Urinary System Flashcards
Learn the urinary system!
What are the main structures that make up the urinary system? (4)
- Kidneys
- Ureters
- Bladder
- Urethra
What are the functions of the kidneys (4)
- FILTRATION: filters plasma constituents from blood.
- REABSORPTION: reabsorbs water and useful constituents from the filtrate.
- EXCRETION: excretes the excess filtrate.
- HOMEOSTASIS: maintaining the constant condition of the internal environment of the body
Where are the kidneys located?
- Dorsal part of the abdominal cavity on either side of the aorta and vena cava.
- Ventral to the first few lumbar vertebrae.
- Outside the peritoneal cavity attached to the body wall
What is the Renal Hilus?
The area of the kidney where blood vessels and nerves enter the ureter and lymphatics leave.
What is the Renal Pelvis?
The expanded origin of the ureter within the kidney.
What is the function of the renal pelvis?
To receive urine from the collecting tubules of the kidneys
What is the Medulla of the kidney?
- The portion of the kidney that is surrounding the renal pelvis.
What is the structure of the Medulla? What does it contain? (2)
The Medulla has a striated appearance due to radially arranged collecting tubules
Contains:
- Loops of Henle
- Collection tubules
What forms the basis of the renal pyramids?
The collection tubules in the medulla of the kidney
Where is the Cortex located?
Between the Medulla (inside) and the thin connective tissue capsule of the kidney (outside)
Where is the Medulla located?
- Below the cortex as the innermost portion of the kidney
What is located in the cortex of the kidney? (3)
- Renal Corpuscles
- Proximal convoluted tubule
- Distal convoluted tubule
What is the appearance of the Cortex and why does it appear that way?
Granular in appearance because fo the large number of renal corpuscles
How much blood does the kidney receive?
About one fourth (1/4) of the cardiac output.
Two renal arteries enter the kidney through the hilus and divide into a number of large branches. What are the names of the branches that the interlobular arteries become? (2)
- Arcuate arteries
2. Afferent arterioles
What is a glomerulus?
A capillary network within the kidney that is formed by the afferent arteriole branches
What do the afferent arterioles of the kidney become?
A capillary network that forms the glomerulus
What do the efferent arteriole branches of the kidney become once they have left the glomerulus?
They break up into a capillary network that surrounds the rest of the Nephron.
What are Arteriae Rectae?
Capillary networks around collecting tubules and loops of Henle in the kidney.
What is the functional unit of the kidney?
The Nephron
What structures does a Nephron include? (4)
- Glomerulus
- Glomerular Capsule (Bowman’s Capsule)
- Proximal Convoluted Tubule
- Distal Convoluted Tubule
What structures are involved in venous drainage of the kidneys? (4)
- Venae rectae
- Interlobular veins
- Arcuate veins
- Renal vein
Where does the lymph drain to from the kidneys?
The renal lymph nodes
What nerves supply the kidneys? (2)
- Sympathetic nerves from the renal plexus which follow blood vessels and terminate largely on glomerular arterioles.
- Vagus nerves may also supply the kidneys
What is the Ureter and what is it’s function?
- The ureter is a muscular tube running from the kidney to the bladder.
- Function: Carries urine from the kidneys to the bladder.
What is the structure and location of the Urinary bladder?
- A hollow muscular organ which varies in size and amount of urine it contains.
- When the bladder is empty it is thick walled, pear shaped and located on the floor of the pelvis
- When the bladder fills the wall becomes thinner and the bladder is displaced cranial toward the abdominal cavity.
What is the function of the urinary bladder?
To store urine received from the kidneys via the ureters before expulsion.
What controls the passage of urine from the bladder into the urethra?
the circular arrangement of muscle at the neck of the bladder which forms a SPHINCTER.
The neck of the bladder is continuous with what structure?
The urethra
What type of tissues line the pelvis, ureter, bladder and urethra? (1)
They are all lined with transitional epithelium
What are the two types of urethra?
- Penile urethra
2. Pelvic urethra
What is Micturition?
- the expulsion of urine from the bladder.
- a reflex activity stimulated by the distention of the bladder
How does Micturition occur?
reflex centers in spinal cord stimulated –> causes contraction of the muscle wall of the bladder by way of parasympathetic nerves.
How can reflex emptying of the bladder be prevented?
by voluntary control of the external sphincter surrounding the neck of the bladder.
What does the kidney regulate to ensure the homeostasis of the body? (5)
- water balance
- pH
- Osmotic pressure
- Electrolyte levels
- Concentration of many plasma substances
What is the Glomerular (Bowman’s) Capsule?
- the expanded blind end of the tubule in the nephron.
- almost entirely surrounds the nephron.
What does the visceral layer of the glomerular capsule do?
Surrounds the capillaries of the glomerulus
What is the parietal layer of the glomerular capsule continuous with?
- it is continuous with the convoluted tubule
What is a Renal (Malpighian) Corpuscle?
The complec formed by the glomerulus and inner and outer layers of the glomerular capsule
What is the function of the Renal Corpuscle?
To filter fluid from the blood
- about 100x as much fluid passes through this filter than is excreted as urine
In order for the Renal Corpuscle to filter effectively what conditions must be met and how are they met?
CONDITION: the blood pressure within the capillaries of the glomerulus must remain relatively high
ENSURED BY:
-the capillaries being on the course of an artery between and artery and a vein.
- the afferent and efferent arterioles are supplied with smooth muscle so they control the glomerular pressure.
where are juxtaglomerular cells located?
in afferent arterioles approaching the glomerulus