Skeletal System Flashcards
What is another word for bone?
Osseous tissue
What is bone?
• Bone (osseous tissue) is a hard dense connective tissue that forms most of the adult skeleton, the support structure of the body.
Name two functions of the skeleton?
Two functions of the skeleton is for support but also to protect structures in the body.
What is the skeletal system?
• The skeletal system is the body system composed of bones and cartilage.
What are the critical functions in the body in which the skeletal system perform?
- Support for the body.
- Facilitates movement – without the skeletal system we would not be able to move.
- Protects internal organs.
- Produces blood cells – haematopoiesis.
- Stores and releases minerals and fat
How do bone facilitate movement?
Bones facilitate movement by serving as points of attachment for muscles
What does the bone matrix do?
Bone matrix acts as a reservoir for minerals e.g., calcium, phosphorus
How many classification of bone is there?
What are they?
Five
- Long Bones
- Short Bones
- Flat Bones
- Irregular Bones
- Sesamoid Bones
Describe Long Bones
a. These are cylindrical in shape.
b. Longer than it is wide.
c. An example is the femur bone.
d. Bones in the arm - the humerus, ulna, radius.
e. Bones within the fingers and toes are also long bones.
f. These bones function as levers therefore they move when muscles contract.
Describe Short Bones
a. Cube-like in shape.
b. Equal in length, width, and thickness
c. An example of a short bone is the carpals of the wrists and the tarsals of the ankles.
d. These bones provide stability and support.
e. They have limited motion therefore do not move a huge amount.
Describe Flat Bones
a. Typically, flat bones are thin but can also be curved.
b. The cranial bones, the scull bones, the scapula, the sternum and the ribs are all examples of flat bones.
c. Flat bones are points of attachment for muscles and are involved often in protection of internal organs.
Describe Irregular Bones
a. Not easily categorised into a particular shape.
b. Do not fit with any other classification.
c. Normally they have a complex shape.
d. For example, the vertebrae and facial bones.
e. Often involved in some kind of protection – for example, the vertebrae has the spinal cord running through it.
Describe Sesamoid Bones
a. These are small, round and shaped like a sesame seed (as the name suggests).
b. These are formed/embedded in tendons where there is a lot of pressure generated by the joint.
c. For example, these are typically found in tendons, in the feet and the hands and the knees.
d. They vary in numbers and placement from person to person.
e. Most people have a patella – a good example of a sesamoid bone.
What is the tubular shaft that runs between the proximal and distal ends of the bone called?
The Diaphysis
What is the hollow region in the diaphysis called?
The medullary cavity
What is the wider section at each end of the bone called?
The Epiphysis
Where does the epiphysis meet the diaphsis?
At the metaphysis (area around the epiphyseal
what is the membrane lining of the medullary cavity called?
The endosteum
What is the endosteum involved with?
It is involved with bone growth, repair and remodelling
What is the periosteum?
It is the fibrous layer on the outside of the bone
What are the three general classes of bone markings?
- Articulations
- A Projection
- A Hole
Bone contains small numbers of cells surrounded in a matrix of collagen fibres which help provide what?
They help to provide a surface for inorganic salt crystals to adhere.
What are the four types of cells found in bone tissue called?
- Osteoblasts
- Osteocytes
- Osteogenic Cells
- Osteoclasts
What cell found in bone is constantly breaking down old bone?
Osteoclasts
What cell found in bone is constantly forming new bone?
Osteoblasts
How do osteoblasts become osteocytes?
When osteoblasts get trapped within calcified matrix, they become osteocytes
What are osteocytes involved in?
Maintaining the bone tissue
What do osteoclasts develop from?
Monocytes and macrophages
What does compact bone do?
Provides support and protection.
What makes up compact bone?
Osteons make up compact bone.
What is spongey bone also known as?
Cancellous bone
How does spongey bone and medullary cavity receive nourishment?
From the arteries that pass through the compact bone
At what stage into embryonic life does ossification (bone development) begin?
6-7 Weeks`
What are the two pathways for bone development?
Intramembranous ossification
Endochondrial Ossification
What does intramembranous ossification do?
• Develops compact and spongy bone directly from sheets of mesenchymal (undifferentiated) connective tissue.
What bones are formed through intramembranous ossification?
• Flat bones of the face, most cranial bones, clavicles are formed via intramembranous ossification
What does endochondral ossification do?
Develops bones by replacing hyaline cartilage.
What type of ossification takes longer?
Endochondral ossification takes longer than intramembranous ossification
What is the perichondrium?
• The perichondrium is a membrane that covers the cartilage.
Where is the area of growth in long bones?
The epiphyseal plate
What are the four zones of activity of cells in bone?
- Reserve Zone
- Proliferation Zone
- Zone of maturation and hypertrophy
- Zone of calcified matrix.
What is the difference between a closed reduction and an open reduction for fractures?
Closed reduction – when a broken bone is manipulated and set into natural position without surgery.
Open reduction – surgery is required to reset the bone.
What is the most abundant mineral in the body?
Calcium
What gland releases a hormone that has an impact on osteoclasts releasing calcium from the bone?
The parathyroid gland releases PTH to do this.
What is osteoporosis?
A decrease in bone mass
What hormone control bone growth?
Growth Hormone
What does GH Trigger?
It triggers chondrocyte proliferation in the epiphyseal plates
What impact in the skeletal system does sex hormones have?
• Sex hormones (oestrogen/testosterone) both promote osteoblast activity and the production of bone matrix
What does calcitonin do?
Inhibits osteoclast activity and stimulates calcium uptake by the bones
What does the hormone thyroxine do?
It promotes osteoblastic activity and synthesis of bone matrix.
What does the skeletal system include?
It includes all bones, cartilage and ligaments of the body that support and give shape to the body and body structures.
How many bones do adults have?
206
How is the skeleton divided?
It is divided into the axial skeleton and the appendicular skeleton
What bones does the axial skeleton include?
All bones of head, neck, chest and back
What bones does the appendicular skeleton include?
All the bones of the upper and lower limbs.
