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Course: High school biology > Unit 8
Lesson 1: Body structure and homeostasisBody structure and homeostasis review
Key terms
| Term | Meaning |
|---|---|
| Homeostasis | The tendency to resist change in order to maintain a stable, relatively constant internal environment |
| Negative feedback loop | Feedback loop that acts to oppose the triggering stimulus |
| Positive feedback loop | Feedback loop that amplifies the starting signal |
| Cell | Smallest unit of life |
| Tissue | Made of a group of similar cells that work together on a specific task |
| Organ | Structure made up of two or more tissues, organized to carry out a specific function |
| Organ system | Groups of organs with related functions |
Maintaining homeostasis
The body maintains homeostasis for many factors. Some of these include body temperature, blood glucose, and various pH levels.
Homeostasis is maintained at many levels, not just the level of the whole body as it is for temperature. For instance, the stomach maintains a pH that's different from that of surrounding organs, and each individual cell maintains ion concentrations different from those of the surrounding fluid. Maintaining homeostasis at each level is key to maintaining the body's overall function.
Feedback loops
Homeostasis typically involves negative feedback loops that counteract changes of various properties from their target values. An example of a negative feedback loop is body temperature regulation.
In contrast to negative feedback loops, positive feedback loops amplify their initiating stimuli, in other words, they move the system away from its starting state.
Body structure
The body has levels of organization that build on each other. Cells make up tissues, tissues make up organs, and organs make up organ systems.
At each level of organization (cells, tissues, organs, and organ systems), structure is closely related to function.
Common mistakes and misconceptions
- Negative feedback is not bad for the body. Although the term "negative" is included, these feedback loops are essential and helpful to the body. In this instance, "negative" simply means that the feedback loop works to counter the stimulus, or cue, not that the feedback loop is detrimental.
- Homeostasis is more than just "keeping things normal, and the body doesn't always know what is best for itself. " The body is constantly regulating itself and the mechanisms to maintain homeostasis are always in play. Sometimes, however, these homeostatic mechanisms can fail. If the conditions are not corrected, a disease or disorder can result. For example, if the amount of calcium in your blood is not properly regulated and becomes too low, you could develop hypocalcemia.
Want to join the conversation?
At what levels of organization does the body need to maintain homeostasis?(4 votes)
All. Homeostasis is maintained at all levels of organizations, from organisms to cells. Cells undergo homeostasis by diffusing different ions and molecules to maintain their balance and organisms have multiple systems working together to maintain homeostasis (e.g. vasodilation (cardiovascular system) and sweating (integumentary system) to give off heat, which affects the body as a whole).(1 vote)
- what happens if your cells start dying(3 votes)
if too many cells die it can lead to cancer and some other diseases(0 votes)
- what does hypocalmcemia mean(2 votes)
Hypocalmcemia is the deficiency of glucose in the bloodstream.(2 votes)
- When does your body leave a homeostatic state?(2 votes)
Never. If the body fails in maintaining homeostasis, that means a disease has been contracted(1 vote)
- It does change temperature when your cold or hot. It usually doesn't change drastically though, unless you are going through something severe like heat stroke or hypothermia.(2 votes)
What are the effects of hypoglycemia?(1 vote)
Hypoglycemia--Low (hypo-) blood (-emia) sugar (-glyc-, refers to glucose)
Glucose is the main source of energy in the body. If a patient does not get enough, either from diet or an underlying condition like diabetes, they will suffer from a myriad of symptoms. There are physical effects like hunger, tiredness and shakiness, and there are also mental effects like anxiety, confusion, and nervousness. If severe, a patient can become unaware or even die.
Does this help?(2 votes)
- what is a easy meaning of hypocalmcemia?(1 vote)
Well, Hypo- means little or low. And -calmcemia refers to calcium levels in the blood. So, an easy definition of this would be "low levels of calcium"
I hope this helps!
FreeRadical(2 votes)
- What are common cause for you body to leave homeostasis and what are way to come back to that state.(1 vote)
- Your body's homeostasis balance can be thrown off as easily as getting too hot from an exercise or drinking too much water.
Example 1: If you're in hyperthermia (>38C or >100.4), the body will act accordingly to cool itself down and maintain homeostasis. This includes vasodilation and sweating.
Example 2: If you're not dehydrated and you drink multiple glasses of water, your body will filter the excess water out of the body via the kidneys and the urinary system. If the over-intake of water is rapid (i.e. water intoxication), the excess water will enter your cells. Sometimes, the body's reflexes will trigger you into vomiting.(2 votes)
- How does the heart , brain and nerves maintain homeostasis?(1 vote)
what cells are in a dense fibrous tissue?(1 vote)