Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Kidneys > Functional histology of the kidney > Flashcards

Functional histology of the kidney Flashcards

1
Q

Main function of the urinary system?

A

Homeostasis of blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does the urinary system regulate the homeostasis of?

A
  • Plasma composition: by regulated excretion of water, ions and organic waste products into urine.
  • Blood pressure: through the enzyme renin
  • RBC content: through secretion of erythropoietin.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What percentage of cardiac output does the Kidneys receive?

A

25%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Purpose of Dialysis machine?

A

Mimics kidney role

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Key parts of the kidney

A
  • cortex
  • renal artery
  • renal vein
  • ureter
  • capsule
  • medulla (divided into pyramids)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is observed within the cortex?

A

Medullary rays: tubes forming this is in a way part of the medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Difference observed between foetal and adult kidney

A

Foetal kidney is more bumpy that adults’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define Nephron

A

The functional unit of the kidney - where blood is filtered at the molecular level (dialysis), to produce urine, while retaining cells and large proteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many Nephrons in each human kidney?

A

About 1 million Nephrons in each human kidney.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Order of parts of the Nephron

A
  1. Bowman’s capsule
  2. Glomerulus
  3. Proximal convoluted tubule
  4. Loop of Henle: thin arm
  5. Loop of Henle: thick arm
  6. Distal convoluted tubule
  7. Collecting duct
  8. Papilla
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the Papilla?

A

This is where the kidney drains into the ureter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the glomerulus

A
  • Site of ultrafiltration (filtration/dialysis of blood through extremely fine molecular filter)
  • A knot of capillaries
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the capillaries in the kidney?

A
  • 50-100 nm

- Fenestrations shows ‘windows’ on the capillary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Pressure in the afferent arteriole?

A

High

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Pressure in the efferent arteriole?

A

Low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Three sites of filtration?

A
  1. Fenestration wall
  2. Joint basement membrane
  3. Podocyte layer itself
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Ultrafiltration definition

A

Molecular filtration through molecular membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Difference between most capillaries in the body and capillaries in the kidney?

A

Most capillaries in the body aren’t fenestrated, but in the kidney they are.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the basement membrane?

A

made by endothelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the podocyte layer made out of?

A

A single-celled simple epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why does fluid move from the glomerulus into the space in the bowman’s capsule?

A

Because of greater pressure in the arterioles, the fluid moves out into the space in the bowman’s capsule.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe movement of fluid during the process of ultrafiltration

A

SEE NOTES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the three layers of the glomerular filter?

A

1) Cytoplasm of capillary endothelial cells
2) Thick, fused basal lamina
3) Filtration slit membranes (with ~4nm pores)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the filter cut-off value?

A

~70 kDa (e.g. albumin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Describe the three layers in 3D view

A

SEE NOTES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What happens to the glomeruli when a patient has nephrotic syndrome?

A
  • Glomerular basement
    membranes become damaged and more leaky – so proteins lost in urine (proteinuria).
  • In one type, the basement membranes become visibly thickened, thought to be through deposition of immunoglobulins (autoimmunity).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What happens to the glomeruli when there is high blood pressure?

A

Some glomeruli destroyed and replaced by masses of clear “hyaline” materia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is Hyaline?

A

Clear material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the function of proximal convoluted tubule?

A

Reabsorption from ultra filtrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is pinocytosis?

A

The ingestion of liquid into a cell by the budding of small vesicles from the cell membrane.

31
Q

By what three means does reabsorption from ultrafiltrate occur?

A
  1. By active transport across membrane into cell: small molecules like Na+, glucose, amino acids
  2. By pinocytosis: macromolecules, especially proteins. These broken down in lysosomes and returned to blood.
  3. By passive flux: water, Cl-
32
Q

Describe structures of the proximal convoluted tubule

A
  • Long microvilli
  • Lytic enzymes on surface
  • Many lysosomes
  • Many mitochondria
33
Q

How are microvilli adapted to carry out function in the PCT?

A
  • Long microvilli for high surface area for reabsorption

- Lytic enzymes on surface to break down macromolecules in the lumen

34
Q

How are lysosomes adapted to carry out function in the PCT?

A
  • There are many lysosomes to break down macromolecules
  • endocytotic vesicles can fuse with lysosomes and be further broken down into single amino acids, which can be transported into the blood
35
Q

How are mitochondrion adapted to carry out function in the PCT?

A

There are many mitochondria to fuel active transport (especially located near the basolateral sodium pumps)

36
Q

What is the basolateral membrane made out of?

A
  • The basolateral membrane of unpolarized cell is the surface of the plasma membrane that forms its basal and lateral surfaces
  • It faces outwards, towards the interstitial and away from the lumen
37
Q

Functions of the loop of Henle?

A
  • Reabsorption of water and salts from filtrate: passive flux across epithelium, by osmosis and concentration gradients
38
Q

What is the ion gradient set by in the Loop of Henle?

A

The countercurrent multiplier system

39
Q

What is countercurrent multiplication in the kidneys?

A

The process of using energy to generate an osmotic gradient that enables you to reabsorb water from the tubular fluid and produce concentrated urine

40
Q

Describe the structure of the epithelial cell in the thin loop of Henle

A
  • Thin squamous epithelium to allow passive fluxes
  • A minimum of organelles
  • Not a lot of mitochondria present like other cells
41
Q

Functions of the DCT?

A
  • Homeostasis by regulated active transport & exchange of ions
  • Na+/K+,H+/HCO3-
42
Q

Function of thick ascending loop of Henle?

A
  • Similar structure to DCT
  • Finished with regulation of macromolecules earlier on in the nephron
  • this part of the nephron focuses mainly on the ions
  • regulating pH of the plasma
43
Q

Describe the structures of the DCT, and how they are adapted to carry out their functions?

A
  • Cuboidal epithelium: thicker than squamous to reduce passive fluxes and accommodate organelles
  • Few, short microvilli (unlike PCT)
  • Many mitochondria to form active transport, mainly at the base of the cell
44
Q

How are the mitochondria observed in an epithelial cell on the DCT?

A

These are mainly basal and can show as a pale or striped basal area in H&E-stained sections.

45
Q

Describe the functions of the Collecting duct

A
  • Transport of urine to ureter
  • Water homeostasis: using ionic gradients passive reabsorption of water
  • This is regulated through epithelial permeability (the channels allowing water to move across)
46
Q

Describe the structure of a collecting duct epithelial cell

A
  • Cuboidal to columnar epithelium, to prevent passive flux of water (and urea etc)
  • Specialized dense membranes at cell contacts (probably to help prevent massive passive flux)
47
Q

What is distinguishable about the membranes of the collecting duct epithelial cell?

A

You can see the cell membranes between the cells – you can’t see them in cell membranes of other types of epithelium:

  • These membrane probably have more proteins
  • They have junctions that are very impermeable and stop water moving between the cells: so the water has to cross the cell and be regulated
48
Q

What happens to the cells as you move down the collecting duct?

A

The cells get taller and more impermeable to the water crossing it

49
Q

What are some differences observed between the lumen of the PCT and DCT cells (under light microscope)?

A
  • Distal has a visible lumen
  • Proximal has a lumen filled with proteins by the time it’s fixed and stained: so the protein that hasn’t been absorbed yet: lumen hard to see + microvilli make the border hard to see
50
Q

What are some differences observed between DCT cells and PCT cells?

A

DCT: cells paler, tubule & cells smaller, lumen smoother
- clear lumen

PCT: bigger tubules and cells, wispy material in the lumen (fixed protein)
- fizzy lumen

51
Q

What is the juxtaglomerular apparatus?

A

A specialized structure formed by the distal convoluted tubule where it loops back to meet the glomerular afferent arteriole of the same nephron

52
Q

Where is the juxtaglomerular apparatus located?

A

Located near the vascular pole of the glomerulus

53
Q

What is the main function of the juxtaglomerular apparatus?

A

Main function is to regulate blood pressure and the filtration rate of the glomerulus.

54
Q

What is different about the macula densa cells?

A
  • In the DCT

- crowded patch of cells, that are taller and thinner than the other cells (in cross-section).

55
Q

Role of juxtaglomerular cells?

A

Smooth muscle cells that are modified and located on the outside of the arteriole

56
Q

What is Renin?

A

A hormone that helps to regulate blood pressure

57
Q

What are Lacis cells?

A

The function for these is unclear, but they are thought to play a role in communication between the macula densa and the juxtaglomerular cells

58
Q

How do the macula densa and juxtaglomerular cells work together?

A
  • The macula densa senses [Na+] in the DCT fluid
  • it appears to signal to the JCs
  • The JCs release renin in response to lower [Na+] in the DCT
  • Renin indirectly increases vascular tone and sodium reabsorption
59
Q

What does Extraglomerular mean?

A

Outside the glomerulus

60
Q

What is mesangial tissue?

A

A sort of connective tissue

61
Q

What are mesangial cells?

A

Contractile cells that constitute the central stalk of the glomerulus

62
Q

What is needed in order for the renin granules to be observed under microscope?

A

A special stain

63
Q

What is observed from a transverse section of the Urea (under low magnification)?

A
  • lining of the ureter
  • transitional epithelium
  • dense connective tissue (lamina propria)
  • layers of the smooth muscle
  • adventitia
64
Q

What can the ureter change according to volume of urine?

A
  • The ureter is able to expand when a lot of urine is coming through
  • Collapse when a lot of urine isn’t coming through.
  • Ureter is actually contractile
65
Q

Peristalsis in the ureter

A

You get waves of contractions pass along the ureter to the bladder

66
Q

What is transitional epithelium?

A

A special stratified epithelium, found only in ureters and bladder

67
Q

What are adaptations of the structure of transitional epithelium to its function?

A
  • Specialized to be impermeable to urine.
  • Changes appearance on stretching
  • Somewhat like stratified squamous epithelium (SSE) when distended,
68
Q

Difference between apical and basal cells?

A
  • Apical cells are biggest and have much apical cytoplasm

- Basal cells are the smallest

69
Q

Function of plaques when bladder distended (bladder full)?

A

These impermeable, rigid membrane patches (plaques) protect apical cells from toxic urine.

70
Q

Function of plaques when bladder contracted (bladder empty)?

A

The rigid plaques are invaginated forming pits and vesicles in the cell, allowing cell surface area to decrease.

71
Q

Where are plaques located?

A

Plaques of specialized (urine-resistant) plasma membrane in apical cells of transitional epithelium

72
Q

Why are urinary infections quite common?

A

Transitional epithelium highly impermeable: leukocytes of immune system cannot readily penetrate.
- The bacteria can therefore multiply without any immune reaction

73
Q

Why are UTIs more commoner in females?

A

Female urethra shorter. More risk of contamination, e.g. from anal region.

74
Q

Advice on prevention of UTIs?

A
  • drink plenty of fluid, to wash the infection away
  • the more you drink the more fluid that flows through the bladder
  • otherwise antibiotics can be used

Kidneys (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions