Figures & Tables

Trnspcy. Acetates

Masters

1

I. Urinary System

System Interactions, p.888; Clinical Focus, p.886

2

A. Kidneys

Fig. 26.1, p.857

TA-352

1. General Size

a. 11 cm X 5 cm X 3 cm

b. 130 g

2. Located in Renal Fat Pad

3. Internally -Hilum to Renal Sinus

Fig. 26.2, p.858

TA-353

a. Renal Artery

b. Renal Vein

c. Ureter

4. Outer Region = Cortex

5. Inner Region = Medulla

a. Renal Pyramids

b. Medullary Rays

c. Renal Columns

6. Tube System from Pyramids

a. Renal Papillae

b. Minor Calyces

c. Major Calyces

d. Renal Pelvis

e. Ureter

3

7. Functional Unit is the Nephron

Fig. 26.3, p.859

TA-354

1. Juxtamedullary and Cortical Nephrons

 

8. Renal Corpuscle

a. Glomerulus and Fenestrated Capillaries

Fig. 26.4, p.860

TA-355

1). Afferent Arteriole

2). Efferent Arteriole

b. Bowman's Capsule

1). Parietal Layer

2). Podocytes of Visceral Layer

9. Filtration Membrane

a. Capillary Epithelium (Fenestrated)

b. Basement Membrane

c. Podocytes and Filtration Slits

Fig. 26.4c,d, p.860

TA-355

10. Juxtaglomerular Apparatus

Fig. 26.4b, p.860

TA-355

a. Modified Smooth Muscle Cells = Juxtaglomerular Cells

b. Macula Densa Cells of Distal Convoluted Tubule

11. Tubules

Fig. 26.5, p.861

TA-356

a. Proximal Convoluted Tubule

1). 14 cm Long X 60 m m Diameter

2). Simple Cuboidal Epithelium with Microvilli

b. Loops of Henle

1). Descending Limb - Simple Cuboidal to Simple Squamous Epithelium

2). Ascending Limb - Simple Squamous to Sim-ple Cuboidal Epithelium

c. Distal Convoluted Tubule

1). Shorter than Proximal Tubule

2). Smaller Cuboidal Cells, Fewer Microvilli

Fig. 26.5d, p.861

TA-356

d. Collecting Ducts

1). Simple Cuboidal Epithelium

2). Form Medullary Ray

3). Extend Through Tip of Renal Pyramid

4

B. Arteries and Veins of the Kidney

Fig. 26.6, p.862

TA-357

1. Renal Artery

2. Segmental Arteries

3. Interlobar Arteries

4. Arcuate Arteries

5. Interlobular Arteries

6. Afferent Arterioles

7. Glomerular Capillaries

8. Efferent Arterioles

9. Peritubular Capillaries & Vasa Recta

Fig. 26.6b, p.862

TA-357

10. Interlobular Veins

11. Arcuate Veins

12. Interlobar Veins

13. Renal Veins

C. Ureters and Urinary Bladder

Fig. 26.7, p.863

TA-358

1. Two Ureters, One from Each Renal Pelvis to Urinary Bladder

2. Trigone Region of Bladder

a. Ureters Enter Urinary Bladder Posteriorly

b. Urethra Leaves Anteriorly

Predict Quest. 1

3. Transitional Epithelium

4. Urethral Sphincters

a. Internal - Smooth Muscle

b. External - Skeletal Muscle

II. Urinary Production

Clinical Focus, p.871; Clinical Focus, p.883; Fig. 26.8, p.864; Table 26.1, p.865

TA-359

A. Filtration

1. Renal Fraction = % of Cardiac Output Passing through Kidneys, 12-30 %

Table 26.2, p.865

2. Renal Blood Flow Rate - Vol. (ml) of Blood Passing through Kidney per min.

3. Filtration Fraction = % of Plasma becoming Filtrate, about 1 %

4. Glomerular Filtration Rate (GFR) = ml of Filtrate Formed per min, about 125 ml / min

5. About 99 % of Filtrate Volume Reabsorbed in Nephron

Predict Quest. 2

5

6. Filtration Barrier

a. 100 to 1000 Times More Permeable than Typical Capillary

b. Molecular Diameters # 7 nm or Molecular Weights to 40,000 Daltons

Predict Quest. 3; Clinical Note, p.866

6

7. Filtration Pressure, about 10 mm Hg

Fig. 26.9, p.866

TM-95

a. Glomerular Capillary Pressure Promotes Filtration (+60 mm Hg)

Predict Quest. 4

1. Decreased by Constriction of Afferent Arteriole

2. Increased by Constriction of Efferent Arteriole

b. Colloid Osmotic Pressure Resists filtration (-32 mm Hg)

c. Capsule Pressure Resists Filtration (-18 mm Hg)

7

B. Tubular Reabsorption

Table 26.1, p.865

1. Movement from Filtrate Back into Blood

Table 26.3, p.867

a. 99 % of Water Reabsorbed

b. 40-60 % of Urea

2. Endocytosis

3. Active Transport and Cotransport Mechanisms

4. Transport in the Proximal Tubule

Fig. 26.10a, p.868

TA-360

a. Most Reabsorption of Nutrients and Ions

Fig. 26.10b, p.868

TA-360

5. Transport in the Loop of Henle

8

a. Thin Descending Limb

1). Mostly Passive Transport

2). Volume of Filtrate Reduced Additional 15 %

9

b. Thick Ascending Limb

1). Impermeable to Water

2). Cotransport of K⁺& Cl^- with Na⁺ out of Filtrate

3). Filtrate Concentration Reduced to 100 mOsmol

Boxed Note, p.869

10

6. Transport in the Distal Tubule and Collecting Duct

Fig. 26.11, p.870

TA-361

a. Active Transport of Na⁺ and Cl^-

b. Impermeable to Water in Absence of ADH

Predict Quest. 5

1. Final 19 % of Water Reabsorbed when ADH Present

7. Changes in the Concentration of Solutes in the Nephron

Clinical Note, p.869

10

C. Tubular Secretion

1. Active or Passive Movement into Filtrate Across Proximal or Distal Convoluted Tubules

Table 26.4, p.870

2. Normal Cellular Products - Ex. Ammonia

3. Drugs and Toxins - Ex. Penicillin, PAH

12

D. Urine Concentration Mechanism

1. Medullary Concentration Gradient

Fig. 26.12, p.872

TA-362

a. 300 mOsmol in Cortex

b. 1200 mOsmol in Deepest Medulla

2. Counter-Current System Maintains Gradient

11

a. Vasa Recta

b. Loop of Henle

c. Variable Permeability to Urea

3. Urea Contributes to High Medullary Concentration

1. Summary of Changes in Filtrate Volume and Concentration

1. Decrease in Filtrate Volume
2. Increase in Filtrate Osmolality
3. Marked Change in Filtrate Composition

Clinical Note, p.875; Fig. 26.13, p.874

TA-363

III. Regulation of Urine Concentration and Volume

13

A. Hormonal Mechanisms

Fig. 26.11, p.870

1. Antidiuretic Hormone (ADH)

a. From Anterior Pituitary

b. Targets Distal Convoluted Tubules and Collecting Ducts

c. Action is to Increase Cell Permeability to Water

d. Secretion Increased when

Predict Quest. 6

1). Blood Osmolality Increases

2). Blood Pressure Declines

13

2. Renin-Angiotensin-Aldosterone

a. Renin from Juxtaglomerular Apparatus when

1). Na⁺ in DCT Decreased

2). BP in Afferent Arteriole Decreased

b. Renin Converts Angiotensinogen to Angiotensin I

c. Angiotensin Converting Enzyme (ACE) Converts Angiotensin I to Angiotensin II

d. Actions of Angiotensin II

1). Potent Vasoconstrictor

2). Increases Aldosterone Secretion

e. Aldosterone From Adrenal Cortex

f. Targets Distal Convoluted Tubules and Collecting Ducts

Fig. 26.14, p.877; Predict Quest. 7

TA-364

g. Action Increases Active Transport of Na⁺ and Cl^- into Blood

h. Aldosterone Secretion Increased When

1). Blood K⁺ Increased

2). Blood Na⁺ Increased

3). Angiotensin II Level Increased

4. Other Hormones

a. Atrial Natriuretic Hormone Source Right Atrium of Heart

b. Action is Decreased ADH Secretion

c. Prostaglandins and Kinins - Precise Roles as Yet Unclear

14

B. Autoregulation

1. Results in Stable GFR

2. Largely Independent of Systemic Arteriolar BP

3. Involves Afferent and Efferent Arterioles

a. Constriction of Afferent Arteriole Decreases Glomerular Capillary Pressure = Increased Filtration

b. Constriction of Efferent Arteriole Increases Glomerular Capillary Pressure = Decreased Filtration

15

C. Effect of Sympathetic Stimulation on Kidney Function

1. Sympathetic Stimulation Constricts Afferent Arterioles

2. Decreases Renal Blood Flow

3. Decreases Filtrate Formation

4. Shock can Lead to Impairment of Blood Flow that Damages Kidney

4. Regulation of Urine Concentration and Volume

1. Regulation of Extracellular Fluid Osmolality
2. Regulation of Extracellular Fluid Volume

1. Neural Mechanisms
2. Renin-Angiotensin-Aldosterone Mechanism
3. Atrial Natriuretic Hormone Mechanism
4. Antidiuretic Hormone Mechanism

Fig. 26.15a, p.879

Fig. 26.15b, pp.880-881

TM-96

TM-97

16

V. Clearance and Tubular Maximum

A. Plasma Clearance (ml/min) = Quantity of Urine Produced (ml/min) X [Concentration of Substance in Urine / Concentration of Substance in Plasma]

Clinical Note, p.882; Table 26.2, p.865

B. Clearance of a Substance Estimates GFR if

Predict Quest. 8

1. Substance Passes Freely Across Filtration Membrane

2. Substance not Reabsorbed Along Nephron

3. Substance not Secreted Along Nephron

4. Inulin = Polysaccharide with these Characteristics

C. Clearance of a Substance Estimates Plasma Flow if

Predict Quest. 9

1. Substance Passes Across Filtration Membrane

2. Remaining Substance Secreted so Very Little Left in Blood Following Single Pass Through Kidneys

3. Para-Aminohippuric Acid has these Characteristics

D. Blood Concentration Influences Clearance

1. Tubular Load = Total Amount of Substance Passing Through Filtration Membrane into Nephron per min.

2. Tubular Maximum = Maximum Rate of Active and Mediated Tubular Reabsorption of a Compound

Fig. 26.16, p.884

3. When Tubular Load > Tubular Maximum, the Excess Passes into the Urine

VI. Urine Movement

Clinical Note, p.884

A. Urine Flow Through the Nephron and Ureters

1. Pressure Gradient Forces Fluid from Plasma to Bowman's Capsule

2. Pressure Gradient from Bowman's Capsule to Renal Pelvis

3. Peristaltic Contraction of Circular Smooth Muscle in Ureters

a. Forces Urine to Urinary Bladder

b. Rate Once Every 2-3 min.

c. Rate Increased by Parasympathetic Stimulation

4. Internal Bladder Pressure Increases

a. Slowly from Volumes of 0-500 ml

b. More Pronounced with Volume Increases Above 500 ml.

17

B. Micturition Reflex

1. Neural Reflex Initiated by Stretch of Bladder or Irritation of Bladder/Urethra

2. Afferent Paths to Sacral Region of Spinal Cord

3. Spinal and Cranial Integration

Clinical Note, p.886

a. Reflex Integration in Spinal Cord Predominates in Infants

b. Reflex Integration in Brainstem Predominates in Adults

4. Efferent Paths of Spinal Reflex in Parasympathetic Fibers

Fig. 26.17, p.885

TA-365

a. Increase Smooth Muscle Contraction in Bladder

b. Decrease Contraction in Internal Urethral Sphincter

5. Fibers from Motor Cortex

a. Control Voluntary Skeletal Muscle of External Urethral Sphincter

b. Conscious Override Develops by Age 2-3 yrs.

VII. Systems Pathology: Acute Renal Failure

Predict Quest. 10