The Integumentary System Flashcards
Topmost layer of skin
Epidermis
What kind of tissue makes the epidermis?
Epithelial tissue.
Epithelial tissues are avascular.
It is a protective layer
Basement membrane
Barrier between epidermis and dermis.
Dermis
Underneath epidermis
Holds blood vessels because epidermis is epithelial and avascular
Holds hair follicles.
Hypodermis
Below the dermis
Region underneath the skin that provides cushioning, thermoregulation and some storage for adipose tissue. Adipose tissue provides cushioning.
Parts of cutaneous membrane
Epidermis and dermis
Cutaneous membrane=skin
Parts of dermis
- Superficial 20% called papillary dermis. Made of mostly loose areolar connective tissue.holds things that help protect if dermis is breached.
-mast cells: initiate inflammatory response. Helps bring WBCs. Release histamine release heparin. Help mediate inflammation response.
-Macrophages
-fibroblasts:help lay down collagen, elastic fibers, new reticular fibers. Help hold damaged area together. - Bottom 80% of dermis:
Very strong. Made of mostly dense irregular connective tissue. Fibers overlap in multiple directions. Called reticular dermis .
Creates tension lines (tension lines are general direction that collagen fibers go) if cut is parallel to tension lines, then the wound will close up reapproximate. If you cut perpendicular to tension lines, the wound gapes.
Surgeons try to cut parallel to tension lines.
Top of dermis has
Dermal papillae: holds sensory nerve endings. Has loose areolar connective tissue
Epidermal derivatives
-hair follicles
-sebaceous glands
-sweat glands
-nails
When dermis and epidermis is damaged
The progenitor stem cells can divide and regrow epidermis
Third degree burn
Below follicles. Burns all the way through dermis below follicles. No more progenitor stem cells left. Situation where you could need a skin graft
Arrector pili muscles
Involuntary muscle, cause goosebumps, causes hair to stand on end
Activated by sympathetic nervous system.
Might help pump sebum onto skin
Sebaceous glands
Attached to hair follicles,
Holocrine glands. (Glandular cells inside are constantly dividing) Glandular cells inside form sebum
Sebum
Lipid protein rich substance. Keeps epidermis and hair healthy.
Sensory nerve endings
Feel temperature and pain
Hair follicle plexus
Innervated structure that connects to hair follicle.
When you pull hair out, it hurts.
Assists skin with perception of touch. When hair glides across a surface, you feel that as perception of touch.
Tactile sensors
Receptors for light touch. In papillary dermis.
Meissner’s corpuscules
Receptors for light touch
Small specialized sensory receptors.
Let you sense textural differences.
Sit in dermal papillae
Lamellar or pacinian corpuscules
Sense deep vibration in skin and various organs like pancreas and urinary bladder.
Ruffini corpuscule
Senses skin stretching movement and finger position.
Merkel cells
In epidermis, modified epidermal cells. Receive touch info.
Eccrine glands
Merocrine glands
Merely secrete.
None of the cell breaks down and becomes part of the secretion. Mostly water. Active during sweating. Water, electrolytes, vitamin c and bit of nitrogenous waste. Important in homeostasis of body temperature.
What mechanism controls body temperature
Negative feedback loop.
Hypothalamus senses that you’re too warm, sweat glands are activated. Sweat evaporates from skin releasing heat.
What kind of blood vessels are in dermal papillae
Fine capillaries