ENDOCRINE SYSTEM LEC Part 1
Allen Dale De Guzman・32 minutes read
The endocrine system, distinct from the nervous system, uses hormones delivered through the blood to target all cells in the body, regulating various processes like metabolism, muscle contraction, and growth. Hormones bind to specific receptors on target cells, triggering responses like changing cell permeability and causing muscle contractions, with regulation involving negative feedback to reduce further release signals.
Insights
- The endocrine system and the nervous system differ in their methods of communication: the nervous system uses neurotransmitters for rapid, localized responses, while the endocrine system employs hormones that travel through the bloodstream to affect all cells in the body.
- Hormones play a crucial role in regulating various bodily functions, including metabolism, growth, immune system activities, and muscle contraction, by binding to specific receptors on target cells and triggering intracellular responses through signal transduction pathways, ultimately influencing cellular actions and maintaining internal balance.
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Recent questions
How do hormones differ from neurotransmitters?
Hormones travel through blood, while neurotransmitters act locally.
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Summary
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Endocrine System: Hormones, Glands, and Functions
- The endocrine system controls various processes in the body, distinct from the nervous system.
- The nervous system uses neurotransmitters, while the endocrine system uses hormones delivered through the blood.
- Neurons transmit messages to the synaptic cleft, while hormones travel through the blood to reach their target tissues.
- The nervous system targets muscle, gland cells, and neurons, while the endocrine system targets all cells in the body.
- The nervous system acts within milliseconds, while the endocrine system may take days to have an effect.
- Exocrine glands secrete products through ducts, like sweat and mucus, while endocrine glands secrete hormones directly into the bloodstream.
- Hormones diffuse into the bloodstream and are carried to target cells throughout the body.
- Endocrine glands include the pituitary, thyroid, adrenal glands, among others, while other organs like the pancreas and ovaries also secrete hormones.
- Hormones regulate the internal environment, metabolism, muscle contraction, immune system activities, growth, and reproductive systems.
- Hormones bind to specific receptors on target cells, triggering responses like synthesis of molecules, changing cell permeability, and causing muscle contractions.
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Cell Signaling and Hormone Regulation in Cells
- Second messengers called molecules pass signals along cells in a cascading process known as signal transduction.
- Hormones carried by receptors trigger intracellular responses, causing changes within cells.
- Second messengers inside cells act upon hormone signals, leading to specific cell actions like substance production or metabolic changes.
- Hormones detach from receptors after causing intracellular signals, stopping the response and returning the cell to normal until another hormone binds.
- Hormone effects on target cells depend on hormone concentration in the blood, the number of hormone receptors on the cell, and interactions with other hormones.
- Hormones can work synergistically or antagonistically, enhancing or blocking each other's effects.
- Hormone secretion is regulated by short bursts in response to signals from the nervous system, chemical changes in the blood, and interactions with other hormones.
- Most hormone regulation involves negative feedback, where hormone effects reduce signals for further release.
- Some hormones operate via positive feedback, where effects increase signals for more hormone release.
- The hypothalamus and pituitary gland work together to regulate bodily functions, with the hypothalamus signaling the pituitary gland to release hormones that control other endocrine glands.
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Hormones regulate growth, metabolism, and reproduction.
- Growth hormone stimulates growth and cell reproduction by increasing protein synthesis, promoting bone and muscle growth, and regulating metabolism.
- Thyroid Stimulating Hormone (TSH) is secreted by cells in the anterior pituitary and stimulates the thyroid gland to produce thyroid hormones (T3 and T4) that regulate metabolism, energy levels, and overall growth.
- Follicle Stimulating Hormone (FSH) stimulates the growth of ovarian follicles and estrogen production in females, while in males, it stimulates testosterone production.
- Luteinizing Hormone (LH) triggers ovulation in females and testosterone production in males, with no hypothalamic inhibiting hormone.
- Prolactin stimulates milk production in the breast after childbirth, while Adrenocorticotropic Hormone (ACTH) and Melanocyte Stimulating Hormone (MSH) have specific functions related to cortisol production and skin pigmentation, respectively.
