Body Systems Unit Skills Check

The two types of feedback systems that help organisms maintain homeostasis are:

• positive and negative 
• receptor and effector
• static and dynamic
• minor and major

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When glucose levels in the blood rise, your brain sends a signal to your pancreas. The pancreas releases insulin, which opens channels in cell membranes to allow glucose to enter the cell, lowering blood sugar levels. This is an example of a:

• Positive Feedback Loop

• Negative Feedback Loop

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Homeostasis

• allows for a wildly fluctuating internal environment
• is impossible in vertebrates
• is the maintenance of a relatively stable internal environment and often incorporates a form of feedback regulation
• is the maintenance of a relatively stable external environment and often incorporates a form of feedback regulation

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When you get cut, your skin cells release hormones that signal platelets to come and stop the bleeding. Platelets then release more hormones that signal even more platelets to help stop bleeding. The hormone signals continue until the cut is closed. This is an example of what type of feedback?

• Positive Feedback Response

• Negative Feedback Loop

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If the calcium in your blood decreases below homeostasis levels, a gland in the brain will sense the decrease and send a chemical message to your bones. Your bones will release calcium into the blood, bringing blood calcium levels back up. This is an example of what type of feedback?

• Positive Feedback Response

• Negative Feedback Loop

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reverses the direction of change

• positive feedback

• effector

• hypothalamus

• negative feedback

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increases or speeds up original change

• negative feedback

• positive feedback

• endotherm

• ectotherm

What are the levels of organization starting from simple to complex?

• cells- tissues- organs- organ systems- organisms- populations- communities- ecosystem

• ecosystem- communitites- populations- organisms- organ systems- organs- tissues- cells

• cells- organs- tissues- organ systems- populations- ecosystem

• tissue- cells- organs- organ systems- organisms- populations- communities- ecosystem

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Feedback interactions in the human body are important because they

• determine the diversity necessary for evolution to occur.

• direct the synthesis of altered genes that are passed on to every cell in the body.

• regulate the shape of molecules involved in cellular communication.

• keep the internal body environment within its normal range.

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Two primary agents of cellular communication are

• chemicals made by blood cells and simple sugars.

• hormones and carbohydrates.

• hormones and chemicals made by nerve cells.

• enzymes and starches.