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Esthetician (NIC Theory Exam) · Scientific Concepts

Esthetician (NIC Theory Exam): Anatomy and Physiology Concepts

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Written by AI. Only units that passed a separate AI check (re-reading facts and numbers) are published. Tell us if you find a mistake.

Overview

This chapter explains how the body is built and how the skin works. It starts with cells and works up to organs and body systems. The exam also asks about skin layers and the muscles and nerves of the face.

The cell is the basic unit of life. Cells of the same kind form a tissue, tissues form an organ such as the skin, and organs working together form a body system. The skin is the body's largest organ and protects against germs, water loss, and the sun.

The skin has three main parts. The epidermis is the thin outer layer with no blood vessels, and it makes new cells that move upward and shed. The dermis lies beneath it and holds blood vessels, nerves, glands, and hair follicles. Under the dermis, the subcutaneous layer stores fat and cushions the body.

Melanin is the pigment made by melanocytes in the deepest layer of the epidermis. It gives skin its color and helps absorb UV light. On the face, the trigeminal nerve carries feeling, and the facial nerve moves the muscles of expression.

Key concepts

  • Cell

    The basic unit of life. Each cell takes in nutrients, makes energy, and divides to make new cells.

    Memory tipCells, then tissues, then organs, then systems.

  • Epidermis

    The outer layer of skin. It has no blood vessels and constantly renews itself as cells move up and shed from the surface.

    Memory tipEpi means upon. It is the part you can see.

  • Dermis

    The thicker layer under the epidermis. It holds blood vessels, nerves, oil and sweat glands, hair follicles, and collagen.

    Memory tipBlood vessels, nerves, and glands are in the dermis.

  • Subcutaneous layer

    The fatty layer below the dermis. It cushions the body, saves energy, and holds heat.

    Memory tipSub means below the skin.

  • Melanin

    The pigment that gives skin and hair color. It is made by melanocytes and helps shield deeper cells from UV light.

    Memory tipMore melanin means more natural sun protection, not full protection.

  • Trigeminal nerve (5th cranial)

    The chief sensory nerve of the face. It carries feelings such as touch and pain from the face to the brain.

    Memory tipTrigeminal = tri means three branches of feeling.

  • Facial nerve (7th cranial)

    The motor nerve that moves the muscles of facial expression, such as smiling and frowning.

    Memory tipFacial nerve = facial movement.

Often tested

  • The epidermis has no blood supply; the dermis does.
  • Collagen and elastin in the dermis give firmness and stretch.
  • Melanocytes make melanin.
  • The trigeminal nerve senses; the facial nerve moves.
  • Skin protects, senses, regulates heat, and holds in water.

Easy to confuse: Epidermis vs. dermis

PointEpidermisDermis
PositionOuter layerMiddle layer
Blood vesselsNoneYes
ContainsDead surface cells and melanocytesNerves, glands, hair follicles, collagen
ThicknessThinnerThicker

3 sample questions

Verified practice questions from this unit.

Practice questionReviewedScientific Concepts › Anatomy and Physiology★★★★☆

Question 1. What is the basic unit of all living things?

  1. ① The tissue
  2. ② The organ
  3. ③ The gland
  4. ④ The cell
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Answer: ④ The cell

Key point: Cell = basic unit of life

All living things are made of cells. Cells group into tissues, tissues into organs, and organs into systems.

Wrong choices

  • The tissue: A tissue is a group of cells.
  • The organ: An organ is made of several tissues.
  • The gland: A gland is an organ that makes a substance.
Practice questionReviewedScientific Concepts › Anatomy and Physiology★★★★☆

Question 2. What is the outermost layer of the skin?

  1. ① The dermis
  2. ② The epidermis
  3. ③ The subcutaneous layer
  4. ④ The papillary layer
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Answer: ② The epidermis

Key point: Epidermis is the outer layer

The epidermis is the thin outer layer you can see. It protects the body and has no blood vessels.

Wrong choices

  • The dermis: The dermis lies under the epidermis.
  • The subcutaneous layer: The subcutaneous layer lies under the dermis.
  • The papillary layer: The papillary layer is the upper part of the dermis.
Practice questionReviewedScientific Concepts › Anatomy and Physiology★★★★☆

Question 3. Which pigment gives skin its color and helps protect it from UV light?

  1. ① Melanin
  2. ② Keratin
  3. ③ Collagen
  4. ④ Elastin
▼ Show answer and explanation▲ Hide answer and explanation

Answer: ① Melanin

Key point: Melanin = skin pigment

Melanin is made by cells called melanocytes. More melanin means darker skin and more natural protection from the sun.

Wrong choices

  • Keratin: Keratin is a hard protein in skin, hair, and nails.
  • Collagen: Collagen gives skin firmness.
  • Elastin: Elastin gives skin stretch.
Practice 5 questions from this unit →