LC 2.9.23 Homeostasis and BodySyst

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

Rapid growth during puberty causes your body to release more and more growth hormones. As you grow, more and more growth hormones are released until puberty is reached, and then the hormones stop.

• Positive Feedback Response
• Negative Feedback Loop 

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.

• Positive Feedback Response
• Negative Feedback Loop 

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. 

• Positive Feedback Response
• Negative Feedback Loop 

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.

• Positive Feedback Response
• Negative Feedback Loop 

Positive feedback is when the change caused by the stimulus is

• decreased
• non existant
• increased
• changes constantly

Homeostasis means that the _____ stays stable while the outside changes

• inside

• outside

• hot

• cold

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

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

Which system brings in oxygen (O₂) and takes out carbon dioxide (CO₂) ?

• digestive system

• respiratory system

• nervous system

• immune system

Which system protects the body from foreign pathogens (invaders) like viruses, bacteria, and fungi?

• immune system

• endocrine system

• nervous system

• skeletal system