B12 - Homeostasis in Action Flashcards

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1
Q

What is body tempertaure controlled by?

A

The thermoregulatory centre in the hypothalamus

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2
Q

How is a change in body temperature detected

A
  • Thermoregulatory centre in the hypothalamus monitor internal body temp
  • Skin receptors monitor surface body temp
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3
Q

How does the body transfer more heat to the surroundings (cool down)

A
  • Vasodilation to bring more blood to skin - heat is lost by radiation
  • Sweating - sweat glands release water which has heat energy in it, when it evaporates, it takes the heat energy with it and cools the skin
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4
Q

What is sweat made of

A

A mixture of urea, water and mineral ions

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5
Q

How does the body reduce heat transfer/heat up

A
  • Vasoconstriction
  • Shivering - skeletal muscles contract and relax quickly releasing heat from respiration
  • Sweat production is slowed
  • Hairs stand on end - traps layer of insulating air
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6
Q

Waste products produced by the body (4)

A
  • Urea from amino acid breakdown - toxic
  • Carbon dixoide from respiration
  • Water - affetcs osmosis
  • Mineral ions - affects osmosis and diffusion
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7
Q

Why does carbon dioxide need to be removed from the body

A

It lowers blood pH so affects enzyme function

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8
Q

How is CO₂ removed

A
  • Diffuse out of cells into blood plasma
  • Diffuses from plasma into alveoli
  • Exhaled by respiratory system
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9
Q

How is urea produced

A

From the breakdown of excess amino acids
* Amino acids —> ammonia
* ammonia + CO₂ —> urea

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10
Q

Name for the breakdown of amino acids and where does this process happen

A

Deamination in the liver

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11
Q

Uncontrolled methods of removing water and mineral ions

A
  • Water - exhalation
  • Mineral ions - sweat
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12
Q

Controlled removal methods

A

Kidneys through urine

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13
Q

How do the kidneys work? (4)

A
  1. All solubles pass from blood into kindneys
  2. Blood cells and proteins stay as they are too large
  3. All glucose is immediately reabsorbed
  4. No urea is reabsorbed
  5. The exactn amount of water and mineral ions reabsorbed is controlled by selective reabsorbtion based on the body’s needs
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14
Q

Where is ADH produced and stored

A

Produced in the hypothalamus and stored in the pituitary gland

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15
Q

What does ADH control

A

The amount of water reabsorbed from the kidneys. It does this by making the kidney tissues more water permeable

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16
Q

What happens when the water concentration is too low

A
  • Detected by the hypothalamus
  • Pituitary secretes ADH
  • Tubules become more water permeable allowing more water back into blood
  • Urine volume is low and concentrated
17
Q

What happens when the water concentration is too high

A
  • Detected by the hypothalamus
  • Pituitary secretes LESS ADH
  • Tubules become less water permeable allowing less water back into the blood
  • Urine volume is high and dilute
18
Q

Methods of reducing kidney rejection

A
  1. Tissue matching with a close family member
  2. Immunosuppresant drugs - risk of other infections
19
Q

Advantages of kidney dialysis

A
  • Readily available
  • Relatively normal lifestyle
20
Q

Disadvantages of kidney dialysis

A
  • Long dialysis sessions
  • Long term dialysis damages body
  • Special diet
  • Expensive
  • Risk of blood clots and infections
21
Q

Advantages of kidney transplant

A
  • Better survival rates
  • Near normal lifestyle
22
Q

Disadvantages of kidney transplant

A
  • Risk of rejection and therefore immunosuppresants
  • More susceptible to other infections
  • Regular check ups
23
Q

Which parts of the blood don’t go into the kidneys?

A

Blood cells and plasma proteins

24
Q

Basic steps in kidney dialysis

A
  1. PAtient attached to dialysis machine and their blood flows into it
  2. The dialysis fluid contains the optimum amount of solubles
  3. Blood passes over a partially permeable membrane with dialysis fluid on other side
  4. This allows urea and excess solubles to leave the blood
25
Q

Why are the kidneys imporant in homoestasis

A
  • Remove urea and toxins so cells don’t get poisoned or damaged
  • Removes excess water and mineral ions to prevent osmotic damage