Urinary System I Functions of the Urinary System

  • Slides: 34
Download presentation
Urinary System

Urinary System

I. Functions of the Urinary System • • A. Maintain Water Balance B. Maintain

I. Functions of the Urinary System • • A. Maintain Water Balance B. Maintain Salt Balance C. Maintain p. H [H+] D. Excretion of metabolic (biochemical) waste products = urea (breakdown product of proteins) and uric acid

 • • Urea – major waste product in the body Uric acid –

• • Urea – major waste product in the body Uric acid – gouty arthritis or gout - formed from the breakdown of nucleic acids feces = food residues

Regions of the Urinary System • • A. Kidneys B. Ureters C. Urinary Bladder

Regions of the Urinary System • • A. Kidneys B. Ureters C. Urinary Bladder D. Urethral Canal (urethra)

Aorta – main artery of the body

Aorta – main artery of the body

Renal Artery

Renal Artery

Purified blood leaves the kidney through the renal vein

Purified blood leaves the kidney through the renal vein

 • Renal vein = lower in waste products, lower in oxygen • Renal

• Renal vein = lower in waste products, lower in oxygen • Renal artery = higher oxygen • Most organs in the body are pink because of the number of blood vessels and present in the vessels are red blood cells other organs that are not pink and most other cells/tissues are transparent or has no color

The Kidneys • A. reddish-brown organs located retroperitoneally • (the reddish color is due

The Kidneys • A. reddish-brown organs located retroperitoneally • (the reddish color is due to the vascularity of the kidneys) • B. the kidneys extend from about T-12 to L-3, with the right kidney located slightly lower than the left kidney

 • C. the kidneys are surrounded by renal capsule and perirenal fat –

• C. the kidneys are surrounded by renal capsule and perirenal fat – the fat is for protecting the kidney • D. renal cortex • “Note: interlobar arteries and veins extend through the renal columns of the cortex dividing the kidneys into lobes

 • E. Renal Medulla (Medullary Pyramids) • Note: the urine collecting ducts pass

• E. Renal Medulla (Medullary Pyramids) • Note: the urine collecting ducts pass downward through the renal medulla (pyramids) and open into the calyces of the ureter

Urinary System • Kidneys – produce urine • Ureters –transport urine to bladder •

Urinary System • Kidneys – produce urine • Ureters –transport urine to bladder • Urinary bladder stores urine • Urethra transports urine to exterior Figure 26. 1

Location and External Anatomy of Kidneys • Located retroperitoneally • Lateral to T 12–L

Location and External Anatomy of Kidneys • Located retroperitoneally • Lateral to T 12–L 3 vertebrae • Average kidney – 12 cm tall, 6 cm wide, 3 cm thick • Hilus – On concave (curving in or hollowed) surface – Vessels and nerves enter and exit • Renal capsule surrounds the kidney

Urinary System in Gross Dissection Figure 26. 3

Urinary System in Gross Dissection Figure 26. 3

Internal Gross Anatomy of the Kidneys • Frontal section through the kidney – Renal

Internal Gross Anatomy of the Kidneys • Frontal section through the kidney – Renal cortex – Renal pyramids – Renal pelvis • Major calicies • Minor calicies • Gross vasculature – Renal arteries – Branch into segmental arteries

Anatomy of the kidneys • Superficial outer cortex and inner medulla – The medulla

Anatomy of the kidneys • Superficial outer cortex and inner medulla – The medulla consists of 6 -18 renal pyramids – The cortex is composed of roughly 1. 25 million nephrons • Major and minor calyces along with the pelvis drain urine to the ureters

Nephron – The Functional Unit of Kidney • Nephron consists of: • Renal corpuscle

Nephron – The Functional Unit of Kidney • Nephron consists of: • Renal corpuscle • Renal tubule: – Proximal convoluted tubule (PCT) – Loop of Henle – Distal convoluted tubule (DCT) • Nephron empties tubular fluid into a system of collecting ducts and papillary ducts

 • Consists of: – Renal Corpuscle Glomerulus – tuft of fenestrated (perforations or

• Consists of: – Renal Corpuscle Glomerulus – tuft of fenestrated (perforations or apertures) capillaries – Glomerular (Bowman’s) capsule • Parietal layer – simple squamous epithelium • Visceral layer – consists of podocytes (cells in the Bowman’s capsule) • Blood travels from efferent arteriole to peritubular capillaries • Blood leaves the nephron via the efferent arteriole

Blood supply to the kidney • Blood flow to the kidney involves a portal

Blood supply to the kidney • Blood flow to the kidney involves a portal system • Renal Artery Interlobar Artery Arcuate Artery Interlobar Artery Afferent Glomerular Arteriole Glomerular Capillaries or Capillary Bed (Glomerulus) Efferent Glomerular Arteriole (Portal Vessel) Peritubular Capillaries (Capillary Bed) & Vasa Recta Interlobar Vein Arcuate Vein

 • Most locations in the body are: Arteries Capillary Bed Vein • But

• Most locations in the body are: Arteries Capillary Bed Vein • But there are 3 places in our body wherein we have what we call portal systems • What are portal systems? • Portal system – 2 capillary beds in between • Artery Capillary Bed Portal Vessel Capillary Bed Vein

Where can you find portal systems? 1. Hepatic Portal System 2. Kidney 3. Hypothalamic-Pituitary

Where can you find portal systems? 1. Hepatic Portal System 2. Kidney 3. Hypothalamic-Pituitary System Example in the liver: Arteries Capillaries Hepatic Portal Vein Liver Or Digestive Tract Arteries Capillaries Hepatic Portal Vein Capillaries Vein • • •

 • Glomerular Capsule or Bowman’s Capsule – named after Dr. Bowman

• Glomerular Capsule or Bowman’s Capsule – named after Dr. Bowman

Microanatomy of the Kidney • A. The Nephrons (Renal Tubules) – cuboidal epithelial cells

Microanatomy of the Kidney • A. The Nephrons (Renal Tubules) – cuboidal epithelial cells with microvilli • 1. Glomerular (Bowman’s) Capsule • a. encloses the glomerular capillaries • 1. glomerular filtration of blood – some of the fluid in the bloodstream filters out into the glomerular capsule

 • 2. Proximal Convoluted Tubule – location for tubular reabsorption • - the

• 2. Proximal Convoluted Tubule – location for tubular reabsorption • - the “good stuff” (sugars & amino acids) is reabsorbed back into the bloodstream (going from the proximal convoluted tubule into the peritubular capillaries)

 • Loop of Henle (“Nephron Loop”) • - located in the renal medulla

• Loop of Henle (“Nephron Loop”) • - located in the renal medulla • - consists of a descending portion and an ascending portion (limb) • Distal Convoluted Tubule – location for tubular secretion – certain specific chemicals are transported out of the peritubular capillaries into the distal convoluted tubule like excess H+, excess Na. Cl, pencillin antibiotics

 • The Urine Collecting Ducts (Papillary Ducts) – the nephrons empty into the

• The Urine Collecting Ducts (Papillary Ducts) – the nephrons empty into the urine collecting ducts, which conduct the urine down to the renal calyces of the ureter • The Ureters – are a 10 -inch long muscular tube that conduct urine from the kidneys to the urinary bladder by peristalsis

 • “Study without thought is labor lost; thought without study is perilous. By

• “Study without thought is labor lost; thought without study is perilous. By nature men are nearly alike, but through experience they grow wide apart. Those who are born wise are the highest type of men; those who become wise through learning come next; those who are dull-witted and yet strive to learn come after that. Those who are dull-witted and yet make no effort to learn are the lowest type of men” – Confucius