SOPHIA will be down Wednesday, December 7, 2016 at 4:30 AM (CST) for a little housecleaning. We are sorry if this causes you any trouble. The outage should last less than 5 minutes.

+
Homeostasis and Bone Remodeling

Homeostasis and Bone Remodeling

Rating:
Rating
(0)
Description:

This lesson will define the role of bone remodeling in maintaining homeostasis in the body.

(more)
See More
Try a College Course Free

Sophia’s self-paced online courses are a great way to save time and money as you earn credits eligible for transfer to over 2,000 colleges and universities.*

Begin Free Trial
No credit card required

25 Sophia partners guarantee credit transfer.

221 Institutions have accepted or given pre-approval for credit transfer.

* The American Council on Education's College Credit Recommendation Service (ACE Credit®) has evaluated and recommended college credit for 20 of Sophia’s online courses. More than 2,000 colleges and universities consider ACE CREDIT recommendations in determining the applicability to their course and degree programs.

Tutorial

What's Covered

In this lesson you will look at how bone remodeling helps to maintain homeostasis by examining:

  1. Bone Remodeling
  2. The Role of Hormones


1. Bone Remodeling

Bone Remodeling is the process bones constantly undergo of taking away and building tissue; is controlled by mechanical stress and hormonal negative feedback loops. Negative feedback is when there is a change that is sensed by the body, and that change is then reversed. Certain levels of calcium in the blood are needed for your nervous and muscle systems to be able to function properly. Bone remodeling is basically the process of recycling calcium to maintain proper levels in your blood.

Two types of cells in your bones play an important role in this process:

  • Osteoblasts are a cell found in bones that builds bone tissue by secreting collagen into bone tissue spaces; the collagen binds to calcium and forms the tough tissue within bones. They are found in the periosteum of bones.
  • Osteoclasts, on the other hand, are a cell found in bones that secretes hydrochloric acid that breaks down bone the bonds between calcium and collagen; the calcium is released from bone. Both of these types of cells have an important role in bone remodeling.

Terms to Know

    • Bone remodeling
    • The process bones constantly undergo of taking away and building tissue; is controlled by mechanical stress and hormonal negative feedback loops.
    • Osteoblast
    • A cell found in bones that builds bone tissue by secreting collagen into bone tissue spaces; the collagen binds to calcium and forms the tough tissue within bones.
    • Osteoclast
    • A cell found in bones that secretes hydrochloric acid that breaks down bone the bonds between calcium and collagen; the calcium is released from bone.

2. The Role of Hormones

The process of bone remodeling is signaled by hormones; either the hormone PTH or Calcitonin. Depending on whether there's too much or too little calcium in the blood, one of those hormones is going to have a role in helping to maintain homeostasis. Homeostasis is the process of maintaining a stable internal environment.

  • When calcium levels in the blood are too high: calcium is going to be removed from the blood and deposited into the bone.This is signaled by the hormone Calcitonin. Calcitonin is a hormone that is secreted by the thyroid glad that lowers osteoclast activity in proportion to osteoblast activity.
  • When calcium levels in the blood are too low: calcium will be removed from the bone and deposited into the blood. This is signaled by Parathyroid hormone (PTH), a hormone that is secreted by the parathyroid glands that activates osteoclasts when our blood calcium levels are too low.The osteoclast will help to break down that bone in order to remove some of the calcium to deposit it into your blood.

Terms to Know

    • Homeostasis
    • The process of maintaining a stable internal environment.
    • Parathyroid hormone (PTH)
    • A hormone that is secreted by the parathyroid glands that activates osteoclasts when our blood calcium levels are too low.
    • Calcitonin
    • A hormone that is secreted by the thyroid gland that lowers osteoclast activity in proportion to osteoblast activity.

Take a look at the diagram to summarize this process


Summary

Bone remodeling is the process the body goes through to maintain proper levels of calcium in your blood. If calcium levels change in the blood, the role of hormones is to signal the body to maintain homeostasis. If blood calcium is too low, PTH activates osteoclasts to release calcium from the bones. If blood calcium is to high, calcitonin activates osteoblast cells to build bone tissue. The body does this to achieve homeostasis.

Keep up the learning and have a great day!

Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND

TERMS TO KNOW
  • Osteoblast

    A cell found in bones that builds bone tissue by secreting collagen into bone tissue spaces; the collagen binds to calcium and forms the tough tissue within bones.

  • Osteoclast

    A cell found in bones that secretes hydrochloric acid that breaks down bone the bonds between calcium and collagen; the calcium is released from bone.

  • Bone remodeling

    The process bones constantly undergo of taking away and building tissue; is controlled by mechanical stress and hormonal negative feedback loops.

  • Homeostasis

    The process of maintaining a stable internal environment.

  • Parathyroid hormone (PTH)

    A hormone that is secreted by the parathyroid glands that activates osteoclasts when our blood calcium levels are too low.

  • Calcitonin

    A hormone that is secreted by the thyroid gland that lowers osteoclast activity in proportion to osteoblast activity.