Download What is the anatomy of the urinary bladder?

Urinary System
John Minor and Jeremiah Shaw
What are the major parts of the urinary system?
Diagram of Urinary System
Celiac trunk
Esophagus (cut)
Left adrenal gland
Diaphragm
Left kidney
Left renal artery
Left renal vein
Inferior vena cava
Right adrenal
gland
Right kidney
Hilum
Aorta
Superior
mesenteric artery
Ureter
Quadratus
lumborum muscle
Left common
iliac artery
Gonadal artery
and vein
Iliacus muscle
Psoas major
muscle
Rectum (cut)
Urinary
bladder
Anterior view
Parts of Urinary System
• Kidneys – organs that have excretory functions and
produce urine
• Ureters – tubes leading from the kidneys to the
urinary bladder
• Urinary Bladder – a muscular sac for temporary
storage of urine
• Urethra – a tube that conducts urine to the exterior
What are the functions of the Urinary System?
Functions of Urinary System
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Regulation of blood pressure
Regulation of concentrations of ions in plasma
Stabilizing blood pH
Conserving valuable nutrients
Assisting liver in detoxifying poisons
What is the anatomy of the kidney?
Structure of the Kidney
Cortex
Medulla
Renal capsule
Medulla
Renal pyramids
Renal
pyramid
Renal sinus
Renal sinus
Connection
to minor calyx
Adipose tissue
in renal sinus
Minor calyx
Major calyx
Renal pelvis
Renal pelvis
Hilum
Major calyx
Hilum
Minor calyx
Renal lobe
Renal papilla
Ureter
Renal papilla
Renal columns
Ureter
Renal lobe
Renal capsule
(a)
(b)
Anatomy of Kidneys
• The kidneys lie on each side of the vertebral column
between T12 and L3
• Surrounded by three layers of connective tissue: renal
capsule, adipose capsule and the renal fascia
• Average kidney: 10cm x 5.5cm x 3cm, weighing
150g
• Left kidney lies slightly superior to the right kidney
Anatomy of Kidneys (cont.)
• Hilum: entry for the renal artery and nerves and an
exit for renal vein and ureter
• Renal sinus: internal cavity within the kidney
• Renal Pyramids: Triangular structures with bases at
the cortex and tips at the renal sinus
• Renal Medulla: structure containing 6 - 18 renal
pyramids
• Renal Columns: bands of tissue that separate renal
pyramids
Anatomy of Kidney (cont.)
• Cortex – superficial part of kidney
• Renal Papilla – the tip of each renal pyramid
• Renal Lobe – consists of a renal pyramid, the
overlying renal cortex and adjacent columns
• Renal Pelvis – a large funnel that drains the kidneys
How does blood flow through the kidney?
Blood flow of kidney
Afferent
arterioles
Interlobular
vein
Interlobular
artery
Arcuate artery
Interlobular
arteries
Arcuate vein
Interlobular
veins
Renal
pyramid
Nephron
Interlobar
arteries
Interlobar vein
Interlobar artery
Segmental
artery
Suprarenal
artery
(b)
Renal
artery
Renal vein
Renal artery
Renal
vein
Segmental arteries
Interlobar
veins
Arcuate
veins
Arcuate
arteries
(a)
Interlobar veins
Interlobar arteries
Arcuate veins
Arcuate arteries
Interlobular veins
Interlobular arteries
Venules
Afferent arterioles
NEPHRONS
Glomerulus
Peritubular
capillaries
Efferent
arteriole
(c)
Blood flow of kidney
• The kidney receives blood from the renal artery and
blood is removed by the renal vein
• Through a system of various types of arteries and
veins blood enters and exits the kidney
• At the lowest level the blood is passed through the
nephron which starts urine production
What is the anatomy of the nephron?
Proximal convoluted tubule
Distal convoluted tubule
Reabsorption of water, ions,
and all organic nutrients
NEPHRON
Secretion of ions, acids,
drugs, toxins
Variable reabsorption
of water, sodium ions, and
calcium ions (under
hormonal control)
Renal
tubule
Capsular space
Glomerulus
Efferent arteriole
COLLECTING SYSTEM
Afferent arteriole
Bowman’s capsule
Descending
limb of loop
begins
Ascending
limb of loop
ends
Collecting duct
Variable reabsorption of
water and reabsorption
or secretion of sodium,
potassium, hydrogen,
and bicarbonate ions
Renal corpuscle
Thick
ascending
limb
Production of filtrate
Thin
descending
limb
Descending
limb
Ascending
limb
Papillary duct
KEY
Water
Solutes
Loop of Henle
Filtrate
Further reabsorption of water
(descending limb) and both
sodium and chloride ions
(ascending limb)
Variable
reabsorption
or secretion
Minor
calyx
Delivery of urine
to minor calyx
Anatomy of the nephron
• The nephron consist of two parts, the renal corpuscle
and the renal tubule
• The renal tubule is a long tubular passage way
measuring about 50mm
• The renal corpuscle is a spherical structure consisting
of the Bowman’s capsule and the glomerulus
• The renal tubule consist of the proximal convoluted
tubule (PCT), distal convoluted tubule (DCT), and
the Loop of Henle
Anatomy of the Nephron (cont.)
• Glomerulus – system of about 50 intertwining
capillaries
• Bowman’s Capsule – a chamber that holds the
glomerulus with a visceral epithelium
How is urine produced?
Filtration
• The renal corpuscle is the site where filtration occurs
• Blood pressure forces water and other solutes out of
the glomerular capillaries
• This process produces a primarily protein free
solution called filtrate
Entry into the renal tubule
• After filtrate is formed it enters the renal tubule
• As filtrate travels through the renal tubule it becomes
tubular fluid with more of the characteristics of urine
• The renal tubule has 3 major functions:
- Reabsorbing all useful organic nutrients in the filtrate
- Reabsorbing more than 90% of water in the filtrate
- Secreting any waste products that failed to enter the
renal corpuscle through filtration
The Proximal Convoluted Tubule (PCT)
• The PCT is the first segment of the renal tubule
• The lining of the PCT is a simple cuboidal epithelium
whose surface bears microvilli
• Reabsorption is the main function of the PCT and it
reabsorbs organic nutrients, ions, water and plasma
proteins (if present)
Loop of Henle
• The second part of the renal tubule is the Loop of
Henle
• The Loop of Henle is divided into the descending
limb and ascending limb
• The descending limb flows toward the renal pelvis
and is lined with a cuboidal epithelium
• The ascending limb flows toward the renal pelvis and
is lined with a squamous epithelium
Distal Convoluted Tubule (DCT)
• The third part of the renal tubule is the DCT
• It is lined with a cuboidal epithelium that is not lined
with microvilli
• The DCT is necessary for three vital processes
- Selective reabsorption of Na and Ca ions
- Active secretion of ions, acids, drugs and toxins
- Selective reabsorption of water
The Collecting System
• The last segment of the nephron is the collecting
system
• The nephron drains into a collecting duct, which
drains into a larger papillary duct, which empties into
the minor calyx
• Final osmotic pressure and urine volume is
determined by the collecting system
General Characteristics of Urine
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pH range: 4.5 – 8.0 (average 6.0)
Specific Gravity: 1.003 – 1.030
Water Content: 93 - 97%
Color : Clear yellow
Odor: Varies with composition
Organic Waste Products
• Urea – most abundant organic waste, generate from
the breakdown of amino acids (21g)
• Creatinine – generated in skeletal muscle through the
breakdown of creatine phosphate (1.8g)
• Uric Acid – waste product from recycling the
nitrogenous base in RNA molecules (.48g)
Basic Processes of Urine Formation
• Filtration – blood pressure forces water from the
blood across the walls of the glomerular capillaries
• Reabsorption – the removal of water and solutes from
the filtrate and their movement across the tubular
epithelium
• Secretion – the movement of solutes from the outside
of the tubular epithelium (peritubular fluid) to the
inside
Glomerular Filtration Rate (GFR)
• GFR is the amount of filtrate produced each minute
• On average a GFR is about 125ml a minute, that is
around 180 liters of filtrate a day
• About 99% of filtrate is then reabsorbed by the renal
tubules
• One can test GFR with a creatinine clearance test
• The GFR can be regulate automatically or with the
use of hormones
What is the anatomy of the urinary bladder?
Urinary Bladder
Middle umbilical
ligament
Ureter
Lateral
umbilical
ligament
Rugae
Ureteral
openings
Internal
urethral
sphincter
External urethral
sphincter (in
urogenital
diaphragm)
Center
of trigone
Neck
Prostate
gland
Prostatic
urethra
Membranous
urethra
Anatomy of the urinary bladder
• The urinary bladder is a hollow muscular organ that is
a temporary reservoir for urine
• The superior surface of the bladder is covered with a
peritoneum and is stabilized by the middle umbilical
ligament and lateral ligaments
• The interior surface of the urinary bladder is thrown
into folds called rugae
• The ureters enter the bladder through ureteral
openings and meets the center of trigone
• The center of trigone lies superior to the neck which
opens to the urethra
Anatomy of urinary bladder (cont.)
• Internal Urethral Sphincter – (sphincter vesicae) an
involuntary sphincter that allows urine to leave the
bladder to the urethra.
• External Urethral Sphincter – a circular band of
muscles that is under voluntary control to allow for
urination
Histology of the urinary bladder
• The wall of the urinary bladder has three layers:
mucosa, submucosa and muscularis
• Muscularis layer has two layers, longitudinal smooth
muscular and circular muscle
• The two muscle layers form the detrusor muscle,
which contracts to expel urine out the urethra
What is the anatomy of the ureters?
Anatomy of the ureters
• The ureters are a pair of muscular tubes that extend
from the kidneys to the urinary bladder
• They are approximately 12in. in length
• The ureters are made from three tissues:
- An inner transitional epithelium layer
- A middle muscle layer made up of circular and
longitudinal layers
- An outer connective tissue in conjunction with the
renal capsule
Micturition Reflex
• The process of urination is coordinated by the
micturition reflex
• The urge to urinate arises when the urinary bladder
contains around 200ml of urine
• Nerves receive the signal that the bladder is
expanding
• The detrusor muscle contracts causing relaxation of
the internal and external urethral sphincters
What are the complications that occur with the
urinary system?
Urinary issues
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Aminoaciduria – amino acid loss in the urine
Calculi – insoluble deposits that form within the urinary tract
Glomerulonephritis – an inflammation of the renal cortex
Hematuria – the presence of blood in urine
Polycystic Kidney Disease – an inherited abnormality that
affects the development of the kidney tubule
• Proteinuria – the presence of protein in urine
• Renal failure – an inability for kidneys to function to maintain
homeostasis
• Urinary obstruction – a blockage of the urinary tract
Aging on the Urinary System
• A decline in the number of functional nephrons, 30 40% between 25 – 85
• A reduction in the GFR due to a lack of renal blow
flow and fewer glomeruli
• Reduced sensitivity to ADH, a hormone that reduces
the amount of water lost in urine
Professions
• Urologist – a doctor that specializes in urinary
diseases and function
• Urology Oncologist – a doctor that specializes in the
cancers of the urinary system
• Nephrologist – a doctor that specializes in the kidneys