Kidney Structure & Flow
What are the two main regions of the kidney and what structures can be found in each?
Cortex- Renal Corpuscles, PCT, DCT
Medulla- Nephron loops, Collecting Ducts, Pyramids
What are the three processes involved in urine formation?
Filtrations, Reabsorption and Secretion
What hormone increases water reabsorption by adding in aquaporin channels?
Antidiuretic Hormone (ADH)
What are the two major fluid compartments in the body?
ICF & ECF
What is the normal blood pH range?
7.35-7.45
What are the three layers that protect & support the kidneys?
Fibrous Capsule, Perinephric Fat, & Renal Fascia
Where does filtration occur, and what drives it?
Glomerulus- Driven by glomerular hydrostatic pressure
What hormone increases sodium reabsorption and potassium secretion?
Aldosterone
Which ions is the main cation in ECF and which in ICF?
ECF- Sodium NA
ICF- Potassium K
Name the three buffering systems in the body?
Chemical- (Bicarbonate, protein, phosphate)
Respiratory
Renal
What is the functional unit of the kidneys and what is its two main parts?
What substances are freely filtered vs not filtered?
Freely Filtered- Water, Glucose, Ions & Small Solutes
Not Filtered- Proteins & Formed Elements
Which hormone promotes natriuresis and lowers blood pressure?
Atrial Natriuretic Peptide (ANP)
What happens to cell volume when placed in a hypertonic solution?
Water moves out of cell, causing the cell to shrink
Respiratory Acidosis is caused by what?
Hypoventilation -> CO2 retention -> increases H concentration
What is the flow of blood into and out of the nephron starting with the renal artery?
Renal Artery -> Segmental -> Interlobar -> Arcuate -> Interlobular -> Afferent Arteriole -> Glomerulus -> Efferent Arteriole -> Peritubular Capillaries (Vasa Recta) -> Interlobular Vein -> Arcuate -> Interlobar -> Renal Vein
Compare the roles of PCT & DCT in reabsorption.
PCT: Reabsorbs most nutrients, ions, and water
DCT: Fine-tunes reabsorption under hormonal control (Aldosterone, PTH)
Describe how the renin-angiotensin system responds to a drop in blood pressure.
Decreased BP -> Kidneys release Renin -> Coverts angiotensin I to angiotensin II -> Vasoconstriction, increase in aldosterone, NA/Water Retention -> Which increases BP
Which four hormones regulate fluid output?
ADH, Aldosterone, ANP, & Angiotensin II
During metabolic acidosis, how do the lungs and kidneys compensate?
Lungs- Hyperventilation (decrease CO2)
Kidneys- increase H secretion, Increase HCO3 reabsorption.
How would narrowing of the afferent arteriole affect glomerular hydrostatic pressure and urine formation?
Decrease glomerular pressure -> Decrease GFR -> Which then produces less filtrate and urine.
If a person has high plasma glucose, how does this affect reabsorption and urine composition?
Glucose transporters become saturated -> glucose remains in filtrate -> causes glucosuria -> Increases urine volume.
Explain how ADH and aldosterone work together during dehydration.
ADH increases water reabsorption in the collecting ducts.
Aldosterone increases NA reabsorption in DCT
Together both raise blood volume and decrease urine output
If ECF sodium concentration increases, what happens to water movement and blood pressure?
Water moves out of the cells into the ECF -> Increasing blood volume -> increasing BP (temporarily)
Explain how prolonged vomiting can lead to metabolic alkalosis and how the kidneys respond.
Loss of H from stomach acid -> Increases blood pH -> Kidneys excrete HCO3- and retain H to restore balance