Chapter 15 Urinary Flashcards
Urinary system functions
Elimination of waste products
Regulates aspects of homeostasis
Waste products
nitrogenous wastes
toxins
drugs
aspects of homeostasis
Water balance
electrolytes
acid-base balance in the blood
blood pressure
red blood cell productoin-Erythropoietin
Activation of vitamin D
Organs of urninary system
Kidneys (2)
Ureters (2)
Urinary bladder
urethra
Kidney location
lateral to the vertebral column
against the dorsal wall (retroperitoneal)
at the level of T12 to L3 vertebrae
Right kidney is slightly lower than left due to liver position
Kidney structure
Regions of kidney
Renal cortex
renal medulla
renal pelvis
renal or medullary pyramids
renal columns
calyces
renal cortex
Renal medulla
inner region of kidney
Renal pelvis
funnel shaped collecting tubes
renal or medullary pyramids
triangular regions of tissue in the renal medulla
contain nephron loops and collecting ducts
renal columns
extensions of cortex-like material inward that separates the mudullary pyramids
calyces
cup shaped structures that receive urine from the collecting ducts
funnel urine towards the renal pelvis
Kidney blood supply
one quarter of total blood of the body passes through the kidneys each minute
renal artery provides each kidney with arterial blood supply
plasma: filtered at glomerous
most filtrate is reabsorbed by pertitubular capillaries
venous blood drains into the inferior vena cava
Nephron
Structural and functional units of kidneys
1 million per kidney
responsible for forming urine
nephron main structures
Glomerulus
capillary bed
site of plasma filtratoin
filtrate enters glomerular capsule
renal tubule
extends from glamerular capsule and ends at the collecting duct
filtrate is processed as it flows through nephron
Collecting duct
receives fluid from many nephrons
concentrates urine by reabsorbing water
directs urine into the calyces and renal pelvis
peritubular capillaries
Urine formation
filtration
reabsorption
secretion
urine filtration
from glomerulus to glomerular capsule
urine reabsorption
nutrients, most electrolytes and most water
reabsorbed substances enter peritubular capillaries
urine secretion
urine characteristics
about 1-1.8 L per day
min .4 L per day (obligitory water loss)
urine and filtrate are different:
urine filtrate
urine
what remains after most of the water, nutrients and necessary ions have been reabsorbed from the filtrate
Urnine characteristics
Ureters
slender tubes about 10”
begin at renal pelvis and end at the posterior aspect of the bladder
lined with mucous membrane to protect against acidic urine
has a muscular layer: peristalsis propels the urine into the bladder
Urinary bladder
Urethra
urethra sphincters
internal: involuntary made of smooth muscle
external: skeletal muscle voluntary
Micturition (urination)
process of voiding the bladder
