Week 1: Skin and Fascia

Question 1

What are the 3 types of connective tissue proper?

Answer 1

1. Adipose tissue ( fat )
2. Loose connective tissue (fascia)
3. Dense regular tissue ( tendons and ligaments )

Question 2

What are the 2 specialised connective tissues?

Answer 2

1. Cartilage
2. Bone

Question 3

What are the functions of connective tissue?

Answer 3

Support, anchor & connect various parts of the body

Question 4

What are the layers of the tissue from out to in?

Answer 4

1. Skin
2. Superficial fascia (hypodermis)
3. Deep fascia
4. Muscle
5. Bone

Question 5

What are the 3 layers of the skin from out to in?

Answer 5

1. Epidermis (epithelium)
2. Dermis (connective tissue)
3. Hypodermis/subcutis (connective tissue)

Question 6

Describe the function and 4 features of the epidermis:

Answer 6

1. Squamous epithelial tissue
2. Keratinised
3. Self-regenerating
4. Avascular
   * Function: protection

Question 7

Describe the 4 features of the dermis:

Answer 7

1. Fibro-elastic connective tissue (dense)
   - Densely packed collagen and elastin in an irregular arrangement
2. Tough, supporting and nourishing layer
3. Contains most of the sensory nerve endings and other ‘appendages’
4. Contains blood vessels, nerves and sensory receptors

Question 8

Describe the function and 5 features of the hypodermis/superficial fascia:

Answer 8

1. Inner layer, between skin and muscle
2. Attaches dermis to underlying tissue
3. Mainly adipose tissue surrounded by collagen (loose irregular connective tissue)
4. Contains sensory receptors
5. Contains the larger vessels which supply and drain the dermal blood vasculature
   * Function: shock absorption, insulation, passage for nerves and blood vessels

Question 9

Describe 4 skin appendages:

Answer 9

1. Hair: Sensory and thermoregulation
2. Sweat glands: Thermoregulation
3. Sebaceous glands: Produce sebum, epidermal barrier
4. Nails: Protect the tips of the fingers and toes and supports the grasping function of the fingers

Question 10

How do different burns affect the layers of the skin?

Answer 10

First-degree burn: Only epidermis affected - sunburn
Second-degree burn: Epidermis and dermis affected - note blister
Third degree burn: All 3 layers affected

Question 11

Name the 2 sensory innervation systems in the skin:

Answer 11

1. Efferent - going from the brain (autonomic), supply is from sympathetic nervous system
2. Afferent - ingoing to the brain (somatic)

Question 12

Name the 3 efferent innervations of the skin?

Answer 12

1. Blood vessels
2. Arrector pili muscle
3. Sweat glands

Question 13

What types of blood vessel functions are controlled by the efferent nerve supply?

Answer 13

Controls blood vessel diameter and hence blood flow – important for temperature control (vasoconstriction and vasodilation)

Question 14

What lifestyle factors may influence the microcirculation of the skin?

Answer 14

Physical activity, diet and smoking, together with increasing age

Question 15

Name the 3 afferent innervations of the skin:

Answer 15

1. Free nerve endings - Simplest form of sensory receptor, myelinated or unmyelinated
2. Meissner corpuscles - small, encapsulated spiral of nerve cells
3. Pacinian corpuscles - large, encapsulated mass of nerve cells

Question 16

Where are free nerve endings found and what type of sensory input do they receive?

Answer 16

1. Epidermis and dermis
2. Pain, itch, temp

Question 17

Where are meissner corpuscles found and what type of sensory input do they receive?

Answer 17

1. Dermal papillae - prevalent in sensitive areas of skin e.g. lips, fingers
2. Small & for light touch

Question 18

Where are pacinian corpuscles found and what type of sensory input do they receive?

Answer 18

1. Deep in dermis and hypodermis - particularly prevalent in fingertips
2. Pressure and vibration

Question 19

What are the 4 main functions of the skin?

Answer 19

1. Protection: against UV, mechanical, chemical and thermal insult; prevention of dehydration; barrier to microbial invasion.
2. Sensation: touch, pressure, pain, and temperature receptors
3. Thermoregulation: hairs, subcutaneous fat, sweat glands, blood vessels
4. Metabolic functions: energy storage in hypodermic fat; Vitamin D synthesis in epidermis

Question 20

What is meant by classifying the epidermal layer of skin as ‘thick’ or ‘thin’?

Answer 20

It refers only to the depth of the epidermal layer, not to the overall thickness of the skin

Question 21

Where in the body do you find thick skin? Why do you think these areas are covered in thick skin?

Answer 21

• Palms of the hands and soles and toes of the feet
• Skin is subjected to considerable frictional and shearing forces in these areas, particularly the feet with walking

Question 22

How much does skin contribute to the bodies total body mass?

Answer 22

Approximately 15-20%

Question 23

Given its vascularity, what is an important role of the dermis?

Answer 23

Important for thermoregulation - adjustments to blood circulation in order to conserve or lose heat

Question 24

What are sweat glands?

Answer 24

Simple, coiled, tubular glands, which secrete sweat onto the skin surface via ducts

Question 25

What is the function of sweat?

Answer 25

Thermoregulation - Increased sweat production leads to cooling of the skin via evaporation of sweat

Question 26

Why is there variation in the amount of adipose tissue in superficial fascia?

Answer 26

Variation due to location (e.g. fat pads in heel of foot) for shock absorption

Question 27

Is superficial fascia designed to transmit force?

Answer 27

No - mostly comprised of loose connective tissue, to allow structures to move on one another

Question 28

What are the 2 main functions of the lymphatic system?

Answer 28

1. Return excess interstitial fluid back to the venous circulation and therefore maintain fluid balance 2. Contribute to immunity (contains immune cells as part of the defense against microorganisms)

Question 29

What is fascia and what does it do? Include its main function.

Answer 29

* Connective tissue containing varying amounts of fat * Separate, support, and interconnect organs and structures * Enable movement of one structure relative to another * Transit of vessels and nerves Function: Limit the spread of infection and malignant disease. Extensive dissection – when infection crosses fascial plain

Question 30

What are the 2 categories of fascia?

Answer 30

1. Superficial fascia 2. Deep fascia

Question 31

Describe the 5 features of superficial fascia:

Answer 31

1. Also referred as the hypodermis/subcutaneous layer 2. Loose connective tissue 3. Significant layer of fat = heat insulation 4. Conveys blood vessels to and from the skin 5. Promotes movement between the skin and underlying structures e.g., dorsum of hand

Question 32

Describe the feature and 4 functions of deep fascia:

Answer 32

Dense irregular connective tissue - ensheaths muscle or viscera Functions: 1. Decreases friction 2.Divides (intermuscular septa) limbs into compartments (muscles in a compartment tend to share a common nerve and blood supply) 3. Enables venous return via ‘muscle pump’ 4. Protection

Question 33

What is compartment syndrome?

Answer 33

Increase in pressure within a defined compartment of the limb, demarcated by a fascia. ↑ intra-compartmental pressure, ↑ pressure on arteries – ↓ perfusion pressure, leading to hypoxemia of the tissues