Dermis And Hypodermis Flashcards
What is the dermis?
The middle layer of skin containing collagen, blood vessels, glands, hair follicles, and nerve endings.
Supports and protects the skin and deeper layers, assists in thermoregulation, and aids in sensation.
What is the hypodermis?
The innermost layer of skin, storing energy and connecting the dermis to muscles and bones.
Insulates the body and protects it from harm.
What are dermal papillae?
Protrusions of dermal connective tissue into the epidermal layer.
What do melanocytes produce?
Melanin, which is a skin pigment.
What are sebaceous glands?
Microscopic exocrine glands in the skin that secrete an oily or waxy matter called sebum.
What are sudiferous glands?
Sweat glands found in the dermis that transport secretion to the surface of the epidermis or into a hair follicle.
What are eccrine glands?
Sweat glands that are the most numerous and widely distributed over the body.
Fill in the blank: The dermis connects to the epidermis by means of _____ structures called dermal papillae.
wavy
List three accessory structures contained in the dermis.
- Hair follicles
- Arrector pili muscles
- Sweat glands
True or False: The dermis is the outermost layer of the skin.
False
What is the primary function of the hypodermis?
To store energy and insulate the body.
What is the dermis?
The middle layer of the integument consisting of loose connective tissue
The dermis houses a number of accessory structures of the skin.
What structures connect the dermis to the epidermis?
Wavy structures called dermal papillae
Name three accessory structures found in the dermis.
- Hair follicles
- Sweat glands
- Sebaceous glands
How many hairs does the human body have approximately?
About 2.5 million
Where is hair not found on the human body?
- Palms of the hands
- Soles of the feet
- Lips
- Parts of the external genitalia
- Sides of the feet and fingers
What are the main components that make up hair?
- Keratin for hardness
- Melanin for color
What is the function of the arrector pili muscle?
To move each hair follicle causing it to stand up during sympathetic nervous system activity
Where does hair growth begin?
At the base of the hair follicle in a structure called the hair bulb
What is the hair papilla?
A structure that surrounds the hair bulb containing blood vessels and nerves
What is the average rate of hair growth per day?
About 0.33 mm per day
How many hairs do normal adults lose per day?
About 50 hairs
What condition results in a net loss of hair?
Loss of over 100 hairs per day
What are the two types of hair?
- Vellus hairs
- Terminal hairs
What is sebum?
An oily substance secreted by sebaceous glands
What triggers the secretion of sebum?
Contraction of the arrector pili muscle
What are the components of sebum?
- Triglyceride
- Protein
- Cholesterol
- Some electrolytes
What are the two types of sweat glands?
- Apocrine sweat glands
- Eccrine sweat glands
True or False: Apocrine sweat glands secrete their substances into the hair follicles.
True
What are the two types of sweat glands?
Apocrine sweat glands and eccrine sweat glands
Apocrine glands secrete into hair follicles, while eccrine glands secrete directly onto the skin surface.
Where are apocrine sweat glands primarily located?
In the axilla and genital regions
Apocrine glands begin to secrete substances at puberty.
What can cause odor from apocrine sweat glands?
The secretion acts as a nutrient for bacteria
Bacteria enhance the odor from the secretions.
What is the primary function of eccrine sweat glands?
To help regulate body temperature
Eccrine sweat glands secrete mostly water with trace electrolytes and a peptide with antibiotic properties.
What does the sweat produced by eccrine glands consist of?
Water, trace electrolytes, and a peptide with antibiotic properties
The primary function is to regulate body temperature through evaporation.
What is the visible portion of the nail called?
Nail body
The nail body sits over the nail bed.
Where does nail growth begin?
At the nail root
The nail root is close to the bone.
What forms the cuticle of the nail?
Eponychium
A portion of the superficial epidermis (stratum corneum) extends over the proximal portion of the nail.
What role does the skin play in temperature regulation?
It helps keep in heat and facilitates heat loss through sweat
The skin opens sweat pores when the body gets too hot.
How does heat move from the body to the surrounding areas?
Heat moves along a gradient from warmer to cooler temperatures
Heat can radiate, conduct, convect, or evaporate.
What is conduction in the context of heat loss?
Heat moves via molecules from the warmer body to cooler objects
An example is leaning against a cooler concrete wall.
What is convection in heat loss?
Heat moves via air molecules circulating around the body
This process helps cool the body down.
What is the role of the hypothalamus in body temperature regulation?
It sets and controls the body’s temperature
The hypothalamus opens and closes sweat glands and controls muscle contractions.
What happens when the body’s temperature rises?
The hypothalamus sends a message to open sweat glands
Sweat evaporates to cool the body down.
What may the hypothalamus signal when the body’s temperature drops?
To close sweat glands and contract muscles
This generates heat to help maintain core temperature.
