Chapter 16 Outline
Introduction to Endocrine Principles
- Hormones bind to receptor molecules expressed by target cells
- Concentrations of hormones in the blood vary in response to varying conditions
- Most hormones fall into three chemical classes
- Hormone molecules exert their effects by producing biochemical changes in target cells
- Water-soluble carrier proteins in the blood transport lipid-soluble hormones and many water-soluble hormones
Synthesis, Storage, and Release of Hormones
- Peptide hormones are synthesized at ribosomes, stored in vesicles, and secreted on demand
- Steroid hormones are synthesized on demand prior to secretion, and are released into the blood by diffusion
Types of Endocrine Cells and Glands
Control of Endocrine Secretion: The Vertebrate Pituitary Gland
- The posterior pituitary illustrates neural control of neurosecretory cells
- The anterior pituitary illustrates neurosecretory control of endocrine cells
- Hormones and neural input modulate endocrine control pathways
The Mammalian Stress Response
- The autonomic nervous system and HPA axis coordinate the stress response to an acute threat
- The HPA axis modulates the immune system
- Chronic stress causes deleterious effects
- Plasma glucocorticoid concentrations show seasonal variations
Endocrine Control of Nutrient Metabolism in Mammals
- Insulin regulates short-term changes in nutrient availability
- Glucagon works together with insulin to ensure stable levels of glucose in the blood
- Other hormones contribute to the regulation of nutrient metabolism
Endocrine Control of Salt and Water Balance in Vertebrates
- Antidiuretic hormones conserve water
- The renin–angiotensin–aldosterone system conserves sodium and excretes potassium
- Atrial natriuretic peptide promotes excretion of sodium and water
Endocrine Control of Calcium Metabolism in Mammals
- Parathyroid hormone increases Ca2+ in the blood
- Active vitamin D increases Ca2+ and phosphate in the blood
- Calcitonin opposes bone resorption and decreases Ca2+ and phosphate in the blood
Endocrine Principles in Review
Chemical Signals along a Distance Continuum
- Paracrines are local chemical signals distributed by diffusion
- BOX 16.1 Hormones, Neurons, and Paracrine Neuromodulators Influence Behavior
- Pheromones and kairomones are used as chemical signals between animals
Insect Metamorphosis
- Insect metamorphosis may be gradual or dramatic
- BOX 16.2 Juvenile Hormone (JH) in the Laboratory, Silk Industry, and Environment
- BOX 16.3 Insects in Forensics and Medicine
- Hormones and neurohormones control insect metamorphosis