Integumentary System Flashcards
Know all components
Integumentary System
What is it and what does it do?
Refers to the skin and underlying tissues.
Objectives:
* Protect internal tissues from the external environment (toxins, pathogens, UV rays)
* Stop fluids from leaking out
* Sensing the environment
* Help regulate body temp
Epidermis
The most superficial layer that touches air with stratified squamous epithelia.
Cells are born at the bottom near the basement membrane and then migrate out (up) throughout their life to be sluffed off.
HAS NO BLOOD VESSELS
Keratin
A protein in the cytoskeleton of all cells that provides structural support, makes the epidermis tough + water resistant (lots in epidermal cells)
Keratinocytes
The most common cells in the epidermis that are full of keratin.
They’re born by the basement membrane + move up, becoming more filled with keratin.
Dermis
Refers to the 2 layers of connective tissues under the epidermis that makes up most of the skin. Giving skin elasticity,
blood vessels to diffuse nutrients through + neurons.
Types of Dermis
- Papillary Dermis
- Reticular Dermis
Papillary Dermis
Superficial areolar tissue with lots of space between the protein fibers and blood vessels throughout to diffuse nutrients to the epidermis.
Dermal papilla
Bumps in the papillary dermis protruding up.
ex: finger prints
Reticular Dermis
Layer below papillary dermis that composes most of the dermis with dense irregular connective tissue. Their dense bundles of collagen figers going in all directions resist stretching in all directions.
Cleavage lines
Are gaps between dense bundles of collagen fibers in the reticular dermis.
Surgeons make incisions parallel to these lines:
Run along the axis of limbs
In circles around the trunk
Sensory receptors
Are located in dermis and have neurons that detect different things you feel and sends signals back to the CNS.
Sensory corpuscles
Neurons wrapped in connective tissue that sense touch and the deeper ones sense pressure
Hair follicle receptors
Receptors that are wrapped around follicles to detect movement.
Free nerve endings
The uncovered ends of neurons that touch other tissue to sense pain and temperature.
Blood vessels
Funtion as a highway to provide nutrients and O2 to cells in the dermis and epidermis, transport white blood cells, and thermoregulation.
Thermoregulation:
Too hot → move blood closer to skin
Too cold → move blood away from the skin
Hair
Also called a filament, is composed of dead epidermal cells with lots of harder keratin.
Vellus hair
Thin & pale
On bodies of: women + children, bald spots
Terminal hair
Thick, long, + colored
Located on: the head, pubic region, and on the body of adult men.
Anatomy of Hair
Medulla – Cortex – Cuticle – Follicle – Root – Shaft – Connective tissue sheath – Epithelial sheath – Bulb – Hair papilla
Melanocytes – Hair follicle receptor – Arrector Pili
Medulla
The middle of hair that gives it strength.
Cortex
Squamous cells around medulla that make up most of the hair’s diameter.
Cuticle
One layer around the cortex with overlapping cells that prevent hair from tangling.