Review of Renal Anatomy and Physiology Flashcards
Kidney
- Paired Organ on posterior of body
– Inside a Capsule
— In surrounding Fat
—- Over the area is Fascia; fibrous tissue
—– Protection: muscles and organs
Kidney Anatomy
Layer:
- Capsule => Cortex => Medulla (inner)
Hilum (central area)
- Entery and exit
Passage of Urine
- Pyramid => Papilla => Calyx => Pelvis => Ureter => Bladder
Nephron
Function unit of kidney (1.2 mil nephrons)
- Subunit of nephron include glomerulus, proxima convoluted tubule, loop of Henle (Thin descending, Thick ascending, Thin descending), distal convoluted tuble
Types:
- Cortical (outer most area -cortex)nephrons (85%)
- Juxtamedullary (inside) nephrons (15%)
Renal Corpuscle
Corpuscle:
- Glomerulus: tufts of capillaries
– 4-8 vessels in fist-like structure
– Afferent arterioles brings blood in
– Efferent arteriole bring blood out
- Bowman’s capsule: surround glumerulus
Bowman’s Space
Molecules from blood => filtered by glumerulus => deposited into capsule space => start making filtrate
Glomerular Filtration
Cell Layers => Pores/fenestration (70-90 nm) => Podocytes on outer epithelium (25 nm slits with pseudopodia (foot like projection)) => Mesangial (stellate) cells (Between basal lamina and endothelium, contractile, secrete ECM(extracellular matrix), clear Immune complexes)
Juxtaglomerular Apparatus
JGA
Role in controlling renal blood flow, glomerular filtration, renin-angiotensin-aldosterone system (RAAS)
- Feed back mech between early and laer part of nephron
Cells:
- Juxtaglomerular Cells: renin producing granular cells
- Macula densa: distal tubule cells in contact with afferent and efferent arterioles
Blood Flow
Blood first enter into kidney
- Renal Artery; 20-25% of CO
- Interlobar Artery
- Arcuate Arteries
- Interlobular Arteries
- Glomerular Capillaries
- Vasa recta
– Along loop of henle
– Blood to medulla
– Permeable to water and solute
– Countercurrent exchange
- Renal Veins
Factors Influencing Blood Flow
Kidney
Vasoconstriction:
- Angiotensin II and renin
- Endothelin
- Sympathetic nerve innervation
Vasodilation
- Nitric oxide
- Prostaglandins
- Atrial naturetic peptide
- Adenosine
- Kinins
- Dopamine
Modify arteriole tonicity to maintain GFR within narrow limits
Kidney Function
Regulatory:
- Regulate body osmolaity, and volume and blood pressure
- Balance electrolytes and minerals
- Regulate acid-base balance
Excretory:
- Excrete waste, drugs, and metabolites
Endocrine:
- Produce renin, erthropoetin, 1,25-dihydroxyvitamin D
Urin Formation
1) Blood flow into Afferent arteriole
2) Filter into glomerulus
3) Drain into bowman’s capsule (filtrate)
4) Proceed through proximal convoluted tubule
5) Passes along the loop of Henle
6) Continune into distale convoluted tubule
7) Urine drain into renal pelvis
8) Urine go to ureter
9) Urine stored into bladder
10) Urethra
Urine Formaton
Glomerular Filtration:
- Ultrafiltration based on size and molecular charge
- Pressue in glomerular increase due to narrowing of capillaries
- Forces plasma to leave capillary and enter Boweman’s capsule
- Filtrate is prtein-free
Reabsorption:
- Tubule lumen to blood
- Active trasport
- Solute reabsorption drive water reabsorption
Secretion:
- Blood to tubule lumen
- Active transport
Excretion= Filtration - Reabsorption + Secreation
Urine Formaton: Inulin
100% excreted
- No reabsorbtion for inulin
- Great at estimating GFR
Urine Formaton: lucose
Reabsorbed into blood
- Little to none in urine
Urine Formaton: Urate
Reabsored, Secreted and excreted
Urine Composition
- Electolytes/Solute
– Sodium, potassium, ammonia, calcium, magnesium, chloride, phosphate, urea, creatinine, drugs - Urine pH ranges from 4.6 to 8.0 but typically acidic
- There should not be
– Glucose, amino acids, protein, blood, ketone, leukocytes, bilirubin (indication of problem)
