Urinary System 1

Question 1

Name the 4 main components that make up the Urinary System

Answer 1

kidneys (2)
ureters (2)
Urinary bladder
urethra

Question 2

Give the main function of the urinary system

Answer 2

maintaining homeostasis by controlling composition and volume of blood

Question 3

Describe the 3 main roles of the kidneys

Answer 3

remove waste, control blood pH, regulate blood pressure

Question 4

Describe the external structure of the kidneys

Answer 4

bean-shaped, reddish in colour, retro-peritoneal between levels T12-L3, protected by 11th & 12th ribs, right kidney is slightly lower, 10cm x 5cm x 3cm, upper pole of each kidney = closer to spine, convex lateral border, concave medial border where the hilus is found - where the ureter, blood vessels, lymph and nerve supply enter and leave the kidney

Question 5

Describe the internal structure of the kidneys

Answer 5

surrounded by a fibrous capsule and made up of outer cortex and inner medulla, medulla house renal pyramid which form collecting ducts, renal cortex and renal pyramids make up the parenchyma - ‘functioning’ portion of kidney - houses the nephrons - regulate blood composition and produce filtrate

Question 6

Describe what happens to the filtrate

Answer 6

drains through large papillary ducts from the nephrons, through the renal papillae of the renal pyramids into cup like extensions called calyces, filtrate drains firstly into the minor calyces (8-18) and then onto the major calcyes (3)

this route allows for reabsorption of water for the body’s needs, once filtrate enters the calyces it becomes urine as no further reabsorption will take place

Question 7

Describe where the calyces open into

Answer 7

open into the renal pelvis where the ureter leaves the kidney

Question 8

Describe nephrons

Answer 8

the ‘functional’ unit of the kidney, consist of a renal corpuscle where blood plasma is filtered and the renal tubule in which the filtered fluid passes

Question 9

Describe the renal corpuscle of the nephrons

Answer 9

made up of a glomerulus (capillary network) and Bowman’s capsule or glomerular - double walled epithelial cup which surrounds the glomerular capillaries, blood passes through the capillary network and is filtered into the tubule

Question 10

Give the tubule route taken by the filtrate

Answer 10

through the proximal convoluted tubule (PCT) > into loop of Henle > returns to distal convoluted tubule (DCT) > collecting ducts > papillary ducts > minor calcyes > major calyces > renal pelvis > ureter > leaves kidney

Question 11

The glomerulus and the PCT & DCT all lie in the …

Answer 11

cortex of the kidney

Question 12

The loop of Henle (descending and ascending limbs) lie in the …

Answer 12

medulla

Question 13

Describe where glomerular filtration occurs

Answer 13

in the glomerular capillaries within the Bowman’s space

Question 14

Which parts of the renal tubule does the filtrate pass through

Answer 14

passes through the PCT, loop of Henle and DCT of renal tubule

Question 15

close contact between the capillary network and the tubule allows …

Answer 15

for reabsorption and secretion to take place effectively

Question 16

Describe the role of microvilli

Answer 16

the tubule wall is made up of microvilli to increase the surface area for the reabsorption and secretion

Question 17

Describe what the reabsorption is

Answer 17

99% water and useful solutes, which are returned to the bloodstream

Question 18

What does the tubule secrete

Answer 18

waste, drugs and excess ions for excretion

Question 19

Describe the reabsorption of glomerular filtrate

Answer 19

within the renal tubule it is very effective

Question 20

glomerular filtration can be altered depending on …

Answer 20

the needs of the body

Question 21

Describe glomerular blood pressure in the renal tubule

Answer 21

its greater than elsewhere in the body thereby increasing the potential for filtration across the membranes

Question 22

Describe how the surface area can be changed in the renal tubule

Answer 22

cell walls can contract or relax altering the surface area available for filtration/reabsorption
when the cell walls are constricted there is less of a s.a. = rate of filtration is decreased

Question 23

Describe the Glomerular Filtration Rate (GFR)

Answer 23

this is the amount of filtrate formed in the renal corpuscles, 125ml/min = males
105ml/min = females

Question 24

Describe what happens if the GFR is too low/too high

Answer 24

GFR too high = substances needed by the body may pass through too quickly for reabsorption to take place
GFR too low = nearly all the filtrate will be reabsorbed, so waste products will not be excreted into the urine

Question 25

Describe how GFR can be affected

Answer 25

severe blood less causes arterial BP reduction, which causes lowering of the GFR - if pressure falls below 45mmHg = filtrations ceases GFR can be affected by altering blood flow in and out of the glomerulus and altering capillary surface available for filtration

Question 26

Describe GFR regulation in muscular contraction

Answer 26

BP rises > GFR rises > causes afferent renal arteriole wall to stretch > stretch receptors in these walls activate the smooth muscles > they contract > lowering renal blood flow > reduces GFR

Question 27

Describe GFR regulation in association with Nitric oxide dilation

Answer 27

greater BP causes rise in renal blood flow = absorption of Na and Cl ions is reduced as less time for reabsorption, less Na and Cl ions inhibits release of Nitric Oxide (NO), NO causes vasodilation so therefore due to a reduction in NO levels > reduced vasodilation, more vasoconstriction > less blood flow > allowing time for reabsorption

Question 28

Describe GFR regulation in association with hormones

Answer 28

Angiotensin II causes vasoconstriction of arterioles = reduces GFR Atrial Natriuretic Peptide (ANP) relaxes capillary surface causing vasodilation with a greater surface area for filtration = increases GFR

Question 29

Describe the tubular reabsorption within the PCT

Answer 29

majority of the reabsorption is of glucose, amino acids, urea, sodium, potassium and calcium ions

Question 30

Describe the role of reabsorption further on in the tubule

Answer 30

maintains homeostasis by fine tuning the balance of ions etc. pH is maintained by controlling reabsorption of H ions

Question 31

Describe water reabsorption

Answer 31

takes place through osmosis although anti-diuretic (ADH) affects the final 10% reabsorption dependent on the needs of the body

Question 32

Describe what materials are removed from the blood and excreted

Answer 32

potassium, hydrogen, ammonium, urea creatine and drugs

Question 33

what % of water is reabsorbed through osmosis

Answer 33

90%

Question 34

what % of reabsorption/secretion is ADH regulated depending on bodily needs

Answer 34

10%

Question 35

Describe what happens when there is no ADH

Answer 35

dilute urine as renal tubules absorb more solutes than water

Question 36

Describe what happens when there is ADH

Answer 36

concentrated urine means more water reabsorbed than solutes

Question 37

Describe the main role of ADH in filtration/secretion/reabsorption

Answer 37

to make sure optimum concentration of urine is produced

Question 38

Name 6 things which could be potentially present in urineand why

Answer 38

``` Albumin Glucose RBCs Ketones Urobilinogen Microbes ```

Question 39

Describe if albumin was in urine

Answer 39

not normally present as its too large for normal filtration, traces would indicate damage to the renal membranes allowing increased permeability - could be raised BP or toxic influence

Question 40

Describe if glucose was in urine

Answer 40

diabetes mellitus or stress causes release of Epinephrine which stimulates breakdown of glycogen in liver to make glucose

Question 41

Describe if RBCs was in urine

Answer 41

inflammation of kidney cells, presence of kidney stones or trauma

Question 42

Describe if Ketones was in urine

Answer 42

diabetes mellitus, anorexia, starvation, reduced carbohydrate intake

Question 43

Describe if Urobilinogen was in urine

Answer 43

this is the breakdown of Hb, result of liver disease, CCF and bilary obstruction

Question 44

Describe if microbes was in urine

Answer 44

infections affecting urinary tract