Renal Flashcards
Name major kidney functions
- Regulation of systemic blood pressure and extracellular fluid volume
- Excretion of metabolic waste and foreign substances
- Regulation of RBC production
- Regulation of acid-base balance
- Regulation of Vit. D production and Ca2+/Ph balance
- Gluconeogenesis
In which 2 major ways do kidneys regulate systemic blood pressure?
1) Determining blood volume -> controls cardiac output
2) Making hormones that regulate the vascular resistance
SBP = CO x VR
CO = heart rate x stroke volume
Stroke volume = end diastolic volume - end systolic volume
What are uremic retention solutes or uremic toxins
Urea (from proteins)
Uric acid (from nucleic acids)
Creatinine (from muscle creatine)
Urobilin (end product of hemoglobin)
If they are not excreted and plasma levels increase -> uremia
Where is erythropoietin produced during embryological development? and in the adults?
Liver
Kidneys
Stimulus to secrete erythropoietin
Reduction in partial pressure of oxygen in the local environment of the secreting cells.
Conditions that stimulate EPO secretion
Anemia
Blood loss
Arterial hypoxia
Inadequate renal blood flow
Why does anemia of chronic renal disease happens
1) Renal metabolism falls -> lower oxygen consumption -> higher local tissue oxygenation.
2) This “fools” the EPO-secreting cells into diminished EPO secretion.
3) Decrease in bone marrow activity - one important causal factor of the anemia.
T/F - Most gluconeogenesis occurs in the liver, but a substantial fraction occurs in the kidneys, particularly during a prolonged fast
TRUE
What does penetrate the renal hilum
Blood vessels
Nerves
Ureters
Describe the major structural components of the kidney
T/F - Pyramids collectively constitute the medulla
TRUE
What are cortex and medulla constructed off?
Almost entirely of tubules (nephrons and collecting tubules) and blood vessels.
Between the tubules and blood vessels -> interstitium, <10% of renal volume.
What does the renal interstitium contains?
Interstitial fluid
Interstitial cells -> fibroblasts and immune cells -> synthesize a matrix of collagen, proteoglycans, glycoproteins and cytokines.
Some of these cells synthesize EPO.
Lymphatics.
Types of nephrons
85% of nephrons - cortical -> glomeruli located in the outer cortex. Short LOH, only penetrates into the outer renal medulla. Reduced vasa recta.
15% of nephrons -> juxtamedullary -> glomeruli near the corticomedullary border. LOH extents deep into the renal medulla. Large network of vasa recta. Provides blood flow to renal medulla.
Where are the renal corpuscules located
Renal cortex
T/F - The cortex contains renal corpuscles, coiled blood vessels and coiled tubules. The medulla contains straight blood vessels and straight tubules.
TRUE
Draw / describe a nephron
Components of renal corpuscule
Bowman’s capsule - epithelial cells
Renal glomerulus - tuft of capillary loops
Draw / describe the structure of the renal corpuscle
- Bowman’s capsule - epithelium
- Glomerulus -> tuft of capillaries -> afferent arteriole brings blood in, efferent drains blood out.
- Mesangial cells and podocytes -> in close association with the capillary loops of the glomerulus.
- Mesangial cells -> act as phagocytes, remove trapped material from the basement membrane of the capillaries.
- Podocytes -> support structure, important role in glomerular filtration.
- Bowman’s space -> where fluid filters from the glomerular capillaries before flowing into the first portion of the tubule.
T/F - Throughout the whole length, the renal tubule is made up of a single layer of epithelial cells resting on a basement membrane.
TRUE.
How are the epithelial cells linked together in the renal tubules?
Via tight junctions
Name the renal tubular segments
Describe the structure of the nephron and where each part falls in relationship with cortex / medulla structure
Is the urine altered once it enters a calyx?
No