Homeostasis Review

Homeostasis

• allows for a wildly fluctuating internal environment

• is impossible in vertebrates

• is the maintenance of a relatively stable internal environment despite a changing external environment

• is the maintenance of a stable internal environment at one constant set value

Tags

NGSS.HS-LS1-3

Homeostasis in the human body is most often maintained by a:

• neutral feedback loop

• solar feedback loop

• positive feedback loop

• negative feedback loop

Tags

NGSS.HS-LS1-3

Positive feedback is when the change caused by the stimulus is

• decreased
• non existant
• increased
• changes constantly

Tags

NGSS.HS-LS1-3

When you are cold, you shiver and your blood vessels contract, which warms you up. When you are hot, you sweat and your blood vessels expand, which cools you down. Is this positive or negative feedback?

• Positive Feedback

• Negative Feedback

Tags

NGSS.HS-LS1-3

When you become dehydrated, your body lacks water. This causes your endocrine system to release a hormone to your kidneys to begin reabsorbing water. Is this positive or negative feedback?

• Positive Feedback

• Negative Feedback

Tags

NGSS.HS-LS1-3

During childbirth, the muscles in the uterus contract. This signals to the brain to trigger contractions at a greater frequency and strength until the baby is born. Is this positive or negative feedback?

• Positive Feedback

• Negative Feedback

Tags

NGSS.HS-LS1-3

Too much carbon dioxide in the blood decrease the pH value of the blood. When the pH value gets too low, you start to breath more heavily, therefore removing carbon dioxide and returning the pH to normal levels. Is this positive or negative feedback?

• Positive Feedback

• Negative Feedback

Tags

NGSS.HS-LS1-3

When you eat, your blood glucose levels rise. This triggers the release of insulin which allows the glucose to be absorbed by cells, therefore lowering the level back to normal. Is this positive or negative feedback?

• Positive Feedback

• Negative Feedback

Tags

NGSS.HS-LS1-3

If you cut yourself, platelets rush to the site of injury to stop the bleeding. The presence of platelets at the injury signals for even more platelets to respond. Is this positive or negative feedback?

• Positive Feedback

• Negative Feedback

Tags

NGSS.HS-LS1-3

Follicles produce eggs in the female ovary. As a follicle develops, hormones are released which trigger additional development of the follicle until the egg is ready to be released. Is this positive or negative feedback?

• Positive Feedback

• Negative Feedback

Tags

NGSS.HS-LS1-3