All movement in the human body, from wiggling a toe or swimming a mile to eating and digesting a sandwich, is the result of muscle action. In previous lessons, you have learned about connective and nervous tissue. In this unit, you will explore the structure and function of another incredible tissue -- the muscle.
When we think of muscles, we usually focus on the muscles that move our bones and allow us to move about the Earth; the tissues we see from the outside. But inside the amazing human, you will find other types of muscle tissue that work silently to move substances around the body. Your heart keeps beating and your food continues to digest even when you fall fast asleep and close your conscious mind for the day. Without muscle moving blood or distributing nutrients from food, the human machine would power down.
There are 206 bones in the human body, but over 600 skeletal muscles allow our bodies to move in different directions. Over sixty of these muscles are found in your face alone. You use forty of these muscles every time you frown, but only twenty muscles when you smile. The human body is even built to make it easier to be happy than to be sad.
Skeletal muscles are attached to bones with tough cords or sheets called tendons and these bones meet other bones at junctions called joints. The contraction or shortening of muscles pulls on bone and moves the body.
In this activity, you will observe and compare the structure and function of the three types of muscle tissue. You will explore the structure of skeletal muscle both by looking at slides and by creating a model of a muscle unit. Before you move on to building actual muscle groups, a series of demonstrations will help you see that the placement of muscles on bones follows specific patterns and rules. These rules will later help you construct specific muscle groups on your Maniken®.
Part I- Types of Muscle Tissue Research the three types of muscle tissue: skeletal muscle, smooth muscle and cardiac muscle. Fill in the table below.
A form of striated muscle tissue which is under the voluntary control of the somatic nervous system. Most skeletal muscles are attached to bones by tendons.
Smooth muscle generally forms the supporting tissue of blood vessels and hollow internal organs, such as the stomach, intestine, and bladder.
Smooth muscle is involuntary not striated.
Cardiac muscle (heart muscle) is involuntary and striated.
Fill in the table below to describe what it means if a muscle is striated and what it means if a muscle is said to be under voluntary control.
Skeletal or voluntarymuscle in whichcross-striationsoccur in thefibers as a result of
regularoverlapping of thickand thinmyofilaments
Muscles are composed of two major protein filaments: a thick filament composed of the protein myosin and a thin filament composed of the protein actin. Muscle contraction occurs when these filaments slide over one another in a series of repetitive events.
Muscle whose action is normally controlled by an individual's will; mainly skeletal muscle, composed of parallel bundles of striated, multinucleate fibers.
Use information from your research to fill in the chart below. Leave the histology box blank until you begin your microscope work.
Use a microscope to view a prepared slide of each type of muscle tissue under both high and low power. Using colored pencils, draw what you see under high power in the histology column of your table. Use a reliable website to help you label what you see.