Chapter 6- Skeletal system Flashcards
what is the skeletal system?
consists of bones, and other structures that make up the joints of the skeleton
what tissues are found in the skeletal system?
bone tissue
cartilage
fibrous connective tissue (ligaments)
what are the functions of the skeleton?
- provide frame work - support body
- protect internal organs from injury
- contains and protect red bone marrow
- provide storage site for excess calcium
define bones
organ composed of 2 tissues (compact bone and spongy bone)
osteocyte cells and a matrix made up of calcium salts and collagen
what is compact bone?
solid but very structured- made up of osteons or haverison systems
what is spongy bone?
contain red bone marrow in cavities.
contains osteocytes, matrix, and blood vessels
There are 4 types of bones. what are they?
- long: arms, legs, hands, feet
- short: wrist and ankles
- flat bones- ribs, shoulders, hipbones, and cranial
- irregular bones- vertebrae and facial bones.
Long bones have a shaft which is called diaphysis and the ends are called epiphyses. Describe the diaphysis and epiphysis parts of long bones
Diaphysis: made up of compact bone and is hallow, forming a cannel within the shaft. The marrow cannel contains yellow bone marrow (adipose tissue).
epiphyses- spongy bone covered with a thin layer of compact bone.
Describe the characteristics of short, flat and irregular bones
spongy bone covered with thin layer of compact bone.
Red bone marrow.
how are bones made?
in the embryonic phase, the matrix is made via ossification and starts in a centre of ossification of each bone. the bones start as fibrous connective tissue, and then fibroblast become specialized and differentiate into osteoblasts , which produce bone matrix.
what are fontanels?
areas of fibrous connect tissues remaining between the bones of the skull in a baby.
they ossify by age 2.
Describe the growth of long bones in children
they develop centres of ossification in their epiphyses, its not complete at birth and the bones continue to grow in the epiphyseal discs.
What are osteoclasts?
special large bone cells with several nuclei and a “ruffled skirt” appearance.
secretes acid and enzymes to dissolve and digest bone matrix > process known as resorption.
* keeps to form marrow cannel in long bones and establish red bone marrow- after birth red marrow turns to yellow in the shaft, but stays red in the spongy bone of short, flat and irregular bones.
what is bone remodelling?
calcium is removed by osteoclasts to raise the blood calcium levels, or calcium salts are made and deposited by osteoblasts to lower blood calcium level.
what are 5 factors that affect bone growth and maintenance?
- heredity
- nutrition
- hormones
- chemical communication from other tissues
- exercise or stress
what is osteocalcin?
a protein created by osteoblasts, which decrease fat storage by adipose tissue and increase insulin production by the pancreas
define a “bone fracture”
Medical term for broken bone
name 6 types of fractures
- simple: bone is still in normal anatomic position
- compound: broken end of bone moved, and possibly pierced skin (risk of infection)
- greenstick- bone split longitudinally, more common in children
- comminuted- two or more intersecting breaks create several bone fragments
- impacted- bones are forced into one another
- pathologic - bone breaks without trauma.
How is Growth Hormone (from the anterior pituitary gland) involved in bone growth and maintenance?
- increases rate of mitosis of chondrocytes and osteoblasts
- increases rate of protein synthesis
How is thyroxine (from the thyroid gland) involved in bone growth and maintenance?
- increases the rate of protein synthesis
2. increases energy production from all food types
How is insulin (from the pancreas) involved in bone growth and maintenance?
- increases energy production from glucose
How is parathyroid hormone (from the parathyroid) involved in bone growth and maintenance?
- increases the reabsorption of calcium from bones to the blood.
- increases the absorption of calcium by the small intestine and kidneys (to the blood)
How is thyroxine (from the thyroid gland) involved in bone growth and maintenance?
decreases the reabsorption of Calcium from bones
How is estrogen (ovaries) or testosterone (testes) involved in bone growth and maintenance?
Estrogen: promotes closure of epiphyses of long bones
Testosterone: helps retain calcium in bones to maintain a strong bone matrix
The human skeleton has which two divisions?
The axial skeleton, which forms the axis of the body and appendicular skeleton which supports the appendages or limbs.
what is a sprain?
stretching or tearing of the ligaments of a joint and though the bone is not broken, the joint is weak and unsteady.
What grouping of bones make up the skull
(2)?
8 cranial bones and 14 facial bones.
what are the cranial bones?
frontal bones, parietal bones (2), temporal bones (2), occipital bones.
sphenoid bone and ethmoid bone form part of the braincase and the sockets for the eyes.
define osteoporosis
excessive loss of calcium from bones without sufficient replacement.
Bones become thin and brittle, and at risk for fracture.
what do you call the immovable joints between cranial bones?
sutures.
the serrated, or sawtooth, edges of adjacent bones fit into each-other.