Integumentary System Flashcards
Functions of Skin?
- Provides a waterproof barrier
- Sensory receptors
- Regulates body temperature
- Aids in vitamin D production
- Excretion and absorption
Skin’s two major components?
- Cutaneous membranes (epidermis and dermis)
2. Accessory structures (nails, hair, glands)
Cutaneous membrane’s principal layers?
Epidermis: the outer layer of skin, made up of stratified squamous epithelium, keratinocytes, melanocytes, Langerhans cells, Merkel cells
Dermis: deep layer of skin, made up of areolar connective tissue (in the papillary region) and dense irregular connective tissue (in the reticular region) containing collagen fibers
Hypodermis/subcutaneous layer: fat
Name the 5 layers of the epidermis from superficial to deep
- Stratum Corneum (25-30 layers of flattened dead keratinocytes)
- Stratum Lucidum (4-6 layers of flattened clear dead keratinocytes. Only in thick skin)
- Stratum Granulosum (3-5 layers of keratinocytes going through apoptosis/ cell death)
- Stratum Spinosum (Many keratinocytes in 8-10 layers, appears rounded)
- Stratum Basale (single layer of cuboidal or columnar keratinocytes)
Name the 2 regions of the dermis
Papillary Region: consists of areolar connective tissue, dermal papillae, and capillary loops
Reticular Layer: consists of dense irregular connective tissue (for strength and elasticity), and some adipose tissue, nerves, and glands
Name the accessory structures of the skin
Hair shaft, hair root, arrector pili muscle, glands (sebaceous, eccrine, apocrine), hair root plexus, hair bulb, papilla of the hair, blood vessels
What are Sudoriferous Glands and what are the two types?
Sudoriferous glands: glands that release sweat or perspiration into hair follicles or onto the skin’s surface through pores.
2 Types: Eccrine (merocrine) glands, Apocrine glands
What are Sebaceous Glands?
Oil producing glands connected to hair follicles.
Location: the secreting portion lies in the dermis and usually opens into the neck of a hair follicle
Functions: secrete sebum. keep hair from drying/ brittleness, prevent excessive evaporation, inhibit growth of some bacteria
Function of Eccrine Sweat Glands?
Helps regulate body temperature through evaporation
Location: secreting portion is in deep dermis, excretory duct projects through the dermis and epidermis and ends as a pore at the surface of the epidermis
Most dense in forehead, palms, and soles
Function of Apocrine Sweat Glands?
Secrete pheromones (body odor) from emotional sweat or sexual activity. Sweat appears milky/ yellow
Location: secretory portion is in the lower dermis of the upper subcutaneous layer and the excretory duct opens into hair follicles
Found densely in the skin of axilla, groin, areolae, and bearded regions in adult male
What are the 4 primary tissue types?
Connective, Muscle, Epithelial, Nervous
Describe muscle tissue
Function: body movement, maintain posture, generate heat, protect internal organs
Consists of fibers, (myocytes) which are elongated muscle cells that shorten to cause movement
What are the 3 types of muscle tissue?
Skeletal, Cardiac, and Smooth
Describe skeletal muscle
Location: attached to bones and skin
Function: moves bones and skin, generates heat
Appearance: striations (light/dark), muscle fibers, nuclei (myocyte), and capillaries
Describe cardiac muscle
Location: wall of the heart
Function: movement of blood throughout the cardiovascular system
Appearance: striations, intercalated disks, nuclei, branching fibers
Describe smooth muscle
Location: walls of arteries and veins, walls of bladder and urethra, intrinsic eye muscle
Function: controls blood flow and blood pressure, movement of urine through urinary tract, control pupil size
Appearance: spindle-shaped fibers, 1 nucleus per cell
Describe nervous tissue
Nervous tissue forms the brain, spinal cord, and nerves
Has two categories:
1. Neurons (receive and send information, has one or more processes, consists of dendrites and one axon)
2. Neuroglia (supports the neurons and helps them to function)
There are lots of neuroglia in one neuron cell
Describe connective tissue
Most abundant primary tissue in the body.
Extracellular matrix: fibers and ground substance synthesized/secreted by connective tissue cells
Ground substance: fluid, semi-fluid, gelatinous, or hard substance that CT cells secrete into the ECM
Function: depends on the properties of the ECM components
5 Categories: Loose, dense, cartilage, bone, blood
Describe areolar connective tissue (loose CT)
Contains fibroblasts, all 3 fiber types (collagen, elastic, reticular), semi-fluid ground substance, and many cells involved in bodily defenses
Location: Beneath all epithelial tissues, subcutaneous layer, and papillary layer
Function: strength, elasticity, support, nutrient diffusion
Appearance: Clearly can see collagen, elastic, and reticular fibers, a few mast cells and granules
Describe adipose connective tissue (loose CT)
Contains adipocytes derived from fibroblasts, has very little ECM
Location: subcutaneous layer of skin, around heart and kidneys, yellow bone marrow, padding around joints, behind eyeball
Function: stores lipid for fuel, thermal insulation, cushions organs and joints and endocrine.
Appearance: White circles with pink borders, nuclei around the borders
Describe dense regular connective tissue (dense CT)
Little ground substance and few fibroblasts.
Location: ligaments, tendons, aponeuroses
Function: Strong attachment between various structures, withstands tension along long axis of fibers
Appearance: Extracellular matrix is filled with parallel bundles of collagen fibers. Looks like compact ocean waves
Describe dense irregular connective tissue (dense CT)
Made up of collagen fibers, usually irregularly arranged with few fibroblasts and little ground substance
Location: reticular region of dermis, fibrous pericardium, periosteum of bone, perichondrium of cartilage, joint capsules, membrane capsules around various organs (kidney, liver, testes, lymph nodes), heart valves
Function: resist pulling forces in MULTIPLE directions
Appearance: Looks like marbled meat
Describe hyaline cartilage connective tissue (cartilage CT)
Most abundant cartilage in the body. Ground substance is a resilient gel, also contains fine collagen fibers, and chondrocytes inside lacunae
Location: ends of long bones, anterior ends of ribs, nose, parts of larynx, trachea, bronchi, embryonic, and fetal skeleton
Function: provides smooth surfaces for joint movement, flexibility, and support
Appearance: looks like a sponge due to the lacunae
Describe fibrocartilage connective tissue (cartilage CT)
Less abundant cartilage than hyaline. Strongest cartilage. Contains fewer lacunae and chondrocytes. ECM is packed with thick collagen fibers to give tension strength.
Location: pubic symphysis, intervertebral discs, menisci of knee, portions of tendons that insert into cartilage
Function: support and joining structures together, strength and rigidity (strongest type of cartilage)
Appearance:
