FTM 51 - Integument 2 Flashcards
What are these two layers?
The top layer is the papillary layer of the dermis
The bottom layer is the reticular layer of the dermis
What type of connective tissues predominate in the papillary and reticular layers of the dermis?
Papillary layer - loose connective tissue
Reticular layer - dense irregular connective tissue
What layer of skin is responsible for the majority of the strength and elasticity of the skin?
Dermis
What is Meissner’s corpuscle and what layer of skin houses it?
An encapuslated nerve ending responsible for detecting light touch. It is located in the papillary layer of the dermis
Other things to know about the papillary layer of the dermis
Contains blood vessels
Predominantly Type I & III collagen fibers
Elastic fibers are threadlike and form an irregular network
What feature is often used to characterize the reticular layer of the dermis?
It is characterized by thick irregular bundles or mostly type-I collagen and courser elastic fibers
Things we need to know about the hypodermis.
What is an epithelial appendage? Provide examples
An outgrowth of the epidermis that extends into the dermis.
Hair follicle and hair
Nails
Glands
Hair follicles are found ___ times more frequently in thin versus thick skin.
Hair follicles are never found in thick skin
What are the three regions of the hair follicle?
Infundibulum
Isthmus
Inferior Segment
What contains the matrix cells for hair formation? What else is found in this structure?
The hair bulb
Melanocyte stem cells are found in the bulb as well
What is a pilosebaceous unit?
The structure consisting of hair, hair follicle, arrector pili muscle and sebaceous gland.
What is the keratogenous zone?
The region just after the matrix where keratinization of the hair and internal root sheath occur.
T/F - the root sheath follow the hair along its entire legth
False - the root sheat stops at about half the distance between the matrix and the skin surface
What separates hair from the the connective tissue of the dermis?
A thick basal lamina called the glassy membrane
What produces the color found in hair?
The melanocytes of the bulb
List and describe the 3 layers of hair
What are the primary functions of nails?
To help with grip and give protection
Describe the basic structure of nails.
Hard plates of epidermal keratinized cells resting on a nail bed consisting of nail matrix and hyponychium.
What is hyponychium?
The area of epithelium, particularly the thickened portion, underlying the free edge of the nail plate on the nail.
At what rate do nails typically grow?
1mm per week
What classification of gland is a sebaceous gland?
Simple branched acinar
Where is the secretory portion of a sebaceous gland located? What do sebaceous glands secreted and what is the mechanism of secretion?
Sebaceous glands are located in the deeper portions of the dermis and they secrete sebum in a holocrine fashion (the secretory cells rupture to release secretions).