The endocrine system is a complex network of glands that produce hormones. These chemical messengers regulate various bodily functions by traveling through the bloodstream to target cells. Understanding the different types of glands and signaling mechanisms is crucial for grasping how the body maintains balance.
Hormones come in different forms, each with unique characteristics. Peptide hormones are water-soluble and bind to cell surface receptors, while steroid hormones are lipid-soluble and work inside cells. Amine and lipid-derived hormones have diverse properties and functions, contributing to the system's versatility.
Endocrine System Components
Glands and Signaling Mechanisms
Top images from around the web for Glands and Signaling Mechanisms Signaling Molecules and Cellular Receptors | OpenStax: Biology View original
Is this image relevant?
The Thyroid Gland · Anatomy and Physiology View original
Is this image relevant?
Endocrine gland - Wikipedia View original
Is this image relevant?
Signaling Molecules and Cellular Receptors | OpenStax: Biology View original
Is this image relevant?
The Thyroid Gland · Anatomy and Physiology View original
Is this image relevant?
1 of 3
Top images from around the web for Glands and Signaling Mechanisms Signaling Molecules and Cellular Receptors | OpenStax: Biology View original
Is this image relevant?
The Thyroid Gland · Anatomy and Physiology View original
Is this image relevant?
Endocrine gland - Wikipedia View original
Is this image relevant?
Signaling Molecules and Cellular Receptors | OpenStax: Biology View original
Is this image relevant?
The Thyroid Gland · Anatomy and Physiology View original
Is this image relevant?
1 of 3
Endocrine glands secrete hormones directly into the bloodstream
Lack ducts to transport secretions
Examples include the pituitary gland , thyroid gland , and adrenal glands
Exocrine glands secrete substances through ducts onto epithelial surfaces
Have ducts to transport secretions
Examples include sweat glands, salivary glands, and mammary glands
Hormones act as chemical messengers that regulate physiological processes
Produced by endocrine glands and released into the bloodstream
Bind to specific receptors on target cells to elicit a response
Autocrine signaling occurs when a cell secretes a substance that binds to receptors on the same cell
Allows for self-regulation of cellular functions
Examples include immune cells and cancer cells
Paracrine signaling involves the release of substances that affect nearby cells
Substances diffuse through the extracellular fluid to reach target cells
Examples include neurotransmitters and local inflammatory mediators
Endocrine signaling involves the release of hormones into the bloodstream
Hormones travel throughout the body to reach distant target cells
Enables systemic regulation of physiological processes
Hormone Types and Characteristics
Peptide hormones are composed of amino acids
Water-soluble and cannot cross cell membranes
Bind to cell surface receptors and activate second messenger systems
Examples include insulin , growth hormone , and oxytocin
Steroid hormones are derived from cholesterol
Lipid-soluble and can cross cell membranes
Bind to intracellular receptors and directly influence gene expression
Examples include cortisol , testosterone , and estrogen
Amine hormones are derived from amino acids
Include catecholamines (epinephrine and norepinephrine ) and thyroid hormones
Catecholamines are water-soluble and bind to cell surface receptors
Thyroid hormones are lipid-soluble and bind to intracellular receptors
Lipid-derived hormones are derived from lipids other than cholesterol
Include prostaglandins and leukotrienes
Act locally as paracrine or autocrine signaling molecules
Involved in inflammation, pain sensation, and smooth muscle contraction