Skeletal System Study Set

Information from Honours Anatomy and Philosophy Skeletal System Slideshow

Functions of the Skeletal System

Firstly, supports the body by providing a framework for the attachment of other tissues and organs. Secondly, serves as levers pulled by muscles in movement. Thirdly, protects soft tissues and organs

Yellow Marrow Function

Storage of Calcium and phosphate ions within the bone tissue and fat

Red Marrow Function

Red blood cell production. Holds stem cells that differentiate into red blood cells, white blood cells, and platelets.

Epiphysis

The rounded end of a long bone, where it forms a joint.

Articular Cartilage

Covers the epiphysis to form a smooth surface

Labeling the epiphysis

Based on its relative position to the body

Proximal Epiphysis

Closest to the main mass of the body

Distal Epiphysis

Farthest from the main mass of the body

Compact Bone

The densest part of the bone

Spongy Bone

Has any space in between the bony rods or struts. It contains red bone marrow.

Epiphyseal Plate

Hyaline cartilage separates the epiphysis from the rest of the bone. Also known as the “growth plate.” In adults, the cartilage is replaced by bone.

Disphysis

The middle shaft of the bone. Covered in periosteum.

Medullary Cavity

A hollow area inside of the diaphysis. Is filled with yellow marrow.

Periosteum

A layer of dense tissue that contains blood vessel and sensory nerves.

Endosteum

The innermost layer of tissue.

Osteocytes

The mineral structure of compact and spongy bone maintained by cells

Osteoblasts

Lay down new bone

Osteroclasts

Dissolve and reshape bone

Osteons

Bone tissue divided into circular units

Lamellae

Thin, calcified ring-like sheets

Lacunae

Pits in each layer of the lamella

Osteocyte

A bone cell found inside of each lacunae

Central Canal

A hollow centre containing blood vessels

Canaliculi

Tiny channels each osteocyte is connected back to the central canal through

Ossification

The process of cartilage gradually being replaced by bone. Begin with osteoblasts forming spongy bone within the centre of the bone shaft.

How does bone development proceed?

Towards the two epiphyses

As long as what happens will the bone lengthen?

As long as the growth plate continually produces new hyaline cartilage.

What forms following the growth plate being fully ossified?

The epiphyseal line

Axial Skeleton

Includes everything around the longitudinal (vertical) centre plane of the body

Appendicular Skeleton

Includes the appendages: the arms and legs.

Suture

A joint make of dense fibrous tissue

What are the skull bones designed for?

To be protective

Fontanels

A few sutures that are much wider that the fetal skull has. Allow the skull to alter its shape during birth. They close within the first two years of life.

Sinuses

Hollow bones with thin plates between them designed to drain fluids.

How do sinus headaches happen?

When they get blocked and the fluids overflow into the nasal cavity.

Hyoid

The only bone is the entire body that does not form a joint with any other bone

What attaches to the Hyoid?

The base of the tongue, aiding in swallowing and speech

Ossicles

Malleus, Uncus, Atapes: The three small bones the middle ear is made up of.

What does the ossicles do?

Bones transmit vibrations from sound to the cochlea of the inner ear

How are vertebrae named?

Based on their location

C1 - C7

Cervical vertebrae in the neck

The atlas

C1 (vertebrae)

The Axis (vertebrae)

C2

T1 - T12

Thoracic vertebrae in the upper back

L1 - L5

Lumbar vertebrae in the lower back

Which are the two bones below the lumbar, made from nine fused vertebrae?

Sacrum and Coccyx

True Ribs

Pairs 1 - 7, are connected directly to the sternum

False Ribs

Pairs 8 - 12, are connected to the sternum through cartilage or not at all

Floating Ribs

Pairs 11 + 12, are only connected to the thoracic vertebrae

Long Bones

Are longer than they are wide, with heads at each end.

Short Bones

Often cube-shaped, and contain higher amounts of spongy bone

What are some long bones in the body?

Femur, humerus, metatarsals, phalanges.

What are some short bones in the body?

Carpals and Tarsals

Flat Bones

Are thinner, flattened, and often curved. Made of thin layers of compact and spongy bone.

What are some flat bones in the body?

Skull bones, pelvic bones, ribs, and sternum

Sesamoid Bones

Are embedded within a tendon (patella).

Irregular Bones

Do not fit into any of the other categories due to their unusual shapes (vertebrae).

Articulations (joints)

Exist wherever two bones meet. Classified according to the range of motion they allow.

Fibrous Joints

Contain fibrous tissue and immovable, including cranial sutures.

Cartilaginous Joints

Are connected entirely with fibrocartilage or hyaline cartilage and allow limited movement.

What are some examples of cartilaginous joints?

The symphysis pubis and the fibrocartilage between the vertebrae.

Synovial Joints

A space called a synovial cavity filled with fluid that separates that bone, allowing free movement. Contain many structures designed to minimise bone-bone contact.

What are some synovial joints in the body?

Knee, elbow, shoulder, fingers

Fibrous Capsule

Continuous with the periosteum

Synovial Fluid

Fills the space between the bones

Synovial membrane

Seals the synovial fluid

Bursa

A fluid-filled sac that cushions the area

Aspirations

Drain fluid from synovial joints due to swelling or inflammation following an injury or surgery.

What causes the cracking noise in joints?

The stretching of a synovial membrane, causing air to quickly escape.

Ligaments

Join bones together, and contain dense regular connective tissue.

Menisci

Shock-absorbing fibrocartilage pads which complex joints may also have

Ball and Socket

Found in the shoulder and hip. Has the greatest range of motion (360 degrees).

Hinge Joints

Allow movements along a single plane (flex and extend only). Elbow, knee, and between the phalanges.

Condylar Joints

Allows angular movement in two planes. Radius and Carpal bones, Phalanges and metacarpals or metatarsals.

Saddle Joints

Allow circular movement and angular movement and angular movement in two planes. Between carpal and metacarpal at the base of the thumb.

Gliding or Plane Joints

Allos multidirectional movement within a single plane. Between the carpals or tarsals.

Pivot Joints

Allows rotations in a single plane. Between the atlas and axis.

Sprains

Stretching/tearing of ligament. This occurs when a joint is forced into an abnormal position.

Dislocations

Caused when a bone is completely displaced from its joint

Simple or Closed Frature

Caused when the bone breaks internally but does not come through the skin.

Open Frature

Projects through the skin. Increased bleeding and risk of infection.

Greenstick fractures

Do not break through the entire bone. More likely in children, due to bones having more cartilage and being more flexible.

Comminuted Fractures

Involve the bone shattering into multiple pieces or fragments

Compression Fractures

Cause a crumpling of the vertebrae. Most frequent with older people experiencing osteoporosis.

Brittle Bone Disease (osteogenesis imperfecta)

A congenital disorder that results in an inability to produce a type of collagen needed in bone tissue.

Osteoporosis

A decrease in bone mass that most often occurs in women after menopause, due to decrease in sex hormones circulation.

Scoliosis

An abnormal sideways curvature of the spine. It occurs most often during the pre-pubescent growth spurt. Mostly, the cause is unknown.

Osteoarthritis

A wearing down of the articular cartilage as a result of aging. Results in pain, stiffness, and loss of flexibility in joints.

Hypermobility

A Condition where a greater range of motion in joints is possible due to abnormally-shaped ends of bones and/or genetic connective tissue defect leading to weakened cartilage and/or tendons. Can lead to osteoarthritis.

The diaphysis is covered with a layer of dense tissue that contains blood vessels and sensory nerves. What is the name of this tissue?

Periosteum

Which bone marrow holds stem cells that differentiate into red blood cells, white blood cells, and platelets.

Red Bone Marrow

Which joint type has the greatest range of motion?

Ball and Socket joint