lecture 28

Question 1

describe the anatomy of the kidneys

Answer 1

• located posteriorly
• they are retroperitoneal meaning they are behind the peritoneal which is a connective tissue encasement that hold in all your organs in your abdominal cavity

Question 2

describe the anatomy of the adrenal gland

Answer 2

• sits like a hat over the kidneys

Question 3

anatomy and function of ureter

Answer 3

• 2 tubes that lead from kidney to bladder
• drain urine from kidney where it is produced to bladder where urine is stored and then excreted from bladder

Question 4

describe the anatomy of the urethra

Answer 4

the tube connecting the urinary bladder to external environment

Question 5

what is the breakdown product of hemoglobin

Answer 5

uribilinogen

Question 6

renin

Answer 6

• an enzyme that is important for regulating blood pressure
• produced by the kidneys

Question 7

General functions of the kidney

Answer 7

• kidneys essentially dictate how much water leaves in urine and how much water stays, and by regulating water loos and water keep we regulate extracellular volume fluid and therefore also blood volume. And if we’re regulating plasma volume we’re also regulating blood pressure
• Regulation of osmolarity
• Maintenance of ion balance (Na+ and K+)
• Homeostatic regulation of pH because kidneys can secrete/offload H+ and HCO3- as needed
• Excretion of wastes (creatinine, urea, hormones, uribilinogen)
• Production of hormones (erythropoietin and renin)

Question 8

renal pelvis

Answer 8

• all nephrons lead here
• a hollow space that fills with urine and drained into bladder via the ureter

Question 9

nephrons

Answer 9

the functional unit of the kidney

Question 10

approximately how many nephrons are there per kidney?

Answer 10

1 million

Question 11

what does the cortex contain

Answer 11

• bowman’s capsule
• proximal tubule
• distal tubule

Question 12

what does the medulla contain

Answer 12

• loop of henle
• collecting duct

Question 13

Why is the anatomy of the loop of henle important

Answer 13

because it is a hair pin like structure it creates a motor that allows us to excrete a very dilute urine or a very concentrated urine depending on bodies needs

Question 14

what is the role of the loop of henle

Answer 14

regulating urine concentrations

Question 15

renal artery

Answer 15

takes blood to your kidneys and filters it

Question 16

renal vein

Answer 16

is blood coming out of kidneys after being filtered and being put back into circulation

Question 17

peritubular capillaries

Answer 17

• deliver nutrients to the nephron (blood)
• serves as a re-entry point for reabsorbed substances to get back into circulation

Question 18

which is the correct order of structures a molecule of glucose might pass through

Answer 18

1. glomerulus
2. bowman’s space
3. proximal tubule
4. loop of henle
5. distal tubule
6. collecting duct
7. renal pelvis
8. ureter
9. bladder

Question 19

Give the % of total plasma volume that filters into the tubule

Answer 19

1. 100% plasma volume entering via afferent arterioles
2. 80% of plasma will re-enter circulation via efferent arteriole and 20% of volume filters
3. 99% of that 20% will be reabsorbed
4. Leaving 1% to be excreted

Question 20

Podocyte

Answer 20

• single cell epithelium
• have foot processes that create windows called fenestrations
• out of capillary through fenestrations and now we’re in bowman’s space

Question 21

Functional anatomy of the nephron

Answer 21

Bowman’s capsule :
- filtration occurs because glomerulus is leaky because there is very few tight junctions, stuff being filtered is glucose, Na+, water, K+
- Stuff will leak into bowman’s space because glomerulus is leaky
- Filter 180 L/ day of blood a day

proximal tubule:
- glucose and Na+ are reabsorbed
- H+ and K+ are secreted

Loop of Henle
- Reabsorption

Distal tubule/ collecting duct
- somewhere here vasopressin causes insertion of water channels for water reabsorption as needed
- How much water we let go (filter) vs. how much we reabsorb will determine concentration of urine but more importantly determines blood volume and blood pressure
- We excrete 1.5 L/ day in form of urine (urea, k+, h+, h2o), this means vast majority of what our kidneys filter is reabsorb

Question 22

Water will move towards

Answer 22

Highest concentration of solutes

Question 23

What pressure is GFR influenced by?

Answer 23

Hydrostatic pressure (Ph): is the blood pressure of blood that enters the glomerulus and it’s gonna cause a push therefore being for filtration

Colloid osmotic pressure gradient (π) water will move from a lower concentration of solutes to a higher concentration of solutes, so if protein is getting left behind and protein acts as a solute that will oppose filtration because it’s gonna tend to pull fluid or plasma back.

Fluid pressure within bowman’s capsule (Pfluid): as fluid collects in bowman’s there will be a hydrostatic pressure that pushes back

Question 24

Give values to pressures GFR

Answer 24

Hydrostatic pressure (Ph) = 55 mm Hg
Colloid osmotic pressure gradient (π) = 30 mm Hg
Fluid pressure in bowman’s capsule (Pfluid) = 15 mm Hg
Ph - π - Pfluid = 10 mm Hg (net filtration pressure)