B5: Cell Bio Exam 2 (currently 12-15) (Renal physio)

don't cry don't cry don't cry

intake

daily (intake/loss) of body water involves:
-ingestion via liquid and food
-metabolism from oxidation of carbs

loss

daily (intake/loss) of body water involves:
-sensible is regulated (sweat, feces, urine)
-insensible is not regulated (transepithelial diffusive evaporation; dictated by barrier thickness & surface area --> Fick's law)

intracellular (ICF) and extracellular (ECF) components

What makes up total body water?

60%

What percent does fluid make up of total body weight?

40%

What percentage of the 60% of total body weight that water makes up, does intracellular fluid make up?

20%

What percentage of the 60% of total body weight that water makes up, does extracellular fluid make up?

80%

What percent of the ECF (20% of the 60% of water body weight) is interstitial fluid?

20%

What percent of the ECF (20% of the 60% of water body weight) is plasma?

kidneys, lungs, feces, sweat, skin

where does water from the plasma (20% of ECF) go (output)?

Cl-, Bicarb

What are the majority of the anions that make up ECF?

Na+

What is the cation that makes up the majority of the ECF?

true

T/F: plasma and interstitial fluid have ~ the same ionic concentration b/c they equilibrate; interstitial fluid is an ultrafiltrate of plasma

RBC

What is the intracellular component of blood?

plasma

What is the extracellular component of blood?

negative

Blood has RBCs, WBCs, platelets, and plasma proteins (e.g., albumin (oncotic pressure)) with a net (positive/negative) charge

55%

What percentage of blood is made up by plasma?

45%

What percentage of blood is made up by RBCs?

hematocrit (male 45%, female 40%)

What is the fraction of blood that is packed RBCs?

K⁺

What is the cation that makes up the majority of ICF?

Phosphate and organic anions, protein

What are the anions that makes up the majority of ICF?

142 mM

What is the concentration of Na⁺ in blood plasma?

4.4 mM

What is the concentration of K⁺ in blood plasma?

102 mM

What is the concentration of Cl^- in blood plasma?

1 mM

What is the concentration of protein in blood plasma?

290 mOsm

What is the osmolality of blood plasma, interstitial fluid, and intracellular fluid?

145 mM

What is the concentration of Na+ in interstitial fluid?

4.5 mM

What is the concentration of K+ in interstitial fluid?

116 mM

What is the concentration of Cl- in interstitial fluid?

0 mM

What is the concentration of protein in interstitial fluid?

15 mM

What is the concentration of Na+ in intracellular fluid?

120 mM

What is the concentration of K+ in intracellular fluid?

20 mM

What is the concentration of Cl- in intracellular fluid?

4 mM

What is the concentration of protein in intracellular fluid?

true

T/F: the water concentration of a solution depends on the quantity of that substance in solution.

osmoles

The total number of particles (e.g., ions, molecules) can be expressed as a coefficient measured in terms of:

the number of particles in solution

What is an osmole?

osmolarity

molecules that readily ionize or dissociate in solution yield an _________ equal to their # of resulting components/particles

osmotic pressure

what is the pulling pressure exerted by ions?

osmosis

What is the net flux of water through a selectively permeable membrane from an area of low [solute] to high [solute]?

true

T/F: osmoles in ECF and ICF remain constant unless solutes are added or removed b/c cell membranes are largely impermeable to many solutes

osmotic equilibrium

water moves rapidly across cell membranes to reach __________, ICF and ECF osmolarity remains equivalent

immediately following a change in one of the compartments (e.g., infusion of a high concentration of saline)

What is the exception to ICF and ECF osmolarity remaining equivalent?

osmolarity

What is the total concentration of all osmotically active particles per L solution?

plasma = interstitial fluid = intracellular fluid

Normally, the osmolarity of _______ = osmolarity of __________ = osmolarity of _________

tonicity

What is the concentration of osmotically active particles only?

impermeable

Only __________ particles contribute to tonicity
ex: Na+, Cl-, bicarb (ECF) or Mg2+, K+, organic anions, protein (ICF)

isotonic

What type of solution tonicity:
-ICF = ECF
-no net flux of water
-cell volume is unchanged

hypotonic

What type of solution tonicity:
-ICF > ECF
-net flux of water is into the cell
-cell volume increases
-cell may lyes (cytolysis)

hypertonic

What type of solution tonicity:
-ICF < ECF
-net flux of water out of cell
-cell volume decreases (crenation)

ECF

If the patient is in a state of osmotic equilibrium (e.g., ICF = ECF), any isotonic solution added will be in addition to the osmotic equilibrium, thus expanding (NOT INCREASING THE OSMOLARITY OF) only the ______
Note: OSMOLARITY does NOT increase

decrease

Addition of a hypotonic infusion will (increase/decrease/not change) the osmolarity of the ECF

decrease

Addition of a hypotonic infusion will (increase/decrease/not change) the osmolarity of the ICF

increase

Addition of a hypotonic infusion will (increase/decrease/not change) the volume of the ECF

increase

Addition of a hypotonic infusion will (increase/decrease/not change) the volume of the ICF

increase

Addition of a hypertonic infusion will (increase/decrease/not change) the volume of the ECF

decrease

Addition of a hypertonic infusion will (increase/decrease/not change) the volume of the ICF

increase

Addition of a hypertonic infusion will (increase/decrease/not change) the osmolarity of the ECF

increase

Addition of a hypertonic infusion will (increase/decrease/not change) the osmolarity of the ICF

1. easily measured
2. non-toxic
3. disperse uniformly
4. delimited to the compartment of interest
5. does not alter the volume of the compartment
6. cannot be metabolized during the test

What are the ideal indicator characteristics?

tissue function

A change in cell size disrupts _________

ECF

A volume contraction will result in a DECREASE of ________ volume

isomotic

During a(n) __________ volume contraction:
-ECF volume decreases
-ECF osmolarity increases
-[plasma protein] increase
-Hct increase
-Ex: diarrhea

hyperosmotic

During a(n) __________ volume contraction:
-ECF & ICF volume decreases
-ECF & ICF osmolarity increases
-[plasma protein] increases
-Hct unchanged
-Ex: dehydration

hyposmotic

During a(n) __________ volume contraction:
-ECF volume decreases
-ICF volume increases
-ECF & ICF osmolarity decreases
-[plasma protein] increases
-Hct increases
-Ex: adrenal insufficiency

diarrhea

What disorder:
-loss of isosmotic fluid from the ECF, causing the ECF volume to decrease
-NO change in ECF or ICF osmolarity because fluid that was lost was isosmotic
-DECREASE in ECF volume is loss of blood volume (decrease in arterial pressure)
-Hct increases because you have lost volume, more area of RBC:solvent

dehydration

What disorder:
-sweat is hypo-osmotic compared to ECF
-osmolarity gradient causes water to shift from the ICF to the ECF
-water shifts out of the ICF cells until ICF osmolarity increases and equilibrates to ECF osmolarity --> BOTH ECF and ICF volumes decrease
-ECF and ICF osmolarities increase and equilibrate
-Hct increases but since fluid flows out of blood cells and into plasma ECF (since hyperosmotic/hypertonic), water will flow out of RBCs and into the plasma --> unchanged

addison's disease (adrenal insufficiency)

What disorder:
-if adrenal destruction is present, you will get an aldosterone deficiency causing Na+ and Cl- to be excreted --> ECF osmolarity decreases
-Both ECF and ICF osmolarities decrease
-ECF volume decreases
-ICF volume increases
-Hct increases due to fluid flux into RBCs

antidiuretic hormone

What is synthesized by magnocellular neurons in the supraoptic and paraventricular nuclei of the hypothalamus, is transported down axons extending into neuropophysis, and stored in secretory granules as amyloid fibrils within neurohypophysis to then be released after angiotensin II stimulation?

supraoptic and paraventricular nuclei

Stimulation of the __________ (e.g., osmoreceptors), anteroventral region of 3rd ventricle (AV3V -- median pre-optic nucleus) by Ang II will induce ADH releasee

ang II

_________ stimulation of AV3V can increase thirst, sodium craving, and ADH secretion

antidiuretic hormone

What substance targets the principle cells of the collecting duct and water reabsorption vasopressin type II (V2) receptors which are a GPCR --> AC --> cAMP --> activation of NKCC in thick ascending limb of loop of Henle --> increased ENaC expression in principle cells --> increased expression of aquaporin II (AQP2) channels in collecting ducts?

ECF

Volume expansion results in an INCREASE in ____ volume

syndrome of inappropriate antidiuretic hormone release (SIADH)

What disorder:
-characterized by hypotonic and euvolemic hyponatremia along w/ urinary hyperosmolarity (urine osmolarity increases), resulting from ADH release in absence of adequate stimuli --> dumping out tons of ADH and allowing for inappropriate reabsorption of water
-euvolemic or hypervolemic dependent upon water intake, rate of solute excretion, and pressure
-commonly due to CNS disturbances (e.g., stroke), surgery, drugs, bacterial or viral pneumonia, ARDS, malignancies, ectopic ADH production, hereditary
-natriuresis (e.g., excessive secretion of Na+) and diuresis (e.g., excessive secretion of water) prevent increase in total body water (generally)

KEY FINDINGs: Urine osmolality is HIGH ( > 50–100) mOsm/kg with LOW serum osmolarity (< 275 mOsm/kg), aka: Salt low in plasma but high in urine

•Etiologies:  CNS disturbances (e.g., stroke, trauma), surgery, drugs (e.g., NSAIDs, SSRIs), bacterial or viral pneumonia, ARDS, malignancies (commonly SCLC – small cell lung cancer; NSCLC - unusual), ectopic ADH production, genetic

Conn Syndrome

-aka primary aldosteronism, hyperosmotic volume expansion

Renin-independent

• Secondary aldosteronism is caused by too much renin i.e., renin-dependent (e.g., renin inhibitors will be therapeutic)

• Too much aldosterone → Na+ reabsorption (retain salt) and K+ secretion

• Very common cause of treatment-resistant hypertension

Common Causes

• 60% bilateral idiopathic

• 35% adenoma or adrenocortical carcinoma

• 5% genetic

Diagnosis

• aldosterone:renin ratio > 20:1

isotonic

What type of volume expansion would cause:
-ECF increases
-ECF and ICF osmolarities unchanged
-Hct decreases -- same amount of RBCs, more solvent (less RBC surface area:solvent ratio)

hypertonic

What type of volume expansion would cause:
-ECF volume increases
-ICF volume decreases (bc goes to ECF)
-ECF and ICF osmolarity increases
-[plasma protein] decreases
-Hct decreases

hypotonic

What type of volume expansion would cause:
-ECF volume increases
-ICF volume increases
-ECF and ICF osmolarity decreases
-Hct decreases

excretion of metabolic waste and foreign substances

What function of the kidney allows it to remove urea, uric acid, creatinine, urobilin and bilirubin, hormone metabolites, and excrete toxins, pesticides, drugs, and food additives?

regulate water and electrolyte balance

The kidney functions to _____________ because the excretion of water and electrolytes must precisely match intake

osmolarity increases in vascular compartment causing a fluid shift

What occurs when you have excessive Na+ intake (more than excretion)?

crystalloids

What is used as a first line for fluid resuscitation?

colloids

What is used as a second line for fluid resuscitation?

regulation of vascular resistance and arterial pressure

Which function of the kidney allows it to utilize RAAS for long term volume/fluid regulation?

hypovolemic shock

What occurs when the arterial pressure is insufficient to maintain adequate perfusion and secondary ischemic injury to organs may occur?

hemorrhagic shock

What occurs when the arterial pressure is insufficient to maintain adequate perfusion and secondary ischemic injury to organs may occur DUE TO BLOOD LOSS?

true

T/F: the kidneys regulate erythrocyte production

hypoxic (hypoxia/hypoxemia)

Under ________ conditions, the kidneys can release erythropoietin (EPO), which stimulates erythropoiesis in hematopoietic stem cells in bone marrow to increase RBC production, and, therefore, oxygen carrying capacity
Hint: can be due to lung disease, blood loss, occlusion of renal artery, or high altitude

erythropoietin

Under hypoxic conditions, the kidneys can release _________, which stimulates erythropoiesis in hematopoietic stem cells in bone marrow to increase RBC production, and, therefore, oxygen carrying capacity

anemia

Kidney disease results in __________ as it progresses because the kidneys lose their ability to release erythropoietin for RBC production

fibroblast-like cells that reside in the cortical interstitium on the medullary border

What produces erythropoietin in the kidneys?

Normal Hct

A 27-year-old male runner has scheduled a competitive race in the peaks of Denver, CO in a few months. However, it will be tough for him to fit in training at altitude prior to the race due to his work schedule. He decides to skip the pre-race altitude training and do the best he can. Which of the following is most likely to impair his performance during the competition?

long

(short/long) term regulation of vascular resistance and arterial pressure of the kidney involves:
-regulating sodium and water excretion

short

(short/long) term regulation of vascular resistance and arterial pressure of the kidney involves:

-secreting hormones and vasoactive factors:
1. renin release stimulated by reduced flow or osmolarity from juxtaglomerular (JG) cells
2. renin cleaves angiotensinogen into Ang I
3. Ang I is cleaved by ACE to Ang II
4. Ang II is a potent vasoconstrictor
5. Ang II will allow renal water and salt retention and go to the adrenal glands to stimulate the release of aldosterone
6. aldosterone will stimulate renal water and Na+ retention

Renin production increases

You are trying to be health conscious and limit your salt intake. The macula densa detects reduced sodium osmolarity in the ultrafiltrate. Which of the following is most likely to occur?

regulation of acid-base balance

what function of the kidney is carried out by alpha and beta intercalated cells to regulate buffering stores (e.g., bicarb + RBCs) to buffer acids and bases?

regulation of vitamin D production

What function of the kidney:
-vitamin D is comprised of inactive precursors derived from cholesterol:
1. D2 (ergocalciferol) often obtained from ingesting plants
2. D3 (cholecalciferol) synthesized in skin by exposure of precursors to UV light
3. dietary supplements may be comprised of either form
-kidneys produce the active form:
1. vitamins D2 and D3 hydroxylated in the liver (inactive) -- calcidiol
2. kidney hydroxylates calcidol to active hormone = calcitriol (1,25-dihydroxyvitamin D) which is ESSENTIAL for Ca2+ homeostasis (e.g., Ca2+ deposition in bone and Ca2+ reabsorption in GI tract)

NEED TO KNOW ACTIVE V. INACTIVE FORMS

kidney

During a prolonged fast, what organ works with the liver to contribute to gluconeogenesis (synthesizing glucose from non-carb sources)?

homeostasis

What is the #1 function of the kidney?

filtration, secretion, excretion, absorption

What are the 4 urgent homeostatic functions carried out by the kidney?

reabsorption

returning needed substances from filtrate back to blood