Lecture 5 biodiversity

Overview of the Endocrine System

• Introduction to the final lecture on the endocrine system.

• Importance of hormones in regulating physiological processes.

Definition of Hormones

• Hormones: Chemical signaling molecules, usually proteins or steroids, secreted by endocrine cells.

• Function: Control or regulate specific physiological processes.

• Diverse structures: Hormones can vary widely.

Types of Hormones

• Lipid-Derived Hormones

  • Derived from cholesterol.

  • Example: Estradiol and testosterone.

• Amino Acid-Derived Hormones

  • Derived from amino acids, such as tyrosine and tryptophan.

  • Examples: Epinephrine and melatonin.

• Peptide Hormones

  • Short or long chains of amino acids (proteins).

  • Example: Insulin, involved in blood sugar regulation.

Homeostasis

• Definition: The ability of an organism to maintain constant internal conditions.

• Role of hormones: Maintain homeostasis through cell signaling.

• Hormones act as ligands binding to receptors, initiating cellular responses.

Examples of Hormonal Regulation

• Water and Electrolyte Balance

  • Hormone: Aldosterone.

  • Function: Stimulates sodium reabsorption when sodium levels are low.

  • Anti-diuretic hormone (ADH): Stimulates water reabsorption when water levels are low.

• Reproductive System Regulation

  • Hormones: Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH).

  • Function: Regulate maturation of sperm and egg cells; trigger ovulation.

• Glucose Levels Regulation

  • Hormone: Insulin.

  • Function: Stimulates uptake of glucose after meals, storing it as glycogen in liver/muscles.

  • Counter hormone: Glucagon.

  • Function: Stimulates breakdown of glycogen to glucose during fasting.

Disorders Related to Hormonal Functions

• Diabetes Mellitus Type 1

  • An autoimmune disease where beta cells in the pancreas are destroyed.

  • Result: Reduced insulin production, leading to high blood glucose levels.

  • Symptoms include sweet-smelling urine due to glucose presence.

Hormonal Production and Feedback Mechanisms

• Negative Feedback Mechanism

  • Hormones regulate their production through feedback loops:

    • When effects of hormone increase, production decreases, and vice versa.

  • Purpose: Maintain homeostasis and concentration within narrow ranges.

• Endocrine Glands

  • Hormones produced by various glands: hypothalamus, pituitary, thyroid, adrenal glands, pancreas, pineal gland, testes, and ovaries.

  • Focus on:

    • Brain (various parts): Many hormones

    • Pancreas: Digestive enzymes and hormones

    • Adrenal Glands: Located above kidneys

    • Thyroid: Located in front of the trachea

Conclusion

• This lecture concludes the material covered for the exam.

• Mention of an upcoming exam covering all discussed topics.