Show Advanced Search

REFINE YOUR SEARCH:

Containing Text
- - -
+
Filter by author or institution
GO
Filter by publication date
From:
October, 2006
Until:
Today
Filter by journal section

Filter by science education

 
 

Classification of Skeletal Muscle Fibers

JoVE 10868

Skeletal muscles continuously produce ATP to provide the energy that enables muscle contractions. Skeletal muscle fibers can be categorized as type I, type IIA, or type IIB based on differences in their contraction speed and how they produce ATP, as well as physical differences related to these factors. Most human muscles contain all three muscle fiber types, albeit in varying proportions. Type I, or slow oxidative, muscle fibers appear red due to large numbers of capillaries and high levels of myoglobin, an oxygen-storing protein. Type I muscle fibers contain more mitochondria, which produce ATP through oxidative phosphorylation, than type II fibers. Slow oxidative muscle fibers use aerobic respiration, involving oxygen and glucose, to produce ATP. In addition to contracting more slowly than type II fibers, type I fibers receive nerve signals more slowly, contract for longer periods, and are more resistant to fatigue. Type I fibers primarily store energy as fatty substances called triglycerides. Type II, or fast, muscle fibers often appear white. Relative to type I fibers, type II fibers receive nerve signals and contract more quickly, but contract for shorter periods and fatigue more quickly. Type II muscle fibers primarily store energy as ATP and creatine phosphate. Type IIA, or fast oxidative, muscle fibers primarily u

 Core: Musculoskeletal System

Tissues

JoVE 10696

Cells with similar structure and function are grouped into tissues. A group of tissues with a specialized function is called an organ. There are four main types of tissue in vertebrates: epithelial, connective, muscle, and nervous.

Epithelial tissue consists of thin sheets of cells and includes the skin and the linings of internal organs and body cavities. Epithelial cells are tightly packed, providing a barrier against injury, infection, and water loss. Epithelial tissue can be a single layer called simple epithelium, or multiple layers called stratified epithelium. In stratified epithelium, such as the skin, the outer cells—which are subject to damage—are replaced through the division of cells underneath. Epithelial cells have a variety of shapes, including squamous (flattened), cuboid, and columnar. Some epithelial tissues absorb or secrete substances, such as the lining of the intestines. Connective tissue is composed of cells within an extracellular matrix and includes loose connective tissue, fibrous connective tissue, adipose (fat) tissue, cartilage, bone, and blood. Although the characteristics of connective tissue vary greatly, their general function is to support and attach multiple tissues. For example, tendons are made of fibrous connective tissue and attach muscle to bone. Blood transports oxygen, nutrients and waste produ

 Core: Cell Structure and Function

Computer-assisted Large-scale Visualization and Quantification of Pancreatic Islet Mass, Size Distribution and Architecture

1Department of Medicine, University of Chicago, 2Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 3Department of Surgery, University of Chicago, 4Diabetes Division, University of Massachusetts

JoVE 2471

 Biology

Droplet Barcoding-Based Single Cell Transcriptomics of Adult Mammalian Tissues

1Hotchkiss Brain Institute, University of Calgary, 2Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, 3Alberta Children's Hospital Research Institute, University of Calgary, 4Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary

JoVE 58709

 Biology
12345678912
More Results...