sci 241 dehydration wk 5

8/10/2019 SCI 241 Dehydration Wk 5

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Assignment - Dehydration Due Week 5 Day 7 (11/22/09)

Post - Indiidua! "orum

Assignment: Dehydration

# Write a 1$050- to 1$750-%ord &a&er a'out the eets o dehydration*

# Includeans%ers to the o!!o%ing+o Why is %ater essentia! to hea!th maintenane,

o What are the untions o %ater in the 'ody,

o What ha&&ens to the 'ody %hen it does not get the %ater it needs,

o om&are and ontrast ho% dierent e!etro!ytes.sodium$ &otassium$ and

h!oride.untion in the 'ody*

o What eets might a!oho! and aeine hae on hydration !ee!s in the 'ody,

o What ste&s may &eo&!e take to ensure they do not 'eome dehydrated,

# Format your &a&er aording to APA standards*

# Post your &a&er as an attahment*

Written Assignment Grading Form for Dehydration, Due in Week Five

Content / Development70 Points

Points Earned

XX/70

Additional Comments:

All key elements of the assignment arecovered in a substantive way.

Why %ater is essentia! to maintaining hea!th

he untions o %ater in the 'ody

What ha&&ens to the 'ody %hen it does not

get the %ater it needs

om&are and ontrast ho% dierent

e!etro!ytes-sodium$ &otassium$ and h!oride-

untion in the 'ody

he eets that a!oho! and aeine on

hydration !ee!s in the 'ody

te&s to take to aoid dehydration

he &a&er is 1$050 to 1$750 %ords in !ength*

The content is comprehensive, accurate, andpersuasive.

The paper develops a central theme or idea,directed toward the appropriate audience.

Major points are stated clearly are supportedby specific details, e!amples, or analysisand are organi"ed logically.

The introduction provides sufficientbackground on the topic and previews major


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points.

The conclusion is logical, flows from the bodyof the paper, and reviews the major points.

eada!ility and "tyle#$ Points

Points Earned

XX/15

Additional Comments:#aragraph transitions are present and logicaland maintain the flow throughout the paper.

The tone is appropriate to the content andassignment.

$entences are complete, clear, and concise.

$entences are well constructed, withconsistently strong, varied sentences.

$entence transitions are present and maintainthe flow of thought.

%e&hani&s#$ Points

Points Earned

XX/15

Additional Comments:

The paper, including the title page, referencepage, tables, and appendices, follow A#Astandards for format.

Citations of original works within the body ofthe paper follow A#A standards.

The paper is laid out with effective use ofheadings, font styles, and white space.

%ules of grammar, usage, and punctuationare followed.

$pelling is correct.

'otal#00 Points

Points Earned

XX/100

(verall Comments)

In an eort to &reent dehydration you %ant to irst a!%ays !isten to your 'ody the need to

onsume %ater is signa!ed 'y the sensation o thirst* hirst is aused 'y dryness in your mouth as%e!! as signa!s rom the 'rain together they motiate you to drink* hough thirst is a &o%eru!

urge it annot 'e re!ied on to regu!ate ho% muh %ater is in the 'ody* he sensation o thirst

oten !ags 'ehind the need or %ater and you dont or ant a!%ays drink %hen you are thirsty*

Water cannot be stored in the body and it is continuously lost, mostly throughevaporation and urinary losses, so a steady supply must be consumed. Gram for gram,we need more water each day than any other nutrient. The DRIs recommend 3. liters!3"" grams# per day for men and $. liters !$"" grams# per day for women.%owever,the amount you actually need is a&ected by your diet and activity level as well asenvironmental temperature and humidity. 'ctivity increases water needs because itincreases the amount of water lost in sweat( losses are greater in hot and humidenvironments. The composition and ade)uacy of the diet also a&ect water needs. ' low*calorie diet increases water needs because as body fat and protein are bro+en down to


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fuel the body, +etones and urea are produced and must be ecreted in the urine. ' high*sodium diet increases water losses because the ecess salt must be ecreted in theurine. ' high*-ber diet increases water needs because more water is held in theintestines and ecreted in the feces.

Dehydration can be life-threatening ven small changes in the amount of waterin the body can be life*threatening. Without food, you could probably survive for about /

wee+s, but without water, you would last only a few days. When water losses are greatenough to reduce blood volume, the ability to deliver oygen and nutrients to cells andremove waste products is a&ected. arly symptoms of dehydration include thirst,headache, fatigue, loss of appetite, dry eyes and mouth, and dar+ colored urine. 0urtherloss a&ects thin+ing ability and physical performance. 1ater symptoms include nausea,di2culty concentrating, confusion, and disorientation. Dehydration is more li+ely tooccur during eercise because water loss through sweat is increased. Drin+ing at regularintervals while you eercise to replace the water you are losing can preventdehydration. Its mild symptoms disappear )uic+ly after consuming uids, but if leftuntreated it can re)uire medical attention. ' loss of about 4" to $"5 of body weight aswater can be fatal. 6oung athletes involved in sports with weight classes, such aswrestling and boing, sometimes use dehydration to reduce their body weight so theycan compete in a lower weight class. 7eing at the high end of the lower weight class isthought to provide an advantage over smaller opponents in that class.8 %owever, whenweight loss is accomplished through even mild dehydration, eercise performance canbe impaired.

Consuming too much water dilutes the internal sea It is di2cult to consumetoo much water under normal circumstances. %owever, overhydration may occur withillness or, in certain situations, during eercise. 0or eample, water and minerals are lostin sweat. When these losses are replaced with plain water the balance of water anddissolved substances is disrupted. Drin+ing plain water after ecessive sweating is li+epouring out half a glass of salt water and re-lling the glass with plain water. The totalamount of water is the same but the salt in the glass is now more dilute. The same thing

can happen to your blood and is referred to as water toicity. The early symptoms ofwater toicity may be similar to dehydration9 nausea, muscle cramps, disorientation,slurred speech, and confusion. It is important to determine if the symptoms are due todehydration or water toicity because drin+ing water alone will ma+e toicity worse andcan result in sei:ure, coma, or death. To help prevent water toicity it is recommendedthat beverages containing dilute solutions of sodium as well as sugar, such as sportsbeverages, be used to replace water losses when eercise continues for more than anhour.

Electrolytes;eeping your body alive and moving re)uires the transmission of nerve impulses andthe contraction of muscles. These activities are triggered by the movement ofelectrically charged ions dissolved in water. These ions conduct an electrical current andare therefore referred to as electrolytes.


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potassium are both positively charged ions( sodium is concentrated outside cells,whereas potassium is concentrated inside cells where it is 3" times more concentratedthan outside the cell. The imbalance of sodium and potassium as well as a greaterconcentration of positive ions >ust outside the cell membrane are forces that attractsodium to the inside of cells. When a nerve cell is at rest sodium stays outside the cellbecause sodium ions cannot pass freely across cell membranes. 7ut, when a nerve is

stimulated, the cell membrane becomes more permeable to sodium, allowing sodiumions to rush into the nerve cell. When this happens, the positive charge inside the cellincreases causing the electrical charge at that location on the cell membrane to bereversed( this triggers an increase in sodium permeability on the ad>acent patch ofmembrane. The change in sodium permeability and electrical charge continues tospread down the nerve as a nerve impulse. If the nerve signal travels to a muscle cell,similar events occur at the muscle cell membranes and result in muscle contraction.?nce the nerve impulse passes, the original resting concentrations of sodium andpotassium inside and outside the membrane are restored so a new nerve signal can betriggered if the nerve is stimulated.

Did you ever weigh yourself after eating a very salty meal to -nd that you had gained afew pounds@ The salt, which is sodium combined with chloride, was absorbed into yourblood increasing the sodium concentration. This imbalance made you thirsty andstimulated you to drin+ enough to dilute the sodium in your blood. The etra poundsyou see on the scale reect the etra water you have temporarily stowed away. 7y thenet day your body will have had time to ecrete the etra sodium and the water alongwith it in your urine, bringing your weight bac+ to normal.

Electrolyte levels are carefully regulated ?ur bodies are e2cient at regulatingthe internal concentrations of electrolytes, even when dietary inta+e varies dramatically.0or eample, in northern Aapan, sodium inta+e is greater than 4".3 grams per day andamong the 6anomamo Indians of 7ra:il, it is less than ".$ grams per day, yet, bloodlevels of sodium are not signi-cantly di&erent among these groups.

When we get thirsty, it means we need water. When we feel li+e a salty snac+,

does this mean we need salt@ Bost li+ely that answer is no. When salt inta+e is very low,there is a salt appetite, which causes you to crave salt, but most of us eat far too muchsalt for this appetite to be activated. The salt cravings that trigger your desire to plungeinto a bag of salty chips is a learned preference, not a physiological drive for salt !0igureC.C#. If you cut bac+ on your salt inta+e you will -nd your taste buds become moresensitive to the presence of salt. 'lthough thirst and salt cravings may cause you toconsume more water and salt, the +idneys, not inta+e, are the primary regulator ofsodium, chloride, and potassium balance in the body. cretion of these electrolytes inthe urine is decreased when inta+e is low and increased when inta+e is high. Theregulation of blood levels of potassium is important because even a small increase canbe dangerous. If blood levels begin to rise, body cells are stimulated to ta+e uppotassium. This short*term regulation prevents the amount of potassium in theetracellular uid from getting lethally high. The long*term regulation of potassiumbalance depends on the release of proteins that cause the +idney to ecrete potassiumand retain sodium.

Controlling sodium excretion helps regulate blood pressure 7ecause waterfollows sodium by osmosis, the ability of the +idneys to conserve sodium provides amechanism to conserve body water. This mechanism helps to regulate blood pressure.0or eample, if you are out eercising on a hot day you will lose water and salt in sweat.If you lose more than you ta+e in it will cause a drop in blood volume, which causes adecrease in blood pressure. The body has sensors that detect changes in blood


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pressure. The drop in blood pressure triggers the production and release of proteins andhormones that a&ect the amount of sodium, and hence water, retained by the +idneys.

The -rst substance to be released when blood pressure decreases is the en:yme renin.It is produced by the +idneys and begins a series of events leading to the production ofa small protein called angiotensin II. 'ngiotensin II increases blood pressure in twoways. 0irst, it causes the muscles in blood vessel walls to constrict. This increases blood

pressure by narrowing the lumen of the blood vessel. 'ngiotensin II also stimulates therelease of the hormone aldosterone, which causes the +idneys to increase sodiumreabsorption. 's more sodium is reabsorbed, water follows, preventing water loss andmaintaining blood volume and, conse)uently, blood pressure !0igure C.4"#. If bloodpressure begins to rise, as might occur if you eat a salty meal, the increase in bloodpressure inhibits the release of rennin and aldosterone, relaing blood vessels andincreasing the ecretion of sodium and hence water by the +idneys and decreasingblood pressure to normal.?ur diet today is high in salt !sodium chloride# and low in potassium. The reason for thisis that we eat a lot of processed foods, which are high in sodium and chloride, and toofew fresh unprocessed foods such as fruits, vegetables, whole grains, and fresh meats,which are high in potassium. 'bout 5 of the salt we eat is from that added duringprocessing and manufacturing !0igure C.44#. ?nly about 4$5 comes from salt foundnaturally in food, while 445 is from salt added in coo+ing and at the table.3


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The electrolytes are found in plentiful amounts in the diet, and the +idneys of a healthyindividual are e2cient at regulating amounts in the body. De-ciencies and ecesses canoccur due to illness or etreme conditions. 0or instance, sodium, chloride, andpotassium depletion can occur with heavy and persistent sweating, chronic diarrhea orvomiting, and +idney disorders that lead to ecessive ecretion. Bedications can alsointerfere with electrolyte balance. 0or eample the diuretic medications, +nown as

thia:ide diuretics, that are used to treat hypertension cause potassium loss. Generally,potassium supplements are prescribed along with or incorporated into medications thatcause potassium loss. De-ciencies of any of the electrolytes can lead to electrolyteimbalance, which can cause disturbances in acid*base balance, poor appetite, musclecramps, confusion, apathy, constipation, and, eventually, an irregular heartbeat. 0oreample, the sudden death that can occur in fasting, anoreia nervosa, or starvationmay be due to heart failure caused by potassium de-ciency.

Too much potassium can be deadly =o E1 has been set for potassium becauseconsuming too much potassium from foods is not a ris+ in healthy people with normal+idney function. If, however, supplements are consumed in ecess or +idney function iscompromised, blood levels of potassium can increase and can potentially cause deathdue to an irregular heartbeat. ' high oral dose generally causes vomiting, but if toomuch potassium enters the blood, it can cause the heart to stop.

Too much salt can contribute to high blood pressure If you eat more salt thanyou need, your +idneys will ecrete the etra. %owever, in many people, themechanisms that regulate blood pressure are unable to prevent rises in blood pressureas salt inta+e increases. These individuals are referred to as saltsensitive. 7ased on therelationship between blood pressure and salt inta+e a E1 has been set at ./ grams ofsalt per day. 0or those without salt*sensitivity, no toic level of sodium inta+e has beendocumented as long as water needs are met and the +idneys are functioning properly.'nother concern with high*sodium inta+es involves the mineral calcium. ' high*sodiuminta+e increases calcium ecretion, thus increasing the ris+ of bone loss.

Dehydration$ a de&!etion o 'ody %ater$ %i!! ause sym&toms more ra&id!y than a deiieny o

any other nutrient* "or e3am&!e$ days and een %eeks %ithout some itamins and minera!s %i!!not ause deiieny sym&toms$ 'ut an hour o e3erise on a hot day an resu!t in dehydration*

Water is an essential macronutrient( to maintain uid balance, inta+e must e)ual losses.

di&usion of water is called osmosis( water moves across membranes from an area witha lower particle concentration to an area with a higher particle concentration. ?smosisnot only drives the movement of water from one body compartment to another, but alsoallows water from the diet to move from the lumen of the gastrointestinal tract into theblood.

When the concentration of particles in one compartment is higher than in another,water will move toward the compartment with the most dissolved substances.


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Water bathes the cells of the body and lubricates and cleanses internal and eternalbody surfaces. Watery tears lubricate the eyes and wash away dirt, synovial uidlubricates the >oints, and saliva lubricates the mouth, ma+ing it easier to chew andswallow food. Water resists compression so it cushions body compartments such as the

>oints and eyeballs against shoc+. The cushioning e&ect of water in the amniotic sacprotects the fetus as it grows inside a pregnant woman. 7lood, which is mostly water,

ows through our bodies, delivering oygen and nutrients to cells and returning wasteproducts to the lungs and +idneys for ecretion. In addition, water functions in chemicalreactions and helps regulate body temperature.

ater functions in chemical reactions Water is an ecellent solvent( glucose,amino acids, minerals, and many other substances needed by body cells dissolve inwater. The chemical reactions of metabolism that support life ta+e place in water. Wateralso participates directly in a number of chemical reactions that >oin small moleculestogether or brea+ large molecules apart.

sci 241 dehydration wk 5

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