Quiz 5 Flashcards
What are the functions of the kidney?
regulation of ECF fluid volume, blood pressure, osmolarity, maintaining ion balance, regulating pH, excreting wastes and foreign substances, and participating in endocrine pathways.
Define Filtration?
movement of fluid from plasma into Bowman’s capsule
Define Reapsorbtion?
Movement of filtered materials from tubule to blood
Define Secretion?
Movement of selected molecules from the blood to tubule
What is the Glomerular Filtration Rate?
GFR is the amount of fluid that filters into the Bowman’s capsule per unit of time.
How can hydrostatic pressure be altered?
changing the resistance in the afferent and efferent arterioles
Where does most reabsorption take place>
proximal tubule
What does the rate of excretion depend on?
- its filtered load
- and whether it is reabsorbed or secreted as it passes through the nephron.
What controls electrolyte balance?
The renal, respiratory and cardiovascular systems
In order to produce dilute urine what must happen?
the nephron must re-absorb solute without reabsorbing water
In order to produce concentrated urine what must happen?
The nephron must reabsorb water without reabsorbing solute
What is the most important function of the kidney?
is to maintain water and ion content of the blood
define osmolarity
the concentration of solute in a solution
What happens when blood osmolarity is higher than target osmolarity?
this sends a signal to the hypothalamus, which sends a signal to the posterior pituitary telling it to release ADH (vasopressin)
When the posterior pituitary releases vasopressin what does it do?
vasopressin will travel to its target on the kidneys to increase water reabsorption. this will decrease the osmolarity of the blood and increase the osmolarity of the urine
What does aldosterone do?
is a hormone that helps regulate blood pressure by stimulating the reabsorption of sodium as well as the secretion of potassium
What happens if the ECF gets too acidic?
the kidneys are going to remove or excrete hydrogen ions and converse bicarbonate ions
What are the two types of nephrons?
Juxtamedullary Nephrons and Cortical Nephrons
What are the two components of a nephron?
Tubular components and Vascular Components
The vascular component of a nephron includes?
Afferent arteriole, glomerulus, efferent arteriole, and peritubular capillaries
How does renal blood flow?
renal artery - afferent arterioles, glomerular capillaries, efferent arterioles, proximal peritubular capillaries, vasa recta, distal peritubular capillaries, collecting duct, renal veins,
The tubular component of the nephron includes?
bowman’s capsule, proximal tubule, loop of henle, distal tubule, collecting duct
What are the three basic renal processes?
Glomerular Filtration, Tubular Reabsorption,
tubular secretion
Glomerular Filtration
is the movement of fluid into the lumen of the nephron
tubular reabsorption
substances from filtrate moved back into the blood
tubular secretion
removes molecules from the blood and added them to filtrate in the lumen
What are the three barriers for glomerular filtration?
Glomerular Capillary Epithelium, Basal Lamina, and Epithelium of Bowman’s capsule
What are the three forces involved in Glomerular Filtration?
Glomerular Capillary Blood (Hydrostatic) pressure, Plasma-Colloid Osmotic pressure, Bowman’s capsule Hydrostatic Pressure
What is glomerular capillary blood (hydrostatic) pressure?
this pressure is causing the blood to flow through the glomerular capillary which forces the fluid through the leaky endothelium
What is plasma Colloid pressure?
Describes the pressure that is needed to be applied to a solution to prevent inflow of pure solvent into the solution
What is Bowman’s Capsule Hydrostatic Pressure?
Where fluid flowing into the capsule generates pressure that opposes more fluid flowing into the capsule
What happens to urine production when blood pressure increases?
urine production will increase
Why does urine production not increase when we exercise?
Less blood is going to the kidney’s as more blood is being used by the muscles
What happens when podocytes relax?
their bases become narrower, which increases the number of “open” slits in the area, which allows more fluid to move and enter the lumen of the bowman’s capsule
What is the driving force for most renal reabsorption?
Na + transport
RAAD
Renin-angiotensin-aldosterone system.
this system increase sodium reabsorption in the tubules which results in water followed by osmosis and therefore causing circulation blood volume to increase, increasing blood pressure
Vasopressin
Causes diuresis, elimination of water
Atrial Natriuretic Peptide (ANP)
secretion by the atria, when it is stretched. When the atria are stretched is signals that the blood volume is too large. When ANP is sensed, more sodium will be excreted and because water moves along with sodium, more water will be lost as well, and blood volume will decrease
Define Homeostasis
is the dynamic state that the body wants to be in
Define Diffusion
Passive movement of solute from an area of high concentration to an area of low concentration
Define Osmosis
movement of solvent molecules through a partially permeable membrane into a region of higher solute concentration
Where is vasopressin released from?
Posterior pituitary
There are three mechanisms of vasopressin release, what are they?
- Hypothalamic osmoreceptors
- left atrial volume receptors
- angiotensin II
What will happen to the RAAS pathway in the presence of low blood pressure and high osmolarity? Why?
the RAAS pathway will be inhibited, this is because the RAAS pathway results in aldosterone secretion to increase sodium reabsorption
What does angiotensin II affect
- increases vasopressin secretion
- stimulates thirst
- potent vasoconstrictor
- activates receptors in the cardiovascular control centre to increase cardiac output and vasoconstriction
- increases Na+ and water reabsorption in the kidney
Define Hypokalemia
low plasma or ECF potassium concentrations - result in muscle weakness
Define Hyperkalemia
high plasma or ECF potassium concentrations - can produce cardiac arrhythmia’s
Hypotonicity
swelling on brain cells
due to water intoxication
hypertonicity
shrinking of the brain neurons
How will the body respond to hyponatremia?
hyponatremia is low sodium, this will activate the RAAS pathway via those macula densa cells
Acidosis
below a pH of 7.3
Alkalosis
Above a pH of 7.4
What are the sources of H+ in the body?
Carbonic Acid Formation
Inorganic acids produced during the breakdown of nutrients
Organic acids resulting from intermediary metabolism
What is a buffer?
A buffer is a molecule that moderates but does not prevent changes in pH by combining with or releasing hydrogen ions
Respiratory Acidosis
occurs when alveolar hypoventilation results in carbon dioxide retention and elevation and plasma partial pressure of CO2
Respiratory Alkalosis
occurs as a result of hyperventilation of increased ventilation where alveolar ventilation increases without increased metabolic CO2 production
Metabolic Acidosis
Is the disturbance of mass balance that occurs when the dietary and metabolic input of hydrogen exceeds hydrogen excretion
Metabolic Alkalosis
Excessive vomiting of acidic stomach contact and excessive ingestion of bicarbonate containing antacids or medication
