Cell Biology - Evolution of the Endocrine System
Vertebrate Biology Essay
Conversion Programme in the Natural Sciences Dr. Colin Stolkin & Professor P.B Gahan
The Vertebrate Endocrine System in specific reference to their role in Human Menstruation, Ovarian and Uterine cycles
Rio Summers April 2009
Word Count: 2693
The vertebrate endocrine system can be best explained as an internal body system collecting multiple organs and glands that produce and regulate hormone secretion into the bloodstream in order to control the many functions of the body. The endocrine system functions alongside the nervous and exocrine system to control and maintain growth, metabolism and sexual development. Hormone substances which are synthesized and secreted from cells involved within the endocrine system, known as endocrine gland cells, act as chemical messengers and perform the role of regulating other cell activities within the body (Hadley, M.E & Levine J.E, 2007 pg. 1-2).
In evolutionary terms, the first evidence of systems working in conjunction with each other to allow for the communication and functional integration between specialized cells, was visible in Metazoa. Metazoa are believed to be the earliest evolved multicellular organisms that make up most of the animal kingdom. The metazoa were the first organisms to posses various layers of specialized tissues or cell groups, evolving after the divergence of plants but before that of the fungi, placing this start of metazoan evolution and consequently endocrine evolution between 2500 and 2100Ma approximately (Hadley, M.E & Levine J.E,
2007 pg. 1-2). Both the nervous and the endocrine system are believed to have evolved alongside each other at the same time, functioning in similar ways by cell to cell signaling from a sender cell that produces and releases the chemical messenger, to a target cell that receives and translates the messenger, generating a response. Despite this similarity however, the two systems perform this cell to cell signaling in contrasting ways; in
Conversion Programme in the Natural Sciences Dr. Colin Stolkin & Professor P.B Gahan
The Vertebrate Endocrine System in specific reference to their role in Human Menstruation, Ovarian and Uterine cycles
Rio Summers April 2009
Word Count: 2693
The vertebrate endocrine system can be best explained as an internal body system collecting multiple organs and glands that produce and regulate hormone secretion into the bloodstream in order to control the many functions of the body. The endocrine system functions alongside the nervous and exocrine system to control and maintain growth, metabolism and sexual development. Hormone substances which are synthesized and secreted from cells involved within the endocrine system, known as endocrine gland cells, act as chemical messengers and perform the role of regulating other cell activities within the body (Hadley, M.E & Levine J.E, 2007 pg. 1-2).
In evolutionary terms, the first evidence of systems working in conjunction with each other to allow for the communication and functional integration between specialized cells, was visible in Metazoa. Metazoa are believed to be the earliest evolved multicellular organisms that make up most of the animal kingdom. The metazoa were the first organisms to posses various layers of specialized tissues or cell groups, evolving after the divergence of plants but before that of the fungi, placing this start of metazoan evolution and consequently endocrine evolution between 2500 and 2100Ma approximately (Hadley, M.E & Levine J.E,
2007 pg. 1-2). Both the nervous and the endocrine system are believed to have evolved alongside each other at the same time, functioning in similar ways by cell to cell signaling from a sender cell that produces and releases the chemical messenger, to a target cell that receives and translates the messenger, generating a response. Despite this similarity however, the two systems perform this cell to cell signaling in contrasting ways; in
References: Adds et al. 2003, Respiration & Coordination, 2nd Edition, Nelson Thornes, Cheltenham UK Alberts et al Hadley, M.E & Levine J.E, 2007, Endocrinology, 6th Edition, Pearson Education Ltd, London Cohen, N.L Parker, Dr. V. 2008, Lecture Notes Purves el al Ollendorff, Dr. A.T, 2008 [online article] The Menstrual Cycle and Ovulation - Updated Dec 8 2008 - Available at: http://www.netwellness.org/healthtopics/pregnancy/pregmenstrualcycle.cfm