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).
Where does a sebaceous gland excrete its sebum? What is the purpose of this?
Secaeous glands open into the hair follicle. The sebum helps the hairs from becoming dry and brittle.
What is this?
A sebaceous gland
How does sebum appear under H&E staining?
clear
From top to bottom:
Hair follicle
Arrector pili muscle
Sebaceous gland
Are eccrine sweat glands located in thick or thin skin?
Both
What classification of gland are eccrine sweat glands?
Simple coiled tubular glands
Describe the basic structure and localization of the entire eccrine sweat gland
The secretory portion is located in the deep dermis. The duct passes through the dermis taking a gental spiral course to the epidermis where the spiral tightens before opening to the suface.
What type of epithelium lines eccrine sweat glands?
Stratified cuboidal epithelium consisting of a basal and lumenal layer (just two layers).
List the 3 primary eccrine sweat gland cell types and describe their most recognizable features.
What is this?
An eccrine sweat gland
Where can apocrine glands be found?
Only in the armpit and perineum
What classification of gland is an aprocrine gland?
Coiled tubular
Describe the general structure and localization of apocrine glands
The secretory portion of apocrine glands is located in the dermis or even hypodermis. The apocrine secretory lumen is larger than that of eccrine glands but the ducts are narrow and straight and open into the hair follicle.
What do spocrine glands secrete? What mode of secretion do they undergo?
Apocrine glands secrete pheromones via merocrine secretion (exocytosis)
What type of epithelium lines apocrine glands?
Stratified cuboidal epithelium
Meissner’s Corpuscle
Pacinian corpuscle
What are the three types of encapsulated nerve endings found in the integument and what do each sense?
Are encapsulated or free nerve endings most numerous in the skin?
Free
Where do the free nerve endings of the skin usually terminate?
The Stratum Graulosum
What is a unique characteristic of the free nerve endings of the skin?
They do not possess myelin or connective tissue
What types of stimuli do the free nerve endings of the skin detect?
Multiple different stimuli are detected and without apparent morphological distinction. Most notable stimuli detected are fine touch, heat, and cold.
Why do hairs seem to detect more sensory information than the rest of the skin?
Where are pacinian corpuscles located? What do they detect? How large can they be?
Pacinian corpuscles are located in the deep dermis and hypodermis, can be more than 1mm in length, and detect pressure and vibration.
Things to know about the composition of pacinian corpuscles.
What is this?
Pacinian corpuscle
Describe the basic appearance, location, and function of Meisner’s corpuscle.
Describe the components of a Meisner’s corpuscle.
Meisner’s corpuscle
What is the simplest encapsulated nerve ending found in the skin? What does this nerve ending detect? What is this the size of this capsule?
Ruffini’s capsule is the simplest encapsulated nerve ending of the skin and is about 1-2μm in length. It is designed to detect stretch and torque.
Describe the structure of Ruffini’s corpuscle and how this structure lends to the corpuscles function.
List the defining features of first, second, and third degree sunburns.
Where on the body is thick skin found?
The palms of the hands and soles of the feet
Define a shallow skin wound and describe how it is healed.
A shallow skin wound is one that only affects the epidermis, leaving the dermis intact. It is healed by the division of the stratum basale cells and their subsequent migration across the wound gap. Once the stratum basale is reformed, normal cell migration occurs to thicken the epidermis
Define a deep skin wound and describe how its healing occurs.
- When an injury extends to tissues deep to the epidermis, the repair process is more complex than epidermal healing, and scar formation results.
- Healing occurs in 4 phases
- inflammatory phase has clot unite wound edges and WBCs arrive from dilated and more permeable blood vessels
- migratory phase begins the regrowth of epithelial cells and the formation of scar tissue by the fibroblasts
- proliferative phase is a completion of tissue formation
- maturation phase sees the scab fall off
