The Urinary System Flashcards
List the organs included in the renal system
- 2 kidneys
- 2 ureters
- 1 bladder
- 1 urethra
State the role of the 2 ureters
transport urine from the kidneys to the bladder
State the role of the bladder
temporary urine storage
State the role of the urethra
transports urine from the bladder to outside the body
Where is urine formed?
In the kidneys
What waste products are eliminated through the renal system?
drugs
toxins
nitrogenous wastes
What aspects of homeostasis is regulated by the renal system?
- water balance
- electrolyte balace
- acid balance in blood
- blood pressure regulation
- red blood cell production
- activation of Vitamin D
Describe the positioning of the kidneys?
- upper, posterior abdominal wall
- left kidney slight higher than right due to the liver sitting above the right kidney
What are the kidneys protected by?
thick outer fibrous capsule, surrounded by bed of fat, protected by lower limbs
What is the ‘hilum’ and what happens there?
The concave border of the kidneys that renal arteries and nerves enter and renal veins and ureters exit
What are the two main parts of the kidney
cortex (inner)
medulla (outer)
Kidney structures: describe the renal or medullary pyramids
triangular regions of tissue in the medulla (outer)
Kidney structures: describe the renal columns
extensions of cortex-like material inward that separate the pyramids
Kidney structures: describe the calyces
cup-shaped structures that funnel urine towards the renal pelvis
Kidney structures: describe the renal pelvis
funnels urine toward the ureter
What does the ureters do?
drain urine from the kidneys to the bladder
Explain the muscle within the ureters
Layers of both longitudinal and circular smooth muscle which propels the urine along the structures
What does the mucosal membrane line?
Renal pelvis and ureters
What does the layers of mucous protect within the pelvis and ureters?
Protects the epithelial cells form urine as the pH of urine can differ drastically and would damage cells
What is the bladder?
A reservoir for urine
A muscular sac that can expand considerably
Where is the bladder situated?
the pelvic cavity but when full it expands not the abdominal cavity
What are the 3 layers of the bladder?
1 - inner and outer layers of longitudinal muscle fibres
2 - middle layer of circular muscle fibres
3 - lined with mucosal membrane
What is the urethra?
A muscular tube that carries urine from the bladder and out of the body
What is a nephron?
the basic functional unit of the kidneys where plasma is filtered and urine is formed
How many nephrons are in each kidney?
about 1 million
What are the 4 main parts of a nephron?
- Glomerular capsule/Bowman’s capsule
- Proximal convoluted table
- Loop of henle
- Distal convoluted tubule
Simplify the blood flow in the kidneys
1 - renal artery enters the kidney
2 - arteriole enters the glomerular capsule of each nephron and divides into capillary network called the glomerulus:
- afferent and efferent arterioles
3 - efferent arterioles forms another capillary network which surrounds the rest of the nephron before reforming as veins
Explain the formation of urine
- the first stage is filtration: water and solutes in blood are filtered out of the blood stream - the filtered fluid is called ‘filtrate’
- filtrate flows out of glomerular capsule through tubule
- most of filtrate is reabsorbed back into blood as it passes through the tubule
- some substances pass from blood into filtrate
3 simple steps for formation of urine
- filtration
- reabsorption
- secretion
Explain when filtrate becomes ‘urine’
After leaving the collecting duct the processes of reabsorption and secretion are completed, the fluid is now classed as ‘urine’
What is urine?
Urine is what remains after the filtrate has lost most of its water, nutrients and necessary ions
What does urine contain?
Water (95%) Nitrogen wastes (5%) urea, creatinine, ammonia, uric acid Electrolytes Hydrogen ions
Define electrolytes
Inorganic compounds which dissociate into ions in solution