Lecture 1: The Kidney Flashcards
(33 cards)
What is the kidney renal function and contribution to homeostasis?
Blood ionic composition
Blood pH
Blood volume
Blood pressure
Blood osmolarity (concentration of solutes)
Excretion of waste
Hormone production
Glucose levels
What are signs and symptoms of hypovolaemia?
DEHYDRATED
Thirst, dizziness on standing, confusion
Low Jugular venous pressure, postural hypotension, weight loss, dry mucous membranes, reduced skin turgor, reduced urine output
What are signs and symptoms and hypervolaemia?
FLUID OVERLOAD
Ankle swelling, breathlessness
Raised Jugular venous pressure, oedema, weight gain, hypertension
What is too little an too much body fluid volume called?
Too little - Hypovolaemia
Too much - hypervolaemia
How is blood pressure controlled through the kidneys?
Regulation of extracellular sodium and water
What is osmolarity?
The measurement of solute concentration or osmotically active solutes osmoles
(osmol/L) or (Osm/L) or (mOsm/L)
What is osmotic pressure?
The pressure which needs to be applied to the solution to prevent an inward movement of fluid across a semi permeable membrane
What is oncotic pressure (colloid oncotic pressure)?
The osmotic pressure exerted by the proteins in the blood plasma or filtrate which attracts water into that compartment
What is hydrostatic pressure?
The force exerted by a fluid against a capillary wall
What are the characteristics of a hypotonic solution?
Low osmotic pressure outside
High osmotic pressure inside
Liquid in
<300 mOsml/L of solute
What are the characteristics of an iso-osmotic solution?
No not movement
Equal osmotic pressure
What are the characteristics of hyperosmotic solution?
> 300 mOsm/L of solute
Very high osmotic pressure outside
High osmotic pressure inside
Liquid out
If hydrostatic pressure > osmotic pressure?
Fluid will leave the capillary promoting filtration of the plasma
Large diameter of afferent arteriole entering capillary bed
Small diameter of efferent arteriole leaving the capillary bed
How does high hydrostatic pressure promote filtration?
Result of different diameters overcomes inward pull of fluid as a result of osmotic pressure
If hydrostatic pressure < osmotic pressure?
Fluid leaving the capillary will be greatly reduced inhibiting filtration of the plasma
Medium diameter of afferent arteriole entering the capillary bed
Medium diameter of efferent arteriole leaving the capillary bed
How does low hydrostatic pressure promote filtration?
Similar diameters only just overcomes the inward pull of fluid as a result of osmotic pressure
What is the structure/ flow of the kidney?
- Collecting duct
- Minor calyx
- Major calyx
- Renal pelvis
- Ureter
- Bladder
What is the Renal corpuscle composed of?
Bowman’s capsule
Glomerulus
What is the renal tubule composed of?
Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule
What is composed of the Juxtamedullary nephron?
Descending limb of the nephron loop
Thick ascending limb of the nephron loop
Thick ascending limb of nephron loop
What is the functional overview of the nephron?
- Filtration (filtration under pressure - water and blood solutes)
- Tubular reabsorption - 99% of water and many solutes reabsorbed back into blood via passive and active processes
- Tubular secretion - renal tubule and duct cells secrete wastes, drugs, excess ions out of blood into filtrate
- Urine excretion - renal tubule and duct cells secrete waste, drugs, excess ions out of the blood into the filtrate
What is the average Glomerular filtrate rate per day/ minute?
180 L/day
125 mL/ min
What is the Juxtaglomerular apparatus functioning?
JG granular cells secrete an enzyme RENIN in response to falls in extracellular volume/ low sodium
Falls in ECF detected by baroreceptors around the body
What is the aim of the Juxtaglomerular apparatus response?
To increase sodium reabsorption and therefore water reabsorption
