renal lecture 1 anatomy, basics of urine formation

Question 1

What are the 4 functions of the kidney?

Answer 1

1. regulation of water, inorganic ion balance, and acid base balance
   2.removal of metabolic waste products from the blood and their excretion in the urine
2. removal of foreign chemicals from the blood and thei excretion in the urine
   4.production of hormones/enzymes

Question 2

What are the 3 main components of hormones/enzymes made by the kidney?

Answer 2

a.erythropoietin
b.renin
c.1,25-dihydroxyvitamin D

Question 3

What does erythropoietin, renin, 1,25-dihydroxyvitamin D make?

Answer 3

1.Erythropoietin: hormone that controls erythrocyte production
2.Renin: enzyme that controls the formation of
angiotensin and influences blood pressure
and sodium balance
3.1,25-dihydroxyvitamin D: active vitamin that
influences calcium balance

Question 4

How much do kidneys weigh?
Where are they located in the body (behind what and on either side of what?
What does renal mean?

Answer 4

Kidneys are paired organs: ~150 grams each
Behind the peritoneum on either side of the vertebral column against the posterior abdominal wall (close to your back)
Renal = pertaining to the kidneys

Question 5

What is the bladder and urethra?

Answer 5

bladder=where urine is retained
urethra=where the urine goes to be excreted from body, longer in men

Question 6

what gender has a shorter urethra and what does this cause more of?

Answer 6

women have shorter urethra causing them to have higher risk of UTI

Question 7

what part of the kidneys make urine?
where does the renal artery come from/go to?
What about the renal vein?

Answer 7

renal cortex and renal medulla
-renal artery goes into kidney and is a branch of the descending aorta
-renal vein goes out of the kidney back to the inferior vena cav

Question 8

What does the afferent arteriole feed into?
What does the arcuate artery go around, what type of branching does it have?

Answer 8

-afferent arteriole feeds into glomerulus
-arcuate artery=going around cortex+medulla and has perpendicular branching towards surface

Question 9

What type of brancing is interlobar artery have, where does it feed into?
waht direction does venous system run relative to the arterial system?

Answer 9

-seconday branching that gives rise to small branch that feeds into glomerulus
-runs side by side in opp, direction

Question 10

How many nephrons are in kidney?
What does eac nephron consist of?

Answer 10

Nephron
* Each kidney contains ~1 million subunits called
nephrons.
* Each nephron consists of:
1.Renal corpuscle –>Glomerulus (capillary loops)
—>Bowman’s capsule
2.Tubule

Question 11

What is the glomerulus?
What is the renal corpuscle composed of?

Answer 11

-it is entangled capillaries
-Bowman’s capsule (parietal layer)
-Bowman’s space
-Bowman’s capsule (visceral layer: podocytes)

Question 12

Where does renin secretion occur?
Where are the podocytes, and what are they?

Answer 12

-in the juxtaglomerular apparatus
-podocytes are in the visceral layer of bowman’ capsule
-it ha many foot/finger like projections

Question 13

What are the layers of the glomerular capillary wall?
What can the fenestrations do?

Answer 13

-visceral glomerular epithelial cells (podocytes)
-glomerular Basement membrane
-fenetrated endothelial cells
-ions can freely filter due to the small size, so cells cannot filter like blood, albumin, and immunoglobin (should not show in urine)

Question 14

What are the components of the renal corpuscle and proximal tubules?

Answer 14

Renal corpuscle: Glomerulus and Bowman’s capsule in the cortex
Proximal tubule: Proximal convoluted tubule (PCT) in cortex, Proximal straight tubule (PST) (in cortex/medulla)

Question 15

What are the components of Henle’s loop and the distal convoluted tubules?
Where is each part located in the kidney

Answer 15

Henle’s loop: Descending thin limb, Ascending thin limb (in medulla), Thick ascending limb (in meduall/cortex), (macular densa at the end, in the cortex)
Distal convoluted tubule: Distal convoluted tubule (DCT) (in cortex)

Question 16

What are the component of the collecting duct?

Answer 16

Collecting duct: Cortical collecting duct (CCD) (in cortex)
Medullary collecting duct (MCD) (in medulla)

Question 17

Where does blood leave through from the glomerulus?
What do venules carry?
What do the peritubular capillaries serve ?

Answer 17

-afferent arteriole
-waste product/Co2
-they serve tubular like epithelial cells

Question 18

What are the 3 processes of urine filtration?
What process is crucial or else urine isnt made?

Answer 18

1.Glomerular filtration (without this urine isnt made)
2. Tubular secretion
3. Tubular reabsorption

Question 19

How does urine formation first start in glomerular filtration, what is first to get filtered and from where?

Answer 19

begins with the filtration of plasma from the glomerular capillaries into Bowman’s space (glomerular filtration).

Question 20

Where is glomerular filtrate, and what is it free of and contain?
What is its concentration similar to

Answer 20

Glomerular filtrate (fluid in Bowman’s space) is cell-free and doesnt have proteins,
-contains all the substances in plasma in virtually the same concentrations as in plasma besides for the proteins

Question 21

What alters the composition of glomerular filtration?

Answer 21

As the glomerular filtrate passes through the tubules, its composition is altered by movements of substances

Question 22

What is the definition of tubules and peritubular capillaries (secretion/absorption?
Where do peritubular capillaries eventually go to?

Answer 22

Tubules (tubular lumen)–> Peritubular capillaries (Reabsorption)
Peritubular capillaries (go into)–> Tubules (Secretion)
-peritbular capillaries eventually goes back into systemic circulation

Question 23

What is the formula for amount excreted in urine formation?

Answer 23

Amount excreted = amt filtered + amt secreted - amt reabsorbed

Question 24

What is an example of 100% ecretion?
What is an emaple of some secretion and some reabsorption?
What is an example of a substance that is 100% reabsorbed?

Answer 24

-Example para-amino-hippurate (PAH)
-example sodium, water
-example, glucose or small amino acids

Question 25

What rates are subject to physiological control?
What happens to excretion/reabsorption if someone drinks too much water?

Answer 25

The rate of filtration, reabsorption, or secretion is subject
to physiological control.
If a normal person drinks a lot of water, reabsorption
of water is decreased and excess water will be excreted in
the urine