Title: Ch 25 Fluid, Electrolyte, and Acid-Base Balance
1Ch 25 Fluid, Electrolyte, and Acid-Base Balance
Too much fluid?
Not enough fluid?
- Learning Objectives
- List the factors that determine body water
content. - Describe the importance of sodium balance in the
body (and the resulting factors from too much
sodium being lost).
2Discussion
- How much water should we really drink per day?
- What happens if we drink too little? What happens
if we drink too much?
http//video.google.com/videoplay?docid5539638143
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3Small Group Activity
- Instructions
- In small groups of no more than 4 people per
group, read the article Can You Drink Too Much
Water? - Discuss and formulate answers to the 6 guiding
discussion points (next page). - Be prepared to share your answers with fellow
classmates.
- For further information http//video.google.co
m/videoplay?docid-6490926615600128267
4Body Water Content
- Infants have low body fat, low bone mass, and are
73 or more water - (In old age, only about 45 of body weight is
water)
What inference can you draw from that?
Healthy males are about __ water healthy
females are around __ This difference reflects
females - Higher body fat - Smaller amount of
skeletal muscle
5Fluid Compartments
- Water occupies two main fluid compartments
- __________ fluid (ICF) about two thirds by
volume, contained in cells - ____________ fluid (ECF) consists of two major
subdivisions - Plasma the fluid portion of the blood
- Interstitial fluid (IF) fluid in spaces between
cells - Other ECF lymph, cerebrospinal fluid, eye
humors, synovial fluid, serous fluid, and
gastrointestinal secretions
6Composition of Body Fluids
- Q - What is the universal solvent?
Q What are solutes?
7Electrolyte Composition of Body Fluids
Q What are some of the greatest electrolytes
found in blood plasma?
8Electrolyte Balance
- Electrolytes are salts, acids, and bases, but
electrolyte ________ usually refers only to salt
balance - Salts are important for
- Neuromuscular excitability
- Secretory activity
- Membrane permeability
- Controlling fluid movements
- Salts enter the body by ingestion and are lost
via perspiration, feces, and urine
9Electrolyte Balance continued
- Changes in plasma sodium levels affect
- Plasma volume, blood pressure
- ICF and interstitial fluid volumes
- Look at Table 25.1 Causes and Consequences of
Electrolyte Imbalance pg 916. Answer the
following questions - What happens to the heart when there is not
enough potassium? - How about too much magnesium?
10Fluid Movement
- Electrolytes have ________ osmotic power than
nonelectrolytes - Water ______ according to osmotic gradients
- To remain properly hydrated, water intake must
_____ water output
11Thirst Management
- What part of the brain regulates thirst? How?
12Thirst continued
- _______________ is stimulated
- By a decline in plasma volume of 1015
- By increases in plasma osmolality of 12
- Via baroreceptor input, angiotensin II, and other
stimuli
Thirst is quenched as soon as we begin to drink
water. Feedback signals that inhibit the thirst
centers include a. __________ of the mucosa of
the mouth and throat b. Activation of stomach and
intestinal stretch receptors
13Abnormalities of Acid-Base Balance
Instructions Explore the following imbalances
and their possible effects with your small group.
Use the text pages 927 928 as reference
material. Note the causes in Table 25.2 page 928.
- What is respiratory acidosis?
- Respiratory alkalosis?
- Metabolic acidosis?
- Metabolic alkalosis?