Urinary System

Question 1

components of the urinary system

Answer 1

kidneys, ureters, urinary bladder and urethra

Question 2

blood supply to the kidneys

Answer 2

25% of total blood pumped by the heart goes to the kidneys at rest
- need such a large blood supply because the kidneys filter the plasma, returning most water and solutes to the bloodstream

Question 3

functions of the kidneys

Answer 3

excretion
regulation of blood volume and pressure
regulation of solute concentration in blood
regulation of pH
regulation of RBC synthesis
vitamin D synthesis

Question 4

excretion as a function of the kidneys

Answer 4

urea
urobillin (a waste product from the heme group of RBC)
toxins
drugs and waste products

Question 5

regulation of blood volume and pressure as a function of the kidneys

Answer 5

flow=pressure/resistance
so if you have a greater volume of blood, BP increases and causes flow to increase.
thus, when you decrease blood volume (by removing fluids) you also decrease BP

Question 6

regulation of solute concentration in the blood as a function of the kidneys

Answer 6

regulates solute concentration of ions such as Na+, K+, Cl-

Question 7

regulation of pH as a function of the kidneys

Answer 7

H+ ion balance is regulated in the kidneys

they work with the bicarbonate system to regulate blood pH

Question 8

regulation of RBC synthesis as a function of the kidneys

Answer 8

erythropoietin, the hormone responsible for RBC synthesis, is produced in the kidney

Question 9

vitamin D synthesis as a function of the kidneys

Answer 9

active form of vitamin D is created by kidneys and aids in calcium absorption from the gut into the blood

Question 10

where are the kidneys found in the body

Answer 10

• they are positioned above the wait
• are retroperitoneal, protected by 11th and 12th floating ribs
• right kidney is slightly lower than the left because the liver is located predominantly on the right side

Question 11

3 layers of CT that surround the kidney

Answer 11

(superficial to deep)

• peritoneum on anterior and lateral sides of kidney
  1. renal fascia
  2. adipose capsule
  3. renal capsule

Question 12

renal fascia

Answer 12

• most superficial layer around the kidney

dense irregular CT layer that connects the kidney to abdominal cavity and other organs on the abdominal wall

Question 13

adipose capsule (CT layer around kidney)

Answer 13

middle layer of protection

• might be thicker in obese people
• surrounds entire kidney, cushions with essential fat

Question 14

renal capsule

Answer 14

innermost layer of protection around the kidney

• surrounding dense irregular CT that gives strength in many directions
• maintains and gives kidney its bean shape and holds everything together

Question 15

renal hilum

Answer 15

medial curved part of kidney where blood vessels and ureters enter/exit the kidney

Question 16

renal cortex

Answer 16

the part of the kidney close to the outside

- some dips down towards hilum called the renal column

Question 17

renal column

Answer 17

parts of renal cortex that dip down between pyramids

Question 18

renal medulla

Answer 18

highly organized into pyramids that are cone shaped structures on the inside of the kidney (deep to cortex)

• a person has 8-18 pyramids
• larger portion is the base of the pyramid, apex is called the renal papilla

Question 19

nephron

Answer 19

functional portion of the kidney where filtration happens

• highly supplied with blood
• long tube, most of it located in cortex, loop runs into medullary region
• most filtrate produced in 1st portion of the nephron

Question 20

path of urine drainage in the kidney

Answer 20

collecting duct > papillary duct > minor calyx > major calyx > renal pelvis > ureter > urinary bladder

Question 21

renal lobe

Answer 21

functional unit of the kidney that produces urine, incl the cortex and medulla surrounding a pyramid

Question 22

blood supply of the kidney

Answer 22

renal artery > segmental arteries > interlobar arteries > arcuate arteries > cortical radiate arteries > afferent arterioles > glomerular capillaries > efferent arterioles > peritubular capillaries > cortical radiate veins > arcuate veins > interlobar veins > renal vein

Question 23

renal sinus

Answer 23

region where renal artery starts branching and smaller veins merge to become renal vein

Question 24

vasa recta

Answer 24

carries mixed oxygenated and deoxygenated blood

- highly organized capillaries in medullary cavity surrounding the loop of Henle in the nephron

Question 25

glomerulus

Answer 25

a bunch of capillaries that form a ball/network where filtrate is produced when blood passes through (lots of surface area here) - pulls about 20% of plasma from blood - endothelial cells are fenestrated here

Question 26

parts of the nephron

Answer 26

2 parts: renal corpuscle renal tubule

Question 27

renal corpuscle

Answer 27

- located in cortex, is the site of plasma filtration where glomerular filtrate is produced - includes the glomerulus, and Bowman's (glomerular capsule which catches filtrate)

Question 28

renal tubule

Answer 28

``` - conveyor belt idea where it picks and chooses what to keep and add 3 portions: - proximal convoluted tubule - nephron loop - distal convoluted tubule ```

Question 29

proximal convoluted tubule

Answer 29

first part of renal tubule - located in cortex, comes off of renal corpuscle - very bendy, giving lots of SA - reabsorbs about 65% of what gets dumped into the tubule

Question 30

nephron loop

Answer 30

aka loop of Henle | - dips down into medulla and comes back into the cortex

Question 31

distal convoluted tubule

Answer 31

last part of renal tubule | - bendy, also found in cortex

Question 32

collecting ducts

Answer 32

where distal convoluted tubules all join together

Question 33

papillary ducts

Answer 33

reach papillary region and drip urine into minor calyx

Question 34

types of nephrons

Answer 34

2 types: cortical nephron juxtamedullary nephron

Question 35

cortical nephron

Answer 35

80-85% of nephrons - most of nephron found in cortex - corpuscle is closer to CT outer part of cortex - shorter loop of Henle, with ascending and descending limbs of equal thickness - blood supply to the loop is via peritubular capillaries which aren't very organized

Question 36

juxtamedullary nephron

Answer 36

15-20% of nephrons - means beside medullary region - corpuscle located near medulla in cortex close to the base of the pyramid - long nephron loop that runs from the base of pyramid to papilla and back again - loops ahs descending and thin (1st half) and thick (2nd half) ascending limbs - can produce dilute or concentrated urine dependant upon the concentration gradient that in generates

Question 37

podocytes

Answer 37

modified simple squamous cells that adhere to glomerulus | - have projections called pedicels which form a sieve like pattern for filtration

Question 38

pedicels

Answer 38

the projections on podocytes

Question 39

capsular space

Answer 39

where glomerular filtrate accumulates

Question 40

glomerular capillaries

Answer 40

arise from afferent arterioles and from a ball before emptying into the efferent arteriole - the blood is essentially the same, just with 20% less plasma in it

Question 41

juxtaglomerular apparatus

Answer 41

- structure where afferent arteriole make contact with the ascending limb of the nephron loop - helps regulate BP in kidneys - components include macula densa, and juxtaglomerular cells

Question 42

macula densa

Answer 42

thickened part of the ascending limb - monitor water and ion concentrations in filtrate - if we need to change this, they send a signal to juxtaglomerular cells when too much water is being release in the filtrate

Question 43

juxtaglomerular cells

Answer 43

modified smooth muscle cells in afferent arteriole which contract when they get a signal from the macula densa that we are losing too much fluids

Question 44

mesangial cells

Answer 44

are in contact with afferent and efferent arterioles and some are in contact with capillaries - change SA of arterioles by constricting when losing too much fluids, thus less filtrate gets made

Question 45

layers of the filtration membrane and what they filter

Answer 45

3 layers: - fenestration of glomerular endothelial cell: filter RBC, WBC and platelets, allowing components of plasma to pass through - basal lamina of glomerulus: prevents filtration of large proteins - slit membrane b/w pedicels: prevents filtration of medium proteins

Question 46

cell type found in proximal convoluted tubule (PCT)

Answer 46

simple cuboidal with brush border microvilli

Question 47

cell type found in descending limb and thin ascending limb of nephron loop

Answer 47

simple squamous, allow free movement of things along their concentration gradients - lots of water absorbed back into blood here

Question 48

cell type found in thick ascending limb of nephron loop

Answer 48

simple cuboidal to low columnar | - highly regulate what moves through

Question 49

cell type found in distal convoluted tubule (DCT) - only in the first part

Answer 49

simple cuboidal | - highly selective

Question 50

cell type found in last part of DCT and collecting duct

Answer 50

simple cuboidal and some specialized cells mixed in that are regulated by hormones (principal and intercalated cells)

Question 51

principal cells

Answer 51

help regulate pH - found in last part of DCT and CD - activity regulated by hormones

Question 52

intercalated cells

Answer 52

help regulate blood volume through movement of Na+, K+ - found in last part of DCT and CD - activity regulated by hormones