Muscle and Nervous Tissue

Muscle Tissue Functions Produces movement Maintains posture Joint stabilization Heat generation generates physical force needed to make body structures move

Characteristics: Composed of cells that have ability to shorten or contract Highly cellular Vascular Cells are long and slender (muscle fibers) Arranged in bundles or layers surrounded by connective tissue

Muscle Tissue Types Skeletal Cardiac Smooth Striated, voluntary Heart, striated, involuntary Smooth Nonstriated, involuntary Table 10.2

Skeletal Muscle Constitutes 40% of the individual’s body weight Description: Long cylindrical, striated fibers with many peripherally located nuclei, voluntary control Function: voluntary movement, posture, heat production, protects internal organs, guard entrances and exits to the digestive, respiratory, and urinary tracts Locations: combined with connective tissues and nervous tissue in skeletal muscles

Smooth Muscle Description: Spindle-shaped (thickest in middle and tapering at both ends), nonstriated fibers with one centrally located nucleus; involuntary controlled Location: Iris of the eyes and walls of hollow internal structures such as blood vessels, airways to the lungs, stomach, intestines, gallbladder, urinary bladder, and uterus

Functions: Constriction of blood vessels and airways, propulsion of foods through gastrointestinal tract, contraction of urinary bladder and gallbladder

Cardiac Muscle Description: Branched striated fibers with one or two centrally located nuclei; contains intercalated discs; involuntary control Location: Heart wall Function: Pumps blood to all parts of the body

Nervous tissue

Description: Neurons (nerve cells) consists of a cell body and processes extending from the cell body called dendrites or axons. Location: Nervous system Function: Exhibits sensitivity to various types of stimuli into nerve impulses, and conducts nerve impulses to other neurons, muscles fibers or glands