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Flashcards in kidney structure & function Deck (26)
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1

what is the function of the kidneys?

excretory organs
process blood and rid the body of the waste products of metabolism via urine

2

what do the kidneys maintain the internal homeostasis of?

fluid & electrolytes-bp
acid/base
calcium/vit. D metabolism
erythropoietin

3

what is the basic anatomy of the urinary system?

2 kidneys-produce urine
ureters-convey urine
bladder-store
urethra-void urine

4

what is the cortex?

contains 85% of all kidney tubules-nephrons

5

what are the 3 distinct parts of the kidney (macroscopic)

cortex, medulla, pelvis

6

what is the medulla?

site urine is concentrated
prevents excess water loss

7

what is the pelvis?

collection area for urine which is funnelled into the ureter

8

describe the bv of the kidney

highly vascular
renal artery delivers blood from abdominal aorta
process 1.2L per min

9

what are the bv of the kidney?

interlobular arteries
afferent arterioles
glomerular capillaries
-glomerulus
efferent arterioles
peritubular capillaries
-vasa recta
interlobular veins

10

what is the nephron?

basic functional unit
filters blood plasma
excrete waste prod. of metabolism in urine
-cortical nephrons
-juxtamedullary nephrons

11

what are the components of a nephron?

glomerulus
bowman's capsule
proximal convoluted tubule
loop of henle
distal convoluted tubule
collecting duct

12

what is the renal corpuscle?

filtration
glomerulus & bowman's capsule

13

what is the renal tubule?

reabsorption and secretion
proximal convoluted tubule
loop of henle
distal convoluted tubule
collecting duct

14

what is the glomerulus?

network of fine capillaries
single layer endothelial cells resting on basement membrane
fenestrated
enables rapid filtration of blood plasma
surrounded by bowman's capsule

15

what is bowman's capsule?

cuplike structure surrounding glomerulus
bowman's space-in between layers
parietal-outer-layer
visceral-inner-layer comprised of specialised epithelium - podocytes

16

how is the filtration barrier formed?

long branched processes (pedicels) of podocytes wrap around glomerular capillaries
glomerular endothelium, basement membrane and pedicels form filtration barrier

17

what can move through the filtration barrier?

water and small molecules
not large proteins or cells

18

what determines which molecules are filtered through the filtration barrier?

size and charge of filtration

19

what are the 3 steps of glomerular filtration?

1. unfiltered blood arrives at glomerulus via afferent arteriole
2. blood components filtered though filtration barried
3. filtered blood exits glomerulus via efferent arteriole

20

what is hydrostatic pressure?

filtration facilitated by pressure gradient
afferent has wider diameter- so blood arrives faster than can leave

21

what is filtered?

water, glucose, amino acids, urea, creatinine, sodium, chloride, calcium, phosphate, potassium, bicarbonate

22

what is not filtered?

cells, large proteins eg. haemoglobin, negatively charged proteins eg. albumin

23

what is glomerular filtration rate? (GFR)

the rate at which blood is filtered through the glomerulus into the bowman's capsule
healthy =125ml/min

24

how is GFR mediated?

driven by glomerular hydrostatic pressure
counteracted by hydrostatic pressure in the bowman's capsule & glomerular osmotic pressure

25

what is GFR influenced by?

hydrostatic pressure
osmotic pressure
systemic bp
renin-angiotensin system
disease

26

how does GFR effect kidney function?

kidney damage reduces GFR
reduced GFR=inefficient blood clearance and waste removal
waste pro. accumulate in blood
serum creatinine (&urea) measurements used to estimate GFR