Urinary System Flashcards
what does the urinary system consist of?
- two kidneys
- two ureters
- one urinary bladder
- one urethra
what are the kidneys main role?
- filter blood to produce urine
- maintain homeostasis by:
-> regulation of ion levels in the blood
-> regulation of blood volume and pressure
-> regulation of blood pH
-> production of hormones
what do kidneys consist of internally?
- renal cortex
- renal medulla
- renal pyramids
- renal columns
- major and minor calyces
- renal pelvis
what is the structure of the kidneys nephrons?
renal corpuscle:
- glomerulus & glomerular (bowman’s) capsule
renal tubule:
- proximal convoluted tube (PCT); nephron loop (of Henle); distal convoluted tubule (DCT)
what are the three basic processes involved in the production of urine?
- glomerular filtration
- tubular reabsorption
- tubular secretion
what occurs in glomerular filtration?
- blood plasma and dissolved substances get filtered into the glomerular capsule
what occurs in tubular reabsorption?
- water, ions, and other substances get reabsorbed from the renal tubule lumen into the peritubular capillaries and ultimately into the blood.
what occurs in tubular secretion?
- substances such as wastes, drugs and excess ions get secreted from the peritubular capillaries into the renal tubule.
- this forms urine.
what membranes are involved in glomerular filtration?
- endothelium of glomerulus
- podocytes of glomerular capsule
what is the path of urine drainage?
- collecting duct
- papillary duct
- minor calyx
- major calyx
- renal pelvis
- ureter
- urinary bladder
ureters function
- transports urine from the kidneys to the bladder
- as bladder fills, it expands and compresses the ureters preventing back flow.
detrusor muscle function
- stretches when the ladder fills and contracts to push out urine
urethra function
- small tube leading from the bladder to the outside
rugae function
- rugae and the lining transitional epithelium allow the urinary bladder to expand as it fills
peritoneum function
- helps hold the bladder in place
internal urethral sphincter function
- involuntary smooth muscle that opens and closes the urethra
external urethral sphincter function
- voluntary skeletal muscle that opens and closes the urethra
external urethral orifice function
- the opening of the urethra to the outside
what occurs during a micturition reflex?
- when vol of urine in bladder is over 200-400ml the pressure increases
- stretch receptors in trigone detect this
- impulses travel to micturition centre in spinal cord and trigger micturition reflex
- bladder filling causes sensation of fullness and conscious desire to urinate before micturition reflex occurs.
impulses during the micturition reflex
- contraction of the detrusor muscle in bladder wall (parasympathetic)
- relaxation of the internal urethral sphincter muscle (parasympathetic)
- inhibition of somatic motor nerves to cause relaxation f skeletal muscle in external urethral sphincter
what are the common problems related to aging and urination?
- UTI’s
- increased frequency of urination
- urinary retention or incontinence
- acute and chronic kidney inflammations
- renal calculi (kidney stones)
summary of abnormal constituents in urine: albumin
- very small amounts of blood plasma appear in urine as it is too large to be filtered
- presence of excessive albumin indicates an increase in the permeability of filtering membranes due to injury or disease, increased blood pressure or damage to kidney cells.
(ALBUMINURIA)
SOACIN: glucose
the presence of glucose in the urine usually indicates diabetes mellitus
(GLUCOSURIA)
SOACIN: red blood cells (erythrocytes)
- can occur with acute inflammation of urinary organs as a result of disease or irritation from kidney stones, tumours, trauma and kidney disease
(HEMATURIA)
