Lesson 33 Comparing the Major Systems of the Human Body Part 2 Skeletal and Muscular Systems

In our last lesson, we learned that the circulatory system is a system that helps blood to transport nutrients, oxygen, carbon dioxide, blood cells, etc. to and from cells in the body to nourish them and help them to survive. systemblood oxygencarbon dioxide bloodcells

We learned the circulatory system is composed of the heart and blood vessels, including arteries, veins, and capillaries.

Also in our last lesson we learned that the respiratory system allows much needed oxygen in the air to be taken into the body, while also enabling the body to get rid of carbon dioxide from the body using the air the body breathes out. lungs

Respiration is when the body exchanges the oxygen it takes in for the carbon dioxide it needs to get rid of.

All of this breathing couldn't happen without the respiratory system, which includes the nose, throat, voice box, windpipe, and lungs.

These two systems work well together. The respiratory system brings the air into the body and releases carbon dioxide from the body.

And the circulatory system transports the oxygen to the cells and the carbon dioxide to the lungs to be released.

Today we are going to learn about two more systems that work well together. Today we will learn about the skeletal system and the muscular system.

What is a skeletal system?

A Skeletal system is made up of the bones of the body.

Every single person has a skeleton made up of many bones. These bones give your body structure, let you move in many ways, protect your internal organs, and more.

The adult human body has 206 bones!

Your skull protects the most important part of all, the brain. You can feel your skull by pushing on your head, especially in the back a few inches above your neck.

Although you can't see it, the smallest bone in your whole body is in your head, too. The stirrup bone behind your eardrum is only.1 to.13 inches (2.5 to 3.3 millimeters) long!

Your lower jawbone is the only bone in your head you can move. It opens and closes to let you talk and chew food.

Your heart, lungs, and liver are all very important, and luckily you've got ribs to keep them safe. Ribs act like a cage of bones around your chest.

It's easy to feel the bottom of this cage by running your fingers along the sides and front of your body, a few inches below your heart. If you breathe in deeply, you can easily feel your ribs right in the front of your body, too. heart

Your ribs come in pairs, and the left and right sides of each pair are exactly the same. Most people have 12 pairs of ribs

All 12 pairs of ribs attach in the back to the spine. The first seven pairs of ribs attach in the front to the sternum, a strong bone in the center of your chest that holds those ribs in place.

Your spine is one part of the skeleton that's easy to check out: Reach around to the center of your back and you'll feel its bumps under your fingers.

The spine lets you twist and bend, and it holds your body upright. It also protects the spinal cord, a large bundle of nerves that sends information from your brain to the rest of your body.

The spine is special because it isn't made of one or even two bones: It's made of 33 bones in all! These bones are called vertebrae and each one is shaped like a ring. vertebrae

The arm is made up of three bones: the humerus which is above your elbow, and the radius and ulna which are below the elbow.

Your legs are attached to a circular group of bones called your pelvis. The pelvis is a bowl-shaped structure that supports the spine.

The pelvis acts as a tough ring of protection around parts of the digestive system, parts of the urinary system, and parts of the reproductive system.

Your leg bones are very large and strong to help support the weight of your body. The bone that goes from your pelvis to your knee is called the femur, and it's the longest bone in your body.

Below the knee are two other leg bones: the tibia and the fibula. Just like the three bones in the arm, the three bones in the leg are wider at the ends than in the middle to give them strength.

D4dKp14 D4dKp14 Let’s watch a video about the skeletal system.

What is a muscular system?

A Muscular System is made up of the muscles of the body.

Did you know you have more than 600 muscles in your body? They do everything from pumping blood throughout your body to helping you lift your heavy backpack.

You control some of your muscles, while others — like your heart — do their jobs without you thinking about them at all.

Muscles are all made of the same material, a type of elastic tissue (sort of like the material in a rubber band). Thousands, or even tens of thousands, of small fibers make up each muscle.

You have three different types of muscles in your body: smooth muscle, cardiac (muscle, and skeletal muscle.

Smooth muscles — sometimes also called involuntary muscles — are usually in sheets, or layers, with one layer of muscle behind the other.

You can't control this type of muscle. Your brain and body tell these muscles what to do without you even thinking about it.

But smooth muscles are at work all over your body. In your stomach and digestive system, they contract (tighten up) and relax to allow food to make its journey through the body.

Smooth muscles are also found in your bladder. When they're relaxed, they allow you to hold in urine (pee) until you can get to the bathroom. Then they contract so that you can push the urine out. urine

You'll find smooth muscles at work behind the scenes in your eyes, too. These muscles keep the eyes focused.

The muscle that makes up the heart is called cardiac muscle. The thick muscles of the heart contract to pump blood out, and then relax to let blood back in after it has circulated through the body.blood

Just like smooth muscle, cardiac muscle works all by itself with no help from you.

A special group of cells within the heart are known as the pacemaker of the heart because it controls the heartbeat.

Skeletal muscles are sometimes called striated muscle because the light and dark parts of the muscle fibers make them look striped (striated is a fancy word meaning striped).

Skeletal muscles are voluntary muscles, which means you can control what they do. Your leg won't bend to kick the soccer ball unless you want it to.

These muscles help to make up the musculoskeletal system — the combination of your muscles and your skeleton, or bones.

Together, the skeletal muscles work with your bones to give your body power and strength. In most cases, a skeletal muscle is attached to one end of a bone. It stretches all the way across a joint (the place where two bones meet) and then attaches again to another bone

Skeletal muscles are held to the bones with the help of. Tendons are cords made of tough tissue, and they work as special connector pieces between bone and muscle.

The tendons are attached so well that when you contract one of your muscles, the tendon and bone move along with it.

Skeletal muscles come in many different sizes and shapes to allow them to do many types of jobs. Some of your biggest and most powerful muscles are in your back, near your spine. These muscles help keep you upright and standing tall.

They also give your body the power it needs to lift and push things. Muscles in your neck and the top part of your back aren't as large, but they are capable of some pretty amazing things.

Try rotating your head around, back and forth, and up and down to feel the power of the muscles in your neck. These muscles also hold your head high.

I will list just a few of the major muscles. In each of your shoulders is a deltoid muscle. Your deltoid muscles help you move your shoulders every which way.

The pectoralis muscles are found on each side of your upper chest. These are usually called pectorals, or pecs, for short. Many athletes and bodybuilders have large pecs, too.

Below these pectorals, down under your ribcage, are your rectus abdominus muscles, or abdominals. They're often called abs for short.

When you make a muscle in your arm, you tense your biceps muscle. When you contract your biceps muscle, you can actually see it push up under your skin.

Your quadriceps or quads, are the muscles on the front of your thighs. Many people who run, bike, or play sports develop large, strong quads.

1eUGV-tA 1eUGV-tA Let’s watch this video about the skeletal system.

e-BgmNTs e-BgmNTs Let’s watch this video about both the skeletal and muscular systems.

Let’s review what we have learned about the skeletal and muscular system. Answer the attached questions on the worksheet entitled L#33 Systems of the body part 2.

In our next lesson we will look at the digestive system and the nervous system in multicellular organisms.

Good Job Today! And remember to….

See you next time!