Integumentary system

Question 1

What are the 5 roles of the integumentary system

Answer 1

1. Shield/barrier to the external environment - physical barrier as skin
2. Protects against disease and infection - Langerhans cells which digest and break down bacteria
3. Regulates body temperature - sweat which when evaporates reduces body temperature
4. Touch/sensitivity - Keratinocytes stimulate Merkel cells which generate action potential in local neurones
5. Retention of body fluids

Question 2

How does the integumentary system regulate body temperature (4)

Answer 2

1. Rise in temperature = vasodialation, sweat production - evaporation cooling effect
2. Fall in temperature = vasoconstriction, no sweat production
3. Hairs stand when cold trapping heat
4. The integumentary system also stores water to prevent dehydration.

Question 3

How does the skin protect the internal organs (4)

Answer 3

1. Skin acts as a physical barrier to bacteria protecting the internal organs.
2. there is also an active population of immune cells present in the skin.
3. Langerhans act like macrophages to digest and break down bacteria.
4. These are activated during the wound healing process and microbial and viral “invasion”. They are our first responders.

Question 4

How does the skin facilitate the sense of touch? (2)

Answer 4

1. keratinocytes in the epidermis when deformed, stimulate Merkel cells
2. Merkel cells secrete chemicals that generate an action potential in local neurones.

Question 5

How does the skin excrete products

Answer 5

Sweat glands eliminate waste by secreting excess water, salts and urea.

Question 6

What are the three major skin layers?

Answer 6

1. Epidermis
2. Dermis
3. Subcutaneous adipose layer

Question 7

What are the four layers of the epidermis, and what cells do they contain (4)?

Answer 7

1. cornified cell layer - corneocytes, specialised cells preventing water loss
2. Granular layer - melanocytes, keratinocytes
3. Squamous epithelial layer - flat and irregularly organised epithelial cells
4. Basal cell layer layer - regular-sized and shaped epithelial cells

Question 8

What cells does the epidermis contain (6)

Answer 8

1. epithelial cells
2. Melanocytes
3. Keratinocytes
4. Corneocytes
5. Merkel cells
6. Langerhans cells

Question 9

What is the dermis, and what does it contain (7)

Answer 9

1. containing fibrous, filamentous and amorphous connective tissue.
2. 2 layers: the papillary and the reticular layers.
3. 15 types of collagen
4. papillary dermis - loosely arranged collagen fibres
5. papillae that extend to the epidermis containing capillaries and corpuscles
6. Reticular dermis - dense connective tissue, collagen and elastic fibres,
7. Dermal fibroblasts - production of fibrillin, elastin and collagen generates connective tissue.

Question 10

What does the subcutaneous layer contain and what are its functions (4)

Answer 10

1. Adipose tissue made up of adipocytes
2. Storage
3. Insulation
4. Control hormones