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Flashcards in Renal Histology Deck (115):
1

the urinary system consists of

- two kidneys and ureters
- the urinary bladder and urethra

2

Each kidney has somewhat of an ____ shape with a _____ lateral border and a slightly _____ or_____ medial border through which pass the renal artery, vein, and the ureter

oval shape, convex lateral border, concave or indented medial border.

3

A sagittal section of the kidney reveals what structures

-an outer capsule surrounding the entire kidney except for the hilum
- an outer cortical area beneath the capsule which has a cup-like form with the open side of the cup facing the hilum
- a juxtamedullary cortex deep to the outer cortical area
- a medullary area made up of triangular-shaped renal pyramids and divided into:
- an outer medullary area deep to the juxtamedullary cortex
- an inner medullary area deep to the outer medullary area
- the renal pelvis into which empty the renal pyramids

4

Each kidney is fed by a large ______ artery branching directly off the

renal artery branching directly off the abdominal aorta

5

___ is the functional unit of the kidney

nephron

6

There are approximately _____ nephrons per kidney

one million

7

Each nephron consists of

- Renal Corpuscle
- Renal tubule

8

A renal corpuscle is composed of

- A cup-shaped capsule referred to as Bowman's capsule
- A glomerulus
- this is a capillary knot situated between two arterioles that lies within the indentation of Bowman's Capsule

9

this is a capillary knot situated between two arterioles that lies within the indentation of Bowman's Capsule

Glomerulus

10

A renal tubule is a continuation of

bowman's capsule

11

nephrons empty into

collecting ducts

12

Collecting ducts empty into

the renal pelvis

13

What are the two types of Nephrons

-Cortical
-Juxtamedullary

14

The renal corpuscles of cortical nephrons are located

The cortex

15

The glomeruli of cortical nephrons empty into

peritubular capillary networks that surround the proximal and distal convoluted tubules of their own nephrons and those of surrounding nephrons

16

Structure of cortical nephrons loops of henle

have short loops of henle that do not extend deeply into the medulla

17

the renal corpuscles of juxtamedullary nephrons are located

in the cortex next to the cortical-medullary junction

18

The glomeruli of juxtamedullary nephrons empty into

vasa recta consisting of long, straight arterioles and venues that run parallel to the loops of Henle and collecting ducts

19

The loops of henle in juxtamedullary nephrons

Juxtamedullary nephrons have long loops of Henle that extend deeply into medulla

20

sequence of branching for the renal artery within the kidney

renal artery----> Interlobar arteries ----> Arcuate arteries----> interlobular arteries----> afferent glomerular arteries-------------->glomerular capillary network (glomeruli)------> efferent glomerular arterioles-----> vasa recta (peritubular capillaries) ------> Interlobular veins -----> arcuate veins -----> interlobar veins -----> Renal veins

21

in general, a capillary network is interposed between

an arteriole and a venule

22

Explain the arterial portal system in the kidneys

An arteriole is interposed between two capillary networks. An afferent arteriole give rise to a mass of capillaries, the glomerulus. These capillaries coalesce to form an efferent arteriole, which gives rise to capillary networks (peritubular capillary network and the vasa recta) surrounding the nephrons.

23

Explain Venous portal system in liver and hypophysis

Arteriole to capillary to vein. the veins then feed into an extensive capillary or sinusoid network draining into a vein.

24

The glomerulus is a ______ inserted between two arterioles

Capillary bed

25

The glomerulus is a ____ inserted between two ____

Capillary bed inserted between two arterioles (afferent arteriole and efferent arteriole)

26

A typical capillary bed is inserted between

an arteriole and a venule

27

The efferent arteriole feeds into either

- a capillary loop, the vasa recta
- a capillary network, the peritubular capillaries

28

Where are peritubular capillaries found

in cortical nephrons
- efferent arterioles drain into them

29

Where are vasa recta found

in juxtamedullary nephrons
- efferent arterioles drain into them in juxtamedullary nephrons

30

Circular smooth muscle cells at the vascular pole

Juxtaglomerular cells

31

Juxtaglomerular cells are located in

the afferent arteriole of the glomerulus

32

what cells secrete renin

juxtaglomerular cells

33

Juxtaglomerular cells secrete

renin (hypertensive factor)

34

components of the glomerulus

-Afferent arteriole (which houses juxtaglomerular cells)
- Glomerular formation of capillaries
- Efferent Arteriole

35

This is a double-layered, cup-shaped dilation of the nephron

Bowman's capsule

36

What are the two layers of Bowman's capsule and there stucture

-Parietal layer
- this is an outer layer of simple squamous epithelium
- The squamous epithelium is continuous with the simple cuboidal epithelium of the proximal convoluted tubule

-Visceral layer
- This is the inner layer of podocytes in contact with the endothelium of the glomerular capillaries

37

_____ is located between the parietal and visceral layers and is continuous with the lumen of the proximal convoluted tubule

Bowman's space

38

The renal corpuscle is involved in producing

a filtrate of blood

39

what parts of the nephron are involved in modifying the nitrate of blood produced by the renal corpuscle

the rest of the nephron, including the convoluted portions and the loop of Henle, as well as the collecting tubules, is involved in modifying the filtrate

40

The formation of the urine involves three process

-Filtration (occurring in the renal corpuscle)
- Reabsorption (occurring in the renal tubule)
- Secretion (Occurring in the renal tubule)

41

The Mesangium is part of the

Glomerulus

42

The mesangium is formed by _____ cells embedded in ______

mesangial cells embedded in a mesangial matrix

43

Intraglomerular mesangial cells are located between _____ in the _____ and cover ______ not covered by _____

nearby capillaries in the glomerulus and cover endothelium not covered by podocytes

44

Extraglomerular mesangial cells are located between _______ and _______ at the ______ and are associated with the _________.

afferent and efferent arterioles at the vascular pole and are associated with the juxtaglomerular apparatus

45

Characteristics and functions of Mesangial cells

-Contractile: utilize cytoskeletal contractile proteins to modify blood flow through glomerular capillaries
- Phagocytic: take up worn out glomerular basal lamina for recycling and also phagocytose immunoglobulins trapped in the basal lamina
-proliferative
- synthesize matrix and collagen
- Secrete prostaglandins and endothelins
- Respond to angiotensin II
- Provide mechanical support and regulate blood flow

46

what are the three components of the juxtaglomerular apparatus

-macula densa
- Extraglomerular mesangial cells
- Juxtaglomerular cells

47

The macula densa is formed by

densely packed cells in the wall of the convoluted tubule. . polarity of these cells is reversed

48

The macula densa responds to changes in

sodium and chloride concentration in the urine or hypotension

49

The macula densa signals _____ release from juxtaglomerular cells

renin

50

Macula densa is involved in regulation of _______ and _______

fluid-electrolyte balance and blood pressure

51

Modified smooth muscle cells associated with macula densa and afferent arteriole

Juxtaglomerular cells

52

Secrete renin into blood when stimulated by the macula densa

Juxtaglomerular cells

53

The juxtaglomerular cells are innervated by ______ which increase renin release

sympathetic nerve endings

54

The simple squamous epithelium of Bowman's capsule becomes continuous with the simple cuboidal epithelium of the _______.

Proximal convoluted tubule

55

What is the first part of the renal tubule

Proximal convoluted tubule

56

What are the parts of the renal tubule

- The proximal convoluted tubule
- The descending limb of Henle (with thick and thin portions)
- The loop of Henle
- The ascending limb of Henle (with thick and thin portions)
- The distal convoluted tubule

57

The distal convoluted tubule is continuous with the

collecting duct

58

What are the components of the renal filtration barrier

-Fenestrated endothelium of glomerular capillaries
- Fused basal laminae of endothelial cells and podocytes
- Flitration slits

59

Filtration slits of the renal filtration barrier are created by? and covered by

-adjacent pedicels of podocytes, covered by filtration slit diaphragm

60

Pedicels are attached to basal lamina via

alpha3beta1 integrins

61

The basal lamina of the renal filtration barrier contains

-type IV collagen
- fibronectin
- laminin
- heparin sulphate

62

Selectivity of the renal filtration barrier

- water, glucose, and most ions pass through filter into Bowman's space
- Proteins are typically excluded from passing across the filter
- Molecules with a large negative charge are excluded

63

The proximal convoluted tubule extends from the _____ of the renal corpuscle to the beginning of the loop of henle

urinary pole

64

The proximal convoluted tubule has what kind of epithelium made up of ________ cells

simple cuboidal epithelium, truncated pyramidal cells

65

Characteristics of the proximal convoluted tubule

- simple cuboidal epithelium made up of truncated pyramidal cells

- Apical tight junctions and brush border

- Basolateral infolding and interdigitations

- Basal striations with abundant mitochondria (for active transport across basal membrane)

- Large, pale-staining nuclei

- Eosinophilic cytoplasm

66

What are the functions of the proximal convoluted tubule

-Reabsorbs most of the filtrate, including water

- Removes essentially all the glucose and amino acids form the filtrate

- Reabsorbs most of the sodium and chloride ions

- Characterized by a complex set of transporters, co-transporters, channels, and exchangers

67

_____ extends form the proximal to distal convoluted tubules

Loop of Henle

68

The loop of henle is made up of a ____ and ____

ascending limb and descending limb

69

The descending and ascending limbs of the loop of Henle each have a

thick and thin segments

70

_____ segments of the loop of Henle are composed of simple low cuboidal epithelium

Thick segments

71

_____ segments of the loop of Henle are composed of simple squamous epithelium

Thin segments

72

Cells of the thick ascending limb have no _____ and more ____ than other parts of the loop of Henle

No brush border, more basal vertical striations

73

The ascending limb is impermeable to

water

74

The descending limb is permeable to

water and sodium chloride ions

75

The ascending limb is impermeable to ____ and actively pumps ____ out of the tubule, allowing ____ to follow

Water, actively pumps chloride ion out of the tubule, allowing sodium ions to follow

76

The major function of the loop of Henle

is to establish the counter-current exchange system which creates the osmotic conditions necessary to pull water out of the distal convoluted tubule and collecting duct in the presence of ADH

77

The distal convoluted tubule is impermeable to water except in the presence of

ADH

78

ADH is derived from the

posterior pituitary

79

What is the function of ADH

Antidiuretic hormone (vasopressin)
-fxn- to reduce water loss

80

The distal convoluted tubule is lined with ____ epithelium with ___ cells than those of the proximal convoluted tubule

simple cuboidal epithelium, smaller

81

The lumen of the distal convoluted tubule is _____ than that of the proximal convoluted tubule and there is no ______

larger, no brush border

82

The cytoplasm of the distal convoluted tubule is ____ eosinophilic than that of the proximal convoluted tubule

less

83

______ has a different embryological origin than that of the nephron

The collecting duct

84

The wall of the collecting duct consists of

simple cuboidal epithelium

85

What are the two major specialized cell types associated with the collecting duct

-Principle cells
- Intercalated cells

86

Function of Principle cells

-Reabsorb sodium ions and water
- Secrete potassium via ATPase pump

87

Function of Intercalated cells

Secrete either hydrogen ion or bicarbonate ion

88

what makes up the excretory passages of the kidney

- Renal Pelvis
- Ureter
- Urinary bladder

89

What are the layers in the excretory passages (renal pelvis, Ureter, and urinary bladder) of the kidney

-Mucosa
-Submucosa (not clearly demarcated)
- Muscularis
- Adventitia (FECT external to muscularis; series over superior surface of bladder)

90

Characteristics of the mucosa of the excretory passages (renal pelvis, Ureter, and urinary bladder) of the kidney

- Transitional epithelium (urothelium)
-Basement membrane
-Lamina propria of FECT
- some loose lymphoid tissue
- A few smooth muscle cells

91

Inner longitudinal and outer circular smooth muscle coat in ureter

Muscularis

92

The _____ ureter has a third external longitudinal smooth muscle coat (muscularis)

Lower third

93

Layers of smooth muscle in urinary bladder form

detrusor muscle

94

Section of the urethra passing through prostate gland

prostatic urethra

95

The mucosa of the prostatic urethra is lined with

transitional epithelium

96

Vascularization of prostatic urethra

-highly vascularized with veins with abundant elastic tissue

97

The membranous urethra extends through ________ and receives striated muscle cells forming the ___________ of the _____

urogenital diaphragm, external sphincter of the bladder

98

The membraneous urethra is composed of _____ cells

tall pseudostratified columnar cells but variable

99

What are the major components of the male urethra

- Prostatic urethra
- Membraneous urethra
- Cavernous urethra

100

The cavernous urethra is lined with ________ epithelium with patches of ______ epithelium

pseudostratified epithelium, with patches of stratified squamous epithelium

101

Glands of the male urethra

- Lucanae of Morgagni
- Glands of Littre

102

________ are invaginations of mucous membrane containing single or groups of intraepithelial mucous cells in male urethra

Lucanae of Morgagni

103

______ are branched tubulara glands opening into the lacunae of Morgagni

Glands of Littre

104

Mucosa of the female urethra is lined primarily with _______ epithelium with intraepithelial nests of ______

pseudostratified columnar epithelium, mucous glands

105

Vascularization of the lamina propria in the female urethra

highly vascularized with veins with an abundance of elastic tissue

106

The submucosa of the female urethra is

not discernible

107

Muscularis of the female urethra has an ________ and ______ but is not

inner longitudinal and outer circular layer of smooth muscle cells but is not well defined

108

The adventitia of the female urethra is not

discernible

109

Angiotensin II stimulates secretion of ______ from _____
and ____ from the ____

Aldosterone from adrenal cortex
ADH from the posterior pituitary

110

Aldosterone acts on the ________ cells of the _______ and the _______

principal cells of the collecting ducts and thick ascending limbs of Henle

111

Angiotensin I is primarily produced in the

lungs

112

Angiotensin-converting factor (ACE) is from _______ and ____ and converts

pulmonary and renal endothelium
converts Angiotensin I to Angiotensin II

113

Renin converts

antiotensinogen to angiotensin I

114

Angiotensinogen is a circulating blood protein produced by the

liver

115

Angiotensin II increases the reabsorption of ______ and ____- which increases

sodium ion and water, which increases blood pressure