Vet Micro Anatomy Kidney

Front 1

1. the renal system receives ____% of cardiac output

2. ____% of diseases involve the kidney in some fashion

Back 1

1. 20-25%

2. 40%

Front 2

fxns of the renal system

Back 2

conservation
- water and electrolytes
- acid-base regulation

excretion
- nitrogenous wastes
- metabolites

endocrine
- renin-angiotensin-aldosterone
- erythropoietin
- thrombopoietin
- calcitrol "D3"

Front 3

components of the renal system & their function

Back 3

Kidney:
- Capsule : organ strx
- Cortex : filtration, modification, endocrine
- Corticomedullary Jxn : modification, concentration
- Medulla : modification, concentration
- Papilla (Renal Crest) : transport
- Pelvis : transport

Ureters/Urethra
- transport

Urinary Bladder
- storage
- controlled release

Front 4

the anatomic unit of the kidney is the ________

what is it composed of

Back 4

lobe

composed of
- cone shaped wedge of tissue renal (pyramid) in the medulla
- the cortex external to it
- one or more pyramids make up the medulla
- contains visible stripes from the parallel "straight" segments of the nephrons

Front 5

who has unilobar kidneys?

multilobar?

Back 5

unilobar
- rodents
- cats

multilobar (completely fused so appears as unilobar externally)
- dogs
- humans
- horses
- small ruminants

multilobar (incompletely fused)
- swine
- large ruminants

Front 6

The ___A_____ delivers urine via the "area cribrosa" to the ____B_____

Back 6

A. renal crest (unilobar) or papilla (multilobar)

B. renal pelvis (unilobar) or minor/major calyx (multilobar)

Front 7

Back 7

Front 8

describe the kidney capsule

Back 8

very little CT in kidney (except at intersections of the lobe in multilobar kidneys)

the strx is provided by the combination of the veins, arteries, and tubules that are enclosed in the capsule

capsule provides an inelastic envelope that lacks CT connections to the renal cortex (except in the horse)

Front 9

_______ provides an inelastic envelope that lacks CT connections to the renal cortex.


What spp is the exception to this rule?

Back 9

Capsule


horse

Front 10

describe the cortex/ medulla

Back 10

cortex includes
- renal corpuscles
- convoluted tubules
- collecting ducts

medulla
- renal tubules
- collecting ducts

Front 11

describe the corticomedullary jxn

Back 11

corticomedullary jxn is not a sharp demarcation but can provide a rough idea proportions b/w the 2

the arcuate arteries follow the jxn

Front 12

describe medullar rays

Back 12

parallel streaks that radiate through the medulla and cortex

composed of straight tubules (loop of henle) and collecting ducts

Front 13

_____ contains no corpuscles, only tubules

Back 13

medulla

Front 14

_____ contains urinary corpuscles and tubules

Back 14

cortex

Front 15

describe the pelvis

Back 15

the upper "expanded" cup-shaped end the beginning of the ureter

large collecting ducts empty inot the pelvis with urine being collected and drained by the ureter

the strx of the pelvis matches the overall strx of the kidney (whether unilobar or multilobar)

mucous glands are present in the horse is the reason for cloudy urine

Front 16

why anatomic abnormality is the reasong that horses have cloudy urine

Back 16

they have mucous glands in the pelvis

Front 17

the vascular system of the kidney is a(n) _________ system

Back 17

end arterial

Front 18

describe the progression of blood through the kidney

Back 18

- renal artery
- interlobar artery
- arcuate artery
- interlobular artery
- intralobular artery
- afferent arteriole
- renal corpuscle (glomerulus)
- efferent arteriole
- peritubular plexes (vesta recta/ rete mirable)
- intralobular vein
- interlobular vein
- renal vein

Front 19

Describe rete mirabile

Back 19

Complex network of post glomerular capillaries (second capillary system)

Covers the nephron but is most dense in the cortex around the glomeruli

Front 20

Describe the vasa recta

Back 20

Capillary loops of the rete mirabile

send straighter segments deeply into the medulla and surround the straight tubules (loop of henle)

play a critical role in maintaining the interstitial Na+ gradient in the medulla

Front 21

_______ is the basic functional unit of the kidney

Back 21

nephron

Front 22

________ functions to filter blood to produce a large volume of plasma filtrate then to modify and concentrate prior to excretion

Back 22

nephron

Front 23

1. Is modification active or passive?

2.Is concentration active or passive?

Back 23

Modification and concentration are both an active and passive process and depend on the vascular system and intersititium

Front 24

What is the function of the nephron?

Back 24

Filters blood to produce a large volume of plasma filtrate

Then modifies and concentrates this prior to excretion

Front 25

Components of the nephron and their fxns

Back 25

Renal corpuscle
- Filtration

Proximal convoluted tubule
- Resorption (water, glucose, protein, Na

Loop of Henle
- Countercurrent ion exchange

Convoluted tubule
- Active Na Transport

Front 26

Renal Corpuscle (glomerulus)
What is it and what does it do?

Back 26

Complex strx uniquely designed to filter blood

Pressure sensitive mechanical filtration

Some electrostatic selective exclusion of proteins

Front 27

Components of the Renal Corpuscle (glomerulus)

Back 27

Afferent & efferent arterioles

Visceral and parietal epithelium

Bowman’s capsule and space

Mesangium

Front 28

What forms the filtration slits that both physically (pressure) and electrostatically produce the glomerular filtrate that empties into bowman’s space which is continuous with the PCT

Back 28

Combination of the basement membrane and podocyte foot processes

Front 29

What is the basis of the fxn of the glomerulus

Back 29

The unique strx of the capillary knot

Front 30

Describe the glomerulus strx (cellular description)

Back 30

Capillary knot is the basis of its fxn

An extra thick 3-layer basement membrane

Specialized viscerial epithelial cells (podocytes) with long extensions (fingers and foot processes) cover the basement membrane

Combination of basement membrane and podocyte foot processes form filtration slits that both physically (pressure) and electrostatically produce the glomerular filtrate that empties into bowman’s space which is continuous with the PCT

Parietal epithelium and its assoc basement membrane make up bowman’s capsule

Mesangial cells provide strx and also have macrophage-like fxn to maintain the integrity of the strx

Front 31

What cells provide structure to the glomerulus and have macrophage-like fxn

Back 31

mesangial cells

Front 32

What makes up bowman’s capsule?

Back 32

Parietal epithelium and its assoc basement membrane

Front 33

What influences the length of henle’s loop and the depth of its penetration into the medulla?

Back 33

the location of the glomerulus w/in the cortex

Front 34

The length of the loop of Henle ______the ability to concentrate urine
(increases or decreases)

Back 34

increases

Front 35

True or false
The number of glomeruli (nephrons) can increase creating the kidney’s significant functional reserve

Back 35

False

The number of nephrons doesn’t increase but some increase in functional capability is possible

Front 36

_____ begins at the urinary pole of the glomerulus and makes up the bulk of the cortex

Back 36

PCT

Front 37

What makes up the bulk of the cortex

Back 37

PCT

Front 38

Where do you see simple cuboidal epithelium with microvillus brush borders?

Back 38

PCT

Front 39

Describe the PCT

Back 39

Simple cuboidal epithelium with microvillous brush borders

Packed with mitochondria (to provide energy)

Highly interdigitated on their lateral sides to form tight jxns

Front 40

______ is where 99% of the water is resorbed

Back 40

PCT

Front 41

______ is where protein/ glucose/ salt are absorbed

Back 41

PCT

Front 42

______ provides birds and mammals with the ability to concentrate urine

Back 42

loop of Henle

Front 43

1. How much water is resorbed in the PCT?

2. how much protein/glucose/salt are absorbed in PCT?

Back 43

1. 99% (over 1 liter/min)

2. over 2.5 kg/day

Front 44

Back 44

Front 46

Back 46

Front 47

Back 47

Front 49

Back 49

Front 52

Back 52

Front 54

Back 54

Front 55

composition of juxtaglomerular apparatus

Back 55

Juxtaglomerular (granular) cells
- Modified myoepithelial cells (pericytes)
- Assoc with afferent arteriole
- Closely assoc with macula densa
- Contain secretory granules


Macula densa
- Modified epithelial cells of DCT
- Assoc with extraglomerular mesangial cells


Extraglomerular mesangial cells (lacis cells)
- b/w the afferent and efferent arterioles

Front 56

____ are the cells that contribute to the juxtaglomerular apparatus and are located between the afferent and efferent arterioles

Back 56

extraglomerular mesangial cells (lacis cells)

Front 57

____ are modified epithelial cells of DCT which contribute to juxtaglomerular apparatus

what do they associate with

Back 57

macula densa

associated with extraglomerular mesangial cells

Front 58

____ are cells which contribute to the juxtaglomerular apparatus and are modified myoepithelial cells (pericytes) containing secretory granules

Back 58

juxtaglomerular (granular) cells

Front 59

______ is located at the vascular pole of the corpuscle and the DCT.

Why is this advantageous

Back 59

Juxtaglomerular complex (apparatus)


this location allows it to sense and regulate the fxn of the nephron by controlling blood flow (pressure) and thus GFR.

Front 60

JG cells secrete ____ in response to low perfusion pressure

Back 60

renin

Front 61

What portion of the renal system fxns to provide active transport of Na+ into the interstitium to maintain the osmotic gradient?

Back 61

distal tubules

Front 62

describe the macula densa

Back 62

Special region of modified epithelial cells near the vascular pole of the glomerulus

Part of the distal tubules

Front 63

describe the distal tubules

Back 63

Shorter in length than proximal tubules

Composed of simple cuboidal epithelium (no microvilli)


Fxn to provide active transport of Na+ into intersititum to maintain osmotic gradient

Includes a special region of modified epithelial cells near the vascular pole of the glomerulus called the macula densa

Front 64

describe the loop of henle

Back 64

Provides birds/ mammals the ability to concentrate urine

An abrupt transition from short straight portion of the proximal tubule is marked by the beginning of squamous epithelium

Loop reverses course in medulla and w/ the beginning of the distal tubule in the cortex transitions back to cuboidal epithelium (that lack brush borders)

During the course of reaching into the depths of the medulla, the loop passes through a concentration gradient, the greatest being deeper in the medulla, where additional water is passively resorbed by diffusion

Front 65

understand the jg apparatus

Back 65

Front 66

Back 66

juxtaglomerular apparatus

Front 67

What are the 3 components of the JG apparatus?

Back 67

Juxtaglomerular (granular) cells
- Modified pericytes around afferent arterial that have myoepithelial fxns


Macula densa
- Modified epithelial cells of DCT
- Interface with JG and mesangial cells


Mesangial (lacis) cells
- Extraglomerular mesangial cells b/w afferent and efferent arterioles

Front 68

How does the macula densa control GFR?

Back 68

Senses salt concentrations in DCT


Produces locally active vasopressor to control GFR

Front 69

The fxn of ______ is to sense and regulate blood pressure/ flow/ volume and thus glomerular filtration rate.

Back 69

JG complex (apparatus)

Front 70

____ senses salt concentrations in DCT and produces locally active vasopressor to control GFR

Back 70

macula densa

Front 71

____ triggers the RAAS in response to low perfusion

Back 71

Juxtaglomerular (granular) cells

By secreting renin

Front 72

Back 72

Front 73

______ converts angiotensinogen to angiotensin I

Back 73

renin

Front 74

Angiotensin I is converted to _______, which is a strong _____ and also stimulates release of ______

Back 74

angiotensin II

strong arterial constrictor

stimulates release of aldosterone

Front 75

what does angiotensin II do?

Back 75

strong arterial constrictor

stimulates release of aldosterone from adrenal
- increases Na & Cl reabsorption (& therefore H2O retention) in the renal tubule

Front 76

What does renin do?

Back 76

converts angiotensinogen to angiotensin I

stimulates production of antidiuretic hormone (vasopressin) from the posterior pituitary
- increase water absorption from collecting ducts

Front 77

_____ increases water absorption from the collecting ducts

_____ increases water retention in the renal tubule

Back 77

1. ADH (vasopressin) from anterior pituitary (in response to renin)

2. aldosterone from adrenal in response to angiotensin II (increases Na & Cl reabsorption)

Front 78

Describe the RAAS

Back 78

low perfusion pressure

JG cells secrete renin

renin converts angiotensinogen to angiotensin I

angiotensin I is converted to angiotensin II (potent vasoconstrictor)

angiotensin II stimulates release of aldosterone from adrenal

aldosterone increases Na+ and Cl reabsorption and thus H2O retention in renal tubule


renin also stimulates the production of ADH (vasopressin) from posterior pituitary
- increases H2O absorption in collecting ducts

Front 79

collecting ______ from multiple nephrons connect into collecting ________ which drain into _______

Back 79

collecting tubules

collecting ducts

the renal pelvis

Front 80

collecting tubules and ducts are lined by _______

Back 80

columnar epithelium

Front 81

_______ fxn as the final stage in water and electrolyte balancing

Back 81

collecting tubules/ ducts

Front 82

collecting tubules/ ducts are regulated by _____

Back 82

ADH (vasopressin)

Front 83

What happens when ADH levels are high

Back 83

the cells of the CD becmoe highly permeable to water

influence the osmotic gradient (increases from the cortex to the medulla)

Front 84

understand the raas

Back 84

Front 85

Back 85

collecting ducts

Front 86

know the arrangement of the kidney

Back 86

Front 87

Back 87

A. Cortex

B. Medulla

C. Medulla

D. Cortex

Front 88

understand the layout of the nephron in relation to the capillary system

Front 89

understand the layout of the nephron in relation to the capillary strx

Back 89

Front 90

Back 90

Front 91

Back 91

Front 92

Back 92

Front 93

what are teh cell types of the ureter/bladder/urethra

Back 93

transitional epithelium (some squamous in urethra)

lamina propria

tunica muscularis (note absences of a muscularis mucosa)

stratum cavernosum (veins w/in submucosa of urethra)

Front 94

Where is the very important valve assoc with the urinary system? What does it do?

Back 94

functional one-way valve b/w ureter and bladder

prevents retrograde flow of urine during micturition

Front 95

1. where is transitional epithelium found

2. why is it advantageous to have it in this location

3. describe the appearance of it

4. what problem can be associated with this type of epithelium

Back 95

1. occurs exclusively in the urinary system

begins in pelvis of kidney and extends towrds the distal end of the urethra where it transitions into squamous epithelium.

2. advantageous b/c
- virtually impenetrable to water
- protects against the custic effects of urine

3. cuboidal when not stretched, flat irregular squamous when stretched


4. rapid turnover (mitotic figures common) makes them prone to some viral infections

Front 96

Back 96

transitional epithelium (urothelium)

begins in pelvis of kidney and extends towards the distal end of urethra where it transitions to squam epi

Front 97

describe the lamina propria of the ureter/bladder/urethra

Back 97

consists mainly of dense CT with bundles of coarse collagenous fibers

Front 98

describe the musclularis of the ureter/bladder/urethra

Back 98

consists of inner longitudinal and outer circular lary of smooth musc cells

in lower parts of ureter and bladder, an additional outer longitudinal layer of muscles is added

Front 99

describe the lamina propria of the urethra

Back 99

contains loose CT with smooth muscles cells in the muscularis mainly oriented longitudinally

Front 100

Back 100

Front 101

Back 101