Chapter 6: Skeletal System Flashcards
What are the primary functions of the skeletal system?
Support: rigidity supports bodyweight, cartilage give firm yet flexible support
Storage: minerals in blood
Protection: protects organs
Production of blood cells
Movement:
- skeletal muscles attach to bones by tendons, the contraction of the muscles move the bones.
- joints allow movement.
Name two major types of fibers and molecules found in the extracellular matrix of the skeletal system. How did they contribute to the functions of tendons, ligaments, cartilage and bones?
Collagen fibre and proteoglycan,
- In tendons: collagen gives it tough properties
- In cartilage: it gives it strength and smooth and resilience
- In bones: the collage: flexibility, minerals: compression strength
Define the terms diaphysis, epiphysis, epiphyseal plate, medullary cavity, articular cartilage, periosteum and endosteum.
Diaphysis: the shaft
Epiphysis: two ends of a bone
Epiphyseal plate: the area between each epiphysis and diaphysis where growth occurs
Medullary cavity: the hollow cavity of a compact bone where marrow is stored
Articular cartilage: the smooth ends of a bone to withstand friction and movement
Periosteum: the outer layer of a bone
Endosteum: the surface covering the medullary cavity
Describe the structure of compact bone.
- Forms most of the diaphysis of long bones. - Most of the lamellae is organized into sets of concentric rings which surround the central haversian canals. These canals are called osteons or haversian systems. They are given the appearance of having tiny spaces or gaps by the canaliculi, which connects each osteocytes and functions as a passage for nutrients and waste excretion.
Describe the structure of a cancellous bone. What are trabeculae?
Cancellous bone forms most of the epiphysis of the bone. It is also called a spongy bone due to it’s structure of spaces and gaps. It consists of delicate interconnecting rods called trabeculae. It adds strength to the bone without any extra strength. The spaces between the trabeculae are filled with bone marrow.
Define and describe intramembranous ossification.
Intramembranous ossification: bone ossification within connective tissue
a. This occurs when osteoblasts produce bone in connective tissues
b. Osteoblasts line up on the surface of connective tissue bones and deposit bone matrix on to form trabeculae
c. This happens in ossification centers where the trabeculae radiates out from the center
Define and describe endochondral ossification.
Endochondral ossification: bone ossification within cartilage
a.This occurs when chondrocytes multiply, hypertrophy and die, forming calcified cartilage matrix
b. The osteoblasts produce a collar of bone around diaphysis and stimulate ossification to occur. The center where this happens is the primary ossification center
d. The osteoblasts invade the spaces in the calcified matrix. And the osteoclasts remove the calcified matrix
A medullary cavity forms as osteoclasts remove bone and calcified cartilage and replace it with bone marrow.
e. Later secondary ossification centers form in epiphyses
How do bones grow in diameter? How do long bones grow in length?
a. Chondrocytes increase in number on the epiphyseal side of the epiphyseal plate. When they line up in columns, they elongate, hypertrophy and dies to form calcified cartilage matrix
b. The calcified matrix is removed by osteoclasts and the dying osteoclasts and replaced by osteoblasts
c. The osteoblasts deposit bone lamellae on the surface of calcified cartilage. This produces bone on the diaphyseal side on the epiphyseal plate.
What is accomplished by bone remodeling? How does bone repair occur?
Changes accomplished by bone remodelling: Bone shape Adjustment of bone due to stress Bone repair Calcium regulation in blood
How does bone repair occur?
Steps of bone repair:
1. When a bone breaks, this damages the blood vessels and forms a clot, 2 or 3 days after injury
- Then a callus forms, to repair the tissue. The cells which invade the clot forms a fibrous network of connective tissues and holds the fragments together to fill the gap
- Osteoblasts enter the callus and form a cancellous bone, while uniting the broken ends of the fracture. This usually takes about 4-6 weeks after injury
- Then the cancellous bone is then replaced with compact bone overtime. This region will be remodelled to bring it back to normal.
Define the axial skeleton and the appendicular skeleton.
Axial skeleton consists of the skull, vertebrae, thoracic cage and sternum.
Appendicular skeleton consists of upper and lower limbs and their girdles.
Name the bones of the braincase and the face.
Braincase bones: frontal, parietal, temporal, sphenoid bones
Facial bones: Orbits and nasal cavity, zygomatic bone, maxilla, mandible
Give the locations of the paranasal sinuses.
Locations: in the nasal cavity, the perpendicular is superior to vomer bone, the middle nasal concha is a projection from ethmoid bone, the inferior nasal concha is a separate bone
What are the functions of paranasal sinuses?
Functions: decrease weight of skull, acts as a resonating chamber during voice production and increase SA
What is the function of the hard palate?
Has uvula, forms floor of nasal cavity and roof of mouth
Through what foramen does the brain connect to the spinal cord?
Foramen magnum
How do the vertebrae protect the spinal cord?
The spinal cord is protected by bones, discs, ligaments, and muscles. The spine is made of 33 bones called vertebrae. The spinal cord passes through a hole in the center (called the spinal canal) of each vertebra. Between the vertebrae there are discs that act as cushions, or shock absorbers for the spine.
Name and give the number of each type of vertebra.
Cervical: 7 Thoracic: 12 Lumbar: 5 Sacral : 1 Coccyx 1
What is the function of the thoracic cage?
Function of thoracic cage: Protects organs, prevent collapse of thorax during respiration
Name the parts of the sternum.
Parts of sternum: manubrium, body and xiphoid process
Distinguish true, false, and floating ribs.
True ribs: 17 directly connected to sternum by costal cartilages
False ribs: 8-12not attached directly to sternum
Floating ribs: 11, 12 no attachment to sternum
Name the bones that make up the pectoral girdle, arm, forearm, wrist and hand. How many phalanges are in each finger and in the thumb?
Pectoral girdle: Clavicle and scapula Arm: humerus Forearm: radius, ulna Wrist: carpals Hand: metacarpals, phalanges 3 phalanges in each finger, 2 in thumb (distal, proximal)
Define the pelvic girdle. What bones fuse to form each coxa? Where do the bones of the coxae articulate?
The pelvic girdle is made up of two coxae. Each coccyx consists of ilium, ischium, and pubis. The coxae, sacrum and coccyx form the pelvis.
Name the bones of the thigh, leg, ankle and foot.
Thigh: femur
Ankle: tarsals
Foot: metatarsals, phalanges