An elderly female patient has a history of chronic type II diabetes mellitus, and high blood pressure. She has come to the doctor today because she has notice blood in her urine. Her doctor is now primarily concerned about the effect of high blood pressure on her kidneys. What could be going on that explains all of this? How are blood pressure and kidney function related?

anatomy of urinary system

functions of urinary system

structure of kidney

filtration, reabsorption and secretion in nephron

GFR: amount of filtrate produced by kidneys each minute

Link from Renin to GFR, macula densa cells and HTN

effects of juxtamedullary nephron on the osmotic gradient

regulation of electrolyte balance w/ aldosterone and anti-diuretic hormone

  1. Regulating plasma ionic concentrations (Na+, K+, H+, Ca2+, Mg2+, Cl-, HCO3-, HPO4 2-

Location: retroperitoneal

structure: looks like a bean

stabilized by 3 layers:

fibrous capsule:

  • a layer of collagen fibers
  • covers outer surface of entire organ

perinephric fat:

  • thick layer of adipose tissue
  • surrounds fibrous capsule

renal fascia:

  • a dense, fibrous outer layer
  • anchors kidney to surrounding structures

ureter: paired tubes that come from kidneys

urinary bladder: muscular sac inferior to ureter and superior to urethra

urethra: exit tube

  1. regulating plasma volume and BP (H2O)
  1. regulating plasma osmolarity (solute vs. H2O)
  1. Regulating pH balance (H+ secretion; HCO3- reabsorption)
  1. Secrete metabolic waste products and toxins/ foreign chemicals

renal cortex: superficial region of kidney (in contact w/ fibrous capsule

renal medulla: layer deep to renal cortex and consists of renal pyramids

renal pyramids: triangular structure part of renal medulla

renal papilla: tip of each renal pyramid which projects into renal sinus

renal column: bands of cortical tissue that extend into medulla and separate adjacent renal pyramids

minor calyx: area that each renal papilla duct discharge urine

major calyx: merging area of minor calyces

renal pelvis: combo of major calyces

hilum: section between renal pelvis and ureter

structure of nephron:

efferent arteriole: arteriole carrying blood away from glomerulus of kidney

afferent arteriole: arteriole that carries blood towards the glomerulus of kidney

bowman's capsule: cup-shaped chamber that envelopes capillary network called glomerulus

glomerulus: knot of capillaries that projects into enlarged, proximal end of nephron; site of filtration, first step in production of urine

proximal convoluted tubule: segment of nephron between the glomerular capsule (Bowman's capsule) and nephron loop; major site of active reabsorption from filtrate

nephron loop: segment of nephron that creates the concentration gradient in renal medulla; composed of descending limb and ascending limb

distal convoluted tubule: segment of nephron closest to connecting tubules and collecting duct; an important site of activation secretion

juxtaglomerular complex: macula densa, extraglomerular mesangial cells, and juxtaglomerular cells; a complex responsible for release of renin and erythropoietin

filtration: glomerulus --> Bowman's capsule:

  • water, small ions/ molecuules, glucose
  • NOT PROTEINS
    -BULK FLOW

Takes place in glomerulus/ bowman's capsule: H2O, glucose, all ions and no protein

reabsorption: tubule --> capillary; selective transport:

  • passive (osmosis)
    -facilitated (co/counter transport)
    -active transport

Proximal convoluted tubule: H2O, glucose, Na+, K+, HCO3-

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descending limb of loop of henle: H2O

Ascending limb of loop of Henle: Na+, K+

Distal convoluted tubule: H2O, Na+

collecting duct: H2O, Na+, K+, HCO3-

secretion: capillary --> tubule

  • passive (osmosis)
  • facilitated (co/counter transport)
    -active transport

proximal convoluted tubule: H+

distal convoluted tubule: K+, H+

collecting duct: H+, K+

GHP is a major driving force for GFR: dictates how much filtrate you have and how much urine you end up with

luminal diameters

afferent arterioles: constriction reduces GFR

efferent arterioles: constriction increases GFR

glomerular capillaries: constriction reduces GFR

Renin: enzyme released by cells of juxtaglomerular complex when renal blood flow decreases; converts angiotensinogen to angiotensin I

purpose of renin: big effect is at regulation that triggers aldosterone --> regulation at distal convoluted tubule

affects macula densa bc of distal convoluted tubule looping around and affecting GFR via increasing blood volume by stimulating sympathetic nervous system to inc arterial pressures throughout body

inc. arterial pressures throughout body --> HTN direct effect

HTN also creates high pressure system which inc GFR as another outcome

filtrate goes through proximal convoluted tubule into descending limb of nephron loop until reaches ascending limb which is permeable to ions

soluttes pushed out into intterstitial fluid --> inc osmolarity of plasma

descending limb permeable to water, which is pushed out of capillary to accomodate inc osmolarity in plasma

aldosterone: rate of Na+ reabsorption and K+ loss in kidneys

ADH: water conservation at kidneys; stimulates thirst

water follows salt

DMII:

High blood glucose levels

result from lack of response to insulin

can result in kidney damage bc stressing filters in kidney from high blood glucose levels

can result in frequent urination because kidneys constantly trying to filter out waste

glucose can be found in urine as a result of constant filtration

Hypertension

high blood pressure

can be caused because of kidney problems

high arterial pressure can lead to inc rate of filtration, reabsorption and secretion which also can cause renal failure and vice versa

How her previous DX relate to her kidney function

Hypertension:

high blood pressure

force of blood high --> vessels stretch more easily

stretching weakens blood vessels especially those in kidney

if damaged --> can result in not removing waste and extra fluid from body

extra fluid raises blood pressure more

DMII:

high blood glucose levels

many solutes being filtered through kidney

can stress filtration system w/ abundance of glucose

results in frequent urination filtering out waste and glucose can be found in urine as result of stressing kidneys

any other factors that could be taken into account:

How often does she urinate?

how much water does she take in?

Does she get thirsty often?

what does her diet consist of?

effects of high blood pressure on kidneys:

constant high blood pressure cause arteries around kidneys to narrow, harden or weaken

  • damaged arteries not able to supply kidney enough blood

damaged arteries can't filter well

  • nephrons cannot get essential nutrients
  • kidneys lose ability to filter blood
    -unable to regulate fluid, hormones, acids and salts

effects of DMII on kidneys:

high levels of blood sugar make kidney filter too much blood

  • hard on filters
  • after years, can start to leak and protein lost in urine
  • if waste products fill up in kidney --> kidneys fail

how they can affect each other:

high levels of blood glucose can lead to renal failure/ damage which can affect GFR, which can affect MAP which can result in high blood pressure

why patient is seeing blood in their urine: This is most likely because the kidneys are failing and are unable to reabsorb large solutes/ hemoglobin --> the pores are allowing larger solutes to get through and is getting lost in urine

what happens if untreated?

if nothing changes --> could possibly lead to seizure, coma or death