Kidneys Flashcards
Parts of the excretory system:
- 2 kidneys
- 2 ureters
- urinary bladder
- urethra
Functions of kidneys:
- excrete wastes as urine
- homeostasis of body fluid and blood volume
- electrolyte balance
- balance pH
- produce and secrete hormones and vasoactive substances
Where are the kidneys located?
retroperitoneal: on posterior wall of abdomen behind peritoneum
Function of ureters:
- 1 in each kidney
- transports urine from renal pelvis into urinary bladder via peristaltic contractions induced by stretching of ureters
Ureters have what kind of muscles and is under what kind of control?
- smooth muscles
- myogenic control
Structure of urinary bladder:
layers of smooth muscle surround transitional epithelium lining and has an internal sphincter
- muscles are stretch activated and produces spontaneous APs
- not under conscious control
How do PNS fibers affect urinary bladder?
causes sustained contractions of the smooth muscles
- promotes emptying
Function of urinary bladder:
stores urine until micturition (pee)
- empties into urethra
How do SNS fibers affect urinary bladder?
causes contraction of internal sphincter
- prevents emptying
The urethra passes through…
the urogenital diaphragm
Structure of urethra:
skeletal muscle forms external sphincter
- under voluntary control
Examples of waste products:
- metabolites
- end products of hemoglobin and hormone metabolism
- drugs
- pesticides
- toxins
Examples of metabolites:
- urea (byproduct of aminio acid)
- uric acid (byproduct of nucleic acid)
- creatinine (byproduct of muscle)
How do the kidneys regulate homeostasis of body fluids?
via regulation of water and NaCl excretion
How do the kidneys balance pH?
- maintained via plasma buffers
- aided by actions of lungs, liver, and kidney
What hormones do the kidneys secrete?
- erythropoietin
- renin
- calcitriol
- prostaglandins and thromboxane
Function of erythropoietin:
in response to low O2 to stimulate RBC production
- eventually increases O2 level
Function of renin:
in response to low BP to activate angiotensin (vasoconstrictor)
- activates aldosterone to increase Na+ retention -> increase blood volume -> increase blood pressure
Function of prostaglandins and thromboxane:
vasoactive products that act locally
- afferent arteriole vasodilation
- increase in Na+ and H2O secretion
Function of calcitriol:
increases intestinal Ca2+ absorption and deposition into bone
Function of NSAIDs on kidneys:
block COX 1 and 2 (prostaglandins)
- Na+ and H2O retention
- hypertension
- hemodynamic acute kidney injury
What is the hilum of the kidney?
indentation on surface of kidney
- where blood vessels and nerves enter and exit kidney
- where ureter leaves kidney
Kidney is surrounded by…
dense CT capsule
Kidneys are internally divided into…
- cortex: vascular outer portion
- medulla: inner portion that is organized into lobes that have renal pyramids
- pelvis: innermost portion that collects urine
The medulla of the kidneys drain into…
minor calyces
The pelvis of the kidneys empty into the…
ureter