Histology
What is the Integumentary System?
—> It includes skin and its accessory organs
What are the types of membranes in the Integumentary System?
—> Mucous: lines cavities that open to outside and secrete mucous
ex: Oral, nasal, digestive tract, respiratory, urinary, reproductive
— > Serous: lines cavities that lack openings to the outside and secretes serous fluid which lubricates membranes
ex: Thoracic and abdominal cavities
—> Cutaneous: skin
—> Synovial: inner linings of joint cavities and secretes thick fluid to lubricate ends of bones at joints
*Skin is the largest organ of the body
What are some of the roles of the skin?
—> important for maintaining homeostasis and excreting waste (through sweat)
—> protection
What are the layers of the skin and in order from outermost to inmost?
—> Epidermis (outer)
stratified squamous tissue
—> Dermis (deeper)
Thicker with many tissues
—> Subcutaneous (loose CT & adipose that anchor skin to underlying organs)
How many layers does the Epidermis have and what are they?
—> 5 layers
—> Stratum corneum = outer most
—> Stratum basale = deepest
What are some qualities of the skin? What is it nourished by? What is it capable of?
—> Nourished by BV in dermis
—> Capable of dividing
Where are the oldest cells in the skin? What do those cells undergo?
—> near the surface
—> undergo keratinization (hardening of cells)
—> that layer of skin has melanin and gives skin its color
*there is no BV in the epidermis
What are the characteristics of the dermis?
—> binds the skin to underlying tissues
—> vascularized (lots of BV)
—> Both strong (collagenous fibers) and elastic (elastin fibers)
—> many nerve fibers- sensory and motor
—> glands and hair molecules
What are the Characteristics of the Subcutaneous layer?
—> Loose CT (connective tissue) & adipose
—> Major BV
—> insulator and regulates body temp
What are the characteristics of each degree of burn?
—> First Degree: Epidermis is damaged, redness, swelling, pain, takes 3-4 days to heal
—> Second Degree: Epidermis and upper layers of dermis damaged, blistering, pain, scarring, takes 3-4 weeks to heal
—> Third Degree: Entire thickness of skin damaged, no pain, skin grafting probably necessary for healing
What are the Accessory Organs?
—> Hair Follicles: develop from epidermal cells
—> Sebaceous glands: release oil called sebum, keeps skin soft, pliable, and waterproof
—> Nails: produced from epithelial cells
—> Sweat glands
What are the two kinds of sweat glands and what do they respond to?
—> Apocrine glands: respond to emotion, usually with a hair follicle
—> Eccrine glands: respond to body temp, not with a hair follicle
*sweat is water, salt, urea, uric acid (somewhat excretory)
What is a normal body temp?
—> 98.6 Fahrenheit (37 degrees Celsius)
What do changes and body temp affect?
—> reaction rates and can cause metabolic disorders
How does the body maintain homeostasis of body temperature?
—> When hot, eccrine glands increase activity and dermal vessels relax
—> When cold, dermal vessels constrict, and involuntary muscle contraction is stimulated
what is the difference between simple and stratified tissue?
—> Simple: an epithelium where there's only one layer of cells.
—> Stratified: Epithelium is made up of more than one layer of cells.
What is the importance of fat?
—> it gives our body energy and to support cell function. it also helps protect our organs and help keep our body warm. Fats help our body absorb some nutrients and produce important hormones, too.
—> IT PROVIDES THERMAL INSULATION FOR THE BODY
what is the function of nervous tissue?
—> helps control body function
—> rapid communication between body structures
What is different about transitional epithelial?
—> it has many layers of cells rather than one
—> it has has cubes and or flat columns
What does it mean when a muscle is striated?
—> it is made up of elongated fibers and is marked by dark and light bands
What is the difference between voluntary and involuntary muscle?
—> voluntary: conscious control
—> involuntary: not under conscious control
^ both characteristics of muscle tissue
What are the four classes (subcategories) of the Connective category of tissue?
—> Dense, Loose, Cartilage, Other: bone, blood
ex of dense: elastic
ex of loose: adipose
ex of cartilage: fibrocartilage