Kidney and renal function

Question 1

The kidneys and urinary tract have a critical role in which four areas?

Answer 1

Excretion and elimination of waste products
Homeostasis
BP regulation
Endocrine function

Question 2

What are the two main functions of the urinary system?

Answer 2

Excretion - removal of organic waste products

Elimination - Discharge of waste products into environment

Question 3

What are the three broad functions of the kidney?

Answer 3

Homestasis
Excretion
Regulation

Question 4

What does homeostasis help regulate in the kidneys?

Answer 4

Water and electrolyte balance

Acid-base balance

Question 5

What is excreted from the kidneys?

Answer 5

Drugs and their metabolites

Endogenous waste products

Question 6

The kidneys regulate and produce which hormones?

Answer 6

Erythropoietin
Renin
Prostaglandins
Active vit D

Question 7

What vertebral level are the kidneys located at?

Answer 7

T12 to L3

Question 8

What vertebral level is the renal hilum located at?

Answer 8

L2

Question 9

What is renal agenesis?

Answer 9

born with one kidney

1 in 1000/2000 people

Question 10

What are the two main layers of the kidney?

Answer 10

Cortex

Medulla

Question 11

What is the cortex of the kidney and what does it contain?

Answer 11

Outer region

Glomerulus and convoluted tubules

Question 12

What is the medulla of the kidney and what does it consist of?

Answer 12

Inner region
Pyramid-like structures
Consists of the bulk of the nephron structure

Question 13

What is the nephron?

Answer 13

functional unit of the kidney

Question 14

What is the nephron responsible for?

Answer 14

Urine formation/composition

Question 15

During the early stages of CKD, the kidney can lose up to 50% of what?

Answer 15

Nephrons

Question 16

What are the five distinct sections of the nephron?

Answer 16

Glomerulus 
Proximal Convoluted tubule
Loop of Henle - descending and ascending limb
Distal convoluted tubule 
Collecting duct

Question 17

What capsule contains the glomerulus?

Answer 17

Bowman’s capsule

Question 18

Where does filtration happen in the kidney?

Answer 18

Glomerulus

Question 19

Where does selective reabsorption happen in the nephron?

Answer 19

Proximal tubule

Distal tubule

Question 20

Where does osmoregulation happen in the nephron?

Answer 20

Loop of henle - salt gradient

Collecting duct - water retention

Question 21

What are the two types of nephrons?

Answer 21

Cortical

Juxtaglomerular

Question 22

Tubular fluid travels through the collecting ducts deep into what structure?

Answer 22

Inner medulla of kidney

Question 23

The tubular fluid that exits the collecting duct at the tip of the renal pyramid enters what?

Answer 23

Renal papilla

Question 24

Why is the renal papilla clinically important?

Answer 24

common site of drug induced nephrotoxicity

Can lead to renal papillary necrosis

Question 25

Which is the most abundant nephron?

Answer 25

cortical - 70-80%

Question 26

Where are cortical and juxtaglomerular nephrons located?

Answer 26

cortical - In the cortex | Juxtaglomerular - In cortex but closer to medulla

Question 27

What is the structural difference between cortical and juxtaglomerular nephrons?

Answer 27

Cortical - short loop of henle into medulla. Small glomerulus Juxtaglomerular - Loop of henle extends deep into renal pyramids. Large glomerulus and vasa recta.

Question 28

What is the juxtaglomerular apparatus and what does it secrete?

Answer 28

Specialised region associated with the nephron but separate from it. Secretes renin from macula densa within JGA

Question 29

Where is the juxtaglomerular apparatus located?

Answer 29

Between thick ascending limb and afferent arteriole

Question 30

What are the three components to the juxtaglomerular apparatus?

Answer 30

Macula densa Juxtaglomerular cells Extraglomerular mesangial cells

Question 31

What are the main glomerular diseases?

Answer 31

Diabetic nephropathy Glomerulonephritis IgA Nephropathy

Question 32

What are the main renal tubular diseases?

Answer 32

Acute tubular necrosis Glomerulonephritis IgA Nephropathy

Question 33

What is the blood supply to the kidney?

Answer 33

Blood from renal artery Into afferent arteriole to glomerulus Exit through efferent arterioles into peritubular capillaries wrapped around tubules Peritubular capillaries form vasa recta Blood leaves through venues into renal vein

Question 34

The kidneys receive what percentage of cardiac output?

Answer 34

20-25%

Question 35

90% of blood in the kidneys supplies what?

Answer 35

The renal cortex

Question 36

Why does the majority of blood in the kidneys supply the renal cortex?

Answer 36

To maintain high active tubular cells. | Required for energy-consuming transport processes

Question 37

What is the major function of the cortical nephrons?

Answer 37

Regulate and excrete

Question 38

What is the major function of the juxtaglomerular nephrons?

Answer 38

Concentrate or dilute urine

Question 39

How does the sympathetic nervous system innervate the kidneys?

Answer 39

From the sympathetic chain and fibres from coeliac ganglion

Question 40

What parts of the kidneys are innervated by the coeliac ganglion and what does this cause?

Answer 40

Arteries - afferent and efferent arterioles and granular cells Reduces blood supply during fight or flight

Question 41

What can the sympathetic supply to the kidneys be associated with?

Answer 41

HTN

Question 42

How does the parasympathetic nervous system innervate the kidneys?

Answer 42

Efferent supply from vagus | ganglion located in hilum

Question 43

What does the vagus nerve control in the kidneys?

Answer 43

Tone of efferent arterioles | Modifies GFR and renal blood flow

Question 44

Where is erythropoietin and prostaglandin produced within the kidneys?

Answer 44

Interstitium surrounding glomerulus

Question 45

what is the glomerular filtration barrier?

Answer 45

4 physical barriers ultra filtrate has to go through before it can enter lumen of bowman capsule

Question 46

What are the four barriers in the glomerular filtration barrier?

Answer 46

Glycocalyx Capillary endothelium Glomerular basement membrane Podocyte foot processes

Question 47

What is glomerular filtration dependent on?

Answer 47

Blood pressure | Renal blood flow

Question 48

For glomerular filtration, the filtrate has to pass through what?

Answer 48

Pores in glomerular capillary endothelium BM of Bowman's capsule (+ contractile mesangial cells) Epithelial cells of Bowman's capsule (Podocytes) via filtration slits in capsular space

Question 49

How does filtrate pass through podocytes?

Answer 49

Through filtration slits

Question 50

Can proteins pass through the glomerular barrier?

Answer 50

No

Question 51

Where are mesangial cells located?

Answer 51

Centre of glomerulus

Question 52

What is the role of mesangial cells?

Answer 52

Phagocytic - clear Ag/Ab complexes | Contract due to AT II and ADH -> reduces GFR by reducing filtration surface

Question 53

What is the initial step in urine formation?

Answer 53

Glomerular filtration

Question 54

Examples of small molecules <60 KDa filtered through the glomerulus?

Answer 54

``` Electrolytes Amino acids Glucose Metabolic waste Some drugs + metabolites ```

Question 55

Examples of molecules that cannot be filtered through glomerulus and remain in the blood?

Answer 55

``` Cells and large molecules RBC Lipids Proteins Most drugs + metabolites ```

Question 56

What is the basic structure of a nephron?

Answer 56

``` Glomerulus Proximal convoluted tubule Loop of henle Distal convoluted tubule Collecting duct ```

Question 57

What is ultrafiltration?

Answer 57

Solution moves via a pressure gradient

Question 58

What is the approx glomerular filtration rate?

Answer 58

125ml/min = 180L/day

Question 59

Does GFR change with blood pressure?

Answer 59

No remains constant due to autoregulation of renal blood flow

Question 60

What metabolite is affected first in AKI?

Answer 60

Creatinine

Question 61

Which marker would you use in CKD as an indicator for renal function?

Answer 61

GFR

Question 62

What are the three major functions of the nephron?

Answer 62

Filtration - of blood to produce filtrate Reabsorption from filtrate Secretion - of waste products into tubular fluid

Question 63

What is transcellular transport?

Answer 63

Passive or active transport through channels | Many passive secondary to active transport

Question 64

What is paracellular transport?

Answer 64

Movement driven by concentration, osmotic or electrical gradients Through tight junctions between cells

Question 65

Some endogenous substances and drugs cannot be filtered into glomerulus due to size/protein binding. How do these substances get into the nephron?

Answer 65

Pumps in proximal convoluted tubule transports from plasma into nephron

Question 66

What are the two types of pumps in the proximal convoluted tubule for?

Answer 66

Organic acids or drugs (uric acid, diuretics, abx) | Organic bases or drugs (creatinine, procainamide)

Question 67

Where is the majority of water reabsorbed in the nephron?

Answer 67

Proximal convoluted tubule

Question 68

How is H20 reabsorbed into the tubules?

Answer 68

Passively along osmotic gradient created by solute (Na+) | Reuptake via aquaporins

Question 69

What % in total of electrolytes, H2O and nutrients are reabsorbed by the renal tubules?

Answer 69

99%

Question 70

What is the Glomerular Filtration Rate?

Answer 70

Rate the glomerulus filters per minute

Question 71

What is osmosis?

Answer 71

Movement of water by concentration gradient

Question 72

What is diffusion?

Answer 72

Movement of solute by concentration gradient

Question 73

What do epithelial cells in the glomerular basement membrane of the glomerular filtration barrier secrete?

Answer 73

Collagen | Glycoproteins

Question 74

What type of capillaries in the glomerulus helps facilitate filtration? (Continuous, fenestrated, or sinusoidal)

Answer 74

Fenestrated

Question 75

How many loops are in the glomerulus?

Answer 75

40

Question 76

What arteriole runs alongside the juxtaglomerular nephron to accommodate the longer loop of henle and supplies blood to the medulla?

Answer 76

Vasa recta

Question 77

What is the main blood supply to the kidneys?

Answer 77

Renal artery

Question 78

What problems can a reduced kidney function cause?

Answer 78

Anaemia - Reduced erythropoietin Hypotension - reduced renin Bone loss/fragility - Reduced Vit D Toxin accumulation - uraemia