The integumentary system consists of the skin and its appendages, including hair, nails, and glands
Functions of the integumentary system:
Sensation
Heat regulation
Absorption
Protection
Excretion
Storage of fats
Frictionblisters are caused by continuous rubbing or pressure on the skin, usually occurring on the feet
Corns and calluses are hard, painful areas of skin that develop in response to pressure or friction, often on the feet
The dermis has two main layers:
Papillary layer: made of loose, areolar connective tissue and projects into the epidermis
Reticular layer: consists of dense, irregular connective tissue and is well vascularized with a rich sensory and sympathetic nerve supply
Arterio-venous anastomoses (AVAs) are direct connections between small arteries and small veins, aiding in heat transport from the body core to surface areas. They regulate blood pressure, blood flow, and temperature and conservation of body heat
Peripheral cyanosis is a bluish discoloration of the hands or feet due to low oxygen levels in the blood
Jaundice is characterized by yellowing of the skin and eyes due to excess bilirubin in the blood
Erythema is redness of the skin or mucous membranes caused by increased superficial capillaries' blood flow(hyperemia), often seen with skin injury, infection, or inflammation
Selected disorders of the integumentary system include:
Albinism: inability to produce melanin
Vitiligo: melanocyte in certain aeas lose the ability to produce melanin
Stretch marks: occur when skin is stretched
Melanoma: cancer that develops from the melanocyte
Wounds can be classified as open or closed:
Closed wounds do not break the skin's surface, like bruises
Open wounds involve a break in the skin, caused by various objects or trauma
Closed wounds can include:
Contusions (bruises)
Hematomas
Seroma
Crushinjuries
Wound healing is a complex process involving four phases: Hemostasis, Inflammation, Proliferation, and Maturation
Types of Human Hair:
Lanugo: Fine, downy, unpigmented hair that appears on the fetus in the last three months of development
Vellus: Fine, pale hair that replaces lanugo by the time of birth, making up two-thirds of women's hair and one-tenth of men's hair
Terminal: Longer, coarser, and more heavily pigmented hair located in eyebrows, eyelashes, scalp, and forms axillary and pubic hair after puberty
Alopecia areata:
An autoimmune disease with non-scarring hair loss in single or multiple areas of the scalp, face, or body
Includes alopecia totalis (complete loss of hair on the scalp) and alopecia universalis (loss of hair in the entire body)
Hirsutism:
Excessive body hair in men and women on parts of the body where hair is normally absent or minimal, such as on the chin, chest, face, or body
Nails:
Horny covering protecting the upper surface of the tip of the finger and toe in humans and other primates
Cutaneous Sensory Receptors:
Meissner's corpuscle: detect light motion against the skin, detect deep pressure, high-frequency vibration
Ruffini corpuscle: detect deep pressure, stretch
Free nerve endings: integrated with sensations including pain, heat, cold, and touch
Merkel cells: function as receptors for sustained light touch and sensing an object's texture
Krauseendbulbs: found primarily in the skin of penis and clit where they sense low freq vib.
Glands:
Sebaceous Glands: secrete oily or waxy matter called sebum to lubricate and waterproof the skin and hair
Ceruminous Glands: specialized sweat glands located in the external auditory canal
Mammary Gland: enlarged and modified sweat glands characteristic of mammals, functional in women during childbearing years
Sudoriferous/Sweat Glands:
Eccrine Sweat Glands: distributed all over the body, discharge secretions directly to the skin surface to regulatebodytemperature
Apocrine Sweat Glands: found in armpits, produce viscous secretion that ends in hair follicle canals after puberty
Key Clinical Terms:
Acne: long-term skin disease caused by clogged hair follicles with dead skin cells and oil, characterized by blackheads, whiteheads, pimples, oily skin, and possible scarring
Athlete's Foot: fungal infection that usually begins between the toes, causing itching, stinging, and burning
Boil: localized skin infection starting in a hair follicle or oil gland, characterized by reddening, tender lump, and presence of pus
Decubitus Ulcer: pressure ulcer, bedsore, open wound on the skin from continual pressure
Wart: small growth with a rough texture caused by viruses in the humanpapillomavirus (HPV) family
Cells of the Epidermis
stem cells
keratinocytes
melanocytes
tactile cells
dendritic cells
langerhans cells
merkel cells
Stem cells
give rise to keratinocytes
found in the deepest layer of epidermis
Keratinocytes
make up majority of epidermal cells and synthesize keratin
Melanocytes
only found in the deepest layer and synthesize melanin
Tactile cells
found in the deepest layer and have touch receptors associated with nerve fibers
Dendritic cells
macrophage like and igrated from bone marrow
guard against pathogens
Langerhans cells
recognize, phagocytose, and process foreign antigens and then present them to T lymphocytes for an immune response.
Merkel cells
found in the stratum basale
most abundant in the fingertips
function as mechanoreceptors for cutaneous sensation
Open wounds classification
abrasion
laceration
avulsion
incision
puncture
amputation
Abrasion
superficial wounds in which the uppermost layer of the skin is scrapedoff
Laceration
irregular tear like wounds caused by some blunt trauma
Avulsion
an injury in which a body part is torn off due to either trauma or surgery
Incision
A wound caused by a clean, sharp-edged object such as a knife, a razor or a glass splinter.
Puncture
caused by an object puncturing the skin such as a nail or needle
Amputation
refer to the removal of a limb due to trauma, medical illness, or surgery
Stages of hair growth
Anagen (growing phase)
Catagen (transition phase)
Telegen (resting phase)
Exogen (shedding phase)
Nail disorders
Beau's lines
Clubbing
Koilonychia
Leukonychia
Beau's lines
refer to depressions that run across fingernail which can be a sign of malnourishment and other conditions
Clubbing
Thickening and curving of nail around fingertips, which can be the result of low oxygen in the blood and is associated with cardiovascular diseases, inflammatory bowel disease, liver disease and others
Koilonychia
condition where fingernails have raised ridges and scoop outward, like spoons.
it can be a sign of iron deficiency anemia, heart disease and other medical condition.