Types of Hormones | Human Physiology

Summary

This video explains the different types of hormones in the human body, categorized into three groups: peptide hormones, steroid hormones, and amino acid-derived hormones. Peptide hormones are protein-based and bind to surface receptors to initiate signaling within cells. Steroid hormones are lipid-based and can pass through cell membranes to bind to intracellular receptors, directly influencing gene expression. Amino acid-derived hormones, such as catecholamines and thyroid hormones, exhibit properties of both peptide and steroid hormones. The video offers an informative overview of how each hormone group regulates bodily functions.

Takeaways

• 😀 Hormones are signaling molecules found in multicellular organisms that regulate bodily functions.
• 😀 Hormones are produced in glands and transported to target organs in the body.
• 😀 There are three main types of hormones based on their structure: peptide hormones, steroid hormones, and amine hormones.
• 😀 Peptide hormones are made of chains of amino acids and are the most common hormone type in the human body.
• 😀 Examples of peptide hormones include insulin, glucagon, and oxytocin.
• 😀 Peptide hormones are hydrophilic, water-soluble, and lipophobic, meaning they cannot cross cell membranes on their own.
• 😀 Peptide hormones initiate a signal transduction process by binding to receptors on the cell surface, triggering secondary messengers.
• 😀 Steroid hormones are lipid-derived, lipophilic, and able to pass through the cell membrane to bind to internal receptors.
• 😀 Examples of steroid hormones include estrogen, testosterone, cortisol, and aldosterone.
• 😀 Amino acid-derived hormones, like catecholamines (dopamine, epinephrine, norepinephrine), bind to receptors on the cell surface, while thyroid hormones act as primary messengers within the cell.
• 😀 Catecholamines are involved in functions like motor control and the fight-or-flight response, while thyroid hormones stimulate the digestive system.

Q & A

What are hormones, and what role do they play in the body?

Hormones are signaling molecules found in multicellular organisms. They are produced in glands and transported throughout the body to specific organs, where they regulate bodily functions.

How are hormones categorized based on their structure?

Hormones are categorized into three groups based on their structure: peptide hormones, steroid hormones, and amine hormones.

What are peptide hormones and how are they formed?

Peptide hormones are composed of chains of amino acids linked by peptide bonds, forming polypeptides. When these chains grow larger, they form protein hormones.

Can you name a few examples of peptide hormones?

Examples of peptide hormones include insulin, glucagon, and oxytocin.

What is the solubility property of peptide hormones, and how does it affect their function?

Peptide hormones are hydrophilic (water-soluble) but lipophobic (unable to cross lipid membranes). They bind to receptors on the cell surface, initiating signal transduction inside the cell.

What process do peptide hormones undergo to exert their effect on target cells?

Peptide hormones bind to receptors on the cell surface, which triggers a signaling cascade through secondary messengers like cyclic AMP, initiating cellular responses.

What are steroid hormones, and how do they differ from peptide hormones?

Steroid hormones are lipid-derived and share a characteristic four-ring carbon structure. Unlike peptide hormones, steroid hormones are lipophilic and can pass through cell membranes to bind to intracellular receptors.

What is the mechanism of action of steroid hormones inside the cell?

Steroid hormones bind to receptors inside the cell, forming a receptor-hormone complex. This complex acts as a transcription factor, moving into the nucleus and directly influencing gene expression.

What are catecholamines, and where are they produced?

Catecholamines are a group of hormones derived from the amino acid tyrosine. They are produced in the adrenal glands, specifically in the adrenal medulla. Examples include dopamine, epinephrine, and norepinephrine.

How do catecholamines and thyroid hormones differ in terms of their mechanism of action?

Catecholamines bind to cell surface receptors and trigger secondary messenger cascades, similar to peptide hormones. Thyroid hormones, on the other hand, bind to intracellular receptors and act as primary messengers within the cell, much like steroid hormones.