Chapter 8

Question 1

-significantly affect all cell functions and are maintained w/in a narrow range primarily by the kidneys

Answer 1

Electrolytes

Question 2

• concentration is controlled by buffers
• imbalance results in either acidosis or alkalosis
• membrane excitability, enzyme systems, and chemical reactions all depend on the concentration being regulated by w/in a narrow physiologic range to function in an optimal way

Answer 2

Hydrogen (H+)

Question 3

• contains 1/3 of the body water in healthy adults in the
• contains all the fluids outside the cells
• contains large amounts of sodium and chloride and moderate amounts of bicarbonate and only small amounts of potassium, magnesium, calcium, and phosphorous
• level of electrolytes in the blood or plasma that are measured clinically

Answer 3

Extracellular Fluid (ECF) Compartment

Question 4

• consists of fluid contained w/in all of the billions of cells in the body
• larger of the 2 compartments
• contains about 2/3 of the body water in health adults
• contains almost no calcium; small amounts of sodium, chloride, bicarbonate, and phosphorous; moderate amounts of magnesium; and large amounts of potassium

Answer 4

Intracellular Fluid (ICF) Compartment

Question 5

• sodium 135-145 mEq/L
• potassium 3.5-5.0 mEq/L
• chloride 98-106 mEq/L
• bicarbonate 24-31 mEq/L
• calcium 8.5-10.5 mEq/L
• phosphorous 2.5-4.5 mEq/L
• magnesium 1.8-3.0 mEq/L

Answer 5

Concentrations of ECF Electrolytes in Adults

Question 6

• sodium 10-14 mEq/L
• potassium 140-150 mEq/L
• chloride 3-4 mEq/L
• bicarbonate 7-10 mEq/L
• calcium <1 mEq/L
• phosphorous variable mEq/L
• magnesium 40 mEq/L

Answer 6

Concentrations of ICF Electrolytes in Adults

Question 7

• positively charged ions=cations
  
  • attracted to the cathode
• negatively charged ions=anions
  
  • attracted to the anode
• all body fluids contain equal amounts of anions and cations

Answer 7

Ions

Question 8

• movement of charged or uncharged particles along a concentration gradient
• particles move from an area of higher concentration to one of lower concentration

Answer 8

Diffusion

Question 9

• movement of water across a semipermeable membrane
• diffuses down its concentration gradient, moving from the side of the membrane with the lesser number of particles and greater concentration of water to the side with the greater number of particles and less concentration of water

Answer 9

Osmosis

Question 10

• a change in water content causes cells to swell or shrink
• refers to the tension or effect that the effective osmotic pressure of a solution with impermeable solutes exerts on cell size because of water movement across the cell membrane

Answer 10

Tonicity

Question 11

• average adult male=60% of body weight (42L of water)

- average adult female=50% of body weight

Answer 11

Body Water

Question 12

• regulated by proteins and organic compounds w/in the body cells and by water and solutes that move between the ECF and ICF
• also affected by the concentration of osmotically active substances in the ECF that cannot cross the cell membranes

Answer 12

ICF Volume

Question 13

• divided between the vascular, interstitial, and transcellular fluid compartments
  
  • vascular compartment contains blood, essential to the transport of substances such as electrolytes, gases, nutrients, and waste products throughout the body
  • interstitial space acts as a transport vehicle for gases, nutrients, wastes, and other materials that move between the vascular compartment and body cells
    
    • also provides a reservoir from which the vascular volume can be maintained during periods of hemorrhage or loss of vascular fluid

Answer 13

ECF Volume

Question 14

• 4 forces control the movement of water between the capillary and interstitial spaces:
  1) capillary filtration pressure-pushes water out of the capillary into the interstitial space
  2) capillary colloidal osmotic pressure-pulls water back into the capillary
  3) interstitial hydrostatic pressure-opposes the movement of water out of the capillary
  4) tissue colloidal osmotic pressure-pulls water out of the capillary into the interstitial spaces
• excess fluid is removed from the interstitium by the lymphatic system and returned to the systemic circulation

Answer 14

Capillary-Interstitial Fluid Exchange

Question 15

• represents an accessory route whereby fluid from the interstitial spaces can return to the circulation
• provides a means for removing plasma proteins and osmotically active particulate matter from the tissue spaces, neither of which can be reabsorbed into the capillaries

Answer 15

Lymphatic system

Question 16

• palpable swelling produced by expansion of the interstitial fluid volume
  
  • interstitial spaces can contract to hold 10-30 L of fluid
• physiologic mechanisms that contribute: factors that increase the capillary filtration pressure; decrease the capillary colloidal osmotic pressure; increase capillary permeability; or produce obstruction to lymph flow

Answer 16

Edema

Question 17

• effects are determined largely by its location
• edema of the brain, larynx, or lungs is an acute, life threatening condition
• edema may interfere with movement, limiting joint motion
• edema increases the distance for diffusion of O2, nutrients, and wastes
• tissues are usually more susceptible to injury and development of ischemic tissue damage, pressure ulcers
• can compress blood vessels
• can be disfiguring, making problems with obtaining proper fitting clothing
• pitting edema=accumulation of interstitial fluid exceeds the absorptive capacity of the tissue gel
  
  • tissue water becomes mobile and can be translocated with the pressure exerted by a finger
• nonpitting edema=reflects a condition in which plasma proteins have accumulated in the tissue spaces and coagulated
  
  • most commonly seen in areas of localized infection or trauma; area is firm and discolored

Answer 17

Clinical Manifestations of Edema

Question 18

• daily weight, visual assessment, measurement of the affected part, and application of finer pressure to assess for pitting edema
• 1L of water weighs 1 kg (2.2lb)
• distinguishing lymphadema from other forms of edema can be challenging
• papillpmatosis=honeycomb appearance to the skin because of dilated lymph vessels that enveloped in fibrotic tissue
• treatment is usually directed toward maintaining life when the swelling involves vital structures, correcting or controlling the cause, and preventing tissue injury
  
  • lower extremities may respond to simple measures; elevating feet
  • diuretic therapy is commonly used to treat edema associated with an increase in ECF volume
• elastic support stockings and sleeves increase interstitial fluid pressure and resistance to outward movement of fluid from the capillary into the tissue spaces
  
  • most efficient if applied before the tissue spaces have filled with fluid, before the effects of gravity have caused fluid tp move into the ankles; in the morning

Answer 18

Assessment and Treatment of Edema