Tissues
What are the four types of tissue?
Epithelial, connective, muscle, and neural
Cutaneous membrane (skin) and accessory structures
What are the primary functions of the skeletal system?
Support and protection, storage of minerals and lipids, blood cell production, leverage
What comprises the matrix of bone tissue?
Calcium salts and collagen fibers
What layer of the skin are accessory structures located?
Derive from embryonic epidermis, but located in the dermis
How is epithelia classified? Explain
Classified by shape and layers
Squamous epithelia: thin and flat
Cuboidal epithelia: square shaped
Columnar epithelia: tall, slender rectangels
Simple epithelium: single layer of cells
Stratified epithelium: several layers of cells
What are the layers of the epidermis from deep to superficial?
Stratum basale (germinativum), stratum spinosus, stratum granulosum, stratum lucidus, stratum corneum
Bone contains four types of cells. What are they?
Osteocytes: mature bone cells; do not divide
Osteoblasts: immature bone cells
Osteogenic (osteoprogenitor) cells: mesenchymal stem cells that divide to produce osteoblasts
Osteoclasts: giant, multinucleate cells that dissolve bone matrix and release stored minerals
Which type of muscle is striated, multinucleate, voluntarily controlled, and does not divide?
Skeletal muscle
Describe the different types of burns and their characteristics.
First-degree burns affect only surface of epidermis (sunburn)
Second-degree burns affect entire epidermis and possibly upper dermis; accessory structures are not affected
Third-degree burns destroy epidermis and dermis, extend into hypodermis; usually cannot repair and require skin graft
Name one location you can find pseudostratified ciliated columnar epithelium.
Lining of nasal cavity, trachea, and bronchi; portions of male reproductive tract
Which type of skin cancer is the most common and why?
Which type of skin cancer is the most dangerous and why?
Basal cell carcinoma is cancer of the stratum basale and is the most common. Melanomas are caused by cancerous melanocytes and metastasize rapidly.
Compare and contrast endochondral ossification and intramembranous ossification.
Endochondral ossification is when bone replaces hyaline cartilage. Contains one primary ossification center and two secondary ossification centers.
Intramembranous (dermal) ossification occurs deep in the dermis and produces dermal bones such as mandible, clavicle, and flat bones of the skull.
Describe the flow of information through a neuron.
Information is received at the dendrite, integrated in the cell body, travels to the axon hillock, carried along the axon, and then to the axon terminal
What vitamins contribute to bone growth/maintenance?
A, B12, C, and K
Name the connective tissue proper cell types.
Fibroblasts, adipocytes, mesenchymal cells, macrophages, mast cells, lymphocytes, melanocytes
What is the relationship between epidermal cells and Vitamin D3?
Epidermal cells produce vitamin D3 (cholecalciferol) in the presence of UV radiation. The liver and kidneys convert vitamin D3 into calcitriol which aids in absorption of calcium and phosphorous by digestive system. Insufficient vitamin D3 can cause rickets.
What hormones help maintain calcium homeostasis within the body? How?
Parathyroid hormone (PTH) increases calcium levels in the body by stimulating osteoclasts, increasing intestinal absorption of calcium, and decreasing calcium excretion at kidneys.
Calcitonin decreases calcium levels in body fluids by inhibiting osteoclast activity and increasing calcium excretion at kidneys.
Calcitriol increases calcium levels by promoting calcium and phosphate ion absorption along the digestive tract.
What is bone remodeling?
Remodeling involves removing older minerals from bone matrix and releasing them into bloodstream and absorbing new minerals from bloodstream to renew bone matrix. Osteocytes remove and replace surrounding calcium salts in bone matrix. Osteoblasts build new osteons, as osteoclasts remove others.
Why do we feel pain when we break a bone?
If the periosteum did not exist, you would not have sensation in the bone; this is where nerve cells are located, which causes us to feel pain when a bone breaks
This type of cartilage is very tough and is used for padding between bones.
Fibrocartilage
Compare and contrast apocrine sweat glands and merocrine (eccrine) sweat glands.
Apocrine sweat glands are found in the armpits, around nipples, and groin. They secrete a sticky, cloudy, odorous secretion into hair follicles, but are not active until puberty.
Merocrine sweat glands are widely distributed on body surface especially on palms and soles. They discharge directly onto skin surface and produce a watery substance.
Explain bone disorders.
Gigantism is the overproduction of growth hormone before puberty.
Acromegaly is the overproduction of growth hormone after puberty; bones abnormally thick in face, jaw and hands
Osteopenia affects epiphyses, vertebrae, and jaws; results in fragile limbs, reduction in height and tooth loss
Osteoporosis occurs when significant bone mass is lost.
Heterotropic bone formation is when bones are found in abnormal locations; caused by abnormal development of osteoblasts in connective tissues under stress.
Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disease where bones form around skeletal muscles after minor injury
Name the three types of cartilage and where each is found.
Hyaline cartilage is the most common and reduces friction between bones; found in synovial joints, rib-sternum junction, trachea and nose.
Elastic cartilage contains elastic fibers and is found in external ear and epiglottis.
Fibrocartilage is used for padding between bones; found between pubic bones, intervertebral discs and around tendons.
What are the four steps of skin regeneration?
1) Inflammatory phase: blood clot/scab forms to plug up epidermis/dermis
2) Migratory phase: stratum basale cells divide rapidly to replace lost epidermal cells
3) Proliferation phase: fibroblasts and mesenchyme cells produce mobile cells that fill in lost dermis
4) Scarring phase: fibroblasts produce new collagen fibers in dermis