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Interactions among systems

+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!

+ Vit. D production

+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.

+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

+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??

+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

+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

+Controlling glucose levels

+Type 1 diabetes Occurs when the body’s immune system destroys the

ability of beta cells to produce insulin.

+Type 2 diabetes