Cells Part II
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Transcript of Cells Part II
Cells Part II
Human Anatomy and Physiology I
Oklahoma City Community College
Dennis Anderson
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Solute Concentration of Cells
0.9% NaCl300 Milliosmoles
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Concentration of Solutions
• Normal Saline or Physiological Saline– 300 millisomoles = 0.9% NaCl
• Ringers Solution– Contains NaCl and other salts that make it more
similar to blood plasma– 300 milliosmoles
Amount of solutes dissolved in water
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Hypertonic
A solution with a higher concentration than another
1% NaCl 0.2% NaCl
Hypertonic
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Hypotonic
1% NaCl 0.2% NaCl
Hypertonic
A solution with a lower concentration than another
Hypotonic
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Isotonic
A solution with the same concentration as another
0.9% NaCl 0.9% NaCl
Osmosis
Water moves across a membrane to the side with a higher concentration of
Solutes
Cell in a Hypertonic Solution
300
350 Crenate
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Cell in a Hypotonic Solution
300
250
Swell
Lyse
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Cell in Isotonic Solution
300
300
0.9%
0.9%
No net movement of water
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Isotonic Solutions
• Have the same amount of solutes as body cells– 300 Milliosmoles
– 0.9% NaCl
– 5% Glucose
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Isotonic IV Solutions
• Normal Saline or Physiological Saline– 0.9% NaCl
• D5W (Dextrose 5% in Water)
– 5% Glucose
• Lactated Ringers – Glucose, lactic acid, salt
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Tonicity
Water
Sea WaterD5 1/2 NS
Hypotonic
Hypertonic
Hypertonic
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310 mosm
300 mosm
Which Way Will Fluid Move?
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Fluid Balance
• Fluid leaving body = Fluid entering body
• Right amount of fluid in each compartment
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Electrolyte Balance
• Having the right concentration of various ions in the body– Sodium
– Potassium
– Calcium
– Magnesium
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Fluids and Electrolytes
• Electrolytes attract fluids by osmosis
• Loss of fluids results in a loss of electrolytes
• IV therapy is often needed to restore fluid balance, electrolyte balance or both
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Organs that Regulate Fluid and Electrolyte Balance
• Brain
• Adrenal glands
• Kidneys
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Hypothalamus of the BrainDecreased volume of ECF or
Increased osmolarity of ECF
Hypothalamus
Decreased saliva
Thirsty
Drink FluidIncrease ECF
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Adrenal Gland
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Hypothalamus & Kidneys
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Application Problem 1
•Richard works as a roofer. He is in the hot sun many hours a day. As a result he loses water by perspiration. How does his body maintain homeostasis?
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Answer to Problem 1
• The hypothalamus will make more ADH causing the kidneys to produce less urine.
• His hypothalamus will make him thirsty. This will cause him to drink a lot of liquids
Application Problem 2
Dawn urinates many times during the day but is able to sleep all night without the need to urinate. How do you explain this?
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Answer to Problem 2
• The kidneys produce less urine when you are asleep because the hypothalamus secretes more ADH during sleep.
Application Problem 3
Claudia has had diarrhea for the past two weeks. Her potassium level is only 25% of the normal value. Why is her potassium so low?
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Answer to Problem 3
• Claudia has lost a lot of fluid and with this fluid she has lost potassium.
• She will need to be given potassium immediately or her heart may develop arrhythmias and stop beating.
Application Problem 4
Melissa has been unable to eat anything following her surgery. Her doctor has ordered an IV of D5W. Why did he do this?
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Answer to Problem 4
• The fluid in the D5W will replace fluid she will naturally lose.
• The sugar will provide an energy source for her body.
Application Problem 5
Dr. Quack has told Sally she needs to flush the poisons out of her body. He has been giving her an IV of distilled water twice a week. What are the risks to Sally of this treatment?
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Answer to Problem 5
• Distilled water is hypotonic to blood cells.
• Many of the red blood cells will lyse creating a burden on the liver to cleanse the blood.
• Lack of blood cells could make Sally anemic.
Application Problem 6
Mike has had a severe head trauma. There is swelling on his brain. His doctor has ordered an IV of 20% glucose. Why did he do this?
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Answer to Problem 6
• 20% glucose is hypertonic.
• It will attract fluid from the brain into the blood.
Application Problem 7
Paul has a history of hypertension. His doctor has placed Paul on a low salt diet. What is the rationale for the low salt diet?
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Answer to Problem 7
• Salt will make Paul’s blood hypertonic.
• Fluid will move by osmosis into his blood.
• Increased blood volume will increase blood pressure. 310 mosm
300 mosm
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Ion
• Atom or molecule with a charge
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Solution
• A mixture of two or more substances
• Salt water–salt
–water
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Solvent
• A substance that dissolves solutes in a solution
• Water
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Solute
• Substance that dissolves in a solution
• Salt is a solute in salt water
• Sugar is a solute in sugar water
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Turgor
• Tightness of the skin or a membrane
• Poor skin turgor is a sign of dehydration
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Equilibrium
• When something is balanced with its environment
• A cell in a solution with the same concentration of solutes as the cell
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Cell in Equilibrium
0.9% NaCl
0.9% NaCl
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Dehydration
• Condition of excessive water loss
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Osmotic Pressure
• Measure of the tendency of a solution to attract water by osmosis
• Osmotic pressure increases when the difference in solute concentration between two solutions increases
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0.9% NaCl 0.9% NaCl
1% NaCl 3% NaCl
Which Solution has the Greater Osmotic Pressure?
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Milliosmole
• Unit of measurement of all the solutes in a solution
• Blood has a concentration of 300 milliosomoles
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Edema• The accumulation of excess interstitial fluid in
interstitial spaces (between cells)• Causes swelling• May be caused by increased hydrostatic
pressure in capillaries– congestive heart failure– hypertension– pregnancy
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The End