Chapter 27 Flashcards

1
Q

Body fluid

A

Consists of water and dissolved solute constitutes between 55 and 60% of total body mass

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2
Q

What are the parts of extra cellular fluid?

A

80% is interstitial fluid and 20% is blood plasma

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3
Q

What are the two general barriers that separate intracellular fluid, interstitial fluid and blood plasma?

A

Plasma membrane and blood vessel walls

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4
Q

Thirst center

A

Found in the hypothalamus governs the urge to drink

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5
Q

What’s the main factor that determines body fluid volume?

A

Urinary salt (NaCl) loss

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6
Q

What’s the main factor that determines body fluid osmolarity?

A

The extent of urinary water loss

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7
Q

What is antidiuretic hormone also known as?

A

Vasopressin

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8
Q

What are the two most important hormones that regulate the extent of renal sodium reabsorption and thus how much is lost in the urine?

A

Aldosterone and atrial natriuretic peptide

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9
Q

Aldosterone

A

Increases sodium reabsorption in the late distal tubules and collecting ducts of the kidneys which relieves the sodium deficiency in the plasma

Occurs after a decrease in blood pressure

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10
Q

Atrial natriuretic peptide

A

Occurs with an increase in blood volume

Stretching of the atria of the heart promotes the release

Promotes natriuesis; elevated excretion of sodium into the urine

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11
Q

What can increase the osmolarity of extra cellular fluid?

A

A salty meal

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12
Q

A decrease in the osmolarity of extra cellular fluid can occur from what?

A

Drinking a large volume of water

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13
Q

Water intoxication

A

A state in which excessive body water causes cells to swell dangerously

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14
Q

What are the four general functions in the body when electrolytes dissolve and dissociate?

A
  1. Because they are largely confined to particular fluid compartments then non-electrolytes certain ions help control the osmosis of water between fluid compartments
  2. Ions help maintain the acid base balance required for normal cellular activities
  3. Ions carry electrical current which allows production of action potentials and graded potential’s
  4. Several ions serve as co-factors needed for optimal activity of enzymes
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15
Q

Sodium

A

Most abundant ion in extracellular fluid

Accounts for half of the osmolarity an extra cellular fluid

Necessary for generation and conduction of action potentials in neurons and muscle fibres

Kidneys excrete and conserve sodium as necessary

Sodium is controlled in the blood by aldosterone, antidiuretic hormone, and atrial natriuretic peptide

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16
Q

Chloride

A

Most prevailant anion in extra cellular fluid

Moves easily between extra cellular fluid and intracellular fluid because most plasma membranes contain many chloride leakage channels and Antiporters

Helps balance the level of an ions in different fluid compartments

ADH helps regulate chloride balance through the urinary system

Processes that increase or decrease renal absorption of sodium ions also affects direction of chloride ions

17
Q

Potassium

A

Most abundant cation in intracellular fluid

Key role in establishing the resting membrane potential and then repolarization phase of action potentials in neurons and muscle fibres

When potassium moves into or out of cells it is often exchange for hydrogen and thereby helps regulate the pH of body fluids

Increase potassium causes more aldosterone secreted into the blood which stimulates principal cells of the renal collecting duct to secrete more potassium through the urine

Needed in repolarization phase of action potentials

18
Q

Bicarbonate

A

Second most prevailant extra cellular anions

Concentration increases when blood flows through systemic capillaries because carbon dioxide released by metabolically active cells combines with water to form carbonic acid

When it flows through pulmonary capillaries concentration’s decrease because carbon dioxide is exhaled

19
Q

Calcium

A

Stored in bone and is the most abundant mineral in the body

Please important rules in blood clotting, neurotransmitter release, maintenance of muscle tone, and excitability of nervous and muscle tissue

Main regulators are parathyroid hormone and calcitonin

20
Q

Phosphate

A

85% of phosphate in adult his present is calcium phosphate salts which is structural components of bones and teeth

Governed by parathyroid hormone and calcitriol

21
Q

Magnesium

A

54% of the total body magnesium is part of bone matrix is magnesium salt the remaining 46% occurs is magnesium ions in ICF

22
Q

The removal of hydrogen from body fluids and it subsequent elimination from the body depends on what three major mechanisms?

A
  1. Buffer systems
  2. exhalation of carbon dioxide
  3. kidney excretion of hydrogen
23
Q

Buffer systems

A

Consist of a weak acid and the salt of that I said which functions as a weak base and prevent rapid drastic changes in pH of body fluids by converting strong acids and bases into weak acids and bases

24
Q

Protein buffer system

A

Most abundant buffer in intracellular fluid and blood plasma

Proteins are composed of amino acids organic molecules that contain at least one carboxyl group and at least one amino group which function as components of the protein buffer system

25
Q

Carbonic acid bicarbonate buffer system

A

Bicarbonate ion acts as a weak base and carbonic acid acts as weak acid

Doesn’t protect against respiratory problems

26
Q

Phosphate buffer system

A

Is it important regulator of pH in the cytosol

can also buffer acids in urine

One way that the kidneys excrete hydrogen to control blood pH

27
Q

Volatile acid

A

Because H2CO3 can be eliminated by exhaling CO2 it is a volatile acid

28
Q

Nonvolatile acids

A

Metabolic reactions that produce acid such as sulphuric acid and is excreted through the urine

29
Q

Acidosis

A

Condition in which blood pH below 7.35

Causes depression of the central nervous system through depression of the synaptic transmission

Can cause individuals to become disoriented, comatose, and die

30
Q

Alkalosis

A

Condition in which blood pH is higher than 7.45

Causes overexcitability in both the central nervous system and peripheral nerves

Neurons conduct impulses repetitively even when not stimulated resulting in nervousness, muscle spasms, convulsions, and death

31
Q

Respiratory compensation

A

Occurs within minutes and reaches its maximum within hours

32
Q

Renal compensation

A

Begins in minutes but it can take days to reach maximum effectiveness

33
Q

Respiratory acidosis

A

Abnormally high PCO2 In systemic arterial blood

In adequate exhalation of CO2 causes the blood pH to drop

Conditions such as emphysema, pulmonary edema, injury to respiratory centre of the medulla, airway obstruction, or disorders of muscles involved and breathing

Reversed by exhalation of CO2

34
Q

Respiratory alkalosis

A

Systemic arterial blood PCO to falls below 35 mmHg

Cause of drop in PCO to and resulting increase in pH is hyperventilation

Conditions like oxygen deficiency due to high altitude or pulmonary disease, cerebrovascular accident, or severe anxiety

Can be treated by breathing through a paper bag

35
Q

Metabolic acidosis

A

The systemic arterial blood HCO3 levels drop below 22mEQ per litre

Caused by loss of bicarbonate like in diarrhea or renal disfunction

accumulation of an acid other than carbonic acid such as with ketosis

failure of the kidneys to excrete hydrogen from the metabolism of dietary proteins

36
Q

Metabolic alkalosis

A

Systemic arterial blood bicarbonate concentration is above 26mEq per litre

A non respiratory loss of acid or excessive intake of alkaline drugs causes a blood pH to increase above 7.45