General Biology lab Lab 7&8 Animal Tissues

Muscle Tissue Muscle Tissue There are three type of muscle fibers tissue composed of fibers capable of contracting to effect bodily movement. There are three type of muscle fibers Skeletal or striated muscle fibers Cardiac muscle fibers Smooth or Visceral Muscle Fiber

Skeletal or striated muscle fibers They are striated and voluntary fibers attached to the skeleton forming skeletal muscles. Skeletal muscle fibers are 1mm to 40mm or more in length. Many fibers fuse together forming syncetium while their nuclei are peripheral. Myofibrils are the contractile elements of muscle fibers. They are contain actins and myosins under light microscope . They show regular alternation of light and dark band striation

Cardiac muscle fibers : They are striated and involuntary (rhythmic) fibers present only in heart muscles. Their nuclei are central. These fibers are branched and forming syncetium with intercalated discs found in-between the syncetia. Intercalated discs connect the ends of cardiac muscle fibers to one another. Have the same arrangement of actin and myosin as skeletal muscle fibers

Smooth or Visceral Muscle Fiber They are non-striated and involuntary. They exist in viscera and blood vessels. Length of these fibers range from 15 microns in blood vessels to 500 microns in pregnant uterus. The fibers are poor in blood supply compared to skeletal muscles. Long, and spindle shaped Have a single, central nucleus

Nervous Tissue Nervous tissue is responsible for sensing stimuli and transmitting signals to and from different parts of an organism. Is the basic tissue from which the nervous system They arise from ectoderm

The nerve fiber is the axon of the nerve cell. Nerve cells called neurons . The neuron consists of the cell body (Soma) axon dendrites The neurons act for impulse transmission . The nerve fiber is the axon of the nerve cell.