Urinary System Flashcards
urinary system function
filter blood and create urine as a waste by-product
organs of the urinary system
kidneys, ureters, urinary bladder and urethra
excretory system functions
separating waste from body fluids and eliminating them
- metabolites - substance made/used when the body breaks down
- drugs
- toxins
homeostatic function
- maintenance of water balance
- electrolyte balance
- regulation of blood pressure (ECF balance) - maintenance of acid-base balance
endocrine function (secretory)
the kidney renin and juxtaglomerular complex
- erythropoietin -> RBC production
- prostaglandins
- kidneys convert vitamin D3 into active 1,25 dihydroxycholecalciferol
excretion
separating wastes from body fluids and eliminating them
body systems that excrete:
- respiratory, integumentary, digestive, urinary system
nitrogenous wastes and metabolic waste
- any substance that is useless to the body or present in excess of the body’s needs
- waste substance produced by the body
urea formation
- molecule that is produced by protein metabolism and found in urine
proteins -> amino acids -> NH2 removed -> forms ammonia, liver then converts ammonia to urea
liver converts ammonia to
urea
uric acid
product of nucleic acid catabolism (breakdown)
creatinine
product of creatine phosphate catabolism
blood urea nitrogen (BUN)
level of nitrogenous waste in blood
azotemia BUN
elevated BUN
- may indicate renal insufficiency
- kidneys are having trouble excreting waste which increases nitrogenous waste
Uremia BUN
syndrome of diarrhea, vomiting, dyspnea, and cardiac arrhythmia stemming from the toxicity of nitrogenous waste (too much waste for body)
- treatment is hemodialysis or organ transplant
dialysis- blood is filtered of waste and pumped back into the body
three protective coverings of the renal organ
- renal fascia - binds to abdominal wall
- perirenal fat capsule- cushions and holds kidneys in place
- fibrous capsule- encloses kidney to protect it from trauma and infection
ureter
tubular continuation that drains urine down from the kidneys to the urinary bladder
micturition
the act of urination
sympathetic stimulation innervation on the bladder
hypogastric nerve
- relaxes detrusor muscle to store urine
- constricts internal urethral sphincter
parasympathetic stimulation in the bladder
Pelvic nerve
- contracts detrusor to evacuate urine
somatic innervation in the bladder
voluntary, Pudendal nerve
- stimulation constricts external urethral sphincter
Sympathetic activity predominates (normal bladder filling)
- Pudendal nerve contracts external sphincter m. (somatic)
- hypogastric nerve contracts internal sphincter m. (sympathetic)
- inhibition of pelvic n. to detrusor m. allows relaxation
- as bladder fills, pressure stimulates sensory branch of pelvic n. and sends information to hypogastric to relax further
Parasympathetic activity predominates (normal micturition)
inhibition of hypogastric n. sympathetic activity on detrusor and internal sphincter m .
- voluntary inhibition of pudendal n. to relax external sphincter
- PSN stimulates via pelvic n. contracts detrusor m.
Renal Circulation
- high renal blood flow does not reflect O2 consumption
- high blood flow relates to the homeostatic function of the kidney (high rate of glomerular filtration)
Renal Blood Flow Chart
renal artery -> afferent arteries -> glomerulus -> THEN efferent arterioles -> venous system
Nephron
functional unit of the kidney
- 1.2 million nephrons in each kidney
- capable of forming urine
- kidneys cannot regenerate new nephrons, so with any damage to nephrons, there is less filtration or urine creation occurring
nephron composed of two principal parts:
- renal corpuscle- filters the blood plasma ( group of blood vessels, glomerulus inside)
- renal tubule- long, coiled tube that converts the filtrate into urine
renal corpuscle
consists of the glomerulus
- parietal outer later
- viscerla internal layer w/ cells called podocytes that wrap around the capillaries of the glomerulus
afferent arterioles
in the glomerulus
- produce filtrate