urinary system Flashcards
functions ?
Excretion:formation of urine to remove
Regulation:Modifying the volume and solute balance in plasma
where does excretion of urine occur in body?
through the kidneys to the Urethra
where does regulation occur in body?
mammalian kidney
position of the kidneys in the body?
near top of abdominal cavity, imbedded in adipose tissue, anchored by renal fascia, covered by renal capsule
Kidney internal structure?
an outer cortex, a medulla in the middle, and the renal pelvis in the region called the hilum
nephron?
produces urine in the process of removing waste and excess substances from the blood.
cortical nephron
-type of nephron(85%)
-tubular system penetrating into the medulla(short loop of Henle)
-function is excretion®ulation
blood flow into and around a
nephron?
Renal artery -> Afferent arterioles -> Glomerulus -> Arterioles(carries out of kidney)
functional role renal corpuscle?
-Blood is filtered by the glomerulus
-filtered fluid (glomerular filtrate) is collected in the Bowman’s capsule
round part of nephron, before the proximal tubular
functional role of proximal convoluted tubule?
-absorption of H2O, organic molecules(glucose amino acids), vitmines & ions
-secretion of materials, drugs
-facilitated diffusion&cotransport.
-osmosis through aquaporins
functional role of loop of Henle?
-absorption of H2O, Na+,Cl-
-reabsorbs 25% H2O, Na+,Cl-
functional role of distal convoluted tubule?
-absorption of Na+, Ca2+, H2O
-Secretion of ions, acids, drugs&toxins
regulating extracellular fluid volume and electrolyte homeostasis
functional role of collecting duct?
-final adjustments to osmolarity of filtrate(by collecting duct)
-Papillary duct receives filtrate from several medullary collecting ducts
processes in urine formation and know where they occur?
-Glomerular filtration:filtered to remove excess fluid and waste
-Tubular reabsorption:back into the bloodstream
-Tubular secretion: removed from the renal tubular cells -> collecting duct. final step in urine formation
how is glomerular filtration rate controlled?
-Local autoregulation
-Hormonal regulation
-Autonomic regulation (involuntary)
how do hormones influence absorption in the tubules?
The hormone also promotes sodium retention and loss of potassium and hydrogen ions by the kidney
flow of urine from the kidneys to the urethral opening (in males)?
Kidney → Ureter → Urinary bladder → Urethra
flow of urine from the kidneys to the urethral opening (in females)?
Kidney → Ureter → Urinary bladder → Urethra
structure/layers of the ureters?
-innermost mucosa:expansion&contraction
-muscularis: consisting of longitudinal&circular smooth muscle
-outermost adventitia:fibrous connective tissue
structure of the bladder?
-Mucosa
-muscularis:detrusor muscle
-adventitia:visceral. peritoneum
structure of the urethra?
thin walled muscular tube
-mucosa
-muscularis
-adventia
processes that lead to urination?
-bladder expands to hold urine, nerve signals are sent to brain
-brain signals the bladder muscles to tighten, or contract, and the sphincter muscles to relax
-squeezed out of the bladder and through the urethra
kidneys?
produce urine
ureters?
transport urine toward the urinary bladder
urinary bladder?
temporally stores urine
urethra
conducts urine to exterior; in males, it also transports semen
mammalian kidney
-filters out everything in blood plasma
-reabsorbs useful organic molecules like amino acids, sugars, vitamins, proteins
juxtamedullary nephron
-type of nephron(15%)
-tubular system extending DEEP into the medulla(long loop of Henle)
-function is excretion, regulation&modulating water concentration of urine
proximal convoluted tubule cell types lining
-simple cuboidal microvillar epithelium
renal corpuscle cell types lining
-outer parietal layer simple squamous epithelium
-visceral layer is simple squamous epithelium lined by podocytes
loop of Henle? cell types lining
-descending limb: simple squamous epithelium
-ascending limb:cuboidal epithelium
Loop of Henle:Descending limb
-permeable to water(via aquaprins) but NOT ions
-part of countercurrent multiplication
Loop of Henle: Asending limb
-permeable to ions, but NOT water (no aquaporins)
distal convoluted tubule cell types lining
-Simple cuboidal epithelium
collecting duct cell types lining
-simple cuboidal epithelium
-principal cells
Aldosterone hormone?
-increases # of Na+/K+ counter transporters
-in DCT&CD
Parathyroid hormone & Calcitriol?
-increase CA+ absorption&phosphate excretion
-in DCT&CD
Antidiuretic hormone (ADH)
-stimulates water reabsorption in distal tubules
-DCT&CD
Healthy urine levels?
low levels of
-glucose
-Ketons
-lipids
-amino acids
-RBC & WBC
if GFR drops?
-blood pressure goes down
-efferent arteriole constricts
-afferent arteriole dilates
increase GFR
in autoregulation to/from the glomerulus
If GFR is too high?
-blood pressure goes up
-efferent arteriole dilates
-afferent arteriole constricts
decrease GFR
in autoregulation to/from the glomerulus
