Endocrine Hormones and Skin Anatomy Facts

Posted on Oct 31, 2025 in Environmental Biology

Essential Facts about Hormones and the Integumentary System

The Endocrine System: Hormones and Their Functions

The endocrine system relies on hormones produced by various glands to regulate critical bodily functions. Below is a summary of key hormones, their source glands, and primary actions.

Major Hormones and Glands

  • Estrogen: Controls the development of female secondary sex characteristics (Ovary).
  • Testosterone: Controls the development of male secondary sex characteristics (Testes).
  • Calcitonin: Decreases blood calcium levels (Thyroid Gland).
  • Parathormone (PTH): Increases blood calcium levels (Parathyroid Gland).
  • Somatotropin (Growth Hormone): Stimulates overall growth (Pituitary Gland).
  • Vasopressin (ADH): Prevents water loss (Pituitary Gland).
  • Melatonin: Helps regulate the sleep-wake cycle (Pineal Gland).
  • Glucagon: Increases blood sugar levels (Pancreas).
  • Insulin: Decreases blood sugar levels (Pancreas).
  • Adrenaline (Epinephrine): Improves reaction to emergencies (Adrenal Medulla Gland).
  • Luteinizing Hormone (LH): Stimulates the ovaries and testes to produce sex hormones (Pituitary Gland).
  • Follicle-Stimulating Hormone (FSH): Stimulates gamete formation (Pituitary Gland).

The Integumentary System: Skin Structure and Function

The skin is the body’s largest component and forms the integumentary system, providing protection and regulation.

Layers of the Skin

Epidermis
The outer layer of the skin. The outermost layer of the epidermis is made up of dead cells.
Dermis
The inner layer of the skin. The dermis contains blood vessels, glands, nerve endings, and hair follicles.

Key Components and Proteins

  • Keratin: A tough, fibrous protein that forms the basic structure of human hair and nails.
  • Melanin: A dark brown pigment.

Melanocytes and Pigmentation

Melanocytes are specialized cells located in the skin that produce melanin.

  1. Most people have roughly the same number of melanocytes in their skin.
  2. Most people have the same distribution of melanocytes in their skin.

Dermal Regulation and Glands

The dermis plays a crucial role in regulating body temperature and maintaining skin health.

Temperature Regulation by the Dermis

The dermis regulates body temperature in two primary ways:

  • By widening and narrowing blood vessels (vasodilation and vasoconstriction).
  • By producing sweat.
Glands of the Dermis

There are two main types of glands found in the dermis:

  1. Sweat glands
  2. Sebaceous glands
Functions of Sweat and Sebum
How Sweat Cools the Body
Sweat evaporates from the skin surface, which removes heat and cools down the body.
Function of Sebum
Sebum waterproofs the skin and hair, and protects against bacteria.

Functions of Head Hair

Head hair serves two important functions:

  • It helps insulate the skull.
  • It protects the scalp from sun rays.