Chapter 6 Flashcards
Skeletal system
provides a framework that supports the body
protects some internal organs from injury
contains and protects red bone marrow
provides a storage site for excess calcium
Bones
Bone cells are called osteocytes
Matrix-calcium salts and collagen
joint surfaces of bones are covered with articular cartilage; covering the rest of the bone is the periosteum
Two types of bone tissue
Compact bone- made of osteons or Haversian systems
Spongy bone- contains osteocytes and bone matrix but not arranged in Haversian systems. Cavities contain red bone marrow.
Long Bones
arms, legs, hands, and feet
each consists of a diaphysis made of compact bone and epiphyses made of spongy bone
the marrow canal contains yellow bone marrow
Short bones
wrist and ankles bones
made of spongy bone covered with a thin layer of compact bone
the spongy bone contains red bone marrow
Flat bones
ribs, shoulder blades, hip, and cranial bones
made of spongy bone covered with a thin layer of compact bone
the spongy bone contains red bone marrow
Irregular bones
the vertebrae and facial bones
made of spongy bone covered with a thin layer of compact bone
the spongy bone contains red bone marrow
Embryonic growth
Osteoblasts- cells that produce bone matrix
Ossification- hardening of bone
Fontanels- permit compression of the baby’s head during birth without breaking the still thin cranial bones
Epiphyseal discs- occurs in long bones
Osteoclasts- destroying cells
Growth Hormone (anterior pituitary gland)
•Increases the rate of mitosis of chondrocytes and osteoblasts
• Increases the rate of protein synthesis (collagen, cartilage matrix, and enzymes for cartilage and bone formation)
Thyroxine (thyroid gland)
•Increases the rate of protein synthesis
• Increases energy production from all food types
Insulin (pancreas)
Increases production from glucose
Parathyroid hormone (parathyroid glands)
• Increases the reabsorption of calcium from bones to the blood (raises blood calcium level)
• Increases the absorption of calcium by the small intestine and kidneys (to the blood)
Calcitonin (thyroid gland)
• Decreases the reabsorption of calcium from bones (lowers blood calcium level)
Estrogen (ovaries) or testosterone (testes)
• Promotes closure of the epiphyses of long bones (growth stops)
• Helps retain calcium in bones to maintain a strong bone matrix
The skeleton
Axial Skeleton- which forms the axis of the body
Appendicular skeleton- which supports the appendages or limbs
206 bones in total
Skull
8 cranial bones and 14 facial bones
3 small bones in each middle ear cavity
Frontal
•air cavity that opens into nasal cavity
•joint between frontal and parietal bones
Parietal
•Joint between the 2 parietal bones
Temporal
•Joint between temporal and parietal bones
•The tunnel-like ear canal
•Oval projection behind the ear canal
•Air cavity that opens into middle ear
•Oval depression anterior to the ear canal; articulates with mandible
•Anterior projection that articulates with the zygomatic bone
Occipital
•large opening for the spinal cord
•Oval projections on either side of the foramen magnum; articulate with the atlas
•Joint between occipital abdominal parietal bones
Sphenoid
•Flat, lateral portion between the frontal and temporal bones
•central depression that encloses the pituitary gland
Ethmoid
•Air cavity that opens into nasal cavity
•Superior projection for attachment of meninges
•On either side of base of crista galli; olfactory nerves pass through foramina
•upper part of nasal septum
•Shelf-like projections into nasal cavities that increase surface area of nasal mucosa
Mandible
•U-shaped portion with lower teeth
•Oval projections that articulate with the temporal bones
•Conical depressions that hold roots of lower teeth
Maxilla
•Air cavity that opens into nasal cavity
• Projection that forms anterior part of hard palate
• Conical depressions that hold roots of upper teeth
Nasal
from the bridge of the nose
