at medial edge with ureter

minor calyx merges to form>…. them merges with→ …

major calyxand then the renal pelvis.

What is the nephron composed of (2 things)?

renal corpuscle and renal tubule

Border between cortex and medulla called?

cortical medullary junction

What is a nephron?

microscopic filtration unit that makes filtrate

Renal corpuscle description and components

bulbus region for filtration site, afferent and efferent arterioles, glomerulus

Glomerulus is a ball of what?

capillary ball

What are the capsules of the glomerulus and what is their permeability

visceral layer (permeable inner), parietal layer (impermeable), capsular space in between

The afferent arteriole is always going to be … than the efferent arteriole

larger

What happens at the renal tubule of the nephron?

Processing

3 parts of renal tubule and their cells types

1. PCT (proximal convoluted tubule): simple cuboidal epithelium with micro villi (high surface area)

2. Nephron loop: descending and accessing limb, simple cuboidal and simple squamous

3. Distal convoluted tubule: simple cuboidal without microvilli that goes to collected tubule

Types of nephrons and amount

cortical (85%) and juxtamedullary (15%)

Describe cortical nephrons

short loop, with renal corpuscles near peripheral cortex

Describe juxtmedullary nephron

next to the medulla, long loop, forms salt gradient in intersitial space

Orders nephrons drain into (3 parts)

collecting tubule→ collecting duct→papillary duct

2 specialized cells in tubule/duct

principal cells and intercalated cells

Principal cells

hornone control for don’t pee, ADH and aldosterone

intercalated cells

regulate pH of blood and urine, type A: remove acid (H) and type B: remove base (HCO3)

Specialized juxtaglomerular apparatus cells

1. Granular cells

2. Macula densa cells

3. extraglomerular cells

Granular cells location and their function

in afferent arteriole, contract with sympathetic stimulations, dont pee signal (renin!)

Macula densa cells location and function

in DCT, sends signals to granular cells based on NACL concentrations

Extraglomerular mesangial cells location and function

contract!, inbetween afferent arteriole and DCT

Steps of artery flow through kindey

in: renal artery→segmental artery→interlobar artery→arcuate artery→interlobular artery→afferent arteriole→glomerulus→efferent arteriole

flow of filtrate starts where?

capsular space

What is fluid called when it can no longer be acted on?

urine!

What happens in glomerular filtration?

Substances are moved from blood within the glomerulus into the capsular space

What happens during tubular reabsorption?

bring back in body, substances move from tubular fluid back to blood

What happens during tubular secretion?

stuff your body wants to get rid of (out of body), substance from blood go to tubular fluid

Filtration membrane of glomerular characteristics

pours, thin, negatively charged

3 layers of filtration membrane (glomerular)

1. Endothelium (inner)

2. Basement membrane

3. Visceral layer

Endothelium of glomerulus description

fennestrated, allows plasma and dissolved substances to be filtered

Basement membrane of glomerulus description

glycoprotein and proteogylcan molecules

visceral layer of glomerular capsules description

outermost, pedicels, flirtation slits and podocytes

Podocytes what are they and what do they do?

extensions of pedicels wrap around glomerular capillaries, thin spaces called filtration slides, don’t allow most small proteins in

What gets through filtration membrane mostly?

water, glucose, amino acids, ions, very small amounts of protein (no big stuff and no charge)

What cannot get through filtration membrane?

Large proteins and different blood cells (white and red)

3 types of substance in blood and description

1. Freely filtered (small stuff get through easy)

2. Not filtered (larger stuff doesn’t enter like blood cells)

3. Limited Filtration (normally blocked, small medium proteins maybe no charge stuff)

Mesangial cells in filtrate of glomerulus

squeeze afferent arteriole to regulate blood flow and glomerular filtration rate.

glomerular hydrostatic pressure increases with increased

blood pressure

blood colloid osmotic pressure (OP_g) is and does what?

osmotic pressure exerted by dissolved solutes, pulls fluid into glomerulus

Capsular hydrostatic pressure is and does what?

The push back in from pressure in capsule does to filtrate, stops additional fluid movement

Glomerular hydostatic pressure is and does what?

the blood pressure inside glomerulus, pushes water and some solutes out of glomerulus

Glomerular hydrostatic pressure has a … blood pressure than systematic capillaries

higher

What is net filtration pressure and what does it determine?

the difference between driving and opposing forces, determines if filtration occurs

If net filtration pressure is positive what happens?

filtrate turns into tubular fluid (push overcomes pull back in)

GFR is the rate of

which filtrate is formed

If your blood pressure increases your … increase

NFP

intrinsic controls what is it and 3 diff types

happening in the kidney maintain constant bp and GFR

1.Myogenic response

2. Tubuloglomeruluar feedback mechanism

Myogenic response

intrinsic control of smooth muscles in arteriole, decrease bp→ vessels dilate more blood in glomerulus (opposite for increased)

Tubuloglmerular feedback mechanism

backup to myogenic response if bp is increased really high, NaCL in tubular fluid increases so vasoconstriction will occur even more!

If you dilate afferent arteriole, you make … urine

more!

Extrinsic controls are

neural and hormonal control

What is the effect of sympathetic stimulation on GFR?

↓ GFR → ↓ urine → ↑ blood volume (renin release)

How does sympathetic stimulation affect renal arterioles?

Vasoconstriction (afferent & efferent)

What triggers ANP release?

↑ heart chamber stretch

Effect of ANP on kidneys?

↑ GFR → ↑ urine → ↓ blood volume (no renin release)

Maintaining GFR is what kind of regulation?

Intrinsic auto regulation

Parasympathetic increases or decreases GFR

increases

Substgances are … when moved from blood to nephron

secreted

substances are … when they move from nephron back to blood

reabsorbed

What ever is not reabsorbed back to blood is excreted as …

urine

Where does the most reaborptiuon occur

PCT

What is paracellular transport?

movement between epithelial cells

What is transcellular transport?

movement of substances through epithelial cells

Transcellular transport uses:

pumps

pumps work … concentration gradient

against

Channels goes … concentration gradient

with

Carriers use energy from other

ions

How much of glucose do you reabsorb?

100%

How much of proteins do you reabsorb?

100%

How much of sodium is reabsorbed in the PCT

65%

How much of sodium is reabsorbed in nephron loop?

25%

How much of sodium is reabsorbed in DCT?

5%

What hormone causes the insertion of pumps?

Aldosterone

What hormones increase Sodium reabsorption?

aldosterone, cortisol, estrogen, growth hormone, thyroid hormone, insulin

What hormones decrease NA reabsorption?

ANP, progesterone, parathyroid hormone, glucagon

What are aquaporins?

Water channels

Common substances that are reabsorbed

potassium, calcium and phosphate, hydrogen ions and bicarbonate ions

What are calcium and phosphate regulated by .. and does what?

parathyroid hormone (releases phosphate and reabsorb calcium)

What secretes potassium?

aldosterone and principal cells