HAP Unit 4: The Skeletal System

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Questions and Answers

What is the main function of the axial skeleton?

To provide movement to the body

To produce blood cells

To store minerals and fats

To support and protect the internal organs (correct)

What type of bone tissue is homogeneous?

Spongy bone

Cartilages

Ligaments

Compact bone (correct)

What is the main characteristic of short bones?

They are longer than wide

They are irregular in shape

They are cube-shaped (correct)

They are thin and flattened

What is the function of Sharpey's fibers?

To secure periosteum to underlying bone Signup and view all the answers

How many bones are there in the adult human skeleton?

206 Signup and view all the answers

What type of bone is the vertebrae?

Irregular bone Signup and view all the answers

What is the main function of the periosteum?

To cover the shaft of the bone Signup and view all the answers

Which of the following is NOT a function of bones?

Production of hormones Signup and view all the answers

What is the function of the bony thorax?

To form a cage to protect major organs Signup and view all the answers

What is the name of the bone that forms the arm?

Humerus Signup and view all the answers

How many bones are in the forearm?

Two Signup and view all the answers

What is the function of the pelvis?

All of the above Signup and view all the answers

What is the name of the bone that forms the thigh?

Femur Signup and view all the answers

How many bones are in the leg?

Two Signup and view all the answers

What is the purpose of the intervertebral discs?

To provide cushioning between vertebrae Signup and view all the answers

How many parts does the bony thorax consist of?

Three Signup and view all the answers

What is a closed fracture?

A break in a bone that does not penetrate the skin Signup and view all the answers

What is the purpose of the hematoma in the repair of a bone fracture?

To form a fibrocartilage callus Signup and view all the answers

What are the three parts of the axial skeleton?

Cranium, vertebral column, and bony thorax Signup and view all the answers

What is the only bone that does not articulate with another bone?

Hyoid bone Signup and view all the answers

What is the function of the paranasal sinuses?

To lighten the skull and give resonance and amplification to voice Signup and view all the answers

What are fontanelles?

Fibrous membranes connecting the cranial bones Signup and view all the answers

Why is the fetal skull large compared to the infant's total body length?

Because the skull needs to accommodate the rapidly growing brain Signup and view all the answers

What is the final stage in the healing of a bone fracture?

Remodeling of the bony callus to form a permanent patch Signup and view all the answers

What is the main function of cartilage in joints?

To decrease friction at joint surfaces Signup and view all the answers

What is the main component of the medullary cavity in adults?

Yellow marrow Signup and view all the answers

What is the function of osteoclasts?

To break down bone matrix for remodeling Signup and view all the answers

During development, what replaces much of the hyaline cartilage in the skeleton?

Bone tissue Signup and view all the answers

What is the primary function of epiphyseal plates?

To allow for growth of long bones during childhood Signup and view all the answers

What is the name of the canal that carries blood vessels and nerves in the Haversian system?

Central canal Signup and view all the answers

What type of bone cells are responsible for forming new bone tissue?

Osteoblasts Signup and view all the answers

What is the term for the process by which bones are reshaped and lengthened during growth?

Bone remodeling Signup and view all the answers

What is the primary function of joints in the skeletal system?

To hold bones together and allow for mobility Signup and view all the answers

What type of joint is characterized by a joint cavity filled with synovial fluid?

Synovial joint Signup and view all the answers

What is the primary function of ligaments in synovial joints?

To reinforce the joint and provide additional support Signup and view all the answers

What is the term for the inflammation of a bursa?

Bursitis Signup and view all the answers

What is the term for the joint that connects the distal end of the tibia and fibula?

Syndesmosis Signup and view all the answers

What is the term for the flattened fibrous sacs that are lined with synovial membranes and filled with synovial fluid?

Bursae Signup and view all the answers

What type of joint is characterized by bones connected by cartilage?

Cartilaginous joint Signup and view all the answers

What is the term for the inflammation of a tendon?

Tendonitis Signup and view all the answers

Study Notes

The Skeletal System

The skeletal system consists of bones, joints, cartilages, and ligaments.
Functions of the skeletal system:
- Support of the body
- Protection of soft organs
- Movement due to attached skeletal muscles
- Storage of minerals and fats
- Blood cell formation

Bones of the Human Body

The adult skeleton has 206 bones.
There are two basic types of bone tissue:
- Compact bone (homogeneous, found in shafts of long bones)
- Spongy bone (small, needle-like pieces of bone with open spaces, found in ends of long bones)

Classification of Bones

Based on shape:
- Long bones (e.g. femur, humerus)
- Short bones (e.g. carpals, tarsals)
- Flat bones (e.g. skull, ribs, sternum)
- Irregular bones (e.g. vertebrae, hip)

Gross Anatomy of a Long Bone

Diaphysis (shaft) composed of compact bone
Epiphysis (ends) composed mostly of spongy bone
Periosteum (outside covering of diaphysis) is a fibrous connective tissue membrane
Sharpey's fibers secure periosteum to underlying bone
Arteries supply bone cells with nutrients
Articular cartilage covers the external surface of epiphyses
Medullary cavity (cavity of the shaft) contains yellow marrow (mostly fat) in adults and red marrow (for blood cell formation) in infants

Bone Markings

Surface features of bones:
- Projections and processes (grow out from the bone surface)
- Depressions or cavities (indentations)
Sites of attachments for muscles, tendons, and ligaments
Passages for nerves and blood vessels

Microscopic Anatomy of Bone

Osteon (Haversian system) is a unit of bone
Central (Haversian) canal carries blood vessels and nerves
Perforating (Volkman's) canal is a canal perpendicular to the central canal, carrying blood vessels and nerves

Changes in the Human Skeleton

In embryos, the skeleton is primarily hyaline cartilage
During development, much of this cartilage is replaced by bone
Cartilage remains in isolated areas (e.g. bridge of the nose, parts of ribs, joints)

Bone Growth

Epiphyseal plates allow for growth of long bones during childhood
New cartilage is continuously formed, and older cartilage becomes ossified
Bones are remodeled and lengthened until growth stops

Types of Bone Cells

Osteocytes (mature bone cells)
Osteoblasts (bone-forming cells)
Osteoclasts (bone-destroying cells, break down bone matrix for remodeling and release of calcium)

Bone Fractures

A break in a bone
Types of bone fractures:
- Closed (simple) fracture – break that does not penetrate the skin
- Open (compound) fracture – broken bone penetrates through the skin
Treatment of bone fractures involves reduction and immobilization

The Axial Skeleton

Forms the longitudinal part of the body
Divided into three parts:
- Skull
- Vertebral column
- Bony thorax

The Skull

Two sets of bones:
- Cranium
- Facial bones
Bones are joined by sutures
Only the mandible is attached by a freely movable joint

The Vertebral Column

Vertebrae separated by intervertebral discs
The spine has a normal curvature
Each vertebrae is given a name according to its location

The Bony Thorax

Forms a cage to protect major organs
Made-up of three parts:
- Sternum
- Ribs
- Thoracic vertebrae

The Appendicular Skeleton

Limbs (appendages)
Pectoral girdle
Pelvic girdle

The Pectoral (Shoulder) Girdle

Composed of two bones:
- Clavicle (collarbone)
- Scapula (shoulder blade)
These bones allow the upper limb to have exceptionally free movement

The Pelvis

Hipbones
Composed of three pair of fused bones:
- Ilium
- Ischium
- Pubic bone
The total weight of the upper body rests on the pelvis
Protects several organs (e.g. reproductive organs, urinary bladder, part of the large intestine)

Joints

Articulations of bones
Functions of joints:
- Hold bones together
- Allow for mobility
Classified functionally:
- Synarthroses (immovable joints)
- Amphiarthroses (slightly moveable joints)
- Diarthroses (freely moveable joints)
Classified structurally:
- Fibrous joints
- Cartilaginous joints
- Synovial joints

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Description

Learn about the parts and functions of the skeletal system, including bones, joints, cartilages, and ligaments. Understand the axial and appendicular skeleton and their roles in supporting and protecting the body.