Intro to Kidney Flashcards Preview

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Flashcards in Intro to Kidney Deck (27)
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1
Q

What are the functions of the kidney?

A

1) Regulate body fluid volume
2) Regulate body fluid composition
3) Excrete metabolic waste and toxins
4) Endocrine functions

Key processes are filtration, reabsorption and secretion to eventually form urine which is excreted.

2
Q

What is a uriniferous tubule?

A

Uriniferous tubule = nephron + collecting duct

Many nephrons drain into the same collecting duct

3
Q

What is a nephron?

A

Nephron is a functional unit of kidney

Nephron = renal corpuscle + proximal convoluted tubule (PT) + Loop of Henle + distal convoluted tubule (DT)

~1 million per kidney

Many nephrons drain into the same collecting duct

4
Q

What is the cortex made up of?

A

Mostly renal corpuscles, PT and DT

5
Q

What is the medulla made up of?

A

Mostly loops of Henle and collecting ducts

6
Q

What are the 2 different types of nephrons?

A

Cortical (~80%) or juxtamedullary (~20%) depending on position of renal corpuscle

7
Q

What is the renal corpuscle made up of?

A

Glomerulus + Bowman’s capsule

8
Q

Describe the blood supply to the kidneys

A

Renal artery –> Segmental arteries –> Interlobar arteries –> Arcuate arteries (run along corticomedullary junction) –> Interlobular arteries (give off afferent arterioles to the renal corpuscles)

9
Q

Describe the two capillary beds that blood to the kidney passes through

A

1) High pressure glomerular capillaries (filtration)

2) Low pressure peritubular capillaries (reabsorption/secretion)

10
Q

Describe the two layers of the Bowman’s capsule

A

Outer layer = parietal layer
Containment -> Simple squamous

Inner layer = visceral layer
Filtration -> Modified simple squamous (podocytes)

11
Q

What are mesangial cells?

A

Mesangial cells provide support between the glomerular capillary loops

12
Q

Why is there an arteriole at either end of glomerular capillary bed?

A

Allows high pressure for filtration

13
Q

What is the filtration barrier formed by?

A

1) Glomerular capillary endothelium (fenestrated)
2) Basement membrane (negative charge)
3) Epithelial cells (podocytes) (interdigitating foot processes and filtration slits)

Limits passage of substances from blood based on their size, charge and shape

14
Q

What type of filtrate is found in the proximal convoluted tubule?

A
  • Unmodified filtrate
  • Majority of water, sodium, chloride, amino acids, glucose reabsorption takes place here
  • Secretion of some drugs and waste molecules
15
Q

What type of cells are found in the proximal convoluted tubule?

A

Simple cuboidal cells with microvilli forming a ‘brush border’ to increase surface area

16
Q

Describe the thin descending limb of loop of Henle

A

Permeable to water - no active reabsorption or secretion of solutes

Simple squamous epithelium

17
Q

Describe the thin ascending limb of loop of Henle

A

Impermeable to water.

Essentially no active reabsorption or secretion of solutes

Simple squamous epithelium

18
Q

Describe the thick ascending limb of loop of Henle

A

Impermeable to water.

Active reabsorption of sodium and other solutes.

Simple cuboidal cells

19
Q

Describe the distal convoluted tubule

A

Divided into early and late parts

Active reabsorption of sodium and other solutes; secretion of potassium and hydrogen ions

Simple cuboidal cells

Variable water permeability depending on precise part of distal tubule and presence of antidiuretic hormone (ADH)

Early distal tubule passes back to the vascular pole of its own renal corpuscle to form part of juxtaglomerular apparatus

20
Q

What is the purpose of the juxtaglomerular apparatus (JGA)?

A

Involved in tubuloglomerular feedback and control of blood pressure

21
Q

What are the three components to the juxtaglomerular apparatus (JGA)?

A

1) Macula densa - specialised cells within part of early distal tubule that passes next to the vascular pole of its own renal corpuscle
2) Extraglomerular mesangial cells (Lacis cells)
3) Granular or juxtaglomerular cells in afferent artieriole

22
Q

Describe the medullary collecting duct

A

Final site for urine processing

Water permeability of this part of nephron under hormonal control by antidiuretic hormone (ADH)

Surrounded by a medullary interstitium with a high concentration of solutes

Key role in regulating degree of urine concentration

Simple columnar cells

23
Q

How much of the body weight is water?

A

~60% of body weight

Varies with age, gender and body fat

24
Q

What are the main cations and anions in Extra Cellular Fluid?

A

Na+ is main cation

Cl- is main anion

25
Q

What are the main cations and anions in IntraCellular Fluid?

A

K+ is main cation

PO4 is main anion

26
Q

Define osmosis

A

Osmosis is movement of water across a semi-permeable membrane from an area of low solute concentration to a region of high solute concentration

27
Q

Define osmoles

A

Osmoles refers to the number of osmotically active particles in a solution