Disruption of Homeostasis in the Skeletal System

What is rickets?

Rickets is a disorder that causes weakening and softening of the bones. It is caused by a Vitamin D, calcium, or phosphate deficiency in the blood.

Vitamin D helps control the calcium and phosphate levels in the blood; when these levels get too low, the body releases calcium and phosphate from the bones which makes them weak and brittle. The skin produces vitamin D in response to exposure to sunlight, vitamin D can also be obtained through food.

How does vitamin D affect the body?

Vitamin D acts as a hormone when involved with calcium. The vitamin D sends signals to the parathyroid gland (PTG), which makes calcium, when it is in the bloodstream. If the parathyroid gland does not sense the vitamin D, it will not make calcium.

Calcium is stored and used in the bones, it provides support and helps bones maintain their strength. It is used by the muscles to move and to help nerves carry messages to and from the brain. Calcium is also used to help blood vessels through the body, release hormones, and enzymes

Disruptions of Homeostasis

Subcellular- no real disruptions until the cellular level

Cellular- cells aren't able to function properly because calcium is not being made in the body

Tissues- Tissues don't have the proper amounts of calcium and become weak. Signals don't get sent to and from the brain to other parts of the body

Organs- Tissues are weak and signals aren't sent so the organs can't function.

Organ Systems- When someone has rickets, the organs are weaker than they normally should be because of the lack of calcium. They also don't receive signals from the brain so the can't actively participate in the organ system.

Organism- If the organ systems can't do their job, it can cause pain, damage, and even death in an organism. With rickets, the person will not die but they will have difficulty participating in everyday activities and may experience pain

Symptoms and Signs of Rickets

  • Bone pain or tenderness
  • Dental deformaties
  • Late formation of teeth
  • Deceased muscle strength
  • Short stature
  • Skeletal deformaties (craniotabes, bowlegs, etc.)

History and Risk Factors

It has been around since at least the 1640's, it was common at the time. The cause of rickets was found in 1930 and since then it has been almost completely eliminated in industrialized countries. Developing countries still have a very high prominence of rickets.

Children and infants are more susceptible to rickets especially dark-skinned infants, children that are ONLY breastfed (breast milk is low in vitamin D), and babies who have mother's with a vitamin D deficiency.


Diagnosis is usually done clinically. Doctors look at complete nutritional history, medical history, and conduct a complete physical examination. If after these examinations doctors suspect rickets, they will perform x-rays.

Things to look for in x-rays:

  • Widening or oddly shaped metaphysis
  • Bowing of the femur
  • Osteopenia
  • Rachitic rosary (rib flaring)
  • Multiple factures that are at different stages of healing


Children with rickets will definitely survive. The disorder can be healed from a few days to months if there is the proper amount of vitamin D and calcium added to the diet. Severe cases of bowing and defects can take years to heal without surgery. Very extreme cases can be permanent.

Recent Research Advances

The only new research found concerning rickets deals with how it is treated. Scientists have found that giving a child one large dose of vitamin D in one day can be just as effective as giving them small doses for a couple of weeks. Opinions vary on which treatment is best but they both seem to help heal the children all the same.


Lymphatic System

The lymphatic system includes capillaries, vessels, nodes and other organs that main purpose is to transport lymph (lymph is a fluid that contains white blood cells) to other tissues rid them of bacteria, pathogens, anything that could be harmful to the tissues and organs.

Immune System

The immune system is made up of many different organs and structures. One of the main structures is the lymphatic system. There are two types of immunity, innate and adaptive:

Innate (non-specific):

  • Made up of various parts of the body; like skin and mucous. The cutaneous membrane is the first line of defense for the body from pathogens. It is water proof, has many microorganisms living on it that provide protection, and have appendages like sweat glands that make it hard for pathogens to survive. Ciliated epithelium is good for removing pathogens that have been released from the body else where. Mucous has a lysozyme that disrupts bacteria cell walls and can help rid your body of it. There are also phagocytes (white blood cells) that move through the circulatory system and lymphatic system and basically destroy anything they don't recognize. And inflammation is part of the immune system. When something aggravates a part of the body. Cells in that area will send out a signal for phagocytes to respond. The movement of the phagocytes to that area brings blood cells with it, causing what we know as inflammation.

Adaptive (specific)

  • The adaptive immune system is controlled by leukocytes in the lymphatic system (lymphocytes). There are two kinds, B-cells and T-cells. Both processes need the helper T-cells to begin. WIth B-cells (humoral), phagocytes give antigens to helper T-cells so specific B-cells can be made. The cells either secrete antibodies into the circulatory system (plasma cells) or stay around to protect the body in case that particular pathogen comes back (memory cells). In the T-cells, phagocytes give antigens to helper T-cell, the helper T-cell then activates the T-cells. T-cells then either find the cell expressing the antigen (cytotoxic) or stay around in case the pathogen comes back (memory).


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