Components of the renal system
-2 kidneys
-2 ureters
-bladder
-urethra
male and female is the same other then the differences in the length of the urethra
Functions of the Kidneys
- Regulate body fluid volume and composition
- Eliminate metabolic wastes
- Synthesis, release or activate hormones
- Regulates Blood Pressure and Blood Volume
- Regulates Blood pH by excreting and reabsorbing H and HCO3 ions
What hormones are synthesized, released or activated in the kidneys?
- Erythropietin- a glycoprotein hormones that controls erythropiesis (RBC production)
- Renin
- Vitamin D
What mechanisms do we have in our bodies that are going to help us regulate H2O in our bodies
- osmoreceptors in the hypothalamus
- the posterior piturary can release ADH which conserves H2O
- The adrenal cortex can release glucocorticoids and mineralcorticoids such as aldostrone which will help retain Na and excrete K.
What happens when there is a decreased renal perfusion?
- Renin is released by the kidneys
- Angiotensin I is converted to angiotensin II (vasoconstrictor and increases BP) with the help of ACE (comes from the lungs)
- Aldostrone is released and Na retention, pulling water to stay inside also.
Hypothalamus and posterior regulation of blood volume
- low blood volume triggers osmoreceptors to send signal of low blood volume and ADH is released and you get thirsty and your kidneys reabsorb H2O at the distal and collecting tubules
- when too much volume, the osmorecpetors tell the posterior piturary to stop release of ADH and water is secreted
Nephrone
- Functional unit of the kidney that filters the blood
- Reabsorb what we need and secretes ions (glucose, Na, AA) in the urine when we don’t need them
Components of the nephrone
- glomerulus
- proximal tubule
- loop of henle
- distal tubule
- collecting duct
Which products should and which shouldn’t be passing the filtration of the kidneys?
- water, small molecules, ions can easily pass
- blood, proteins, are big and cannot easily pass
Glomerular Filtration Rate (GRF)
Amount of filtrate produced every minute
-generally 99% of the filtrate is reabsorbed and 1% goes into the urine
What supplies the kidneys with blood
-the renal artery
- How much blood passes through the kidney’s every minute?
- In an healthy person how much of the cardiac output goes to the kidneys
- 1,000 ml
- 20-25%
Describe the renal circulation of blood
- renal artery
- afferent arterioles
- glomerular capillaries
- efferent arterioles
- peritubular capillaries
- vasa recta
- How much urine does an adult produce per day?
- What factors influence the amount of urine produced in a day
- 1- 2 Liters
- environmental factors, level of hydration, activity levels, weight, health of the individual
Classifications for polyuria, oliguria, anuria
- polyuria- more then 2.5 L in an day
- Oliguria- less then 400 ml in a day
- anuria- less then 100 ml in a day
How does urine move from the ureters to the bladder?
- peristalsis
Explain how throughout life when urine is in voluntary control or not
- in healthy adults- voluntary
- infants and elderly and those with a neurological injury urine release becomes an involuntary relfex
Micturition
involves the coordination of the central, autonomic and somatic nervous system
Full Bladder
- Activates stretch receptors
- signal stimulates the contraction of detrusor skeletal muscles via the parasympathetic cholinergic motor fibers
- relaxation of internal and external urethral spinchter results in micturition
Urinalysis - appearance and Odor 3 causes
- should be straw colored and mild in odor
- Cloudy Urine- may indicate presence of large amounts of proteins, blood, pus and bacteria
- Dark Urine- hematuria, excessive bilirubin or could be highly concentrated
- Unpleasant or Unusual Odor- could be due to infection or result of certain dietary components ( asparagus) or medications
Urinalysis- Abnormal Constituents
3 things and the presence of each signifies what issue?
- blood aka hematuria- if present in small amounts indicates infection, inflammation, tumors in urinary tract
- large amounts indicates increased glomerular permeability or hemorrhage
- elevated protein called proteinuria, albuminuria. so having protein in your urine indicates the insufficiency of reabsorption or impaired filtration of protein or leakage of albumin or mixed plasma proteins into filtrate, the most common cause of this is DM due to damaged nephrons
- presence of bacteria in urine has to do with a urinary infection
Urinalysis- Infection what will you see?
-take a look microscopically and we will see heavy purulence and presence of gram negative and gram positive organisms
Urinary Casts
pH
what area of kidney is impact?
- cylindrical structures produced by kidneys
- present in certain disease states
- tell us that there is an inflammation of kidney tubules
- environment favoring protein denaturation and precipitation
- there is low blood flow to the kidneys
- concentrated salts and there is low pH
Specific gravity
which structures filter the urine
- indicates ability of tubules to concentrate urine (toxic and metabolic wastes )
- concentrates urine so waste products excreted with minimal loss of water and nutrients
- low specific gravity- dilute urine with normal hydration
- high specific gravity- concentrated urine with normal hydration. this is related to renal failure
- glucose and ketones- found when DM is not well controlled. we do not want these things in the urine
