Montessori Biology

The Muscular System: Free Educational Worksheets for K-12 Students

Quick lesson and free printable/live worksheets on the muscular system for learners from kindergarten up. Includes the types of muscles, how muscles work, and possible muscle injuries.

Contents:

Muscular System: Quick Facts
Worksheets
- Introduction to The Muscular System: Live Worksheet for Kindergarten to Grade 2
- Types of Muscles: Muscular System Live Worksheet for Grade 3
- How the Muscular System Works: Live Fill in the Blanks Worksheet for Grade 4
- How the Muscular System Works: Live Multiple Choice Worksheet for Grade 5
- Muscle Types and Injuries: Live Muscular System Worksheet for Grade 6

Muscular System: Quick Facts

Muscles work closely with our bones and connective tissues in order to make our body move.

There are three types of muscles in the body:

Skeletal muscles

These are the muscles attached to bones (thus the name “skeletal”) and are responsible for voluntary movement.
You can use conscious thought to control them, that’s why they are also called voluntary muscles.
When you look at them under a microscope, skeletal muscles are striated; that is, they have regular stripes or lines.

Smooth muscles

These are the muscles in places like the walls of your arteries and veins (which make your blood vessels wider or narrower as needed) and the walls of your intestines (which push food along the length of your gut).
They work automatically without you being aware of them. You can’t control them — you can’t make your intestines stop squeezing the food along their length, for example — and so smooth muscles are also known as involuntary muscles.
When you look at them under a microscope, smooth muscles are not striated.

Cardiac muscle

Your heart is made up of a muscle that’s strong enough to pump out blood to your entire body.
It’s a special kind of muscle: it’s striated (like skeletal muscles) but it’s involuntary (like smooth muscles) — you can’t tell it to stop working.
The muscle part of your heart is called the myocardium from myo (muscle) + kardia (heart).

Muscles are attached to bones by tough cords of connective tissue called tendons.

There are around 650 muscles in the human body. This number only refers to the muscles that have been named — mostly skeletal muscles — and do not include countless nameless smooth muscles.

How Muscles Work

Muscles work by becoming shorter or contracting. When muscles contract, they pull on the tendons that connect them to bones. When the tendons are pulled, they also pull on the bones to which they are attached. This creates movement.

Muscles can only pull. They cannot push. For this reason, muscles need to work in pairs, so that bones can move in opposite directions.

The biceps and triceps muscles in the upper arm are an example of a pair of muscles that work to create movement in opposite directions. They work on the elbow joint to move the forearm.

When the biceps contracts, the elbow is bent. The triceps relaxes.
To straighten the elbow, the triceps contracts and the biceps relaxes.
This coordinated movement is a result of instructions from the brain. When you decide to bend or straighten your elbow, your brain sends signals along the appropriate nerves, telling which muscle to contract and which to relax.

Muscle Health and Injuries

Protein is the building block of muscle tissue, so you need to have enough protein in your diet to keep your muscles healthy. You can do this by eating food rich in protein, such as (but not limited to) meat, fish, beans, eggs, and milk.

Exercising your muscles make them stronger.

There are several types of injuries that can happen to your muscles.

Strain

This is the overstretching or partial tearing of a muscle or tendon.
It is often called a “pulled muscle.”
This is different from a sprain, which is an injury to a ligament (the connective tissue that connects bones to other bones).

Cramps

These are also called “muscle spasms.”
They are sudden, involuntary, and often painful contractions of one or more muscles.
They can be caused by overuse of a muscle or by holding a position for a very long period. Sometimes, however, the cause of a cramp is not known.

Bruise

This is what happens when something hits a part of your body and it doesn’t tear open the skin in that part BUT it causes damage to the muscles and connective tissue underneath.
The medical term for a muscle bruise is a “muscle contusion.”

First aid for soft tissue injuries like muscle injuries is known by the acronym R.I.C.E.

Rest – Stop whatever you’re doing. Continuing to use the part that is injured may just make the damage worse. Rest that part for a few days.
Ice – Cold will reduce the pain and swelling. It doesn’t have to be ice, necessarily; you could also use other things from your freezer, like a bag of frozen peas. Make sure you wrap whatever cold thing you use in a light towel so you won’t get frostbite. This should only be done for the first 2-3 days, until the swelling is gone.
Compression – Wrapping the injured area will help prevent or reduce swelling. Don’t wrap it too tight, though! An elastic bandage is the best thing to use for this.
Elevation – Keep the injured part of your body at or above the level of your heart — or at least above hip level — to keep the pain, throbbing, and swelling down. You can prop it on a chair when you’re sitting down or on a pillow when you’re in bed.

Worksheets

The worksheets below are interactive “live worksheets” — they can be answered and corrected/submitted right on this page.

Printable (PDF) versions of these worksheets are also available for free download — just click on links provided before each worksheet.

Note on the Worksheets

You can reduce the size of the worksheet by zooming out your browser screen. For Windows users, scroll down the mouse wheel while pressing the Ctrl key in your keyboard. If there are any errors/glitches, just refresh and try again.

Introduction to The Muscular System: Worksheet for Kindergarten to Grade 2

A printable version of this worksheet can be downloaded here: Introduction to The Muscular System: Worksheet for Kindergarten to Grade 2 PDF

Muscular System - HunterWoodsPH.com Worksheet, an interactive worksheet by hunterswoodsph
liveworksheets.com

Types of Muscles: Muscular System Worksheet for Grade 3

A printable version of this worksheet can be downloaded here: Types of Muscles: Muscular System Worksheet for Grade 3 PDF