Now let us continue. We're now in the endocrine system.
Together with the nervous system, the endocrine system is responsible for the regulation and maintenance of homeostatic processes in the body. It responds more slowly than the nervous system but it produces more lasting effects. These effects are produced by intracellular chemical signals known as hormones. They are produced by endocrine glands which make up the endocrine system. Hormones are released in the blood to reach specific tissues at another site of the body. These tissues contain target cells that serve as receptor sites for hormones. When the hormones have reached their target cells, desired effects are observed in the body depending on the function of the hormone.
There are different Classes of Chemical Messengers
Together with the nervous system, the endocrine system is responsible for the regulation and maintenance of homeostatic processes in the body. It responds more slowly than the nervous system but it produces more lasting effects. These effects are produced by intracellular chemical signals known as hormones. They are produced by endocrine glands which make up the endocrine system. Hormones are released in the blood to reach specific tissues at another site of the body. These tissues contain target cells that serve as receptor sites for hormones. When the hormones have reached their target cells, desired effects are observed in the body depending on the function of the hormone.
There are different Classes of Chemical Messengers
The Functions of the Endocrine System are:
Features of Hormones
1. Chemical Components
- Metabolism
- Control of food intake and digestion
- Tissue development
- Ion regulation
- Water balance
- Heart rate and blood pressure regulation
- Control of blood glucose and other nutrients
- Control of reproductive functions
- Uterine contractions and milk release
- Immune system regulation
Features of Hormones
1. Chemical Components
- Proteins- Most hormones are large proteins molecules, while others are oligopeptides or short-chain amino acid peptides. Some are amino acid derivatives which mean that they are composed of single amino acids that have been chemically modified. Hormones secreted by the adrenal medulla are amino acid derivatives.
- Lipids- Lipid hormones are mostly derived from cholesterol. These are also known as steroid hormones. They are produced by the adrenal cortex and the gonads. Another class of lipid chemical signals is derived from the fatty acid arachidonic acid.
2. Regulation of Secretion
The secretion of hormones is regulated by a negative feedback mechanism. Levels of the hormone under consideration are influenced by the levels of other chemicals or ions in the blood, by the levels of other hormones (regulatory or inhibitory hormones), and by nervous system stimulation.
The secretion of hormones is regulated by a negative feedback mechanism. Levels of the hormone under consideration are influenced by the levels of other chemicals or ions in the blood, by the levels of other hormones (regulatory or inhibitory hormones), and by nervous system stimulation.
3. Action of Hormones
Hormones produce very specific responses because of their nature. Molecules of hormones have a certain configuration which can only fit specific receptors found in their target cells. These receptors may be found in the cell membrane or within the cytoplasm of the target cells. Protein hormones have membrane-bound receptors, while lipid hormones have intracellular receptors.
After binding with these receptors, the target cells may, in turn, produce other substances. Their activity may also be stimulated or inhibited. These effects are then manifested in the body as the effects of the hormone.
Hormones produce very specific responses because of their nature. Molecules of hormones have a certain configuration which can only fit specific receptors found in their target cells. These receptors may be found in the cell membrane or within the cytoplasm of the target cells. Protein hormones have membrane-bound receptors, while lipid hormones have intracellular receptors.
After binding with these receptors, the target cells may, in turn, produce other substances. Their activity may also be stimulated or inhibited. These effects are then manifested in the body as the effects of the hormone.
Here are the Endocrine Glands
The table shows the endocrine glands, their hormones, and their target tissues.
Some associated disorders of the endocrine system.
We will now start with the discussion of the cardiovascular system. First to be tackled is the blood.
Blood is a specialized connective tissue that consists of two components: the formed elements of blood and plasma. Blood accounts for about 7 to 9% of the total body weight. An average man has approximately 5 to 6 liters of blood while an average woman has about 4 to 5 liters of blood in the body.
Functions:
Plasma is the liquid portion of the blood and is made up of the following:
Blood is a specialized connective tissue that consists of two components: the formed elements of blood and plasma. Blood accounts for about 7 to 9% of the total body weight. An average man has approximately 5 to 6 liters of blood while an average woman has about 4 to 5 liters of blood in the body.
Functions:
- Transport of gases, nutrients, and waste products
- Transport of processed molecules
- Transport of regulatory molecules
- Regulation of pH and osmosis
- Maintenance of body temperature
- Protection against foreign substances
- Clot formation
Plasma is the liquid portion of the blood and is made up of the following:
- Water
- Plasma Proteins
- Plasma Electrolytes
- Nutrients and Waste Products
- Gases and Buffers
These are the formed elements of the blood.
Hematopoieses is the formation of blood cells. It occurs in the red bone marrow, which is also known as myeloid tissue.
Platelet Plug Formation
Clot Formation
Blood Grouping
Blood groups are determined by antigens on the surface of red blood cells. In transfusion reactions, antibodies can bind to red blood cell antigens, resulting in agglutination or hemolysis of red blood cells.
Blood groups are determined by antigens on the surface of red blood cells. In transfusion reactions, antibodies can bind to red blood cell antigens, resulting in agglutination or hemolysis of red blood cells.
ABO Blood Group
Type A blood has A antigens and has anti-B antibodies, type B blood has B antigens and has anti-A antibodies, type AB blood has A and B antigens and has neither anti-A nor anti-B antibodies, and type O blood has neither A nor B antigens and has both anti-A and anti-B antibodies. Mismatching the ABO blood group can result in transfusion reactions.
Type A blood has A antigens and has anti-B antibodies, type B blood has B antigens and has anti-A antibodies, type AB blood has A and B antigens and has neither anti-A nor anti-B antibodies, and type O blood has neither A nor B antigens and has both anti-A and anti-B antibodies. Mismatching the ABO blood group can result in transfusion reactions.
Rh Blood Group
Rh-positive blood has Rh antigens, whereas Rh-negative blood does not. Antibodies against the Rh antigen are produced when an Rh-negative person is exposed to Rh-positive blood. The Rh blood group is responsible for hemolytic disease of the newborn, which can occur when the fetus is Rh-positive and the mother is Rh-negative.
Some diseases and disorders of blood.
Rh-positive blood has Rh antigens, whereas Rh-negative blood does not. Antibodies against the Rh antigen are produced when an Rh-negative person is exposed to Rh-positive blood. The Rh blood group is responsible for hemolytic disease of the newborn, which can occur when the fetus is Rh-positive and the mother is Rh-negative.
Some diseases and disorders of blood.
Thanks for reading again my post! Be sure to return for more because the next post is the continuation of the cardiovascular system and about the circulatory system. Don't forget to leave your comments and suggestions.