Skin and Temperature Regulation

Question 1

Define the Integumentary System

Answer 1

A group of organs working together, forming cutaneous membrane (skin)

Question 2

Describe 3 Properties of the Skin

Answer 2

• Covers external surface of body
• Contains accessory structures
• 1.2-2.2 square meters- 4.5kg- skin, average adult

Question 3

Name 3 Accessory Structures to the Skin

Answer 3

Hair
Sweat and oil glands
Nails

Question 4

Name the 3 layers of the integumentary system

Answer 4

1. Epidermis
2. Dermis (mesoderm)
3. Hypodermis- superficial fascia (mesoderm)

Question 5

Describe the Epidermis

Answer 5

Epidermis (ectoderm)
Contains epithelial cells that are the thinnest outer layer of the skin.
Contains 4 main layers (5 in areas of greatest wear- i.e. soles of feet, palms and fingers
Non-vascularised

Question 6

Describe the Dermis

Answer 6

• Below epidermis (bulk of skin)
• Tough and strong containing flexible and fibrous connective tissue
• Contains collagen and elastin 2-4mm thick at birth
• Contains structures (glands, hair follicles, blood supply and nerves
• Vascularized
• Sensation- heat, touch, pressure and pain

Question 7

Describe the Hypodermis (Superficial Fascia)

Answer 7

• Subcutaneous (not strictly skin)
• Shares some protective functions- superficial tough tissue wrapping skeletal muscle
• Stores adipose tissue (fat)
• Anchors skin
• Provides insulation and calorie reservoir

Question 8

Name the Cellular Skin Layers (Epidermis)

Answer 8

In order from bottom (newest cells) to top (oldest cells)
Stratum Basale
Stratum Spinosum
Stratum Granulosum
Stratum Lucidum
Stratum Corneum
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Question 9

Describe the Stratum Basale

Answer 9

• Deepest layer
• Lies next to dermis
• Mitosis cells (makes epidermal cells: keratinocytes)
• Daughter cells are pushed upward to become the more superficial layer (cells of the other strata)

Question 10

Describe the Stratum Spinosum

Answer 10

• Connected to other cells by ‘spindles’
• Cells tightly connected to adjacent cells, helps resist tension
• Cells become flattened and start to die as they move upward
• 8 to 10 layers of cells

Question 11

Describe the Stratum Granulosum

Answer 11

• Cells contain granules (lamellar granules) that release lipid (fat) rich secretion, helping waterproof the skin

Question 12

Describe the Stratum Lucidum

Answer 12

• Only occurs in thick, hairless skin of the palms of hands and soles of feet
• 3-5 layers of cells
• Contain large amounts of keratin (tough fibrous protein)

Question 13

Describe the Stratum Corneum

Answer 13

• Outermost layer of epidermis
• 20-30 layers of cells in the healthy adult
• Shingle-like dead cells are filled with keratin
• Protects from abrasion
• Contain lipids and proteins
• Outer layer sloughs off
• Basal layer replaces stratum corneum keratinocytes

Question 14

What are the Types of Skin Cells?

Answer 14

Keratinocytes (90%)- produce keratin
Melanocytes (8%)- produce melanin pigment which is transferred to other cells
Langerhan Cells- from the bone marrow, involved in immunity
Merkel Cells- in the deepest layer, form touch receptor with sensory neuron

Question 15

What are the Functions of the Skin?

Answer 15

• Protection
• Body Temperature Regulation
• Cutaneous Sensation
• Excretion
• Blood Reservoir
• Metabolic Functions
• Sensation
• Preventative

Question 16

What is Skin Colour Determined By?

Answer 16

• Melanin
• Carotene
• Haemoglobin

Question 17

Name the Properties of the Skin in a Term Baby

Answer 17

• Dermis 2-4mm thick
• Sweat gland mature 1 week
• Subcutaneous layer of lipid deposits- brown adipose (BAT) for energy and insulation
• Vernix caseosa protects, moisturises and facilitates colonisation

Question 18

Name the Properties of the Skin in a Pre-Term Baby

Answer 18

• Dermis thinner
• Transparent and gelatinous
• Ruddy red connectivity between layers less
• Sweat glands mature 21-33 days (longer for extreme pre-term)
• +/- vernix caseosa
• Oedema

Question 19

Name the Appendages to the Skin

Answer 19

• Cutaneous glands are all exocrine glands (contents released via a duct)
• Sebaceous glands
• Sweat gland
• Hair
• Hair follicles
• Nails

Question 20

What are the Two Types of Sweat Glands

Answer 20

1. Eccrine- open via duct to pore on skin surface

2. Apocrine- ducts empty into hair follicles

Question 21

What is the Composition of Sweat?

Answer 21

Mostly Water

• Salts and vitamin C
• Some metabolic waste
• Fatty acids and proteins (apocrine only)

Question 22

What is the Function of Sweat?

Answer 22

• Helps dissipate excess heat (by the evaporation of sweat from skin surface)
• Excretes waste products

Question 23

Name Some Properties of Sweat Glands

Answer 23

Produce sweat

Widely distributed in skin

Question 24

Name Some Properties of Sweat

Answer 24

• Acidic nature inhibits bacteria growth

- Odour is from associated bacteria

Question 25

Name Some Properties of Nails

Answer 25

• Has scale-like modifications of the epidermis
• Heavily keratinised (tough fibrous protein produced by keratinocytes)
• Stratum basale that extends beneath the nail bed is responsible for nail growth
• Lack of pigment makes them colourless

Question 26

Outline the Structure of Nails

Answer 26

• Free edge, body is the visible attached portion

- Root of nail embedded in skin

Question 27

What is a Homeostatic Imbalance?

Answer 27

A disturbance in homeostasis, resulting in ill health

Question 28

What are some examples of homeostatic imbalances in the body

Answer 28

• Extreme stretching
• Blister
• Age
• Oxygenation
• Sebaceous blockages

Question 29

Explain the process of blood clotting

Answer 29

Smooth muscle contracts causing platelets to release chemicals equaling in vasospasm which causes reduced blood loss
Platelets stick to damage vessel, chemical release increases sticky property of platelets= platelet plug formation
Clotting factors activate each other creating fibrin threads resulting in blood clotting