6URI

6 Urinary System

WORK ON ALL THE HIGHLIGHTED QUESTIONS

Key Terms

Gross Structures of the Kidney

Renal cortex __________________________________________________________________________________________

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Renal medulla ________________________________________________________________________________________

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Renal pyramid _______________________________________________________________________________________

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Renal column ________________________________________________________________________________________

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Renal pelvis __________________________________________________________________________________________

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Major and minor calyces ___________________________________________________________________________

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Other Structures of the Urinary System

Ureter _______________________________________________________________________________________________

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Urinary bladder ______________________________________________________________________________________

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Urethra ______________________________________________________________________________________________

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Microanatomy of the Kidney

Nephron _____________________________________________________________________________________________

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Glomerulus __________________________________________________________________________________________

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Peritubular capillaries _____________________________________________________________________________

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Proximal tubule _____________________________________________________________________________________

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Nephron loop _______________________________________________________________________________________

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Distal tubule _________________________________________________________________________________________

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Cortical collecting duct ______________________________________________________________________________

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Medullary collecting duct __________________________________________________________________________

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Papillary duct _______________________________________________________________________________________

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Structures:

Kidneys

Ureters

Urinary bladder

Ureteral orifices / openings

Trigone

Rugae

Internal urethral sphincter

Urethra

External urethral sphincter

External urethral orifice

External Kidney Features

Renal hilum

Renal artery

Renal vein

Internal Kidney Features

Cortex

Medulla

Renal pyramid

Papilla of pyramid / renal papilla

Renal column

Renal sinus

Renal pelvis

Major calyx/calyces

Minor calyx/calyces

Microscopic Anatomy

Renal corpuscle

Glomerulus

Bowman’s/glomerular capsule

Visceral layer

Capsular space

Parietal layer

Proximal convoluted tubule

Loop of Henle (thick and thin portions)

Descending limb

Ascending limb

Distal convoluted tubule

Collecting duct

Juxtaglomerular apparatus

Granular (juxtaglomerular) cells of afferent arteriole

Macula densa of distal convoluted tubule

Blood Supply

Renal artery and vein

Interlobar artery and vein

Arcuate artery and vein

Interlobular/cortical radiate artery and vein

Afferent arteriole

Glomerulus

Efferent arteriole

Peritubular capillaries

Vasa recta

Following is an anterior view of the entire urinary system Select different colors for the following organs and use them to color the coding circles and the corresponding organs.

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· Kidney

· Bladder

· Ureters

· Urethra

Following is the image of a longitudinal section of a kidney. Using the correct anatomical terminology, label the following regions/ structures indicated by leader lines on the figure and after each description.

· Fibrous membrane immediately surrounding the kidney.

· Structure/Region: _______

· Basin-like area of the kidney that is continuous with the ureter.

· Structure/Region: _______

· Cuplike extension of the pelvis that drains the apex of a pyramid.

· Structure/Region: _______

· Area of cortex-like tissue running through the medulla.

· Structure/Region: _______

· Area of the kidney that contains the greatest proportion of nephron structures.

· Structure/Region: _______

· Striped-appearing structures formed primarily of collecting ducts.

· Structure/Region: _______

Beginning with the renal artery,
draw in the vascular supply to the cortex on the figure. Include and label the interlobar artery, arcuate artery, and cortical radiate artery. Color the vessels bright red.

Segmental artery

Renal vein

Renal artery

Ureter

Following is a diagram of the nephron and associated blood supply. Match each of the numbered structures on the figure to one of the terms below the figure. Place the terms in the numbered spaces provided below.

Color the following on the figure:

· Structure on the figure that contains podocytes:
green.

· Filtering apparatus:
red.

· Capillary bed that directly receives the reabsorbed substances from the tubule cells:
blue.

· Structure into which the nephron empties its urine product:
yellow.

· Tubule area that is the primary site of tubular reabsorption:
orange.

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Afferent arteriole

Cortical radiate vein

Interlobar artery

Arcuate artery

Distal convoluted tubule

Interlobar vein

Arcuate vein

Efferent arteriole

Nephron loop

Collecting duct

Glomerular capsule

Peritubular capillaries

Cortical radiate artery

Glomerulus

Proximal convoluted tubule

Trace the path of blood from the heart to the kidneys, to the nephron, and back to the heart.

Trace the movement of fluid from the glomerulus to the external urethral orifice.

Histology:

Urinary Bladder:

· Mucosa

· Transitional epithelium

· Lamina propria

· Submucosa

· Muscularis

· Smooth muscle layers

· Adventitia

On low power, note the folds of mucosa; these are rugae or mucosal folds. On high power, note that the mucosa is composed of transitional epithelium and lamina propria. This type of epithelium and rugae allow the bladder to distend and relax to accommodate changes in urine volume. Just deep to the lamina propria is submucosa. On low power, look beneath the submucosa, to find the thick muscularis, composed of several layers of smooth muscle. Finally, the outermost layer is the adventitia, which may or may not be visible on some slides.

Kidney:

· Cortex

· Medulla

· Pyramids

· Collecting ducts

· Simple cuboidal epithelium

· Loops of Henle

· Renal corpuscle

· Glomerulus

· Capsular space

· Parietal layer of Bowman’s capsule

· Proximal convoluted tubule

· Distal convoluted tubule

Observe the longitudinally sectioned kidney on the lowest power and locate the cortex; the outer darker-stained area and medulla; the inner lighter stained area with distinct pyramids. Next, observe the low power photomicrograph of the medulla. This region is made of closely packed tubules. These tubules make up the pyramids and are mostly collecting ducts with loops of Henle interspersed and appear tough shaped on the longitudinal section. On the high power transverse view, the collecting ducts are circular in appearance, consisting of simple cuboidal epithelium.

On low power, observe that the cortex contains darkly stained bulbous structures called renal corpuscles. The presence of renal corpuscles indicates that the region of the kidney being viewed is the cortex.

Observe the high power photomicrograph of the cortex. The corpuscle consists of two parts; a ball of capillaries, the glomerulus, and surrounding it, bowman’s/ glomerular capsule. Bowman’s capsule has two layers; the parietal layer, composed of simple squamous epithelium, and the visceral layer which adheres to the glomerulus. The visceral layer is not distinguishable on a slide. The clear space between these two layers is the capsular space.

The tissue surrounding the corpuscles consists of tubules of the nephron viewed in either cross section, oblique or longitudinal. These tubules which consist of simple cuboidal epithelium are typically either proximal convoluted tubules or distal convoluted tubules. To distinguish between these, note the differences in luminal surface. Proximal tubules are lined with microvilli and give the lumen a fuzzy appearance; distal tubules have a clearly defined lumen.

Acid-Base

What is the range of the pH scale? ________________

Which end of the pH scale is the acidic end? ________________

Which end of the pH scale is the basic end? ________________

What is the normal range for blood pH? ________________

More H+ causes the pH to be ________________

Less H+ causes the pH to be ________________

What effect does increased CO2 have on pH? ________________

What effect does increased bicarbonate have on pH? ________________

When pH falls, the body becomes more _______________________________

Intracellular pH is (higher / lower) than blood pH.

In the GI tract, pH varies from ________________ in the stomach to ________________ in the small intestine.

True/False: the pH of urine can vary anywhere from 4.5 to 8.

Substances that donate hydrogen ions are called ________________

Substances that accept hydrogen ions are called ________________

The only strong acid (pH = 1) found in the body is ________________ and is found in the ________________

________________ (chemical formula) is carbonic acid. With a pH of 4.5 it is a (strong/weak) acid because it (does/doesn’t) completely dissociate in water.

Lactic acid, pH = 2.5 is a (strong/weak) acid.

Lactic acid is a (stronger/weaker) weak acid than carbonic acid.

Only (strong/weak) bases are found in the body.

________________________________ means the same thing as alkaline.

The pH of a neutral solution is ________________.

Electrolytes can act as both acids and bases in the body True/false

The shape of proteins may be changed by very tiny changes in pH True/False

Name the three types of mechanisms the body uses to help maintain acid-base balance.

________________

________________

________________

Deep, rapid breathing releases more ________________.

Three ways the kidney can help control acid levels in the body are ________________ HCO3-, ________________ new HCO3-; and secrete ________________ into the urine.

The kidney’s role in pH regulation is relatively (slow/fast).

In terms of time, chemical ________________ are fastest, taking only seconds.

The ________________ system is slower, taking minutes.

Slowest of all, taking hours to days, is the ________________ system.

Ketosis can cause (acidosis/alkalosis)

True/False: Excess vomiting or diarrhea can cause pH to vary outside normal range.

A disease associated with ketoacidosis is ________________.

Beyond a pH of 7.8, ________________ occurs.

Lis some causes of respiratory acidosis.

Acidosis caused by insufficient HCO3- levels is called ________________ acidosis, and if there is any compensation it is done by the ________________ system.

Alkalosis caused by low levels of carbon dioxide is called ________________ alkalosis, and if there is any attempt by the body to compensate, it will be done by the ________________.

When the lungs are unable to sufficiently operate (HCO3-/CO2) levels will rise, and the pH will ________________.

Hyperventilation may cause the body to rid itself of too much (HCO3-/ CO2) thereby causing the pH of the blood to ________________.

Metabolic acidosis can be caused by low levels of (HCO3-/CO2) or by excess acid in the body.

List in the table below some common causes of acid-base disturbances

Metabolic Acidosis	↓ HCO3-	Respiratory Acidosis	↑ CO2
Metabolic Alkalosis	↑ HCO3-	Respiratory Alkalosis	↓ CO2

Analyze arterial blood gas data and identify acid-base imbalances and correlate disorders with their effects on acid-base balance.

1. You need to know the normal values of pH, partial pressure of carbon dioxide (P CO2) and bicarbonate (HCO3-)

1. You need to look at the patient’s ABGs – arterial blood gases – to determine what’s abnormal and whether the abnormal values are too high or too low.

1. You need to correlate the abnormal values of P CO2 and HCO3- to the abnormality of pH.

1. You need to name the disorder, the cause, and the source of any compensation.

Normal values:

· PH range 7.35 – 7.45

· Carbon dioxide partial pressure 35-45 mmHg

· Bicarbonate 24-28 mEq/L

Evaluate the ABGs:

· Is the pH normal? Is it too high or too low? Is it acidosis or alkalosis?

· Is the CO2 normal? Is it too high or too low? Will it cause acidosis or alkalosis? Will it correct acidosis or alkalosis?

· Is the HCO3- normal? Is it too high or too low? Will it cause acidosis or alkalosis? Will it correct acidosis or alkalosis?

Correlate the abnormal values:

· If only one of the two parameters (CO2 or HCO3-) is abnormal, then its value should be consistent with the pH. (For example, if the CO2 is high, since that causes a drop in pH, the pH should be low.)

· If both of the parameters are abnormal, then usually one is CAUSING the problem, and the other is trying to CORRECT (COMPENSATE FOR) the problem. (For example, if the CO2 is high and is causing the pH imbalance, then the pH must be low since CO2 behaves as an acid. If HCO3- level is also abnormal, then usually it will be high, to compensate for the low pH since it is a base.)

Name the disorder.

· Respiratory acidosis (with or without renal compensation)

· Respiratory alkalosis (with or without renal compensation)

· Metabolic acidosis (with or without respiratory compensation)

· Metabolic acidosis (with or without respiratory compensation)

Acid Base Problems

Example:

pH 7.31

P CO2 55 mmHg

HCO3- 28 mEq/L

Explanation:

· pH is too low: Acidosis

· P CO2 is too high, would cause acidosis or correct alkalosis

· HCO3- is normal, neither causing nor correcting imbalance.

· High P CO2 is correlated with low pH, which is consistent with patient’s report

· Because P CO2 is causing the problem, this is respiratory acidosis.

· Because bicarbonate is normal there is no compensation

Answer: Respiratory acidosis without renal compensation.

1. pH 7.31

P CO2 55 mmHg

HCO3- 35 mEq/L

1. pH 7.31

P CO2 35 mmHg

HCO3- 20 mEq/L

1. pH 7.31

P CO2 25 mmHg

HCO3- 20 mEq/L

1. pH 7.48

P CO2 25 mmHg

HCO3- 28 mEq/L

1. pH 7.48

P CO2 25 mmHg

HCO3- 20 mEq/L

1. pH 7.48

P CO2 45 mmHg

HCO3- 33 mEq/L

1. pH 7.48

P CO2 55 mmHg

HCO3- 33 mEq/L