Biology 8 Lesson 41: Structure and function of the skin
1. Summary of theory
1.1. Structure of the skin
Skin is composed of:
- stratum corneum (1)
- Living Cell Layer (2)
+ The dermis:
- Consciousness (3)
- Sebaceous glands (4)
- Leg muscle contraction (5)
- Feathers and coats (6)
- Sweat glands (7)
- Nerves (8)
Subcutaneous fat layer:
- Fat layer (9)
- Blood vessels (10)
– In the dry season, we often see small white flakes that flake off like chalk on clothes → Because the outermost layer of cells turns horny and dies
– Our skin is always soft, when wet, it is waterproof → Because the connective tissue fibers are tight together and on the skin there are many sebaceous glands that secrete sebum
– We perceive hot and cold, hardness, softness of objects that we touch → Because the skin has many receptors
How does the skin react when it’s too hot or too cold? → In hot weather, blood capillaries under the skin dilate sweat glands, and in cold weather, blood capillaries under the skin contract, muscles contract and leg hairs contract.
What is the role of subcutaneous fat? → As a buffer against mechanical influence against heat loss in cold weather.
– What are the effects of hair and eyebrows? → Hair creates an air cushion to prevent ultraviolet rays, regulate temperature, eyebrows prevent sweat and water
1.2. Functions of the skin
- Body protection.
- Air conditioning.
- Energy storage.
- Creating human beauty.
2. Illustrated exercise
Lesson 1: What is the nature of feathers and nails?
A. A type of cell in the skin structure
B. Product of vesicles composed of living cell stratum
C. The receptors
D. An array of proliferative tissue
- Choose the answer: NO
- Explanation: Hair and nails are secreted by cells in the stratum corneum.
Lesson 2: What function is not performed by human skin?
B. Temperature regulation
D. Create beauty for the body
- Choose the answer: A
- Explanation: In human skin, there are no structures that perform respiratory functions like frog skin.
Lesson 3: What is the most important function of the skin? Why?
The skin has the functions of covering, protecting and contributing to the regulation of body temperature, is the sensory organ thanks to the tactile receptors (pressure, heat, cold, pain receptors), the excretory function thanks to the sweat glands. sweat and sebaceous glands.
Among the above functions, the function of protecting and regulating body temperature is the most important because the skin covers the entire body, no organs or parts can replace it. 90% of the heat released through the skin surface ensures a stable body temperature.
3.1. Essay exercises
Question 1: What is the structure of the skin? Should makeup by plucking eyebrows, using eyebrow pencil to shape? Why?
Verse 2: Describe the functions of the skin?
Question 3: What are the functions of the skin? What structural features of the skin help it perform these functions?
Verse 4: Which part of the skin is responsible for the protective and protective function of the skin?
3.2. Multiple choice exercises
Question 1: Which layer is the outermost, exposed layer in the structure of the skin?
B. The dermis
C. Lower fat layer
D. Vascular layer
Verse 2: What feature is not present in the stratum corneum of the skin?
A. Easy to peel
B. Dead cells
C. Contains pigment granules
D. Cells close together
Question 3: Pores can be retracted by the action of which part?
B. Sebaceous glands
C. Pore contraction muscle
D. Blood vessels
Verse 4: Which part does not appear in the structure of the skin?
B. Fat layer
D. Light receptor
Question 5: What is the role of subcutaneous fat?
A. Insulation class
B. A product of skin cells
C. The place where waste products from the upper layers of the skin cells are stored
D. Nourish the nerves
After completing this lesson, you should know the following requirements:
- Describe the structure of the skin.
- Analyze the relationship between structure and function.