Urinary System Flashcards
Why must the internal environment of the body be maintained?
Must be maintained in specific limits in order for its chemical reactions and cellular activities to continue normally
How does the body get rid of waste and how much?
Most waste, excess and toxic substances are eliminated from blood plasma through the kidneys and excreted from body in the urinary system. 200L a day
How do the kidneys adjust blood chemistry?
By regulating levels of waste from cell metabolism, acid water balance, water balance, ion level, hormones (erythropoeitin and renin) and metabolises vitamin D
What does the urinary system consist of?
2 kidneys (left higher than right), urinary bladder, 2 ureters and the urethra
Define excretion or secretion.
the passage of substances and fluid from the blood into the nephron (the tubules and the collecting duct)
Define reabsorption
passage of substances and fluid from the filtrate back into the blood (the peritubular capillaries or vasa recta)
Where is the location of the kidneys?
Posterior to the abdominal peritoneum on either side of the vertebrae
Where do the adrenal glands sit?
On top of the kidneys
What colour are the kidneys?
Reddish brown
What is the indentation on the kidney called and what does it contain?
It is called the hilus and is where the ureter, blood vessels, lymph vessels and nerves enter the renal pelvis.
How does blood flow occur in the kidneys?
Blood flows in via the renal arteries (from abdominal aorta) and flows out via renal vein to inferior vena cava
What does the renal capsule do?
Directly surrounds kidney
What does the adipose capsule do?
Layer of fat to help cushion the kidney
What does the renal fascia do?
covers adipose capsule and kidney. Also anchors kidney to surrounding structures
What are the 2 main regions of the kidneys?
The cortex (reddish outer region )and the medulla (reddish brown inner region containing renal pyramids)
How does the renal pyramids and the ureter connect?
Small tubules from the pyramids join together to form a large cavity called the renal pelvis. The urine from the renal pelvis passes into the ureter
What is a nephron?
Functional unit of kidneys with more than a million in each kidney
What are the 2 types of nephrons?
Juxtamedullary (extend deep into the medulla-urinary concentration) and Cortical (85% occasionally penetrate the medulla)
What does each nephron consist of?
A dense network of capillaries called glomerulus surrounded by a cup shaped Bowmans capsule and the renal tubules.
What do the glomerulus and the Bowmans capsule make up and where are they found?
A filtration system through which blood is filtered. Found in the cortex of kidney
What are the 2 types of tubular secretion?
Active and passive
What is active tubular secretion?
Sodium ions takes up 80% of our transport because its needed to produce energy (na/k pump) in order to power the other solutes as well as glucose, amino acids and vitamins
What is passive (diffusion) tubular secretion?
Along the pressure gradient; H2O, fats K+, Cl, lipid soluble drugs are difficult to excrete because of above
What is GFR?
The total amount of filtrate formed per minute by the kidneys
What are factors governing filtration rate at the capillary bed?
Total surface area available for filtration, filtration membrane permeability and net filtration pressure
What is normal GFR in both kidneys?
120-125 ml/min
Why do the kidneys adjust their smooth muscle?
In response to changes of blood pressure. If blood vessels are stretched, smooth muscle contracts. If BP is too low, smooth muscle dilates
What do the specific cells that are part of the juxtaglomerular apparatus do?
Surround distal tubule and monitor the concentration of NaCl in the filtrate. If concentration is high, smooth muscles of arterioles constrict and too low dilation occurs
What occurs to the sympathetic nervous system under stress?
Noradrenaline released by sympathetic nervous system, adrenaline released by adrenal medulla, overall effect is constriction of afferent arterioles and inhibition of filtration and renin-angiotensin mechanism is stimulated
What are the uteters?
Continuation of renal pelvis and enter bladder at angle so when bladder is full, ureters compressed to prevent backflow
