6.6 Skeletal System Flashcards
What are the 4 functions of the skeleton?
Skeleton provides protection for internal organs, along with muscles, enables movement, stores minerals and fats, and is the site of blood cell formation.
How many bones does the skeleton contain?
Human skeleton contains 206 individual bones.
How many bones are in the axial skeleton and appendicular skeleton?
80 bones form the axial skeleton
126 bones form the appendicular skeleton.
What bones does the axial skeleton include?
Includes bones of the skull, vertebral column, and rib cage.
What does the skull do? How many bones?
Protects the brain
29 bones in the skill
8 = cranium
14 = facial bones
6 = middle ear
1 = under the tongue
What is the vertebral Column? What is the function?
26 vertebrae separated by cartilage
Protects spinal cord, supports rib cage, and attaches to pelvic bones
Has 4 normal curvatures
What are the 4 normal curvatures (from top to bottom) of the vertebral column?
Cervical, Throacic, Lumbar, Sacrococcygeal
What do the ribs do?
Forms a cage to protect major organs including the heart and lungs
What are the 3 parts of the ribs and explain them?
Ribs
12 ribs connected to spinal vertebrae
Sternum
Flat, blade shaped bone
Thoracic vertebrae
12 thoracic vertebrae
What bones does the appendicular skeleton include?
Includes shoulders, arms, pelvis, and legs.
Are the arms and legs attached to the axial skeleton?
YES
What does your shoulder do?
Allows upper limb movement
What are the 4 bones of the shoulder?
2 clavicles
S shaped bones that help stabilize the shoulder
2 scapulas
What are the components of the arm?
Humerus
Radius and ulna
Carpals, metacarpals, and phalanges
What does the pelvis do? Specify what parts?
Protects several organs and supports upper body weight
Reproductive organs
Urinary bladder
Parts of the large intestine
What 5 things is the pelvis composed of?
Sacrum
Coccyx
Coxal bones
Ilium
Ischium
Pubis
What are the 4 components of the legs?
Femur
Patella
Tibia & fibula
What is the femur?
Thigh bone
Strongest and longest bone in the body
What is the patella?
Triangular bone that protects the knee
What is the tibia?
Medial
Thicker (bears weight of femur)
What is the fibula?
Lateral
Stabilizes the ankle
What bones are the feet composed of?
Tarsals, metatarsal, phalanges
What are bones composed of?
Bone is composed of osseous tissue, cartilage, blood vessels, and nerves.
What is osseous tissue?
Osseous tissue is a type of hard and mineralized connective tissue that is made up of different types of bone cells
What are the 3 types of bone cells?
Osteocytes
Osteoblasts
Osteoclasts
What are osteocytes?
Mature bone cells
What are osteoblasts?
Bone forming cells responsible for bone growth
What are osteoclasts?
Bone destroying cells
Useful in the release of calcium and repair of the skeletal system
What are the two bone types?
Compact bone
Spongy bone
What is compact bone?
dense connective tissue; hard outer layer of bone.
What is spongy bone?
loosely structured network of separated connective tissue.
Some cavities in spongy bone are filled with soft tissue called bone marrow.
What is the periosteum?
Bones are surrounded by a tough exterior membrane called the periosteum.
Contains many blood vessels that supply nutrients to bones.
What is compact bone organized into?
Compact bone is organized into osteons
What are osteons?
circular structure surrounding a central (haversian) canal where blood vessels, nerves, and lymphatic vessels pass through
What are lamellae?
Circular rings called lamellae surround the central canals in each osteon
What is trabeculae?
Spongy bone is the internal tissue of bone
Consists of trabeculae surrounded by bone marrow tissue
Red bone marrow
Yellow bone marrow
How are bones classified?
Bones are classified based on their shape.
What are the 4 types of bone classifications?
Long bones
Short bones
Flat bones
Irregular bones
What are long bones?
Have a shaft with heads on both ends
Contain mostly compact bone
Support weight; movement
What are short bones?
Generally cube shaped
Contain mostly spongy bone
Stability; movement
What are flat bones?
Thin, flat, usually curved
Made up of layers of compact bone around a layer of spongy bone
Protection
What are irregular bones?
Irregular shape
Protection
Explain the general growth of bones?
In early development, skeleton is made mostly of cartilage made of connective tissue that serves as a template.
Most cartilage is replaced by deposited minerals (e.g. calcium).
In compact bone, new bone cells are added in layers around hollow channels called Haversian canals.
Bone cells called osteocytes become embedded within the new tissue.
What are intramembranous bones? EX?
Originate within sheetlike layers of connective tissue
Broad, flat bones
Examples: Flat bones of the skull, clavicles, sternum, and some facial bones (mandible, maxilla, zygomatic)
What is intramembranous Ossification?
Process of replacing embryonic connective tissue to form intramembranous bone:
Mesenchymal cells in primitive tissue differentiate into osteoblasts
Osteoblasts: bone-forming cells that deposit bone matrix around
themselves
When osteoblasts are completely surrounded by matrix, they are now
osteocytes in lacunae
Mesenchyme on outside forms periosteum
What are endochondral bones? EX?
Begin as masses of hyaline cartilage
Most bones of the skeleton
Examples: Femur, humerus, radius, tibia, phalanges, vertebrae
What is endochondral Ossification?
Process of replacing hyaline cartilage to form an endochondral bone:
Begin as hyaline cartilage models
Chondrocytes (cartilage cells) enlarge, lacunae grow
Matrix breaks down, chondrocytes die
Osteoblasts invade area, deposit bone matrix
Osteoblasts form spongy and then compact bone
Once encased by matrix, osteoblasts are now osteocytes
What is a joint?
A joint is where two bones meet that holds bones together and allows for mobility.
What are the three parts of joints?
Bursae, Ligaments, Tendons
What are bursae?
Bursae are fluid filled sacs that cushion joints.
What are ligaments?
Ligaments are strong bands of connective tissue that hold together the bones of a joint.
What are tendons?
Tendons connect bone to muscles to further stabilize a joint
How are joints classified?
Joints are classified by the amount of movement allowed
What are the three main types of joints?
Fibrous joint
Cartilaginous joint
Synovial joint
What is a fibrous joint? EX?
Generally immovable
Fibrous connective tissue joins bone to bone
Example
Cranium (skull) bones
What is a cartilaginous joint? EX?
Immovable or slightly moveable
Fibrocartilage found between bones
Example
Ribs
Sternum
Vertebrae
Pelvis
What is a synovial joint? EX?
Freely movable
Most common type of joint in the body
Example
Elbow joint
