Title: The Urinary System Chapter 24 Lecture Notes
1The Urinary SystemChapter 24 Lecture Notes
- to accompany
- Anatomy and Physiology From Science to Life
- textbook by
- Gail Jenkins, Christopher Kemnitz, Gerard Tortora
2Chapter Overview
- 24.1 Kidney Functions
- 24.2 Urinary Path
- 24.3 Nephron Structure
- 24.4 Nephron Function
- 24.5 Glomular Filtration
- 24.6 Tubular Reabsorption and Secretion
- 24.7 Hormonal Regulation
- 24.8 Antidiuretic Hormone
- 24.9 Urine Transport
- 24.10 Fluid and Acid-Base Balance
3Essential Terms
- kidney
- produces urine to remove waste from the body by
filtration of blood - nephron
- structure within kidney that actually filters the
blood and composed of several parts - nitrogen waste
- produced by protein catabolism
- micturition
- process of releasing urine from the body
4Introduction
- Urinary System
- Eliminates non-useful metabolic byproducts such
as nitrogenous wastes - Comprised of two kidneys, two, ureters, one
urinary bladder and one urethra - Returns most water and useful solutes are to
bloodstream - Urine results from filtration of blood plasma
- Kidneys help maintain homeostasis
5Concept 24.1Kidney Functions
6Kidney Functions
- Regulate various properties of the blood
- Ionic composition
- pH
- Volume
- Pressure
- Glucose level
- Produces hormones
- Excretes waste and foreign substances
7Figure 24.1
8 Concept 24.2 Urinary Path
9- Paired kidneys are retroperitoneal organs
- Renal hilum
- Area for entry and exit of nerves, blood and
lymphatic vessels and ureter exit - 3 layers of connective tissue
- Renal capsule deep
- Maintains shape and forms barrier
- Adipose capsule middle
- Cushions and supports
- Renal fascia superficial
- Anchors to abdominal wall
10Figure 24.2a
11Figure 24.2b
12Internal Anatomy
- Renal cortex
- Renal Medulla
- Renal Pyramids
- Renal papilla
- Renal columns
- Renal lobe
- Nephrons functional unit of kidney, filters
blood - Papillary ducts
- Minor and major calyces
- Renal pelvis
- Renal sinus
13Figure 24.3a
14Figure 24.3b
15Blood Supply
- Renal arteries
- Afferent vessels supply 20 - 25 of resting
cardiac output - Segmental arteries
- Interlobar arteries
- Arcuate arteries
- Interlobular arteries
- Afferent arteriole
- One per nephron and divides into glomerulus
- Glomerulus
- Network of glomerular capillaries to filter blood
16(No Transcript)
17Figure 24.4b
18Blood Supply
- Glomerulus
- Glomerular capillaries form efferent arteriole
- Peritubular capillaries
- Vasa recta
- Interlobular veins
- Arcuate veins
- Interlobar veins
- Renal vein
- Efferent vessel carries blood to inferior vena
cava
19Concept 24.3 Nephron Structure
202 Parts of Nephron
- Renal corpuscle
- Filters blood plasma
- Glomerulus
- Glomerular (Bowmans) capsule
- Renal tubule
- Refines filtered fluid
- Proximal convoluted tubule (PCT)
- Loop of Henle (LOH)
- Distal convoluted tubule (DCT)
21Figure 24.5a
22Figure 24.5b
23Nephron Structure
- Loop of Henle
- Descending limb of loop of Henle
- Ascending limb of loop of Henle
- Cortical nephrons 80-85 of nephrons
- Corpuscles in outer cortex with short loops of
Henle - Juxtamedullary nephrons 15-20
- Corpuscles deep in cortex with long loops of
Henle - Thin and thick ascending limb
- Distal convoluted tubule
- Collecting duct
- Papillary ducts
24Nephron Structure Histology
- Glomerular Capsule
- Podocytes
- Capsular space
- Renal tubule and collecting duct
- Macula densa
- Juxtaglomerular (JG) cells
- Both comprise Juxtaglomerular (JGA) apparatus
- Regulate blood pressure within kidneys
25Figure 24.6a
26Figure 24.6b
27Concept 24.4 Nephron Function
28Functions of Nephron
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
- Removes substances from blood as waste
29Figure 24.7
30Concept 24.5 Glomerular Filtration
31Filtration Membrane
- Leaky barrier formed by endothelial cells and
podocytes - 3 layers
- Glomerular endothelial cell
- Fenestrations
- Mesangial cells
- Basal lamina
- Pedicles form filtration slits
32Figure 24.8a
33Figure 24.8b
34Filtration Process
- Use of pressure to force fluids and solutes
through a membrane - 3 reasons for large volume through renal
corpuscles - Large surface area of glomerular capillaries
- Mesangial cells
- Thin, porous filtration membrane
- High glomerular capillary blood pressure
35Net Filtration Pressure (NFP)
- NFP GBHP CHP BCOP
- Glomerular blood hydrostatic pressure (GBHP)
- Promotes filtration
- Capsular hydrostatic pressure (CHP)
- Opposes filtration
- Blood colloid osmotic pressure (BCOP)
- Opposes filtration
36Figure 24.9
37Glomerular Filtration Rate (GFR)
- Mechanisms that affect filtration pressure
- Adjust blood flow
- Alter available glomerular capillary surface area
- GFR controlled by 3 mechanisms
- Renal autoregulation
- Negative feedback by macula densa
- Neural regulation
- Hormonal regulation
38Figure 24.10
39Renal Autoregulation
- Renal Autoregulation
- Myogenic mechanism
- Tubuloglomerular feedback
- Neural Regulation
- Sympathetic neurons release norepinephrine to
vasoconstrict afferent arterioles - Hormonal Regulation
- Angiotensin II reduces GFR
- Atrial natriuretic peptide (ANP) increases GFR
40Table 24.1
41Hormonal Regulation of Tubular Reabsorption and
Secretion
- Angiotensin II and Aldosterone
- Regulate electrolyte reabsorption and secretion
- Antidiuretic hormone (AH)
- Water reabsorption
- Atrial natriuretic peptide
- Inhibits electrolyte and water reabsorption
42Renin-Angiotensin-Aldosterone System
- Blood pressure decrease results in renin release
by JG cells - Renin converts angiotensin into Angiotensin I
- Angiotensin I converted to active form
Angionensin II which - Decreases glomerular filtration rate
- Enhances reabsorption of NA, Cl-, and water
- Stimulates release of aldosterone to reabsorb
more Na, Cl-, and water
43Antidiuretic Hormone / Vasopressin
- Released by posterior pituitary
- Regulates facultative water reabsorption
- Principal cells
- Negative feedback mechanism
- ADH release stimulated by decreased
- Blood water concentration in blood
- Blood volume
44Figure 24.17
45Atrial Natriuretic Peptide
- Inhibits electrolyte and water reabsorption
- Released from heart in response to large increase
in blood volume - Suppresses secretion of aldosterone and ADH
- Results in increased urine output to decrease
blood volume and blood pressure
46Table 24.3