chapter 27- water, electrolyte and balance (A&P)

Which statement is correct?

Sodium is more abundant in the extracellular fluid, and potassium is more abundant in the intracellular fluid.

strong acids

completely dissociate in solution -hydrochloric acid

When carbon dioxide is produced by cellular respiration, it reacts with Blank______ to form carbonic acid.

water

Sensible perpiration

water excreted by sweat glands

what happens if blood osmolarity becomes greater than interstitial fluid

water will move out into the plasma by osmosis

When carbon dioxide increases, the pH Blank______.

decreases

Electrolyte

A substance that dissolves in water to give a solution that conducts electric current -ions derived from salts, acids, bases, and proteins

Hyperhydration

A temporary excess of water; beyond the normal state of hydration. -dangerous

major extracellular ions

Na, cl, ca2+, mg2, po43(phosphate)

what happens if na+ increases in extracellular fluid

-osmolality increases -this promotes adh secretion

mechanisms that decrease thrist

-osmoreceptors detect normal solute levels -baroreceptors detect increased stretch -mouth isnt dry -stomach is distended

aldosterone

"salt-retaining hormone" which promotes the retention of Na+ by the kidneys. na+ retention promotes water retention, which promotes a higher blood volume and pressure -increases na+ reabsorption from the distal convoluted tube and collecting duct

chloride ions

-predominant anions in extracellular fluid -tied to regulation/movement of sodium -has an inhibitory effect on electrically excitable cells such as neurons and skeletal muscle fibers

Effect of alkalosis

- increases neuronal excitability. - pH change from 7.4 to 8.0 usually will induce seizures.

extracellular solutes

- sodium - chloride - proteins - glucose - exogenous substances

phosphate in the body

-85% of phosphate is in the form of calcium phosphate salts in the bones and teeth. -many are covalently bound to organic molecules -important components of dna,rna and atp -regulates enzyme activity -acts as buffers

Describe the process by which nephron cells move H+ into the kidney tubule lumen and HCO3- into the extracellular fluid.

-by increasing or decreasing the rate of H+ secretion and the rate of HCO3- reabsorption

potassium ions

-critical factor for determining the resting membrane potential for electrically excitable cells (decreased k+= cell hyperpolarizes)

Secretion of H+ in the nephron can

-decrease filtrate ph to 4.5, low ph inhibits the secretion of additonal h+

osmolality of a solution

-determined by number of solutes in a volume of a solution

sodium ions

-dominant extracellular cations -exert osmotic pressure -osmotic pressure causes water to move toward an area with a higher solute concertation -too much= water moves outside the cell -too little= water moves inside the cell

carbonic acid bicarbonate buffer system

-hco3- acts as weak base =h2co3 acts as a weak acid -cannot protect ph changes due to respiratory problems

stomach distension and thirst

-influential in decreasing thrist

regulation of phosphate in the body

-kidneys reabsorb some -pth increases phosphate levels by promoting bone reabsorption

Arterial Juxtaglomerular apparatus baroreceptors

-low blood pressure causes arterial baroreceptors to send ap to the hypothalamus -in the kidney juxtaglomerular apparatus baroreceptors stimulate juxtaglomerular cells to secrete renin when blood pressure drops

during respiratory acidosis what happens?

-low ph (high CO2) -buffers help to resist the decrease in ph -kidneys increase rate of H+ secretion and reabsorb HCO3- (kidneys not very effective if it happens quickly)

Na+ in kidneys

-major route in which Na+ is excreted -concentration of Na+ in the urine is determined by the amount of na+ and water reabsorbed from the filtrate -high reabsorption = low quantities in urine and vice versa

hypothalamic osmoreceptors

-neurons in the supraoptic nucleus of the hypothalamus function as osmoreceptors by detexting increases in the concetration of extracellular fluid -when these receptors shrink they send ap

what causes edema

-results from an increase in permeability of capillary walls or change in hydrostatic pressure -this allows proteins to go through into the interstitial fluid -reduced concentration of plasma proteins -increased venous pressure -blockage of lymph vessels

respiratory alkalosis

-results from hyperventilation -increased ph -kidneys decrease H+ secretion

calcitonin

-secreted by parafollicular cells of the thyroid gland -lowers extracellular calcium levels by preventing calcium levels from rising (inhibits osteoclasts)

parathyroid hormone regulation of ca2+

-secreted when levels are too low -pth increases blood ca2+ through 1.esteoclasts- reabsorbing of bone 2.renal tubules-reabsorption from kidney tubules 3.vitamin d3-increases rate of active vd3 formation which increases ca2+ levels

regulation of k+

-secretion of aldosterone -elevated levels of k+ stimulate aldosterone secretion which increases na+ reabsorption and K+ secretion by na+/K+ pump -aldosterone increases the rate of k+ secretion in the kidney which lowers k+ levels in the blood

Na+ excreted in sweat

-small amount -heavy exercise and warm environments can increase amount excreted

what happens if you sweat too much and dont drink enough fluids?

-sweating decreases the volume of fluid in the body but increases concentration of body fluid -

protein buffer sytsem

-the most abundant in intracellular fluods and in plasma -hemoglobin buffer in rbc -albumin is plasma buffer -

Na+ transport mechanisms of the distal convoluted tube and collecting

-under hormonal control

carbonic acid-bicarbonate buffer system responds to

1. addition of substances such as co2 or lactate during exercise 2.increased fatty acid and ketone body production 3. addition of basic substances (NaHCO3)

Rank men, women and infants from greatest to least amount of body water.

1. infants 2.men 3.women

Put the following statements in order to explain the process of acid-base regulation by the kidney, starting with the decrease in blood pH.

1.blood ph decreases 2. co2 diffuses into the kidney tubule cells 3.the carbonic aicd-bicarbonate equation is driven to the right (forming H+ and HCO3-) 4.H+ is secreted into filtrate in exchange for na+ 5.na+ and bicarbonate are symported into the interstitial fluid and diffuse into the blood 6.in the blood bicarbonate ions are combined with h+ to increase the blood ph

Put the following mechanisms in order of their buffering capacity on acid-base balance (least to greatest).

1.buffer system 2.respiratory system 3.renal system

regulation of H+ concentration

1.buffers-resists changes in ph -carbonic acid -protein -phosphate 2.respiraotry system 3. kidneys

regulation of fluid balance

1.hypothalamic osmoreceptors 2.arterial and juxtaglomerular apparatus baroreceptors 3.dryness of mouth 4. distension of stomach

ca2+ regulation

1.kidneys-long term regulation 2.digestive tract-long term regulation 3.bones- short term regulation -pth, vitamin d3, and calcitonin also regulate

An individual takes in 2,000 ml of water during the day. Ideally they should lose Blank______ ml of water during the day.

2000

water loss from evaporation

35%

water loss in feces

4%

How much of body weight is water?

50% or more

water loss in urine

60%

Infant body weight (Water)

75%

What hormone is released in response to changes in blood osmolality and results in changes in extracellular sodium concentration?

ADH

Which of these mechanisms is the most important for regulating blood osmolality?

ADH

When blood pressure is increased, Blank______ is released and the reabsorption of Blank______ is decreased.

ANH, sodium

Na+/K+ pump

Active transporter that moves three Na+ out of a cell and two K+ into the cell against their respective concentration gradients.

What is the principle hormone that regulates potassium ion concentrations in body fluids?

Aldosterone -Aldosterone causes sodium to be absorbed and potassium to be excreted into the lumen by principal cells

intracellular fluid compartment

All fluids inside cells of body About 40% of total body weight

Bicarbonate acts as a weak Blank______ by binding H+, removing the ions from solution, and raising pH

Base

Name the most important buffering system in the blood.

Bicarbonate/carbonic acid system

The primary mechanisms that regulate Na+ levels in the ECF directly monitor what two variables? Select all that apply.

Blood pressure Blood osmolality

Which of the following is correct?

Chloride is the most abundant anion in extracellular fluid, and proteins are the major anions in intracellular fluid.

plasma anion

Cl

regulation of cl-

Coupled to Na+ reabsorption Filtered and Reabsorbed

Which is under hormonal control?

Distal convoluted tubule

Which of the following structures are involved in the renin-angiotensin-aldosterone mechanism?

Distal convoluted tubules Cells of the juxtaglomerular apparatus

What causes osmotic pressure and movement of water between the fluid compartments?

Electrolytes

extracellular fluid compartment

Fluid outside cells; (interstitial fluid, plasma, lymph, csf, synovial fluid) 20% of body weight

What pressure drives filtration

Glomerular Blood Hydrostatic pressure (GBHP)

The kidneys directly regulate acid-base balance by Blank______. Select all that apply.

H+ secretion bicarbonate reabsorption

interstitial fluid cation

Na+

plasma cation

Na+

osmotic pressure of the extracellular fluid is caused mostly by

NA+

What is the purpose of buffers in the urine? Describe how the ammonia buffer system operates.

NH3 is produced in the cells of the nephron when amino acids, such as glutamine, are deaminated. Subsequently, NH3 diffuses from the nephron cells into the filtrate and combines with H+ in the filtrate to form ammonium ions

intracellular anion

Phosphate

What chemical buffer system is important for regulating intracellular pH?

Phosphate system

intracellular cation

Potassium (K+)

Name the factors that cause an increase and a decrease in H+ secretion.

The rate of H+ secretion and HCO3− reabsorption increases when the pH of the body fluids decreases, and this process slows when the pH of the body fluids increases

When blood pH decreases, which of the following occurs to correct the imbalance?

The respiratory center increases the breathing rate.

If blood pH increases, which of the following occurs to correct the imbalance?

The respiratory rate is decreased.

Which of the following is an important function of electrolytes in the extracellular fluid?

They control the movement of water between fluid compartments.

Indicate which of the following explain why electrolytes are physiologically important.

They strongly affect the osmolarity of the body fluids and the body's water content and distribution. They determine the electrical potential (charge difference) across cell membranes.

High levels of ammonium ions in the urine indicate:

a high level of H+ secretion into the urine

The carbonic acid/bicarbonate buffer system has Blank______ capacity to resist changes in blood pH.

a limited

High levels of bicarbonate ions in the urine indicate:

a low level of H+ secretion into the urine

In the bicarbonate buffer system, carbonic acid acts as a weak Blank______ by releasing H+ and lowering pH.

acid

A blood pH of 7.20 indicates Blank______.

acidosis

protein buffer system

acts inside & outside the cell; binds with acids & bases to neutralize them -proteins provide 3/4 of body's buffer capacity -hemoglobin is an important buffer -histone proteins

Hyperchloremia

an excess of chloride in the blood plasma -indication of dehydration -Cushing syndrome

ADH

antidiuretic hormone -stimulates water reabsorption in the kidneys and thrist

In what part of the renal tubule is most Mg2+ reabsorbed?

ascending limb (loop of henle)

Hypophosphatemia

below-normal serum concentration of inorganic phosphorus

Most phosphate in the body is found in Blank______.

bone and teeth

The level of extracellular Blank______ ions is regulated by the kidneys, bones, and digestive tract.

calcium

intercalated cells

cells in the collecting ducts of the kidneys that can absorb potassium if necessary -Regulate the amount of HCO3- and H+ in the urine in order to maintain the body's acid-base balance

carbonic acid-bicarbonate buffer system

chemical system that helps maintain pH homeostasis of the blood -regulating extarcellular ph -H+ added due to increase in acidic substances , binds to HCO3- this resists a decrease in ph (acts as a base) -H+ removed= H2CO3 forms HCO3- and H+ to resist change from basic substances (acts as an acid)

The most abundant anion in extracellular fluid is

chloride

interstitial fluid

cl-

Magnesium ions serve as Blank______.

cofactors for important enzymes

Aldosterone Blank______ urine output.

decreases

Which of these results in an increased blood Na+ concentration?

decrease in ADH secretion

Which of these conditions decrease extracellular fluid volume?

decreased aldosterone secretion

metabolic acidosis

decreased pH in blood and body tissues as a result of an upset in metabolism -hyperventilation

Hypochloremia

deficiency of chloride in the blood plasma -heart failure or addison disease

Hypocalcemia

deficient calcium in the blood

Hypokalemia

deficient potassium in the blood -due to elevated aldosterone levels -insulin administration

Hyponatremia

deficient sodium in the blood

blood osmolarity increases when

dehydrated

nonelectrolyte

do not dissociate into ions in water -lipids, urea, and glucose

when does permeability to capillary wall increase

during inflammatory response

Hyperphosphatemia

excessive phosphate in the blood

Hyperkalemia

excessive potassium in the blood

The carbonic acid/bicarbonate buffer system is important for regulating the pH of fluid in the ____ compartment.

extracellular

True or false: Both the adrenal medulla and the juxtaglomerular cells of the kidney play an important role in regulating blood volume.

false

True or false: Water loss is constant per kilogram of body weight.

false

Intracellular and extracellular are two major Blank______ of the body.

fluid compartments

fluid input

food/beverages- 90% cellular respiration- 10%

Solutions with a higher sodium ion concentration have a Blank______ osmotic pressure than solutions with a lower sodium ion concentration.

greater

Water loss varies Blank______ depending on physical activity level and environmental conditions.

greatly

Too much sodium can cause?

high blood pressure

metabolic alkalosis

high pH, high HCO3

Hypernatremia

high sodium

Osmosis is the diffusion of water toward a solution with a Blank______ solute concentration.

higher

renin-angiotensin system

hormone pathway that *increases thirst and raises blood pressure* if blood volume falls (often due to *dehydration*), detected as decreased blood flow to the kidneys; aka *RAS* or renin-angiotensin-aldosterone system (*RAAS*)

Slight deviations from the normal concentration of Blank______ ions can shut down metabolic pathways as well as alter the structure and function of other macromolecules.

hydrogen

The structure that promotes the thirst sensation is the Blank______.

hypothalamus

When blood pressure is decreased, the release of renin is Blank______ and the reabsorption of sodium is Blank______.

increased, increased

What would the effect of constricting the efferent arteriole be on glomerular filtration rate?

increases

decreased osmolality

inhibits thirst and ADH secretion

Water input and output

input: - ingested fluids - ingested foods - metabolism total: 2400-3200 mL output: - urine - feces - swear - exhaled air total: 2400-3200 mL - urine output is typically 1.5 L a day - can be as great as 20 L per day or as little as 0.5 L per day - kidneys alter urine output to compensate for variations in water intake/loss

insensible perspiration

interstitial fluid lost by evaporation through the stratum corneum

Which organ is primarily responsible for removing excess electrolytes from the body?`

kidney

The sodium ion reabsorption from the renal tubule decreases, Blank______ are excreted in the urine.

large amounts of sodium ions

Proteins are Blank______ abundant than bicarbonate ions in extracellular fluids.

less

When carbon dioxide decreases, the carbonic acid/bicarbonate equation is driven to produce Blank______ H+ ions.

less

Of the magnesium that is reabsorbed, most is reabsorbed through the Blank______.

loop of Henle (nephron loop)

Acidosis:

may lead to coma

Dehydration

occurs when body fluid drops below its set point -increasing osmolaity -the concentration of solutes in ef increases which allows water to move out of the cell by osmosis -

body fluid osmolality

osmolality maintained at 280-300

Parathyroid hormone increases the activity of Blank______ cells in bone and increases the rate of calcium Blank______ in the kidney tubules.

osteoclast; reabsorption

HPO42- and H2PO4- are components of the Blank______ buffering system.

phosphate

What electrolyte is important for bone composition, as a component of nucleic acids and ATP, and as an intracellular buffer?

phosphate

The renal system is an example of a Blank______ buffer.

physiological

An imbalance in this ion is very dangerous because this ion influences the resting potential of excitable cells.

potassium

Imbalances in , ___ ionsthe most dangerous of all electrolyte imbalances because this ion influences the resting membrane potential of excitable cells.

potassium

The most abundant cation in intracellular fluids is Blank______.

potassium

osmotic pressure

pressure that must be applied to prevent osmotic movement across a selectively permeable membrane

Which cells found in the collecting duct of the nephron, adjust urine in order to maintain the body's water, Na+, and K+ balance?

principal cells

Which buffer system is the most abundant in the body?

protein

The three major chemical buffer systems of the body are the Blank______ buffer systems.

protein phosphate carbonic acid/bicarbonate

intracellular solutes

proteins/potassium/magnesium/sulfate/monohydrogen phosphate ions

phosphate buffer system

reacts with acids & bases to form compounds that alter pH; especially effective in renal tubules

phosphate buffer system

reacts with acids & bases to form compounds that alter pH; especially effective in renal tubules -intracellular -when ph decreases ions bind to H+ and vice versa

Long-term suppression of thirst is regulated by Blank______ of blood osmolarity.

reduction

acids

release H+

weak acids

release h+ into solution but nit completely dissociated -carbonic acid

bases

remove H+ from solution

The addition of CO2 to the body fluids raises H+ concentration and lowers pH, while the removal of CO2 has the opposite effect. This is the basis for the strong buffering capacity of the Blank______ system.

respiratory

Hypoventilation can lead to Blank______.

respiratory acidosis

Insensible perspiration:

results in heat loss from the body

A decrease in extracellular K+:

results when aldosterone levels increase -aldosterone causes the release potassium

The kidneys directly regulate acid-base balance by increasing or decreasing the rate of H+ Blank______ and the rate of bicarbonate Blank______.

secretion, reabsorption

The most significant solute in determining total body water and the osmotic pressure of the ECF is Blank______.

sodium

Which two ions are most affected by aldosterone?

sodium and potassium

Examples of electrolytes

sodium, chloride, potassium

increased osmolality

triggers thirst and ADH secretion

the sensation of thirst increases when

the levels of angiotensin II increase

hydrostatic pressure

the pressure within a blood vessel that tends to push water out of the vessel

males body weight due to water is more than a female bc

they have low % of adipose tissue (adipose tissue has low water content)

low blood pressure increases

thrist

True or false: Although Na+ levels affect blood pressure and blood osmolality, Na+ itself is not directly monitored for the primary mechanisms regulating its concentration.

true -it monitors blood osmolarity and blood pressure

calcium absorption from the digestive track is dependent on

vitamin d 3

Calcium ion concentration in the blood decreases when

vitamin D levels are lower than normal

mechanisms that increase thirst

•Osmoreceptors detect increased solute concentrations. •Baroreceptors detect less stretch in vessels. •Decrease in saliva production.