bio

major structures of urinary system

kidneys, ureters, bladder, urethra

function of urinary system

elimination of wastes/toxins, regulation of fluid and other levels/substances

relationship with cardiovascular system

production of RBCs (EPO), regulation of BP/fluid content/electrolytes, regulation of calcium

what wastes does the urinary system eliminate

metabolic wastes, N containing compounds (urea), hormones, drugs

where does urea/uric acid come from

breakdown of proteins in the liver

what electrolytes are in the blood

Na+, K+, PO4 3+

what does calcitriol do

increase in blood Ca2+

gluconeogenesis location

live and kidney cortex

when does gluconeogenesis happen

during extended fasting or starvation

what does gluconeogenesis do

produce glucose from non-carbohydrates, maintains BGL and protect the brain

kidney location

retroperitoneal

anterior surface of kidney covered by

parietal peritoneum

kidney covered by

fibrous capsule, perinephric fat, renal fascia, paranephric fat

what happens in the cortex

production of EPO and urine

what makes up the medulla

pyramids and major/minor calyxes

what does the medulla do

collect urine

renal corpuscle

glomerulus and bowmans capsule

renal tubule

proximal convoluted tubule, nephron loop, distal convoluted tubule

where does reabsorption happen

proximal convoluted tubule

principal cells

bind aldosterone and ADH

intercalated cells location

distal convoluted tubule

type A intercalated cells

H+

type B intercalated cells

HCO3-

cortical nephrons

in cortex, 85%

juxtamedullary nephrons

corticomedullary junction, 15%

what do juxtamedullary nephrons do

salt balance, activity of ADH

what are granular cells made of

modified smooth muscle

what do granular cells do

produce and store renin, restore perfusion in kidneys

where is the macula dense

distal convoluted tubule near afferent arteriole only

what does the macula dense do

detect NaCl concentration, release renin

what does filtration do

monitor BP and components, flow of blood in and out of kidneys, flow though nephron and other structures

what does reabsorption do

movement of water/substances back into plasma, a balancing act from tubules

glomerular filtration

water and solutes (no protein), pressure differences

tubular reabsorption

into the blood, passive and active processes, pertubular capillaries and vasa recta

tubula secretion

into urine

filtration details

materials from the fenestrated capillaries move thru the membrane

what does the filtration membrane block

formed elements (endothelium), large proteins (basement membrane), small proteins (slits)

mesangial cell location

capillary loops in capsule

what do mesangial cells release

cytokines, prostaglandins

what do mesangial cells do

phagocytize macromolecules

hydrostatic pressure in glomerulus

HPg

blood colloid osmotic pressure

OPg

capsular hydrostatic pressure

HPc

intrinsic controls of filtration pressure

mean arterial pressure, afferent arteriole response

extrinsic controls that adjust rate

decrease to glomerular filtration rate

ANS- decreased blood flow from afferent arteriole, mesangial cells contract

results of extrinsic controls

decreased urine production, retain fluid, maintain BP

small plasma proteins

insulin and angiotensin II

transmembrane proteins

thresholds determined by # of proteins, reabsorb all nutrients

reabsorption of glucose

active transport

reabsorption of Na+

facilitated diffusion

reabsorption of H2O

thru aquaporins, follows Na+

reabsorption of ADH

independent

reabsorption of K+

passive transport, concentration gradient set up by movement of Na+ and H2O

where is 10-20% of K+ reabsorbed

nephron loop

what are affected by aldosterone

collecting tubules and ducts

effect of ADH

reabsorb H2O

where does the exchange of water and salt occur

nephron loop, vasa recta, interstitial area

renal plasma clearance

volume of plasma that can be cleared in a given amount of time (1 min), useful for medicine dosage

how much of the kidney is renal failure

90%, damage to glomerulus and blood vessels

treatments of renal failure

peritoneal dialysis, hemodialysis, kidney transplant

urine composition

95% H2O and 5% solutes

urine pH

4\.5-8

urine volume

1-2L/day

what is specific gravity

solutes

decrease urine volume

increase ADH and aldosterone, decrease ANP/fluid intake/BP, increase in fluid output

increase urine volume

decrease ADH and aldosterone, increase ANP/fluid intake/BP, diabetes mellitus and diuretics

micturition- sympathetic division of ANS

contraction of internal sphincter, inhibits detrusor muscle, storage reflex, reduce filtration in glomerulus, suppress urination

micturition- parasympathetic division of ANS

relaxation of internal sphincter, contraction of detrusor muscle, urination

where is the micturition center

pons

at what mL does urination occur

500-600mL

storage reflex

autonomic and somatic control, allows filling of bladder, detrusor muscle relaxes, internal sphincter contracts

intracellular fluid

K+, Mg2+, PO4 3-, 60%

extracellular fluid

Na+, Ca2+, Cl-, HCO3-, plasma and interstitial fluid, 40%

what causes fluid movement

hydrostatic pressure, osmosis

fluid depletion

hemorrhage, burns, vomiting, hyper secretion of aldosterone

dehydration

profuse sweating, diabetes mellitus, hypo secretion of ADH, cold exposure

hypotonic hydration

hyper secretion of ADH, more usually drinking excess water

edema

changes in cardiovascular and lymphatic system, changes in net filtration pressure at capillaries

ascites

accumulation of fluid in peritoneal cavity

pericardial effusion

fluid in pericardial cavity

pleural effusion

fluid in pleural cavity

where is the thirst center

hypothalamus → cerebral cortex

activation of thirst center

decreased salivary secretions, increased blood osmolarity, decreased blood volume → pressure

what does the release of renin do

angiotensin II → signals thirst center

deactivation of thirst center

distention of stomach, inhibition of thirst center, increased salivary secretions, decreased blood osmolarity, increased blood volume

hormonal control of fluid output

angiotensin II, ADH, aldosterone, ANP

nonelectrolytes

do not disassociate in water, do not form ions (glucose, urea, creatine)

electrolytes

disassociate in water (salts, ions, negatively charged proteins, acids, bases)

sodium balance

99% in ECF, maintained by pumps, NaHCO3 and NaCl

potassium balance

98% in ICF, control of heart rhythm, regulation complicated by other cations

Cl-

most abundant anion in ECF, regulated with Na+

Ca2+

stored in bones and teeth with PO4 3-, removed from cells or stores in muscle

PO4 3-

most abundant anion in ICF

Mg2+

stored in bone and cells

what produces constant angiotensinogen

liver

angiotensin II

increases BP and volume, response to decrease in blood volume or pressure and SNS stimulation

ADH

increase thirst and retain fluid, responds to low blood volume/pressure and increased osmolarity

aldosterone

decreased urine output and increased blood volume/pressure; responds to increased angiotensin II, decreased plasma Na+ levels, increased K+ levels

atrial natural peptide (ANP)

decreased urine output and increase blood pressure and volume; responds to increased angiotensin II and plasma K+ levels, decreased plasma Na+ levels

blood pH

7\.35-7.45