kidney anatomy/function

What part of LOH does water reabsorption occur?

descending limb

What type of cell is located between afferent and efferent arterioles?

mesangial cell

Which region of the kidney contains the glomerulus?

renal cortex

Which arteriole carries blood without waste?

efferent arteriole

Which arteriole supplies blood with waste to the glomerulus?

afferent arteriole

What does a blood pH below 7.35 indicate?

acidosis

What does a blood pH above 7.45 indicate?

alkalosis

What are the 3 key hormones produced by the kidneys?

1. Erythropoietin (EPO)

2. Renin

3. Active Vitamin D (calcitrol)

What is the primary filtration unit of each nephron?

glomerulus

How does capillary hydrostatic pressure relate to blood osmotic pressure during filtration?

HP > OP

How does capillary hydrostatic pressure relate to blood osmotic pressure during reabsorption?

HP < OP

What are the 2 ways that kidneys regulate blood pressure?

1. fluid balance

2. hormonal control

What are 5 things the kidney regulates to maintain body homeostasis?

1. blood osmolarity

2. pH

3. blood volume

4. blood pressure

5. filtration

What does the kidney do when blood volume increases?

excrete excess water and sodium to reduce fluid volume and lower blood pressure

What are 3 ways high blood pressure harms kidneys?

1. vessel damage

2. impaired filtration

3. hormonal imbalance

Where does renal autoregulation occur?

afferent arteriole

What are the 2 mechanisms of autoregulation?

1. myogenic

2. tubuloglomerular feedback (TGF)

Which autoregulation mechanism is the macula densa involved in?

Tubuloglomerular Feedback (TGF)

Which ion is assosciated with the myogenic mechanism?

calcium

Which autoregulation mechanism is assosciated with increasing NaCl delivery to distal tubule?

tubuloglomerular feedback

Which autoregulation mechanism is slower (20-60 seconds)?

tubuloglomerular feedback

What is the functional unit of the kidney?

nephron (2 million per kidney)

Which layer of Bowmans Capsule contained podocytes which serve as a barrier for filtration?

visceral (inner)

Which layer of Bowmans Capsule contains simple squamous epithelial cells that solely helps to provide structural support?

parietal (outer)

What is the 3 layer filtration barrier present in the renal corpuscle?

1. fenestrated endothelium of glomerular capillaries

2. glomerular basement membrane

3. filtration slits formed by podocytes

What is the large driving force for filtration within the glomerulus?

pressure difference between hydrostatic pressure of blood and osmotic pressure in capillaries

Which layer of the filtration barrier allows small molecules to pass into bowmans space?

fenestrated endothelium of glomerular capillaries

Which layer of the filtration barrier acts as a size/charge barrier?

glomerular basement membrane

Which layer of the filtration barrier prevents large proteins from leaving the blood?

filtration slits formed by podocytes

What are the 3 key places reabsorption occurs in the kidney?

1. PCT

2. LOH

3. DCT

What type of cells are present in the PCT?

cuboidal epithelial cells with brush border

What is the primary responsibility of the PCT?

reabsorption of glucose, AA, electrolytes, and water

How does "convolution" helps with reabsorption?

increased length allows for maximized surface area for reabsorption

Which electrolyte is ACTIVELY reabsorbed on the basolateral membrane of the PCT?

Na+

Which electrolyte is PASSIVELY reabsorbed on PCT?

Cl- by following Na+

How is water reabsorbed in the PCT?

through osmotic gradients created by solute reabsorption

How does the PCT facilitate reabsorption of glucose and AA?

sodium-dependent co-transport

What is the PCT responsible for secreting?

1. urate

2. medications/toxins

Where does the PCT receive it's blood supply from?

peritubular capillaries which are branches of the efferent arterioles

Which part of the LOH is responsible for passive water reabsorption into medullary interstitium?

descending limb

Which part of LOH is responsible for movement of ions?

ascending limb

In which portion of the ascending limb does passive diffusion of ions occur?

thin limb

In which portion of the ascending limb do we expect to see a larger number of mitochondria present?

thick limb

What is the thick portion of the ascending limb responsible for actively reabsorbing?

1. Na+

2. 2 Cl-

3. K+

What type of cell is present in the thin portion of the ascending limb in the LOH?

cuboidal epithelial cells (more mitochondria/less brush border)

What type of cells do the descending limb and thin portion of the ascending limb in the LOH have?

simple squamous epithelium

Which will have more mitochondria and microvilli in the simple squamous epithelial cells, DCT1 or DCT2?

DCT1

What are DCT and the Collecting Duct under the control of primarily?

hormones

Which portion of the kidney is the final step for balancing blood & urine concentrations?

DCT

Which portion of the kidney is responsible for fine-tuning urine concentration?

Collecting Duct

Where is the collecting duct located?

1. Cortex

2. Medulla

What 2 hormones are important for concentrating urine?

1. ADH (vasopressin)

2. Aldosterone

What type of cell allows the collecting duct to regulate the bodys acid-base balance?

intercalated cells

What type of cells in the collecting duct are involved in sodium reabsorption and water permeability?

principal cells

What type of cells does Aldosterone act on in the kidneys?

principal cells to enhance sodium reabsorption and lead water to follow osmotically

Which type of intercalated cells are responsible for reabsorbing bicarbonate (HCO3-) and contributing to blood pH regulation?

Type A

What part of the kidney establishes the osmotic gradient which allows for water reabsorption in the collecting duct?

LOH