Muscular System

3 Types of Muscle

1. Cardiac- Found in heart- involuntary and striated

2. Smooth- Found in bladder- involuntary and striated

3. Skeletal- Found attached to bone by tendon- voluntary and non striated

Function of Muscular System

Flexibility and movement

Fasciles

Bundles of skeletal fibers grouped together and surrounded by connective tissue

Myofibril

A long filamentous organelle found within muscle cells that is responsible for muscle contraction.

Sacromeres

The basic unit of a muscle’s cross striated myofibril and the site of a muscle contraction, composed of long, fibrous proteins.

Actin

A protein that forms (together with myosin) the contractive filaments of muscle cells and is also involved in motion with other types of cells.

Myosin

A fibrous protein that forms (with actin) the contractive filaments of muscle cells; also involved in cellular transport

T-Tubules

Extensions of the cell membrane that penetrate into the center of skeletal and cardiac muscle cells, helps transmits the signal to contract.

Ischemic

Relating to or characterized by the restriction of blood supply to tissues, causing a shortage of oxygen and glucose needed for cellular metabolism.

Soma

The cell body of a neuron, containing nucleus and cytoplasm

Dendrites

The branched projections of neurons that act to conduct the electrochemical stimulation from other neural cells to the cell body or soma.

Axon

The long, slender projection of a nerve cell or neuron that typically conducts electrical impulses away from the cell body.

Action Potentials

Short lasting events in which the electrical membrane potential of a cell rapidly rises and falls, constituting the signal that passes along the axon of a neuron

Polarization

The state of a cell membrane when the outside is positively charged compared to the inside, which is key in the generation of action potentials.

Myelin

A fatty white substance that surrounds the axon of some nerve cells, forming an electrically insulating layer and is essential for the proper functioning of a nervous system.

Multiple Sclerosis

A disease in which the immune system eats away at protective covering of nerves (myelin), disrupting communication between the brain and the rest of the body.

Synapse

The junction between neurons or a neuron and a muscle cell, where nerve impulses pass by a diffusion of neuro transmitters

Neurotransmitters

Chemicals that transmit signals across a synapse from one neuron to another “target” neuron, muscle, cell, or gland cell.

Neuromuscular Junction

A synapse between a motor neuron and skeletal muscle, allowing the neuron to transmit a signal to the muscle and provide movement.

Acetylcholine

A neurotransmitter in the nervous system, particularly at neuromuscular junction, involved in muscle activation and other functions.

Motor Unit

A single motor neuron and all the fibers it innervates, functioning as a single unit in muscle contraction.

Atrophy

The wasting away or decrease in size of an organ or tissue in the body, often due to disease or lack of use

Muscle Fatigue

The decline in ability of a muscle to generate force, often experienced after prolonged activity or stress.

Lactic Acid

A substance found in the muscles during intense activity, often associated with muscle fatigue and soreness

Muscle Strain

An injury to a muscle or tendon, often results for overuse, force, or stretching.