The document discusses interactions among organ systems and how disruption of homeostasis can occur. It provides examples of thermoregulation, which requires interaction between the skin, muscles, circulatory, endocrine, nervous and respiratory systems. Disruption of homeostasis can be short term, like a cold virus, or long term, like diabetes where the pancreas fails to control blood glucose levels over time.

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Interactions among systems

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Learning Objectives:
To be able to:
 Explain how each organ system affects other organ systems
 Describe the effects of the disruption of homeostasis
 Thermoregulation
Keywords:

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 All the organ systems form a type of community regulated by
feedback mechanisms. This interaction among organ systems
means that if one organ system is affected – so is the whole
body!

4. + Vit. D production

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Thermoregulation…
 …. is the process of maintaining a steady body temperature
under a variety of conditions.
 The skin and muscles are the main organ systems involved in
thermoregulation – but also requires close interaction of the
circulatory, endocrine, nervous and respiratory systems.

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The body’s temperature is monitored by the brain. If you are too hot or
too cold, the brain sends nerve impulses to the skin, which has three
ways to either increase or decrease heat loss from the body’s surface:
1. Hairs on the skin trap more warm air if they are standing up, and
less if they are lying flat. Tiny muscles in the skin can quickly pull
the hairs upright to reduce heat loss, or lay them down flat to
increase heat loss.
2. If the body is too hot, glands under the skin secrete sweat onto the
surface of the skin, to increase heat loss by evaporation. Sweat
secretion stops when body temperature returns to normal.
3. Blood vessels supplying blood to the skin can swell or dilate -
vasodilation. This causes more heat to be carried by the blood to
the skin, where it can be lost to the air. Blood vessels can shrink
down again - vasoconstriction. This reduces heat loss through the
skin once the body’s temperature has returned to normal.
Muscles can also receive messages from the brain when you are cold.
They respond by shivering, which warms you up.

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Disruption of homeostasis!!
 Some changes cannot be controlled by the body because they
are either too big or too fast, causing homeostasis to be
disrupted.
 There are a number of reasons homeostasis can be disrupted:
- Sensors do not detect changes in the environment
- Wrong messages are sent
- Messages do not reach their target
- Injuries
- Bacteria or viruses can change the body’s chemistry

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Short term vs. Long term
 Short term effects of homeostasis disruption last only a few
days and there is no long lasting harm to the body.
 Long term effects cause more damage.
Can you think of an example of each??

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Short term effect
 When a cold virus enters your body, your immune system may not
be able to prevent the virus from multiplying.
 You develop cold symptoms: cough, sore throat, runny nose, etc.
 Within a few days, your immune system begins to kill the virus and
restore homeostasis

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Long term effect
DIABETES... occurs when the body fails to control the amount of
glucose circulating in the blood.
The level of glucose in the body is controlled by 2 hormones
released by the pancreas

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Controlling glucose levels

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Type 1 diabetes
 Occurs when the body’s immune system destroys the ability of
beta cells to produce insulin.

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Type 2 diabetes