Lecture
This lecture covers the various ways animal cells can signal to each other, including endocrine, paracrine, neuronal, and contact-dependent signaling. It explains the differences between surface receptors and intracellular receptors, the actions of protein and steroid hormones, and the genetic basis of red hair inheritance. The lecture also delves into the communication pathways involved in hair color determination, focusing on melanocytes, melanin production, and the role of regulatory molecules like CAMP. Additionally, it discusses the significance of switches in defining hair color in humans and explores examples from mouse fur phenotypes. The lecture concludes with insights into paracrine signaling in different body locations and the impact of Mc4R mutations on food intake regulation in the hypothalamus.