The Integumentary System

Question 1

What is the integumentary system?

Answer 1

The outer covering of the body, including skin, glands, hair, and nails.

Question 2

What is the largest organ in the body?

Answer 2

The skin.

Question 3

What are the main functions of the integumentary system?

Answer 3

Barrier/protection, sensation, temperature regulation, vitamin D production, and water loss prevention.

Question 4

What are the three main layers of the skin?

Answer 4

1. Epidermis (outer layer) 2. Dermis (middle layer) 3. Hypodermis (subcutaneous layer).

Question 5

What is the function of the epidermis?

Answer 5

Prevents water loss and protects against abrasion.

Question 6

What is the function of the dermis?

Answer 6

Provides structural strength, elasticity, and contains sensory structures.

Question 7

What is the function of the hypodermis?

Answer 7

Anchors the skin to underlying tissues and stores fat

Question 8

Is the epidermis vascular or avascular?

Answer 8

Avascular (lacks blood vessels).

Question 9

How many layers does the epidermis have?

Answer 9

4-5 layers (strata).

Question 10

Where are new epidermal cells generated?

Answer 10

Stratum basale.

Question 11

How long is the epidermal cell turnover cycle?

Answer 11

~35 days.

Question 12

What are the main cell types in the epidermis?

Answer 12

1. Keratinocytes 2. Basal cells 3. Melanocytes 4. Langerhans cells 5. Merkel cells.

Question 13

What is the function of keratinocytes?

Answer 13

Produce keratin for waterproofing and strength.

Question 14

What is the function of basal cells?

Answer 14

Precursor cells for keratinocytes (undergo mitosis).

Question 15

What is the function of melanocytes?

Answer 15

Produce melanin for UV protection.

Question 16

What is the function of Langerhans cells?

Answer 16

Immune defense (phagocytose bacteria).

Question 17

What is the function of Merkel cells?

Answer 17

Sensory receptors for touch

Question 18

What are the layers of the epidermis (deep to superficial)?

Answer 18

1. Stratum basale 2. Stratum spinosum 3. Stratum granulosum 4. Stratum lucidum (only in thick skin) 5. Stratum corneum.

Question 19

What happens in the stratum basale?

Answer 19

Cells divide and migrate upwards (keratinocytes, melanocytes, Merkel cells present).

Question 20

What happens in the stratum spinosum?

Answer 20

Keratinocytes are connected by desmosomes; Langerhans cells are present.

Question 21

What happens in the stratum granulosum?

Answer 21

Cells begin producing keratin and start to die.

Question 22

What happens in the stratum lucidum?

Answer 22

Present only in thick skin (palms, soles); contains dead, flattened cells.

Question 23

What happens in the stratum corneum?

Answer 23

Dead, keratinized cells (corneocytes) form a waterproof barrier.

Question 24

What are the two layers of the dermis?

Answer 24

1. Papillary layer (superficial) 2. Reticular layer (deep).

Question 25

What is the main cell type in the dermis?

Answer 25

Fibroblasts (produce collagen and elastic fibers).

Question 26

What structures are found in the dermis?

Answer 26

Hair follicles, sensory receptors, sweat glands, sebaceous glands, blood vessels, lymphatic vessels.

Question 27

What is the function of dermal blood vessels?

Answer 27

Supply oxygen and nutrients to the epidermis.

Question 28

What are the functions of hair?

Answer 28

Protection, sensory input, thermoregulation.

Question 29

What structure produces hair?

Answer 29

Hair follicle.

Question 30

What is the function of the arrector pili muscle?

Answer 30

Causes hair to stand (goosebumps) due to cold or fear.

Question 31

What are the two main types of glands in the skin?

Answer 31

Sweat glands and sebaceous glands.

Question 32

What is the function of sweat glands?

Answer 32

Produce sweat for cooling and waste elimination.

Question 33

What is the function of sebaceous glands?

Answer 33

Produce sebum (oily substance) for lubrication and antimicrobial activity.

Question 34

What is the "surface film" on the skin?

Answer 34

A protective barrier of sweat, sebum, and sloughed epithelial cells.

Question 35

What are the functions of the surface film?

Answer 35

Antibacterial, antifungal, lubrication, hydration, toxin protection.

Question 36

How does the epidermis prevent dehydration?

Answer 36

Keratin and lipid layers reduce water loss.

Question 37

What happens if the epidermal barrier is damaged?

Answer 37

Water loss increases, leading to dry/cracked skin

Question 38

What determines skin color?

Answer 38

1. Melanin 2. Beta-carotene 3. Stratum corneum thickness.

Question 39

What is the function of melanin?

Answer 39

Protects DNA from UV radiation.

Question 40

What stimulates melanin production?

Answer 40

UV light, hormones, genetics.

Question 41

Where is melanin produced?

Answer 41

Melanocytes in the stratum basale

Question 42

What triggers vitamin D production in the skin?

Answer 42

UV light converts cholesterol into cholecalciferol (Vitamin D3).

Question 43

Where is Vitamin D3 converted into active vitamin D?

Answer 43

Liver and kidneys.

Question 44

What are the main functions of vitamin D?

Answer 44

1. Calcium and phosphate absorption 2. Bone health.

Question 45

Why is the stratum corneum important for drug absorption?

Answer 45

Acts as a barrier; drugs must penetrate this layer to be effective.

Question 46

Why does skin thickness vary in different body regions?

Answer 46

Thicker in high-friction areas (palms, soles) for protection.

Question 47

What is the role of the skin in thermoregulation?

Answer 47

Sweat glands and blood vessel dilation/constriction regulate temperature