Hormones In Animals

Key Notes:

Introduction to Hormones

  • Definition: Hormones are chemical messengers produced by glands in the endocrine system that regulate various physiological processes in the body.
  • Function: They travel through the bloodstream to target organs and tissues, influencing growth, metabolism, reproduction, and mood.

Major Endocrine Glands and Their Hormones

Pituitary Gland:

  • Often referred to as the “master gland” because it regulates other endocrine glands.
  • Produces hormones such as:
  • Growth Hormone (GH): Stimulates growth and cell reproduction.
  • Prolactin: Promotes milk production in lactating females.
  • Adrenocorticotropic Hormone (ACTH): Stimulates the adrenal glands.

Thyroid Gland:

  • Produces hormones like:
  • Thyroxine (T4) and Triiodothyronine (T3): Regulate metabolism, energy production, and growth.
  • Calcitonin: Helps lower blood calcium levels.

Adrenal Glands:

  • Located on top of the kidneys, produce:
  • Cortisol: Helps manage stress and metabolism.
  • Adrenaline (Epinephrine): Increases heart rate and energy levels during stress (“fight or flight” response).
  • Aldosterone: Regulates sodium and potassium levels.

Pancreas:

  • Produces insulin and glucagon to regulate blood sugar levels.
  • Insulin: Lowers blood sugar by facilitating the uptake of glucose by cells.
  • Glucagon: Raises blood sugar by promoting the release of glucose from the liver.

Gonads (Ovaries and Testes):

  • Produce sex hormones:
  • Estrogens: Regulate female reproductive functions and secondary sexual characteristics.
  • Testosterone: Regulates male reproductive functions and secondary sexual characteristics.

Functions of Hormones

  • Metabolism: Hormones regulate the conversion of food into energy and manage how the body uses nutrients.
  • Growth and Development: Hormones influence physical growth, sexual maturation, and development of body structures.
  • Homeostasis: Hormones help maintain stable internal conditions (e.g., temperature, pH, hydration).
  • Reproduction: Hormones control the menstrual cycle in females and sperm production in males.

Hormonal Imbalances

  • Causes: Can result from disease, genetic factors, stress, or environmental factors.
  • Effects: Can lead to various health issues such as diabetes (insulin imbalance), hypothyroidism (low thyroid hormones), or hyperthyroidism (excess thyroid hormones).

Conclusion

  • Hormones are essential for regulating numerous body functions. Understanding their roles helps us grasp how our bodies respond to different stimuli and maintain balance.

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