key term - Target cells

Definition

Target cells are specific cells that possess receptors for particular hormones, allowing them to respond to those hormones' signals. The interaction between hormones and target cells is crucial for the regulation of various physiological processes, as only cells with the appropriate receptors can be affected by specific hormonal messages.

5 Must Know Facts For Your Next Test

1. Target cells can be located in various tissues and organs throughout the body, enabling hormones to exert their effects on multiple systems.
2. The number of hormone receptors on target cells can vary, affecting their sensitivity to hormones; more receptors can lead to a stronger response.
3. Hormones can have different effects depending on the type of target cell they interact with, highlighting the specificity of hormonal action.
4. The responsiveness of target cells can change over time due to factors like desensitization or upregulation of receptors, impacting hormonal effectiveness.
5. Some hormones can affect multiple target cells simultaneously, leading to widespread physiological changes such as growth, metabolism, and stress responses.

Review Questions

• How do target cells determine their response to hormones?
  • Target cells determine their response to hormones based on the presence of specific hormone receptors. When a hormone is released into the bloodstream, it travels until it encounters a target cell with the appropriate receptor. If binding occurs, it triggers a series of events within the cell that leads to a specific physiological response. This selective interaction is what makes hormonal signaling precise and effective.
• Discuss the impact of receptor number variation on target cell sensitivity to hormones.
  • The sensitivity of target cells to hormones is significantly influenced by the number of receptors present on their surface. If a target cell has a high density of hormone receptors, it is more likely to respond strongly when the hormone binds. Conversely, if there are fewer receptors, the cell may not respond as effectively. This variability allows the body to fine-tune its responses based on changing physiological needs and conditions.
• Evaluate the implications of altered target cell responsiveness on homeostasis in the body.
  • Altered responsiveness of target cells can have profound implications for maintaining homeostasis. For instance, if target cells become desensitized due to prolonged exposure to high hormone levels, it may result in inadequate physiological responses, leading to conditions like insulin resistance in diabetes. Conversely, increased receptor expression could enhance sensitivity and exacerbate reactions to hormones. Understanding these dynamics is essential for addressing metabolic disorders and ensuring balanced physiological functions.

Related terms

Hormone Receptors:

Proteins located on the surface or inside target cells that bind to hormones, initiating a cellular response.

Endocrine Glands:

Glands that secrete hormones directly into the bloodstream, influencing target cells throughout the body.

Signal Transduction: The process by which a cell converts an external signal (like a hormone binding) into a functional response, often involving multiple steps.