Body Temperature And Fluid Homeostasis Flashcards

1
Q

What is your core body temperature?

A

Temperature of organs of the body cavities

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2
Q

What is shell temperature?

A

Temperature of the surface of the body

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3
Q

What are the four ways heat is transferred in the human body?

A
  • conduction
  • convection
  • radiation
  • evaporation
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4
Q

Which types of heat transfer can you gain and lose heat?

A
  • conduction
  • convection
  • radiation
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5
Q

Which type of heat transfer do you only lose heat?

A

Evaporation

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6
Q

What is conduction? (3 points)

A
  • transfer of heat from a warm object to a cool object
  • occurs between solids
  • small amounts of heat lost or gained
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7
Q

What is convection? (2 points)

A
  • transfer of heat by movement of a fluid or gas between areas of different temperature
  • slow process
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8
Q

What is radiation? (3 points)

A
  • transfer of heat in the form of infrared rays between a warmer object and a cooler object
  • dull or black objects absorb infrared radiation more readily than light ones
  • silvered surfaces reflect infrared rays
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9
Q

What is evaporation? (5 points)

A
  • conversion of a liquid to vapour
  • helps you lose heat ie sweat
  • main heat dissipation method for the body
  • ability to sweat depends on the bodies water levels
  • once humidity is above 70% it’s hard for sweat to evaporate
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10
Q

Heat production in the body? (3 points)

A
  • basal metabolism
  • muscular activity (shivering)
  • thyroxine and epinephrine (stimulating effects on metabolic rate)
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11
Q

What is homeostasis?

A

The ability to maintain a relatively stable internal state ie. body temperature and fluid balance

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12
Q

What is hyperthermia?

A

Persistent elevation of body temp above 37.5

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13
Q

What is hypothermia?

A

Persistent low body temperature below 36.5

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14
Q

What are the two types of hyperthermia?

A
  • heat exhaustion

- heat stroke

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15
Q

What is pyrexia?

A

A fever - body temperature increases due to a resetting of the temperature set point of the hypothalamus by pyrogens.

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16
Q

What are the benefits of a fever? (3 points)

A
  • hinders replication of some pathogens
  • intensifies effects of interferons and phagocytic activity of macrophages
  • quicker delivery of white blood cells to infection site
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17
Q

How do you treat a fever?

A

Antipyretic eg. Panadol, ibprofen, aspirin

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18
Q

What is the second stage of a fever?

A

Temperature set point returns to normal however the core temp is higher than the set point at this time therefore methods of heat loss need to be used

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19
Q

Hypothermia?

A
  • caused by low environmental temperature
  • severe shivering at 35
  • severe hypothermia at 33
  • shivering stops at 32 (loss of body temp controls)
  • heart beat irregular at 28
  • heart stops at 20
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20
Q

What does fluid homeostasis do?

A
  • maintains normal total body water and electrolytes

- maintains distribution of water and electrolytes between ECF and ICF

21
Q

How are fluids and electrolytes lost?

A
  • vomit
  • sweat
  • oxalated gut
  • diarrhoea
  • urine
22
Q

How are fluids and electrolytes replaced?

A
  • orally
  • IV drip
  • intra-peritoneal drip
23
Q

What are 5 mechanisms to maintain homeostasis?

A
  • Thirst
  • ADH (anti-diuretic hormone)
  • Aldosterone and renin-angiotensin pathway
  • ANH ( atrial natriuetic hormone)
  • sodium potassium pump
24
Q

What is a regulation of intake?

A

Thirst

25
Q

What is thirst?

A

An increase in osmotic pressure (overall salt concentration of body fluids) of ECF caused by dehydration or blood volume loss. Makes you thirsty, therefore you drink water which restores the balance

26
Q

Mechanisms for regulation of output?

A
  • anti diuretic hormone
  • aldosterone
  • atrial natriuretic peptide
27
Q

What is ADH responsible for?

A

Reabsorption of water aka vasopressin

28
Q

What are the two functions of ADH?

A
  • causes vasoconstriction

- increases reabsorption of water in kidneys

29
Q

What is the overall effect of ADH?

A

To increase the water content and lower plasma sodium content

30
Q

What suppresses ADH?

A

Alcohol and caffeine

31
Q

ADH controls?

A

Only the movement of water

32
Q

What inhibits ADH release?

A

When the blood volume and pressure is too high or the blood osmolarity is too low

33
Q

What does aldosterone regulate?

A
  • The sodium balance, regulation of electrolytes (particularly Na+) in the ECF
  • acts on kidneys to reabsorb Na+, which as a consequence reabsorbs more water which lowers urine output
34
Q

Where is aldosterone produced?

A

Adrenal glands

35
Q

What is aldosterone regulated by?

A

The renin-angiotensin mechanism

36
Q

What does aldosterine cause?

A

Vasoconstriction

37
Q

What does the atrial natriuetic peptide do? (4 points)

A
  • inhibits vasoconstriction
  • inhibits Na+ and water retention
  • increases renal water loss
  • reduces blood pressure/volume
38
Q

What does the sodium/potassium pump do? (3 points)

A
  • sodium ions are pumped out of the cell while potassium ions are pumped in
  • maintains cell volume and action potentials
  • energy to drive the pump is released by hydrolysis of ATP
39
Q

How does dehydration occur? (3 points)

A
  • excessive loss of water from ECF
  • ECF osmotic pressure rises
  • cells loose water to ECF by osmosis, cells shrink
40
Q

What is diabetes insipidis?

A

Body doesn’t produce enough ADH and therefore produces a lot of urine

41
Q

What is volume depletion?

A

When you loose equal proportion of water and salt due to vomiting and diarrhoea

42
Q

Which groups are at risk of dehydration?

A
  • babies
  • elderly
  • diabetics
  • excessive vomiting and diarrhoea
  • excess physical exertion in heat
43
Q

What is a haematocrit reading?

A

The ratio of the volume of red blood cells to the total volume of blood

44
Q

How does hypotonic hydration occur?

A
  • excessive water enters ECF
  • ECF osmotic pressure falls
  • water moves into cells by osmosis, cells swell
45
Q

What is oedema?

A
  • Swelling of the tissue
  • fluid overload
  • increases in interstitial (ECF) fluid volume, not cells swelling
46
Q

Hypotonic drinks?

A
  • for endurance sports
  • quickly replaces fluids lost by sweating
  • 1-3 % carb content
47
Q

Isotonic drinks?

A
  • team sports
  • quickly replaces fluids lost by sweating and provide carb boost
  • 6-8 % carb content
48
Q

Hypertonic drinks?

A
  • supplement carb intake

- 10% + content