L16 - urinary system

Question 1

The principal role of the kidneys is to control the levels of body constituents and metabolic waste products. This requires the kidneys ‘to filter’, actually 3 processes:

Answer 1

filtration,
reabsorption and secretion from the plasma
and excrete the excess essential body constituents and metabolic waste products.

Question 2

Nerki odpowiedzialne są za regulacje (5):

Answer 2

blood ionic composition,
blood pH
blood volume
blood pressure
blood glucose level

Question 3

Kidneys are responsible for production, maintenance and excretion of (3):

Answer 3

• Production of hormones (calcitrol and erythropoietin)
• Maintenance of blood osmolarity
• Excretion of wastes from metabolic reactions and foreign substances (drugs or toxins)

Question 4

• Although kidneys constitute less than … of total body mass, they receive …. of resting cardiac output

Answer 4

0.5%,20-25%

Question 5

• Each nephron receives …

Answer 5

one afferent arteriole

Question 6

Renal nerves are part of …..nervous system

• Most are …. regulating …

Answer 6

the sympathetic autonomicvasomotor nerves blood flow

Question 7

Nephrons consist of (2):

Answer 7

Renal corpuscle – filters blood plasma

Renal tubule – filtered fluid passes into its components

Question 8

Renal corpuscle – filters blood plasma (2):

Answer 8

• Glomerulus – capillary network

* Glomerular (Bowman’s) capsule – double-walled cup surrounding glomerulus

Question 9

Renal tubule – filtered fluid passes into (3):

Answer 9

• Proximal convoluted tubule
• Descending and ascending loop of Henle (nephron loop)
• Distal convoluted tubule

Question 10

• Cortical nephrons – …. of nephrons

Answer 10

80-85%

Question 11

Cortical nephrons (opisz renal corpuscle):

Answer 11

• Renal corpuscle in outer portion of cortex and short loops of Henle extend only into outer region of medulla

Question 12

• Juxtamedullary nephrons – … of nephrons

Answer 12

20-25%

Question 13

Juxtamedullary nephrons (opisz renal corpuscle):

Answer 13

• Renal corpuscle deep in cortex and long loops of Henle extend deep into medulla
• Receive blood from peritubular capillaries and vasa recta
• Ascending limb has thick and thin regions
• Enable kidney to secrete very dilute or very concentrated urine

Question 14

Opisz Glomerular (Bowman’s) capsule (3)

Answer 14

• Visceral layer
• Parietal layer
• Fluid filtered from glomerular capillaries

Question 15

(Glometular (Bowman’s) capsule) Visceral layer has…

Answer 15

has podocytes that wrap projections around single layer of endothelial cells of glomerular capillaries and form inner wall of capsule

Question 16

(Glometular (Bowman’s) capsule) Parietal layer forms ….

Answer 16

forms outer wall of capsule

Question 17

(Glometular (Bowman’s) capsule) Fluid filtered from glomerular capillaries enters …

Answer 17

enters capsular (Bowman’s) space

Question 18

Proximal convoluted tubule cells have …, which …

Answer 18

microvilli with brush border, increases surface area

Question 19

Juxtaglomerular apparatus składa się z (2):

Answer 19

Macula densa, Juxtaglomerular cells

Question 20

Juxtaglomerular apparatus helps….. in kidney

Answer 20

regulate blood pressure

Question 21

Macula densa –

Answer 21

cells in final part of ascending loop of Henle

Question 22

Juxtaglomerular cells –

Answer 22

cells of afferent and efferentarterioles contain modified smooth muscle fibers

Question 23

Parts of distal convoluted tubule and collecting duct (3)

Answer 23

1. Proximal convoluted tubule cells
2. Juxtaglomerular apparatus (Macula densa, Juxtaglomerular cells)
3. Last part of distal convoluted tubule andcollecting duct (Principal cells, Intercalated cells)

Question 24

Last part of distal convoluted tubule andcollecting duct składa się z (2):

Answer 24

• Principal cells – receptors for antidiuretic hormone(ADH) and aldosterone
• Intercalated cells – role in blood pH homeostasis

Question 25

Opisz Glomerular filtration:

Answer 25

Water and most solutes in blood plasma move across the glomerular capillaries wall into the glomerular capsule and then the tubule

Question 26

Opisz Tubular reabsorption:

Answer 26

As filtered fluid moves along tubule and through collecting duct, about 99% of water and many useful solutes reabsorbed – returned to blood

Question 27

Opisz Tubular secretion:

Answer 27

As filtered fluid moves along tubule and through collecting duct, other material secreted into fluid such as wastes, drugs, and excess ions – removessubstances from blood

Question 28

Renal Blood flow determines....

Answer 28

glomerular filtration rate (GFR).

Question 29

The most common cause of renal failure is ...

Answer 29

Reduction of renal blood flow

Question 30

total blood flow [i.e. to both kidneys] is.... l/minthat’s .... resting cardiac output

Answer 30

1.25, 25%

Question 31

renal blood flow remains constant if arterial BP (blood pressure) is altered [between.....mmHg]

Answer 31

80-200

Question 32

Renal blood flow remains constant even when renal nerves are cut (therefore intrinsic control). What are the mechanisms of auto regulation?

Answer 32

1. Myogenic hypothesis 2. Tubuloglomerular hypothesis 3. Metabolic hypothesis

Question 33

Renal blood flow is autoregulated by varying RVR, i.e. + rozwinięcie skrótu

Answer 33

renal vascular resistance, i.e. the resistances of the afferent and efferent arterioles.

Question 34

Myogenic Hypothesis (7):

Answer 34

Response of renal afferent arterioles to stretch 1. Increase in perfusion pressure 2. Distension of afferent arteriole wall 3. Smooth muscle fibres stretch 4. Smooth muscle fibres then contract [vasoconstriction] 5. Increases vascular resistance 6. Decreases blood flow 7. Smooth muscle relaxes

Question 35

Tubuloglomerular Hypothesis (4):

Answer 35

1. GFR is originally increased if renal perfusion pressure is raised. 2. In consequence filtrate flow rate through the nephron increases. 3. The raised flow causes a factor to be released from the juxta-glomerular apparatus (renin?). 4. This increases afferent arteriolar resistance. Flow and therefore GFR are normalised

Question 36

Metabolic hypothesis (4):

Answer 36

Renal tissue metabolites maintain a degree of vasodilation 1. Increase in perfusion pressure. 2. Increase in blood flow. 3. Leaching out of metabolites from renal tissue. 4. Decrease in vasodilation (vasoconstriction).Humoral factors derived from vascular endothelium i.e. NO may act as vasodilators.

Question 37

How else is renal blood flow controlled? (extrinsic factors) (2)

Answer 37

1. Renal nerves (sympathetic and parasympathetic) 2. Humoral factors in the blood- adrenaline/noradrenaline = vasoconstriction (in cortex)- vasopressin = vasoconstriction (next lecture)

Question 38

renal blood flow control extrinsic factor: Renal nerves (sympathetic and parasympathetic) (2):

Answer 38

- sympathetic stimulation = vasoconstriction of afferentarterioles- parasympathetic = vasodilation

Question 39

renal blood flow control extrinsic factor: Humoral factors in the blood (2):

Answer 39

- adrenaline/noradrenaline = vasoconstriction (in cortex)- vasopressin = vasoconstriction