Homeostasis and Peptide Hormones

Study Notes

Homeostasis

Homeostasis is the ability of an organism to maintain a stable internal environment despite external changes.
This involves maintaining consistent levels of various factors like temperature, blood glucose, and water balance.
Negative feedback loops are crucial for maintaining homeostasis. These loops detect deviations from the set point and trigger responses to counteract the deviation, returning the system to equilibrium.
Examples include the regulation of body temperature through sweating or shivering, and the maintenance of blood glucose levels by insulin and glucagon.
Key components of homeostasis include sensors, control centers, and effectors. Sensors detect deviations from the set point, control centers process the information and send signals, and effectors carry out the response to restore balance.
Homeostatic mechanisms are vital for survival as they ensure optimal conditions for cellular function.

Peptide Hormones

Peptide hormones are made from chains of amino acids.
They are usually water-soluble and can travel freely in the bloodstream.
Their effects are often rapid and short-lived, primarily due to their fast degradation.
They bind to receptors on the cell surface, activating intracellular signaling pathways.
Examples include insulin, glucagon, and growth hormone.
Peptide hormones generally act by binding to cell surface receptors located on the plasma membrane. This binding triggers a cascade of intracellular events without the hormone needing to enter the cell.

Steroid Hormones

Steroid hormones are derived from cholesterol.
They are lipid-soluble, meaning they can readily diffuse across cell membranes.
Their effects are generally slow but long-lasting. This is due to changes in gene expression over time after their action.
They bind to receptors located within the cell, typically in the cytoplasm or nucleus.
This binding complex then acts as a transcription factor to influence the expression of specific genes.
Examples include cortisol, testosterone, and estrogen.
Steroid hormones bind to intracellular receptors. Transport proteins within the bloodstream are crucial because they are lipid-soluble, meaning that without these proteins, they wouldn't be able to travel through watery environments such as blood.
The hormone-receptor complex influences gene transcription and translation, leading to changes in protein production and cellular function.

Description

This quiz explores the concepts of homeostasis and peptide hormones, focusing on how organisms maintain stable internal environments. It discusses key elements such as negative feedback loops, sensors, control centers, and effectors. Understanding these mechanisms is essential for grasping the physiological processes that ensure survival.