General Introduction

1
General Introduction
Excretory Organs
Lungs Liver Skin Kidneys
2
Functions of the Urinary System
A. Conserves Valuable Nutrients B.
Separates/Eliminates Wastes C. Regulates Blood
Volume and Blood Pressure D. Regulates Ion Levels
In Plasma E. Regulates Blood pH
3
Organs of the Urinary System

• Kidneys
• Ureters
• Urinary bladder
• Urethra

4
Kidneys Location
Retroperitoneal
5
Kidneys Structure
Renal capsule Several layers of fat
6
Kidneys Structure
2 layers Cortex Medulla
7
Kidneys Structure
Calyx Renal Pelvis Renal Hilus
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Nephron

• Glomerulus
• Bowmans capsule
• Proximal convoluted tubule
• Loop of Henle
• Distal convoluted tubule

9
Glomerulus and Bowmans Capsule
10
Bowmans Capsule
Podocytes Pedicels Filtration Slits
11
Collecting Duct
12
Summary of Flow of Fluid
Glomerular capsule Proximal convoluted
tubule Loop of Henle Distal convoluted
tubule Collecting duct Renal papilla Calyx Renal
pelvis Ureter Bladder Urethra Out of body
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Kidneys Function

• Filter wastes and produce urine by
• Filtration
• Reabsorption
• Secretion

14
Ureters Structure

• Mucosa epithelium
• Muscularis two layers
• Adventitia connective tissue

a lumen b mucosa c circular muscle layer d
longitudinal muscle layer e adventitia
15
Ureters Structure
16
Ureters Function

• Carry urine from the kidneys to the urinary
  bladder

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Urinary Bladder Structure

• Mucosa (rugae)
• Muscularis (Detrusor muscle)
• Adventitia

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Urinary Bladder Function

• Stores and expels urine

19
Urethra Structure
Mucosa Muscularis Adventitia
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Urethra Function
Transports urine from bladder to outside body
21
Female Urethra
22
Male Urethra
Prostatic Membranous Spongy/Penile
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Blood Flow Through the Kidney (A RAGE PRV I)

• Abdominal Aorta
• Renal Artery
• Afferent Arterioles
• Glomerular Capillaries
• Efferent Arterioles
• Peritubular Capillaries
• Vasa Recta
• Renal Vein
• Inferior Vena Cava

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Tubular Section of Nephron
Figure 23.4b
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Regulation of Water and Electrolytes

• The body gains water through 2 processes
• Absorption
• Metabolism

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Water Loss

• Urinary System
• Lungs
• Skin
• Intestines

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Cardiac Output and Renal Function

• Cardiac Output
• Stroke volume (ml) ? Heart Rate (beats/min)

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Hormones that Regulate Electrolyte Balance

• Antidiuretic Hormone (ADH or vasopressin)
• Renal-Angiotensin Aldosterone
• Erythropoetin
• Atrial Natriuretic Hormone

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Antidiuretic Hormone (ADH)

• Released in response to increase in concentration
  of electrolytes in blood or a fall in blood
  volume or pressure
• ADH decreases the amount of water lost at the
  kidneys, which reduces the concentration of
  electrolytes.
• ADH also constricts peripheral blood vessels,
  which helps to increase blood pressure.

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Renin-Angiotensin-Aldosterone

• The enzyme renin is released by kidney in
  response to a decrease in blood volume, blood
  pressure or both.
• Renin starts chain of reactions that lead to
  formation of hormone in liver called angiotensin
  II.
• AG II stimulates adrenal cortex to make
  aldosterone and posterior pituitary gland to make
  ADH.
• Both inhibit salt and water loss at kidneys
  resulting in increased blood volume and blood
  pressure.

31
Erthyropoietin

• Released by kidneys in response to low O2 levels
• Stimulates production of RBCs in bone marrow.
• Increase number of RBCs elevates blood volume.

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Atrial Natriuretic Hormone

• Cells in right atrium make this hormone in
  response to increased blood volume.
• Stimulates loss of sodium ions and water at the
  kidneys
• Inhibits renin release
• Inhibits secretion of ADH and aldosterone
• Result is reduced blood volume and blood pressure.