What do kidneys regulate?
2
- Blood volume
- Blood Pressure
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| Term | Definition |
|---|---|
| What do kidneys regulate? 2 | - Blood volume - Blood Pressure |
| What do kidneys excrete? 2 | - Urea, creatinine, bilirubin - Removes foreign chemicals |
| What does the kidney synthesize? What is the process called? 1 | - Glucose via gluconeogenesis |
| What does the kidney secrete? 3 | Hormones - Erythropoietin (EPO) - Renin - Vitamin D |
| What are the body fluid compartments? 3 | 1. ICF: intracellular (fluid inside cell) 2. ECF: (fluid outside cell, plasma + interstitial + CSF) 3. Plasma: non-cellular part (fluid inside blood vessels) |
| What is [water] measured in? | - Osmoles (osm) 1 osm = 1 mol solute particles |
| T/F: "Low osmolarity" = low water conc | False, it is equal to pure water (aka high water conc) |
| T/F: The partition between compartments of cell membrane is permeable to just water | False, it is permeable to water AND the solute |
| What is osmotic pressure? | Pressure necessary to prevent solvent movement |
| T/F: Osmosis occurs with a selectively permeable membrane | True |
| How does water flow during osmosis? | High water conc -> low water conc Low solute conc -> high solute conc |
| What is tonicity? | Concentration of non-penetrating solutes of an extracellular soln relative to intracellular environment |
| What are the 3 conditions of tonicity? | 1. Isotonic: same osmolarity inside and out 2. Hypertonic: higher osmolarity outside the cell 3. Hypotonic: higher osmolarity inside the cell |
| What is absorption? | Movement of solute/water INTO blood |
| What is filtration? | Movement of solute/water OUT of blood |
| What is the formula for Net Filtration Pressure? What are the starling forces? | Capillary Hydrostatic pressure + Interstitial Hydrostatic pressure - Osmotic force due to plasma protein concentration - Osmotic force due to interstitial fluid protein concentration |
| What does positive net filtration pressure indicate? | Favours filtration |
| Anatomy of the kidney 3 | - Outer cortex - Inner medulla - Nephron |
| Parts of the nephron 2 | - Renal corpuscle - Renal tubule |
| What is the difference between afferent and efferent arteriole? | Afferent: fluid goes IN Efferent: fluid goes OUT |
| What is stage 1 of the development of the renal corpuscle? | Nephrons develop as tubules composed of single layer simple epithelium |
| What is stage 2 of the development of the renal corpuscle? | Capillaries penetrate expanded end of tubules |
| What are the two other things that happen during stage 2? | - Basal lamina trapped between endothelial cells and epithelial layer - Epithelial layer differentiates into parietal and visceral layer |
| What is stage 3 of the development of the renal corpuscle? 2 | - Parietal layer flattens to become wall of Bowmans capsule - Visceral layer becomes podocyte cell layer |
| What are the components of the glomerular capillary? 3 | - Fenestrated endothelial layer - Basement membrane - Podocytes with filtration slits |
| Where are all the renal corpuscles found? | The cortex |
| What are the types of nephrons? 2 | - Cortical (major) - Juxtamedullary |
| What are the functions of the nephrons? 3 | - Filtration - Reabsorption - Secretion |
| What is something the juxtamedullary nephron specially does? | Regulate conc of urine |
| What are the types of capillaries around the nephron? 3 | - Glomerular - Peritubular - Vasa recta |
| What are the 3 basic renal processes? | 1. Glomerular filtration 2. Tubular secretion 3. Tubular reabsorption |
| What processes get you entry into lumen? 2 | - Filtration - Secretion |
| What processes get you exit out of lumen? 2 | - Reabsorption - Excretion of urine |
| What is the formula for Amount Excreted? | Amount filtered + Amount secreted - Amount reabsorbed |
| Why are large proteins/albumins held back? 3 | - Pore sizes too small - Pores and BM are negatively charges and repel negatively charged proteins - Podocytes have slits that are covered w/ semiporous membranes |
| What is in the glomerular capillary? 3 | - Fenestrated endothelial layer - Basement membrane (BM) - Podocytes w/ filtration slits |
| T/F: Glomerular filtration is always negative | False, it is always positive |
| How does GF pressure initiate urine formation? | By forcing protein-free filtrate from plasms out of glomerulus into Bowman's space |
| What is glomerular filtration rate (GFR) | Volume of fluid filtered from glomerulus into bowmans space per unit time |
| What factors influence GFR? 4 | - Net GF pressure - Neural and endocrine control - Permeability of corpuscular membrane - SA for filtration |
| Does GFR remain change due to changes in arterial pressure or renal blood flow? | No, it stays constant |
| How is autoregulation regulated and how does it occur? | - regulated by changes in myogenic reflex - occurs by changing renal blood vessel resistance to compensate for any pressure changes |
| T/F: resistance changes in renal arterioles alter renal BF and GFR | True |
| What makes up the juxtaglomerular apparatus (JGA)? 2 | - Macula densa - Juxtaglomerular cells (JG) |
| What is the purpose of the macula densa? | - Cells on wall of distal tubule - Sense increased flow through tubule - Secretes vasoactive compounds - Changes afferent arteriole resistance (paracrine effect) - Signals JG cells |
| What is the purpose of JG cells? | - On wall of afferent arteriole - Secretes renin |
| What factors control GFR? 4 | - Myogenic reflex - Neuroendocrine input - Paracrine effects - Mesangial cells |
| What does contraction of mesangial cells cause? 2 | - Reduced SA of glomerular capillaries - Reduces GFR |
| What is the formula for Filtered Load? | GFR x [substance in plasma] |
| What happens if substance excreted in urine < filtered load? | Reabsorption has occurred |
| What happens if substance excreted in urine > filtered load? | Secretion has occurred |