Endocrine Web - The Endocrine System control with chemicals Produces chemical signals(hormones that integrate with nervous system to maintain

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

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

Unformatted text preview: The Endocrine System: control with chemicals Produces chemical signals (hormones) that integrate with nervous system to maintain homeostasis stimulus received stimulus converted to molecular signal Cells respond Sensory flow of Hormones Low on water , stomach full, or low blood sugar , for example… Response may be determined by multiple hormones Hormone travels through blood stream to target cells ( kidney , stomach, liver , for example) Retain water , release digestive enzymes, release glucose , etc. Hormones control many major processes Reproduction Growth and development Mobilization of body defenses Maintenance of much of homeostasis Regulation of metabolism Hormones can be classified chemically Most are 3 major types Amino acid– based (amines, peptides, and proteins) Steroids— made from cholesterol Prostaglandins— made from other lipids Mechanisms of Hormone Action Hormones affect only certain tissues = target cells or target organs Target cells have specific protein receptors Hormone-binding to receptors alters cellular activity Effects Caused by Hormones Change membrane permeability Synthesize proteins (enzymes) Activate or inactivate enzymes Stimulate mitosis Promote secretion Calcium homeostasis of blood 9–11 mg/100 ml Rising blood Ca 2+ levels Thyroid gland releases calcitonin Osteoclasts degrade bone matrix and release Ca 2+ into blood PTH Calcitonin Calcitonin stimulates calcium salt deposit in bone Parathyroid glands release parathyroid hormone (PTH) Thyroid gland Thyroid gland Parathyroid glands Falling blood Ca 2+ levels I m b a l a n c e I m b a l a n c e Why do they do all this again? … to help control these… Reproduction Growth and development Mobilization of body defenses Maintenance of much of homeostasis Regulation of metabolism Two basic chemical mechanisms (i.e. how hormones interact with molecules) Direct gene activation steroid hormones mainly, also thyroid hormone Second-messenger system Direct Gene Activation (Steroid Hormone Action) 1. Steroid diffuses through plasma membrane of target cells Nucleus Cytoplasm Steroid hormone Plasma membrane of target cell Figure 9.1a, step 2 Nucleus Cytoplasm Steroid hormone Plasma membrane of target cell 1. Lipid-like hormone diffuses through plasma membrane of target cells 2. Then it diffuses through nuclear membrane Direct Gene Activation (Steroid Hormone Action) Why? What’s in there? DNA!! Figure 9.1a, step 3 Nucleus Cytoplasm Steroid hormone Receptor protein Hormone-receptor complex Plasma membrane of target cell 1. Lipid-like hormone diffuses through plasma membrane of target cells 2. Diffuses through nuclear membrane 3. Binds to protein receptor in nucleus Direct Gene Activation (Steroid Hormone Action) Figure 9.1a, step 4 Nucleus Cytoplasm Steroid hormone Receptor protein Hormone-receptor complex DNA Plasma membrane of target cell Direct Gene Activation (Steroid Hormone Action)...
View Full Document

This note was uploaded on 01/13/2012 for the course ANATOMY 10 taught by Professor Prestongalusky during the Fall '11 term at Riverside Community College.

Page1 / 58

Endocrine Web - The Endocrine System control with chemicals Produces chemical signals(hormones that integrate with nervous system to maintain

This preview shows document pages 1 - 13. Sign up to view the full document.

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