3-28 hormones in behavior and development

3-28 hormones in behavior and development - HORMONES IN...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
HORMONES IN BEHAVIOR AND DEVELOPMENT LIFE 53.2.4-6; 41-41.1; 41.3.10-41.3.12 53.2.4 Imprinting takes place at a specific place in development -Male songbirds use a species-specific song in territorial displays and courtship. For many species , such as the white-crowned sparrow, learning is an essential step in the acquisition of this song. If eggs of white-crowned sparrows are hatched in an incubator and the young male birds are reared in isolation, they will not sing the typical species-specific song when they mature. White- crowned sparrows cannot produce their species-specific song unless they hear it as nestlings -Deprivation experiments have demonstrated that young male sparrows do not learn the songs of other species , even if they hear them many times, but exposure to just a few songs of their own species is sufficient for imprinting . 53.2.6 Hormones influence behavior at genetically determined times -females form a memory of their species-specific song when they are nestlings and have the capability to express it, but they normally lack the hormonal stimulation (need testosterone). -an increase in testosterone causes certain parts of the male’s brain necessary for learning and developing song to grow larger. Individual neurons in those regions of the brain increase in size and grow longer extensions, and the number of neurons in those regions increases. 41.1 What are hormones and how do they work? -information is transmitted as electric signals and as chemical signals . The electric signals are impulses generated by the nervous system, conducted along cell processes of nerve cells to their targets on specific cells. The chemical signals are hormones , secreted by cells of the endocrine system into the extracellular fluid. 41.1.1 Hormones can act locally or at a distance -cells that secrete hormones are called endocrine cells , and the cells that have receptors for those hormones are called target cells . Hormones secreted into the extracellular fluid can diffuse into the blood, which distributes them throughout the body so they can activate
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/02/2009 for the course BIO 315H taught by Professor Payne during the Spring '08 term at University of Texas.

Page1 / 3

3-28 hormones in behavior and development - HORMONES IN...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online