SKELETAL SYSTEM

The body is made of cells.

Cells group together to form tissues, which join to make organs.

Organs are tissues joined together to perform specific functions, such as the heart, kidneys, and lungs.

When different organs join together, they are called organ systems.

There are 9 main organ systems in the human body.

digestive excretory circulatory respiratory reproductive nervous muscular endocrine skeletal

The nervous system includes the spinal cord and the brain.

The vertebrae are bony structures that create the spine.

VERTEBRAEVERTEBRAE

They form a protective shield for the spinal cord.

spinal cord vertebrae

the brain

The brain has 4 basic parts cerebellum cerebrum brain stem hypothalamus

The cerebrum is the largest section of the brain. It is divided into two halves.

The left side mainly controls language and speech

The right side controls math and music.

The cerebellum controls balance, posture, and coordination.

At the top of the spinal cord is the brain stem.

The brain stem controls involuntary actions such as breathing, swallowing, heart contractions, digestion, and movement of blood through various vessels.

The medulla is an enlarged area of the brain stem. It controls the function of internal organs.

The hypothalamus controls blood pressure, heart rate, temperature, hunger, thirst, and emotions.

Muscular System

The muscular system works with the skeletal system to allow movement of our bodies.

There are 3 types of muscles.

smooth involuntary muscles long, thin, pointed at each end form into sheets examples: intestines, stomach

smooth muscle

skeletal voluntary joined in bundles cylinder shaped

skeletal muscle

cardiac involuntary heart muscle

cardiac muscle

Muscles receive nerve signals to work. When a message is sent, a muscle contracts or gets smaller. When the message stops, the muscle relaxes.

Flexor muscles bend body joints. Extensor muscles straighten body joints.

Flexor and extensor muscles usually work in pairs.

If a movement is not caused by bending or straightening a body joint, it is called abduction or adduction.

Abduction is when movement away from the body occurs. Adduction involves moving toward the body.

Some muscles are attached to bones by tendons. They are non- elastic and firmly join bones together.

Others are attached by ligaments. They are elastic tissues that attach bone to bone in moveable joints.

The skeletal system has 5 functions shape and support the body allows movements protect tissues and organs store certain materials produce blood cells

Bones are living tissues and contains cells, nerves, and blood vessels.

The primary function of bones is to support and give shape to the body and to provide protection for the soft internal structures.

There are 206 bones in the human skeleton.

axial skeleton skull, vertebrae, ribs, sternum appendicular skeleton arms and legs

Bones start as soft, flexible cartilage and gradually harden into hard bone over a period of several years.

A bone is like a tube. The outside is made of hard, dense compact bone.

A living skin called periosteum covers the bone.

Inside is a jelly-like tissue called marrow. There are 2 types of marrow found in bones.

Red marrow is located in the ends of long bones, such as arm and leg bones, sternum, ribs, vertebrae, and parts of the skull.

Red marrow manufactures red and white blood cells the body needs to survive.

Yellow marrow is located in the center of other bones. It stores necessary fats and minerals.

JOINTS

Joints are locations where bones connect to allow a movement to occur.

These movements are controlled by the muscles, which are attached to the bones at the joint.

DIFFERENT TYPES OF JOINTS DIFFERENT TYPES OF JOINTS

BALL AND SOCKET shoulder and hip allows movement in many directions

ball socket

ball socket

HINGE elbow, knee, phalanges, and jaw injury can occur if twisted

ELBOWELBOW

KNEEKNEE

PHALANGESPHALANGES

PHALANGESPHALANGES

PIVOT head, neck and forearm 180 degree limited movement

forearm

NECKNECK

SADDLE thumb ELLIPSOID wrist

THUMBTHUMB

ELLIPSOIDELLIPSOID

GLIDING wrist, ankle, spine movement in many directions, but amount of movement is limited

ANKLEANKLE

GLIDINGGLIDING

SPINESPINE

FIXED skull no movement

Bones involved in joints have a slippery, shiny cartilage at the end where they meet.

This covering keeps a joint’s movements smooth and prevents the bones from wearing out.

LIGAMENT tough strand of tissue that joins bones

tendons tendons are elastic supports that attach bone to bone and allow flexible movement

CARTILAGE padding between joints that acts as shock absorber and prevents bones from rubbing together.

CARTILAGECARTILAGE

SKULL

The skull consists of 8 curved bones linked firmly at wiggly lines called sutures.

sutures

The skull’s purpose is to protect the brain and cushion blows to it.

SPINAL COLUMN

There are 24 vertebrae in a human body.

Between each of these vertebrae are washer-like disks of flexible cartilage.

This cartilage is a tough, elastic tissue that allows movement between the vertebrae.

It also cushions the pieces of the spine so that they do not rub against each other.

vertebrea spinal disc vertebrea

There are 5 main parts to the spinal column.

SPINAL COLUMN

SPINESPINE

CERVIVCAL SPINE supports the neck and skull and consists of 7 vertebrae

THORACIC SPINE supports the thorax (chest of 24 ribs) and consists of 12 vertebrae

LUMBAR SPINE carries most of the body’s weight and consists of 5 vertebrae

SACRUM fusion of 5 sacral vertebrae into 1 vertebra that transmits body weight to the hip joints

COCCYX 2-4 fused coccygeal vertebrae that represents tail of our ancestors

THORAX Consists of 24 flexible ribs joined by cartilage. Their purpose is to protect the structures (heart and lungs) inside the chest.

The ribs connect to a fibrous, spongy bone in front called the sternum.

Bones of the Body

SHOULDER There are 3 bones that make up the area of the body called the shoulder. They are the scapula, clavicle, and humerus.

SHOULDERSHOULDER

ARM The 3 bones of the arm are the humerus, radius, and ulna

HAND There are 27 small bones that connect the hand to the arm at the wrist area.

We are going to combine them into three main groups: the carpals, metacarpals, and phalanges.

METACARPALS PHALANGES CARPALS

HIPS The bones in the hips are grouped together and called the pelvis or pelvic girdle.

LEG There are 4 major bones that combine to make a leg. They are the femur, tibia, fibula, and the patella, which is also known as the kneecap.

FOOT As with the hand, there are many small bones that are in the ankle area where the foot attaches to the leg.

We are going to group them into 3 main groups. They are the tarsals, metatarsals, and phalanges.

metatarsals tarsals phalanges