Skin Flashcards
Function of the skin is…
(1) Protection, (2) Waterproof (hydroregulation), (3) Temperature Regulation [radiation/perspiration or constriction of vessels], (4) Secretion [sweat, sebum/oil], (5) Selective Absorption, (6) Sensory Reception
Integumentary System consists of…
Skin, glands, hair, nails, associated blood vessels, associated nerves
Skin layers are…
Epidermis, dermis, hypodermis
Cell type in the epidermis
4-5 layers of stratified squamous epithelium
Thick skin consists of ____ layers of epidermis; thin has ____ layers.
Thick = 5 layers of epidermis; thin = 4 layers of epidermis.
Stratum Basale is also known as stratum ______
Stratum Basale = Stratum Germinativum
The stratum basale (germinativum) is a single layer of _____ cells resting on ______ membrane
Stratum germinativum = single layer of cuboidal cells resting on basement membrane.
Stratum germinativum cells are constantly dividing via meiosis or mitosis?
Stratum germinativum cells divide constantly via mitosis.
Superficial 3-4 layers of epidermis consist of cells that gradually do 3 things…
(1) gradually dehydrate, (2) die, (3) become keritinized (inclusion of keratin as cells die; filled with keratin). Top layer sloughs off with friction. Top layer varies a lot in thickness.
3 cell types in the epidermis
(1) Keratinocytes, (2) Melanocytes, (3) Tactile Cells (Merkel Cells)
Keratinocytes represent ___% of epidermal cells, are found in ____ layers of epidermis, and produce ______.
Keratinocytes: 90% of epidermal cells (most numerous); found in ALL layers of epidermis, and produce keratin
Melanocytes represent ____ % of epidermal cells. These cells are found in the ______, and they produce _____.
Melanocytes: ~8% of epidermal cells; found in stratum basale; produce melanin.
People with different skin colors differ in the (A) number of melanocytes or (B) the level of activity of melanocytes?
(B) The # of melanocytes does NOT vary across people of different skin colors; only the level of ACTIVITY of melanocytes differs
Heat is lost through the skin via…
Radiation and/or perspiration
Heat is conserved in the body by…
Constriction of blood vessels
Tactile Cells are also referred to as…
Merkel Cells
Tactile cells are found in the _____.
Stratum basale
For the most part, the epidermis is with or without sensation?
The epidermis is mostly WITHOUT sensation.
The dermis is the _____ layer of the integument and consists of _____, ______ connective tissue.
Dermis = middle layer of integument. Consists of dense, irregular connective tissue.
The dermis contains…
Dermis contains many blood vessels; contains nerve endings, hair follicles, glands, and dermal papillae (projections of dermal tissue into the epidermis)
What are dermal papillae?
Projections of dermal tissue into the epidermis
What are the layers of the dermis?
Papillary layer and reticular layer
The Papillary layer of the dermis is the most ____ layer, has papillae, and is the layer that creates the ____.
Papillary layer - most superficial layer of dermis, has papillae, and creates the fingerprint (epidermis follows the papillary layer indentations)
The reticular layer of the dermis is ____ to the papillary layer, contains A, B, and C, and is [thinner/thicker] in thick skin.
Reticular layer - deep to the papillary layer, contains (A) sweat glands, (B) sebaceous glands, (C) hair follicles, and is THICKER in thick skin.
Other structures found in the dermis include…
Blood vessels (arterioles and venules), lymphatics, sensory receptors, and nerve fibers (sympathetic and somatic sensory)
Epidermal derivatives (developmentally) include…
Hair, nails, and exocrine glands (sebaceous and sweat glands)
Hair consists of three parts:
Bulb, root, and shaft
The function of hair is:
Protection
The arrector pili muscle is associated with the ____ of hair and is innervated by a _____ neuron
Arrector pili: associated with the ROOT of hair and has SYMPATHETIC innervation
Exocrine glands are found in the ______.
Dermis
Two types of exocrine glands are:
Sebaceous (oil glands) and sweat glands
Sebaceous (oil) glands are associated with _______, secrete ______, and functions in _____ and _____.
Sebaceous glands: associated with hair follicles, secrete sebum (oil), and functions in lubrication and waterproofing.
Sweat glands are innervated by the _____ nervous system.
Sweat glands = Sympathetic
The hypodermis is the ____ layer of the integument and is also known as the _____.
Deepest layer, AKA epimysium. This is a subcutaneous layer.
The hypodermis consists of ______ tissue and _____ tissue.
Hypodermis consists of loose connective tissue and adipose tissue.
The deep fascia consists of _____ connective tissue covering _____. It is also known as the _____.
Deep fascia = dense connective tissue covering muscles; AKA epimysium
What does the lymphatic system do?
Lymphatic system drains, filters, and recirculates extracellular fluid.
Tiny lymph vessels are found ______ and collect ______.
Throughout the body & collect extracellular fluid.
As lymph fluid is drained into the thorax, it passes through ______ which contain _____, immune cells that monitor to see if there are any _____ in the lymph fluid.
Lymph fluid passes through LYMPH NODES which contain LYMPHATOCYTES that monitor for antigens in lymph fluid. They mount an immune response and send antibodies if they find antigens
Lymph fluid is recycled in _____.
Venous blood
Partial thickness burn results in loss of ____.
Epidermis and/or portion of dermis
Full thickness burn results in loss of ____.
Total disruption of epidermis and dermis - may involve deeper structures to bone
First degree burns affect ____. Burn site is _____.
Epidermis. Burn site is red, painful, NO blisters. E.g. mild sunburn. Long term tissue damage may be skin coloration (darker or lighter)
Second degree burns affect ____. Burn site is ___.
Epidermis and part of dermal layer. Red, blistered, swollen, painful.
Third degree burns affect ____.
Epidermis, dermis, and potentially deeper (may damage underlying, bones, muscles, or tendons).
Third degree burn sites appear ______. There is ______ sensation in the area because ____.
Appear white and charred. There is NO sensation in the area because nerve endings have been destroyed.
Tendons connect ___ to ___.
Muscle to bone.
Most tendons are _____ in shape, but some are flat and broad, known as _____.
Most tendons are thick and round, but some are flat and broad = aponeurosis.
Ligaments connect ____ to ____. Their function is to _____.
Bone to bone. Function: support/add stability to the joint.
Two types of fascia are considered connective tissue: ___ and ___. Other fascia are found around _____.
Superficial and deep fascia are connective tissues. Other fascia are found around neurovascular bundles.
If you cut your finger and you do NOT bleed, what layer(s) of skin did you cut? Why aren’t you bleeding?
Cut only epidermis - it is AVASCULAR. Blood that gets to living cells (i.e. stratum germanitivum) gets there via effusion.
Is the epidermis innervated? If so, which layers?
Yes - basal layer has some receptors and nervous innervation, but other layers do NOT.
Is the dermis innervated?
YES
If you cut your finger and you have pain AND blood, what layer(s) of skin did you cut?
Epidermis AND dermis. Epidermis is AVASCULAR, so you must have cut into the vascularized dermis. Epidermis has some innervation, but the dermis is HIGHLY innervated - a cut there would definitely induce pain.
____, ____, and ____ originate in the dermis and pass through the epidermis.
Sweat glands, sebaceous glands, and hair
A dermatome is _____.
Dermatome = area of skin innervated by a single spinal cord segment.
A myotome is _____.
Myotome = a group of muscle fibers innervated by a single spinal cord segment. Note: Fibers do not have to be from the same muscle!
Muscles, bones, and dermis develop from ____.
Somites
Somites form from ______ on the _____ surface of the embryo.
Somites form from MESODERM on the DORSUM of the embryo.
By week 5 of development, there are ___-___ pairs of somites.
42-44 pairs of somite pairs by week 5
List the 5th week of development somite pairs.
4 occipital; 8 cervical; 12 thoracic; 5 lumbar; 5 sacral; 8-10 coccygeal (5-7 of these disappear)
By beginning of week 4, cells of somite most ____ and ____ migrate _____ (direction) to develop into _______.
Cells of somite most VENTRAL and MEDIAL migrate MEDIALLY to develop into VERTEBRAE (sclerotome)
Remainder of somite (after differentiation into vertebrae) differentiates into ______ and _______.
Dermatome (forms dermis) and myotome (forms muscle).
Each somite develops into ____, ____, and ____.
Bone, muscle, and part of skin (ie. dermis).
Limb muscles begin to develop around week ___ and appear near the ____ of the limb bud.
Week seven, appear near base of limb bud.
Limb muscles are derived from ____.
Myotome
Cells from the ____ and _____ migrate into the limb bud in a ____ fashion.
Myotome and dermatome cells migrate into limb bud in a segmental fashion.
Each myotome is innervated by ____ spinal segment(s).
Myotome innervated by a SINGLE spinal segment.
As limb bud lengthens, myotomes divide into ___ and ____ groups. They loose their segmentation and fuse, so individual muscles in the limb are derived from _____ somite(s).
Myotomes divide into FLEXOR and EXTENSOR groups. Segmentations are lost as the myotomes fuse, so individual muscles are derived from MORE THAN ONE somite.
The biceps are comprised of myotomal fibers from ____ and ____.
Biceps = myotomal fibers from C5 & C6.
Muscle fibers derived from the SAME myotome function to produce [the same/opposing] muscle action(s).
Same myotome = tend to produce SAME action (e.g. C5, C6 elbow flexion)
Each ______ is associated with the same spinal nerve and innervate the same patch of ____.
Dermatome; innervate same patch of SKIN
Dermatomes that migrate into the limb bud eventually lose their physical skin-connection with the axial portion as the limb bud lengthens, but they retain their ______.
Segmental innervation
Dermatomal pattern of ____ and myotomal pattern of _____ can indicate spinal cord or nerve root pathology.
Dermatomal = sensory loss, myotomal = weakness
Embryo develops with three layers: ___, ___, and ____.
Ectoderm (outer), mesoderm (middle), and endoderm (inner)
