The Muscular System An Overview of Unit 7

Muscles Composed of over 600 organs Each muscle is an individual organ

Muscle Types 3 types Differ in Skeletal Cardiac Smooth Cell structure Body location How they are stimulated to contract

Let’s make a table! Characteristic Skeletal Cardiac Smooth Body location Cell appearance and shape Regulation of contraction

Body Location Skeletal Cardiac Smooth Attached to bones or skin (in the case of facial muscles) Cardiac Walls of the heart Smooth Mostly in the walls of hollow organs, with the heart as the exception Small intestine, stomach, esophagus, blood vessels, uterus

Cell Shape and Appearance Skeletal Single, very long, cylindrical, and multinucleated cells Striations What does that mean? Striped

Cell Shape and Appearance Cardiac Branching chains of cells Gap junctions “intercalated disks” What do those look like? Uninucleated Striations

Cell Shape and Appearance Smooth Single Uninucleated No striations “fusiform” Like a seal

Voluntary vs Involuntary What does that mean?

Regulation of Contraction Skeletal Voluntary Cardiac Involuntary Smooth involuntary

Functions Produces movement Skeletal Smooth Cardiac Movement of limbs foodstuff, a baby Cardiac Blood

Functions Maintain posture Allows us to be upright Question: Which muscle type mostly does this function? Skeletal

Functions Stabilizing joints Allow for controlled movements

Functions Generating heat Question: Why do we shiver? By-product of muscular activity Question: Why do we shiver? When our body senses that we are decreasing in body temperature, a signal is sent to our skeletal muscles They begin to rapidly contract and relax This is muscular activity so heat is generated!

Worksheet #1!