Musculoskeletal and Cellular Adaptations

Differentiation

The outcome of Determination in which a Stem Cell or some other cell will change and specialize into a specific cell type with a specific function (i.e. Osteocytes --> Osteoblasts)

Determination

The process a cell uses that involves gene activation and expression to changing from one cell type to the other during differentiation.

Differentiation Potential

The ability of a cell to change or differentiate into other types.

Totipotent Stem Cell

An embryonic cell found right after fertilization that has total or complete potential to turn into any and all cells found within your body.

Pluripotent Stem Cell

An embryonic cell that has the ability to differentiate into all cells except the placenta and some sex cells.

Multipotent Stem Cell

A stem cell that can differentiate into multiple cell types but is limited to a certain lineage of cells (i.e. blood cells)

Unipotent Stem Cell

A Stem cell that can change into one type of cell when signaled to do so.

Gene Activation

The turning on of specific genes by proteins known as Transcription Factors. This results in certain protein products being made.

Gene Expression

The outcome of gene activation. The evidence of a specific protein being made and carrying out its function

Transcription Factors

Proteins that act like "switches" that turn on and off genes during gene activation. They influence which genes are used.

Gene

A segment of DNA that acts as a "recipe" for a specific protein within your DNA.

Cellular Adaptation occurs because a cell or tissue is trying to

Avoid injury or death

Hyperplasia

Cell Adaptation that is an increase in cell number resulting in growth of the tissue. Occurs regularly in some tissues such as the intestines and skin. Another name for mitosis.

Hypertrophy

An increase the size of a cell and its functional parts (i.e. mitochondria, ER, etc.) that can result in an increase in organ size and function.

Atrophy

A decrease in cell size and functional parts often time associated with disuse.

Metaplasia

Cellular response to an injurious stimulus in which the normal cell tissue will differentiate into another cell type that is better suited to handle the stress or stimulus. Can lead to dysplasia if the injurious stimulus is not removed.

Dysplasia

An abnormal form of hyperplasia. Not a true cell adaptation, but often the result of an injurious stimulus that causes the tissue to lose control of cell reproduction, growth, and tissue boundaried. Often found in cancerous tissue.

Hematopoeisis

The creation of blood cells that occurs in the marrow of long bones.

The purpose of the Skeletal System is to

Provide Structural support, provide attachments for muscles to create movement, protection of vital organs, storage of minerals and other growth factors.

Cortical Bone (Compact)

Bone tissue that contributes the strength of bone by resisting bending forces

Trabecular Bone (Spongy)

Bone tissue that contributes the strength of bone by resisting compressive forces

Bone Modeling is

The process of increasing bone density via the action of Osteoblasts without Osteoclast activity

Bone Remodeling is

The process of optimizing bone tissue involving the activity of both Osteoclasts and Osteoblasts.

Osteoblasts

Bone cells that rebuild and lay down new bone tissue

Osteoclasts

Bone cells that break down bone tissue for resorption of the materials

Osteoporosis

Degenerative bone disease in which a person has weak brittle bones.

Variables that impact the activity of Osteoblasts and in turn Bone Density

Age, Activity level

Variables that impact the activity of Osteoclasts and in turn Bone Density

SAD (Acidifying), Activity level, Decreased Sex Hormones, Cortisol, Medications, Parathyroid Hormone, Amount of OPG or Rank Ligand

A skeletal muscle is composed of

Muscle fiber bundles, which are made up of groups of muscle fibers, which are made up of groups of myofibrils, which are made up of the contractile fibers Actin and Myosin

A neuromuscular junction is

where a neuron and a muscle fiber meet.

A synapse is

the small space between a neuron and its target tissue in which neurotransmitters must cross to send a signal.

A neurotransmitter is

A compound use to communicate within the nervous system. All NT have a specific receptor on the target tissue much like hormones.

Sarcoplasmic reticulum

Calcium is stored in the ________ of muscle fibers

Calcium is important to muscle contraction because it

interacts with its receptor Troponin and causes Tropomyosin to move exposing binding sites on the actin fiber that the myosin bulbs attach to during a contraction.

Troponin is

the Calcium ion receptor found on actin fibers

Tropomyosin is

the long, ribbon-like protein found on actin fibers that covers the bindings sites for Myosin.

ATP is necessary to make Myosin

Extend, attach to actin, generate a power stroke, and release for another contraction or relaxation.

A cascade in biology refers to

A series of events or chemical reactions that occur in a step-wise manner where each step contributes to the next.

The two skeletal muscle types

Type I (Slow twitch) and Type II (Fast twitch)

The two subtypes of Type II fibers

Type IIa and IIb (IIX)

Type I muscle fibers

Muscle fibers that are aerobic in nature and do not fatigue easily

Type IIa

Category of Fast twitch muscle fibers that have both aerobic and anaerobic capacity.

Type IIb (now referred to as IIX)

Category of Fast twitch muscle fibers that are extremely anaerobic, capable of generating a lot of contractile power, but fatigue quickly

To proliferate

Increase in number (i.e. reproduce in this context)

Plasticity

term used to describe a cell's ability to differentiate back and forth between cell types.