The Skeletal System

Skeletal System

• The skeletal system is composed of bones and cartilage, forming the body's framework.
• Bones give the body structure, preventing it from being a shapeless mass.
• Babies are born with approximately 300 bones.
• Adults have 206 bones.

Inside a Bone

• Bones are composed of salts, water, and tissue.
• Bone marrow, a jelly-like substance, is located inside bones.
• Bone marrow's main function is to produce blood cells for the body.

Functions of the Skeletal System

• Protects the body and provides its shape.
• Shields internal organs from damage.
• Acts as a scaffolding for muscles, allowing movement.
• Stores minerals and produces blood cells.

Skeletal System Structure

• Axial
• Appendicular
• Connective Tissues Include:
  • Cartilage
  • Joints
  • Ligaments
  • Tendons

Axial Skeleton

• Consists of 80 bones, including the skull, spine, ribs, and sternum (breastbone).
• The vertebrae protect the spinal cord.
• Ribs attach to the sternum and safeguard the heart and lungs.

Axial - Skull

• The human skull has 22 bones.
• The skull includes eight cranial bones and fourteen facial bones.
• Neurocranium bones include the occipital bone, (two) temporal bones, (two) parietal bones, the sphenoid, ethmoid, and frontal bones.

Axial - Spine

• The spine is composed of 33 individual vertebrae.
• Vertebrae interlock to form the spinal column.
• Vertebrae are divided into several regions with numbered: cervical, thoracic, lumbar, sacrum, and coccyx.
• Only the top 24 vertebrae are moveable; the vertebrae of the sacrum and coccyx are fused.

Axial - Ribs

• The ribs are a set of 12 bones that form the protective cage of the thorax.
• Ribs articulate with the vertebral column posteriorly.
• They terminate anteriorly as cartilage (coastal cartilage).
• The ribs as part of the bony thorax protect the internal thoracic organs

Axial - Sternum

• The sternum is a long, flat breastbone located in the center of the chest.
• The sternum connects to the ribs via cartilage.
• Forms the front of the rib cage, protecting the heart, lungs, and major blood vessels from injury.

Appendicular Skeleton

• The appendicular skeleton consists of 126 bones.
• The bones of the shoulder, arms, hands, hips, legs, and feet are all part of the appendicular skeleton.
• Enables a wide range of body motions.

Appendicular - Pectoral Girdle

• The pectoral girdle (shoulder girdle) connects the arms to the axial skeleton.
• Consists of the clavicle and scapula in humans.
• In species with a third shoulder bone, the pectoral girdle includes the clavicle, scapula, and coracoid.

Appendicular - Clavicle

• The clavicle (collarbone) acts as a strut between the shoulder blade and sternum.
• There are two clavicles, one on the left and one on the right.
• The clavicle is the only long bone in the body that lies horizontally.

Appendicular - Scapula

• The scapula, also known as the shoulder blade, wing bone, or shoulder bone, connects the humerus (upper arm bone) with the clavicle (collar bone)

Appendicular - Pelvic Girdle

• The pelvic girdle supports the lower limbs and connects them to the axial skeleton.
• Os coxae refers to the pelvic girdle,.
• It consists of fused bones individually identified as the ilium, ischium, and pubis.

Appendicular - Humerus

• Long bone in the arm running from the shoulder to the elbow.
• Connects the scapula to the radius and ulna of the lower arm.
• It has 3 sections.

Appendicular - Radius

• One of the two large bones in the forearm, the other is the ulna.
• The radius extends from the lateral side elbow to the thumb side of the wrist and runs parallel to the ulna.

Appendicular - Ulna

• The ulna is a long bone in the forearm.
• Stretching from the elbow to the smallest finger.
• It is located on the medial side of the forearm in anatomical position.
• The ulna runs parallel to the radius, the other forearm long bone.

Appendicular - Carpals

• There are eight small carpal bones,.
• They make up the wrist connecting the hand to the forearm.
• Carpus means "wrist" derived from the Latin carpus and Greek karpós.

Appendicular - Metacarpals

• Metacarpal bones form the intermediate part of the skeletal hand.
• It is located between the phalanges (fingers) and the carpal bones (wrist).
• Forming the connection to the forearm.
• Metacarpal bones are analogous to the metatarsal bones in the foot.

Appendicular - Phalanges

• The bones that form the fingers and toes.
• There are 56 phalanges in the human body
• There are 14 on each hand and foot.
• All fingers and toes have 3 phalanges each, with exception of the thumb and large toe ( big toe) having two.

Appendicular - Femur

• The only the bone located within the human thigh.
• It is both, the longest and strongest bone in the human body.
• Extending from the hip to the knee.

Appendicular - Patella

• Referred to as the kneecap.
• Flat, circular-triangular bone articulating with the femur (thigh bone).
• Covers and protects the anterior articular surface of the knee joint.

Appendicular - Tibia

• The tibia bone forms the shine.
• Is the larger of both lower-lag bones.
• The top of the tibia connects to the knee joint.
• The bottom part connects to the ankle joint.
• Although mainly carries the body's weight, supports support of the fibula.

Appendicular - Fibula

• The fibula leg bone (or calf bone) is on the lateral side of the tibia.
• Connected to the tibia above and below.
• Smaller of the two bones.
• Compared to its length, the slenderest of all the long bones.

Appendicular - Tarsal/Metatarsal/Phalanges

• Tarsals a set of seven irregularly shaped bones.
• Proximally situated in the foot in the ankle area located here.
• Metatarsals connect the phalanges to the tarsals.
• Five in number and 1 per digit.
• Phalanges the bones of the toes.

Types of Bones

• Types of bones include:
  • Long
  • Short
  • Flat
  • Irregular.

Long Bones

• Predominantly found in the arms and legs.
• Known for their strength.
• These bones include:
  • femur
  • tibia
  • fibula
  • humerus
  • ulna
  • radius,
  • metacarpals
  • metatarsal
  • phalanges
  • clavicle

Short Bones

• Shaped roughly as a cube and contain mostly spongy bone.
• They have a thin layer of compact bone on the outside.
• Short bones are located in the hands and feet

Short Bones - Carpal

• Scaphoid
• Lunate
• Triquetral
• Hamate
• Pisiform
• Capitate
• Trapezoid
• Trapezium
• Patella

Short Bones - Tarsal

• Calcaneus
• Talus
• Navicular
• Cuboid
• Lateral cuneiform
• Intermediate cuneiform
• Medial cuneiform

Flat Bones

• These bones provide broad surfaces for muscular attachment.
• Provides for the body a function as extensive for the body.
• These bones are expanded into broad, flat plates.
• Consist of the cranium, ilium (pelvis), sternum, and rib cage.

Irregular Bones

• Irregular bones vary in shape and structure and therefore do not fit into any other category (flat, short, long, or sesamoid).
• Complex shape to help protect internal organs.
• These bones include the vertebrae, sacrum, and mandible.

Connective Tissue

• Cartilage
• Joints
• Ligaments
• Tendons

Cartilage

• Strong, flexible connective tissue.
• Different types of cartilage line the surface of bones at joints allowing smooth movement.
• Cushions the vertebrae, and also, functions include supporting the ear and nose include among others.
• A baby's skeletal system is mostly made up of cartilage.
• The cartilage is replaced as the baby grows
• This process, Ossification, uses bone minerals and cells.
• Ossification refers to the process by which bone is formed, renewed, and repaired.

Joints

• Where 2 bones meet.
• Some joints provide a small range of motion.
• Considered immovable (ex.skull).
• Most joints are mobile and provie a range in movement.

Types of Joints

• Synovial joints are classified into six categories based on the shape and structure of the joint.
• The joint's shape affects the movement.
• These joints consist of:
  • Planar
  • Hinge
  • Pivot
  • Condyloid
  • Saddle
  • Ball-and-socket

Types of Joints: Planar

• Planer joints have articulating surface and are flat or slightly curved.
• The joints allows for a gliding movement type.
• Also referred to and known as: gliding joints.

Types of Joints: Hinge

• Typical class of synovial joints consisting of the: ankle, elbow, and knee joints.
• Hinege joints consists and formed of 2 o more bones with the bones only able to move along one axis.
• Enable bones to flex or exten

Types of Joints: Pivot

• Pivot joint is in the form of synovial.
• This is a joint type when 2 bones meet, 1 ends being a cylinder shape the other being a ring shape.
• Inside som jointts, the cylinder may rotate inside the ring..
• While others feature a ring shape that rotates around the cylinder.

Types of Joints: Condyloid

• Condlyloid joints (ellipsoidal,condylar or bicondylar) have articular type surfaces that are ovoid.
• Cavities that are eliptical and are well received.
• Movement in 2 planes, enabling flexon, adduction abdution extension and cricumduction.

Types of Joints: Saddle

• Saddle joints refers type of synovial
• 1 bone forms forming the joint
• It is typically shaped with a form of the the bones is shaped like a saddle, forming a rider like experience on the horse.
• Joints like this give stability to the bone, while providing more flexibility .
• Over types such an hinge or gliding joint.

Types of Joints: Ball-Socket

• Ball and socket joint (or spheroid joint) are a type of synovial joint
• This joint type is shaped like a circle with a surface type of joint.
• Shaped like a rounded bone, it fits with the rounded end to the cup-like end.
• This depression occurs on the distal bone.
• It is capable of different range types but can be indefinite.
• around different axis and may have centers in commmon.

Ligaments

• Ligaments are defined as bands that are tough with with that which is both elastic and fibrous.
• Binds the joint from the bone
• Prevents movement in the excessive form during movement.

Tendons

• Cords that are fibrous
• Join muscle with bone, otherwise joining it to. - Visible examples that can typically include your hands that can be seen with ease.

Proper Bone Function

Importance of Bone Function

• Is both a storage center along with a blood cell process location.
• Can store materials such as red bone marrow and important minerals for the body in the form of calcium or phosphorus.

Proper Diet

• Calcium is a mineral that is essenitial for the body.
• Calcium is responsible for strength and is most often assocaited with the use of dairy products.
• Combine phhorous in combination with calcium
• Can create the bones with higher ridgitiy and use products like peas or broccoli to achieve this proper diet.

Physical Exercise

• Regular activity is important for the health of bones.
• Increases nourishmen and bloodflow to to the bones
• Exercises that require weight bearings will add to the bone mass.
• Activities such are walking, lifting weights, and exercise with ground pressure, may increase bone mass
• Other examples are swimming or bicycling.

Explore the skeletal system, comprised of bones and cartilage, which provides body structure and protection. Discover the functions, from shielding organs to producing blood cells. Learn about the axial and appendicular skeletons, including the skull, spine, ribs and connective tissues.