(TBBS) The Musculoskeletal System Lesson Five

The Musculoskeletal System

Structure and Function

The Musculoskeletal system is composed of bones, muscles, ligaments and tendons of the body.

image of skeletal system with the following labelled: Skull Cranium Spinal Column Cervical Vertebrae Thoracic Vertebrae TH Lumbar Vertebrae Sacrum Coccyx Mandible Clavicle Manubrium Scapula Stemum Ribs Humerus Ulna Radius Pelvic Gird Carpals Metacarpals Phalanges Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges

The Skeletal System

Bones

  1. Bones, cartilage, and the connective tissue that holds bones together make up your skeletal system.
  2. Bone Structure- Bone tissue without any visible open spaces is called compact bone. Bone tissue that has many open spaces is called spongy bone. Bones contain a soft tissue called marrow.
  3. Bone Growth- Most bones start out as a flexible tissue called cartilage. Eventually, most cartilage is replaced by bone.

image of skeleton with the following labelled: The Skeleton Skull Ribs Radius Clavicle Patella Femur Ulna -Humerus Tibia Fibula Pelvic girdle Vertebral column

Protection

Storage

Movement

Blood Cell Formation

Your heart and lungs are protected by ribs, your spinal cord is protected by vertebrae, and your brain is protected by your skull.

Bones store minerals that help your nerves and muscles function properly. Long bones store fats that can be used for energy.

Skeletal muscles pull on bones to produce movement. Without bones, you would not be able to sit, stand, walk or run.

Some of your bones are filled with a special material that makes blood cells. This material is called marrow.

Types of Joints

A place where two or more bones meet.

Gliding Joint

Ball-and-Socket Joint

Hinge Joint

Gliding joints allow bones in the hand and wrist to glide over one another and give some flexibility to the area.

As a video-game joystick lets you move your character all around, the shoulder lets your arm move freely in all directions.

As a hinge allows a door to open and close, the knee enables you to flex and extend your lower leg.

  image of thumb joint

image of shoulder joint  

image of knee joint

The Muscular System

Muscles Attach to Bones

  • Tendons are strands of tough connective tissue that connect your skeletal muscles to your bones.

Muscles Work in Pairs  

  • Skeletal muscles often work in pairs. A muscle that bends part of your body is called a flexor. A muscle that straightens part of your body is an extensor.

A Pair of Muscles in the Arm Skeletal muscles, such as the biceps and triceps muscles, work in pairs. When the biceps muscle contracts, the arm bends. When the triceps muscle contracts, the arm straightens. Following labelled on two pictures: Biceps muscle Triceps muscle Flexor Extensor

  • Involuntary Muscles - I don't have to think about it, I don't control it.
  • Voluntary Muscles - I control when it happens.

 The muscular system is made up of the muscles that let you move.

image of muscle diagram with the following labelled: Facial muscles Stemociedo- mastoid Trapezius Clavicle- Deltoid Pectoralis major Biceps. brachil Brachialis Wrist and fingers flexors Triceps brachil Gastrocnemius- Tribialis anterior Tibia Platysma Latissimus dorsi Rectus abdominis -Linea alba External oblique muscles that flex fingers Gluteus medius Gracilis Sartorius Quadriceps femoris Patella Soleus

Involuntary muscle found in the digestive tract and the walls of the blood vessels is called smooth muscle. Involuntary muscle found in your heart is called cardiac muscle. Muscle attached to your skeleton for movement is called skeletal muscle.   Skeletal muscle can be voluntary or involuntary.

image of muscle fibers: Smooth muscle fiber Nucleus Cardiac muscle fiber Striation Nucleus Striation O Skeletal muscle fibers, while also striated, are under voluntary control. Nucleus Skeletal muscle fiber A Smooth muscle fibers are under involuntary control and appear spindle-shaped. B Cardiac muscle fibers, which are also under involuntary control, appear striated or striped when magnified.

Conditions that Require Emergency Care

  • Bones may be fractured or broken.
  • Ligaments can be stretched or torn, also known as sprains.
  • A strain is an injury in which a muscle or tendon is overstretched or torn.

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