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- Joined
- Sep 30, 2011
- Messages
- 308
Intrecellular Communication:
Signals that are transmitted between animal cells are often classified by two criteria; type of secretion and the route taken by the signaling hormone.
Types of Signaling:
a. Endocrine Signaling: secretion directly into the blood stream that then trigger further response in target cells located all around the body. Example: Insulin
b. Paracrine Signaling: Secretion of local regulators act over a short distance affecting neighboring cells, this and autocrine signaling rely on diffusion. Autocrine Signaling is again the secretion of local regulators but the target cell is the cell releasing the signal. These signaling methods play a role in blood pressure, nervous system functions, and reproduction (just a few).
c. Synaptic and Neuroendocrine Signaling: In synaptic signaling neurotransmitters diffuse across synapses triggering a response. While in Neuroendocrine Signaling, nuerohormones are released into the bloodstream producing a response from target cells. Example: Vasopressin (an anti-diuretic hormone)
d. Pheromone Signaling: These are hormones that don't affect you as directly but your environment; as they are excreted or released. Example: Body Odor
Endocrine Glands/ Tissues/ Organs:
Endocrine system cells are found in organs all over your body, such as your digestive track (stomach contains isolated endocrine cells), while other endocrine cells are grouped in ductless organs, these are called endocrine glands. Endocrine glands secrete hormones directly into the surrounding cells, this should be noted as the complete opposite of salivary glands which have ducts to carry secreted substances.
Major Endocrine Glands:
Organs Containing Endocrine Cells:
Cellular Response Pathways:
Hormones vary in size and chemical properties.Some of these differences are more apparent than others but I would like to look at the three major classes of hormones polypeptides, steroids, and amines. Steroids hormones are lipids containing four fused carbon rings. all are derived from the steroid cholesterol (example would be testosterone or cortisol). Polypeptides are made up of two polypeptide chains and most in this group are formed by cleavage of one long polypeptide chain (example insulin). Amine hormones are synthesized from a single amino acid either tyrosine or tryptophan (examples are ephindrine or thyroxine). Hormones vary in their solubility while polypeptides and amines tend to be water soluble steroids tend to be lipid soluble. Water soluble hormones are hydrophilic and must bind to a cell surface receptor. Lipid soluble hormones are Lipid soluble and tend to diffuse into the cell as my post on testosterone diffusion explained. While I will need to explain signaling transduction (process water soluble hormones take) another time.
This is all the time I have today guys, hope you like it
Signals that are transmitted between animal cells are often classified by two criteria; type of secretion and the route taken by the signaling hormone.
Types of Signaling:
a. Endocrine Signaling: secretion directly into the blood stream that then trigger further response in target cells located all around the body. Example: Insulin
b. Paracrine Signaling: Secretion of local regulators act over a short distance affecting neighboring cells, this and autocrine signaling rely on diffusion. Autocrine Signaling is again the secretion of local regulators but the target cell is the cell releasing the signal. These signaling methods play a role in blood pressure, nervous system functions, and reproduction (just a few).
c. Synaptic and Neuroendocrine Signaling: In synaptic signaling neurotransmitters diffuse across synapses triggering a response. While in Neuroendocrine Signaling, nuerohormones are released into the bloodstream producing a response from target cells. Example: Vasopressin (an anti-diuretic hormone)
d. Pheromone Signaling: These are hormones that don't affect you as directly but your environment; as they are excreted or released. Example: Body Odor
Endocrine Glands/ Tissues/ Organs:
Endocrine system cells are found in organs all over your body, such as your digestive track (stomach contains isolated endocrine cells), while other endocrine cells are grouped in ductless organs, these are called endocrine glands. Endocrine glands secrete hormones directly into the surrounding cells, this should be noted as the complete opposite of salivary glands which have ducts to carry secreted substances.
Major Endocrine Glands:
- Hypothalamus
- Pineal Gland
- Thyroid Gland
- Parathyroid Glands (Behind Thyroid)
- Adrenal Gland (on kidneys)
- Pancreas
- Testes
Organs Containing Endocrine Cells:
- Thymus
- Heart
- Liver
- Kidneys
- Small Intestine
Cellular Response Pathways:
Hormones vary in size and chemical properties.Some of these differences are more apparent than others but I would like to look at the three major classes of hormones polypeptides, steroids, and amines. Steroids hormones are lipids containing four fused carbon rings. all are derived from the steroid cholesterol (example would be testosterone or cortisol). Polypeptides are made up of two polypeptide chains and most in this group are formed by cleavage of one long polypeptide chain (example insulin). Amine hormones are synthesized from a single amino acid either tyrosine or tryptophan (examples are ephindrine or thyroxine). Hormones vary in their solubility while polypeptides and amines tend to be water soluble steroids tend to be lipid soluble. Water soluble hormones are hydrophilic and must bind to a cell surface receptor. Lipid soluble hormones are Lipid soluble and tend to diffuse into the cell as my post on testosterone diffusion explained. While I will need to explain signaling transduction (process water soluble hormones take) another time.
This is all the time I have today guys, hope you like it
