Briefly describe the three distinct processes of kidney function
Filtration - only at the renal corpuscle, podocyte foot.
Reabsorption - path of bring from the tube and bring it back into the body, reclaiming stuff.
Secretion - putting stuff in the blood back into the tube.
Distinguish between four major types of carrier-mediated transport
Simple diffusion - lipid soluble
Facilitated diffusion - channels that allow things that are large in size or polar; water or ions
Active transport - moving things against it’s gradient.
Cotransport - When two things are moving in the same direction from one side of the membrane to the other.
Countertransport - when things are going in opposite directions, with or against their gradient.
Understand the importance of the five characteristics of carrier-mediated transport
- a specific substrate binds to a carrier protein that facilitates movement across the membrane
- a given carrier protein normally works in one direction only
- the distribution of carier proteins can vary from one portion of the cell surface to another
- the membrane of a single tubular cell contains many types of carrier protein
- carrier proteins, like enzymes, can be saturated
Describe the relationship between renal threshold and transport maximum (Tm)
- Tm - transport maximum - channel can only support a certain amount at a time.
- renal threshold - When Tm is reached and substances is now being excreted through the kidneys
Understand the unit of milliosmoles and how it relates to kidney function.
The osmotic concentration, or osmolarity, of a solution is the total number of solute particles in each liter. osmolarity in osmoles per liter (Osm/L) or milliosmoles per liter (mOsm/L).
Identify the components of the filtration membrane of the glomular capsule
Podocytes, basement membrane, Fenestrated endothelium
Describe the relationships between GHP, CsHP, NHP, BCOP, and FP.
- GHP - Glomerular hydrostatic pressure which is the push from out from the glomerular capillaries. (50 mmHg)
- CsHP - Capsular hydrostatic Pressure which is is the pressure that is already in the nephron when you push stuff in it automatically pushes stuff back (like putting more water in a full hose)
- BCOP - Blood Colloid osmotic pressure which is caused because of all the big solutes that can not move accross the barrier causing a push back into the capillaries. 25mmHg
- NHP - Net Hydrostatic Pressure is when the math is done of the out vs the in. Usually a normal NHP is 10 mmHg.
- FP - Filtration pressure -
Describe GFR and how it can be estimated
GFR - a measure of how well your kidneys filter blood. average is about 125mL /min. And 180 liters filtrate per day. This rate depends the NFP (net filtration pressure).
Discuss the 3 mechanisms of control of the GFR
- Autoregulation - the efferient constriction, affereint arterioles dialation, and mesangial cell constriction (if the blood pressure is to low).
- Endocrine - Release of renin, which is released by the juxtaglomerular complex, and goes through the process of converting to angiotensin II that triggers endocrine response as well as neural. in endocrine: aldosterone increases Na+–>increases blood pressure–>increases systemic blood pressure–>homeostatis; angiotensin II constricts prepheral arterioles and efferent arterioles–>increases systemic blood pressure and glomerular pressure–>homeostasis.
- Nueral - increases thirst (increases fluid consumption), increase ADH (increases fuild retention), and increase symathetic motor tone (constricts venous reservoir, increase cardiac output, and stimulates peripheral vasoconstriction).
Identify and understand the five major functions of the PCT
- Reabsorption of organic nutrients
- Active reabsorption of ions
- Reabsorption of water
- Passive reabsorption of ions
- Secretion - of hydrogen ions
Reabsorbs: Glucose+, Sodium, Bicarb, water
Secretes: H+
Understand the idea of countercurrent multiplication in the loop of Henle
It is this current of absorption of water, that increases the concentration of the fluid in the nephron loop, that drives the absorption of solutes on the way back up. One drives the other.
Describe the concentration gradient of the medulla
It goes from lower concentration to higher concentration towards the bottom. 30mOsm/L to 1200mOsm/L. Which drives the countercurrent multiplcation.
Discuss the process and the benefits of countercurrent multiplication
With the amount of solutes left over in the nephron loop after giving up water in the decending side, and water not allowed to pass while only solutes can pass the membranes on the accending side….this drives the concentration gradient to be higher
Identify the substances reabsorbed at the DCT
Na+
Cl-
H2O
H3CO-
Identify the substances secreted at the DCT
K+
H+
Discuss and understand reabsorption and secretion at the collecting system (duct)
Reabsorption: Bicarb, Na+,
Secretion: H+, Cl-, NH4+
H+ and H3CO- can swap
Identify and understand the roles ADH and aldosterone have on urine volume and concentration
ADH places aquaporins for water reabsorption to conserve on water. increases the concentration of the urine and decreases the water in the urine
Aldosterone has reabsorption exchange pumps that in the presence of aldosterone reabsporb sodium ions and the loss of potassium ions.
Understand the function of the vasa recta
Carries both water and solutes from the medulla back into general circulation.
Know the normal values for urine
Describe the structures and functions of the ureters, urinary bladder, and urethra
- Urine production ends when tubular fluid enters the renal pelvis. The rest of the urinary system transports, stores, and eliminates urine.
- The ureters extend from the renal pelvis to the urinary bladder. Peristaltic contrations by smooth muscles more the urine along the tract
- the urinary bladder is stabilized by the middle umbilical ligament and the lateral umbilical ligaments. Internal features include the trigone, the neck and the internal urethral sphincter. The mucosal lining contains prominent rugae. Contractions of the detrusor compreses the urinary bladder and expels urine into the urethra.
- Both sexes, a circular band of skeletal muscles forms the external urethral sphincter, which is under voluntary control.
Discuss the voluntary and involuntary regulation of urination and describe the micturation reflex
- Urination is coordinated by the urine storage reflex and the urine voiding reflex, which are initiated by stretch receptors in the wall of the urinary bladder. Volunatry urination involves coupling these reflexes with the volunatry relaxation of the external urethral sphincter, which allows the relaxation of the internal urethral sphincter.
Define and know the difference between ECF and ICF
ICF - Intracellular fluid. Cytosol
ECF - extracellular fluid. Plasma, lymph, intersticial fluid.
Define and understand the concepts of fluid balance
- Water follows solutes. If there is too much solutes on one side of the plasma membrane the water will follow to make each side even.
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Define and understand the concepts of electrolyte balance
- total electrolyte concentrations directly affect water balance
- the concentration of individual electrolytes can affect cell funtions.
- they are the major contributors to the osmotic concentrations of ECF (sodium) and the ICF (potassium).
- they directly affect the normal functioning of all cells.
