Module 25- GU Anatomy Flashcards
What are the two main functions of the urinary system?
- keep track of electrolytes, water content, and acids of the blood
- removes metabolic wastes, drug metabolites, and excess fluids
What is part of the urinary system?
- kidneys
- filter 200 L of blood each day
What is a renal disorder?
- kidney disease
On an average how many Canadians are told their kidneys have failed?
- an avg of 15
- Each year there is a 7% increase in the number of people diagnosed with kidney disease
- 43,200 are being treated for kidney failure
What does kidney disease also contribute to?
- risk of cardiovascular disease
- hypertension
- other chronic diseases
What do our kidneys do?
- filter blood and produce urine
- bean-shaped
- found in the retroperitoneal space
- Aid electrolyte balance
What is the hilum of the kidneys?
- Cleft formed on the medial side of the kidney
- Where ureters, renal blood vessels, lymphatic vessels and nerves enter and leave kidney
What does the urinary bladder do?
- stores urine until is released
What do ureters do?
- transport urine from the kidneys to the bladder
What does the urethra do?
- transports urine from the bladder out of the body
What is the renal fascia? What does the renal fascia do?
- layer of dense fibrous connective tissue
- anchors the kidney to the abdominal wall
What is the internal anatomy of the kidney?
- Cortex
- Medulla
- Renal pelvis
Cortex
Light colored, outer region closest to the capsule
Medulla
- Middle layer
- Includes the cone-shaped renal pyramids, and renal columns
Renal pyramids
- Flat, funnel shaped tube that fills the sinus at the level of the hilum
What is the calyces?
- Branch off the pelvis and connect with the renal pyramids to receive urine draining from the collecting tubules
Approximately how much of the body’s systemic cardiac output of blood flows through the kidneys each min?
-approx one-fourth
How does blood flow from the abdominal aorta into the kidney?
- By the way of the renal artery
Branches into the:
- Afferent arteriole, then into
- Glomerulus- (main filter for the blood) then enters
- Efferent arteriole, branches into
- Peritubular capillaries (tubular reabsorption occurs)
What is unique to the kidney?
- The secondary set of capillaries is unique to the kidney
- No other organ in the body has two distinct capillary beds
- The capillaries merge to form venules and veins
- Until the rebel vein leaves the hilum
- Carrying cleansed blood to the inferior vena cava
Where are nephrons found?
- In the cortex
What are the nephrons?
- Structural and functional units of the kidney
What are nephrons composed of?
- Glomerulus
- Glomerular capsule
- Proximal convoluted tubule (PCT)
- Loop of Henle
- Distal convoluted tubule (DCT)
Each kidney contains approximately 1.25 million nephrons
What is the glomerular capsule?
- Double-layered cup
- Podocytes
- Glomerular filtration rate (GFR)
What are podocytes?
- Wrap around the capillaries forming filtration slits
- Filtrate passes through, and into the capsule
- Inhibits large proteins from entering
What is the Glomerular filtration rate (GFR)?
- Amount of filtrate produced
- Maintained at a relatively constant rate of 125 ml/hr
- Changes in the GFR cause many of the renal emergencies
What occurs at the Loop of Henle?
This where additional resorption of water and electrolytes occur
What are the 2 sections of the Loop of Henle?
- Descending limb (permeable to water but impermeable to sodium and chloride)
Ascending limb (impermeable to water but permeable to sodium and chloride)
What is the Juxtaglomerular apparatus?
- Site where the efferent arteriole comes in contact with the DCT
- Sensitive to pressure changes
- Release renin with changes in blood pressure
What two hormones control the final adjustment to the composition of urine?
- Antidiuretic (ADH): produced by hypothalamus, stored in pituitary
- Aldosterone- produced by adrenal glands
When is ADH released?
- When solute concentration of blood increases due to sweating or decreased fluid intake
- Increases permeability to water
- Water leaves DCT and collecting ducts and re enters the bloodstream
What does aldosterone do?
- increases the rate of active resorption sodium and chloride into the blood
What are diuretics?
Chemical that increase urinary output, work in a variety of ways
- A substance that is not reabsorbed from the filtrate will increase the amount of water retained in the urine
- alcohol encourages diuresis by inhibiting the production of ADH
- Caffeine and common diuretic medications such as Lasix inhibit the sodium importers in the DCT and collecting ducts
Where is the bladder?
Most of the bladder sits anterior abdominal cavity
- Dome of the bladder sits posterior or retroperitoneum
What does the bladder do when empty?
- The bladder collapses and the muscular walls fold over onto themselves
- When urine accumulated the bladder becomes pear shaped
- Stretching of the bladder produces the micturition reflex
What is micturition reflex?
- Stretching of the bladder wall stimulates nerve impulses
- Spinal reflex that causes contraction of the bladder’s smooth muscles, which in turn produces the urge to void as pressure is exerted
What is the female urethra?
- Exits at the site of the external genitalia
- 4 cm long on average
What is the male urethra?
- 20 cm long
Divided into three regions: - Prostatic- from bladder to prostate
- Membranous- prostate to penis
- Penile- through penis to external urethral opening
