Unit 13 Patho Flashcards
What happens when extracellular fluid volume decreases?
Blood pressure decreases
What happens if ECF volume and BP fall too low?
The body cannot maintain adequate blood flow to the brain and other essential organs.
The kidneys work with the cardiovascular system to ensure what?
That blood pressure and tissue perfusion remain within an acceptable range.
What is the function of the kidneys?
Clear harmful substances by filtering the blood.
Regulates: Blood pH, Volume, Pressure, and Osmolality
Produce hormones
The Primary function of the proximal tubule, in a nephron, is?
Reabsorption of ions, organic molecules and water
The primary osmoreceptors are located in the:
Hypothalamus
What is the kidneys role in regulation of osmolarity?
The body integrates kidney function with behavior drives (from hypothalamus), such as thirst, to maintain blood osmolarity at a normal value of 290 mOsM.
What is the kidneys role in maintenance of ion balance?
They keep concentrations of key ions within a normal range by balancing dietary intake with urinary loss
Sodium (Na+) is the major ion involved in the regulation of ECF and osmolarity
What is the kidneys role in homeostatic regulation of pH?
(what happens if too acidic or alkaline)
-The pH of plasma is normally kept within narrow range.
-If ECF becomes too acidic, the kidneys remove H+ and conserve bicarbonate ions (HCO3-) which acts as a buffer
-If ECF becomes too alkaline, kidneys remove HCO3- and conserve H+
What is the kidneys role in excretion of wastes?
The kidneys remove metabolic waste products or foreign substances such as drugs and environmental toxins.
-Metabolic waste include creatinine form muscle metabolism and the nitrogenous wastes urea and uric acid
-A metabolite of hemoglobin called urobilinogen gives urine its yellow color
-Hormones are another endogenous substance the kidneys clear from the blood
What is the kidneys role in hormone production? (3 pathways)
Although kidneys are not endocrine glands, they play an important role in three endocrine pathways:
1) Cells synthesize erythropoietin, the cytokine/hormone that regulates RBC synthesis
2) They also release renin, an enzyme that regulates the production of hormones involved in sodium balance and BP homeostasis
3) Renal enzymes help convert vitamin D3 into a hormone that regulates Ca2+ balance
Describe the anatomy of the urinary system. (From kidneys to urethra)
Urine production begins in the kidneys -> passes through smooth muscle tube called ureter -> from the two ureters leading from each kidney they go to the urinary bladder -> the bladder expands and fills with urine until, a reflex called micturition or urination, the bladder contracts and expels through the urethra.
What occurs in the Glomerulus?
(Part of nephron)
Filtration occurs (first step of urine formation)
-Does not filter RBCs and proteins
Filtration is the movement of fluid from blood into the lumen of nephron.
Once the filtered fluid is entered its called filtrate.
What occurs in the Proximal tubule?
(part of nephron)
(Found in Cortex of Kidney)
Reabsorption occurs here. Salts, water, Potassium, glucose and amino acids are reabsorbed back into the blood flowing through the capillaries.
What occurs in the Loop of Henle?
(Typically found in Medulla of Kidney)
Has some role in reabsorption of sodium, calcium, potassium, and magnesium (Electrolytes)
Main role in concentrating the urine
What occurs in the Distal Tubule?
(part of nephron)
(Found in Cortex of Kidney)
More reabsorption occurs of sodium and calcium
However secretion takes place. Substances like: Hydrogen, potassium, and ammonium.
(Also takes in waste that escaped filtration)
Then takes urine to the collecting duct
What is water balance?
Homeostasis of water and electrolytes.
This depends on the integration of kidneys (slow), respiratory and cardiovascular systems.
-Thirst and cravings for salts are behavior mechanisms. (Only major way of replacing water that is lost
What is the response to decreased blood pressure and volume?
-There is an increase in cardiac output, vasoconstriction.
-Increased thirst
-The kidneys conserve salt and water to minimize volume lost