Chapter 7 - Bones Flashcards
The bones of the skeletal system:
- Organs of the skeletal system
- Composed of many tissues: bone tissue, cartilage, dense
connective tissue, blood and nervous tissue - Alive and multifunctional:
- Support and protect softer tissues
- Movement
- Blood cell formation
- Mineral storage
- Skeletal system has 2 divisions:
- Axial
- Appendicular
Bones of the skeletal system vary greatly in these ways:
Size
&
Shape
Bones are similar in these features:
Structure, Development, and Function
What are the bone classifications by shape?
long bones, short bones, flat bones, irregular bones
Long Bones
long and narrow, have expanded ends
Short bones
cube-like, length = width, include Sesamoid (round) bones, which are embedded in tendons
Flat Bones
plate-like, with broad surfaces
Irregular bones
Variety of shapes,most are connected to several other bones
Parts of a Long Bone…?
E D M A P C S T M E B
(MAKE AN ACRONYM)
- Epiphysis: expanded end
- Diaphysis: bone shaft
- Metaphysis: between diaphysis and epiphysis, widening part
- Articular cartilage: covers epiphysis
- Periosteum: encloses bone; dense connective tissue
- Compact (cortical) bone: wall of diaphysis
- Spongy (cancellous) bone: makes up epiphyses
- Trabeculae: branching bony plates, make up spongy bone
- Medullary cavity: hollow chamber in diaphysis; contains marrow
- Endosteum: Lines spaces, cavity
- Bone marrow: Red or yellow marrow, lines medullary cavity, spongy
bone spaces
Microscopic structure of Bone…?
Osteocyter, Lacunae, Canaliculi, Collagen Fibers and Inorganic Salts
Osteocytes
Mature Bone Cells
Lacunae
Chambers occupied by Osteocytes
Canaliculi
Tiny passageways through which the cell
processes of osteocytes exchange nutrients and wastes
The extracellular matrix of bone is largely…?
Collagen Fibers and Inorganic Salts
What does Collagen and Inorganic Salts do for bone?
- Collagen gives bone resilience
- Inorganic salts make bone hard
Compact Bone
- Consists of cylindrical units called osteons
- Osteons and layers of matrix, lamellae, cluster around
central canal in each osteon - Strong and solid
- Weight-bearing
- Resists compression
Spongy Bone:
- Consists of branching plates called trabeculae
- Somewhat flexible
- Has spaces between trabeculae that reduce the bone’s
weight
Cylindrical units in compact bone is…?
Osteons
Branching plates in spongy bone…?
Trabeculae
What are the major functions of bones?
- Provide shape to body
- Support body structures
- Protect body structures
- Aid body movements
- Contain tissue that produces blood cells
- Store inorganic salts
What is Hematopoiesis?
Blood cell formation
Blood cell productions occurs in…?
Red Bone Marrow
Blood Cell Formation facts
- Hematopoiesis: Blood cell formation
- Blood cell production occurs in red bone marrow
- Red blood cells, white blood cells, and platelets are
produced in red bone marrow - With age, some red bone marrow is replaced by yellow
bone marrow, which stores fat, but does not produce
blood cells - Red marrow remains in adult in skull, ribs, sternum,
clavicles, vertebrae, hip bones - Bone marrow transplants are used to treat a variety of
conditions
Inorganic Salt Storage
About 70% of bone matrix consists of inorganic mineral salts
Most abundant salt is crystals of hydroxyapatite
(calcium phosphate)
Other salts include:
* Magnesium ions
* Sodium ions
* Potassium ions
* Carbonate ions
Osteoporosis
condition that results from loss of bone
mineralization
Since calcium is vital in nerve impulse conduction and
muscle contraction, blood calcium level is regulated by…?
Parathyroid hormone and Calcitonin
Parts of the skeletal system begin to develop in…?
the first few
weeks of prenatal development
Bone structures continue to grow and develop into…?
Adulthood
Bones form when bone tissue replaces existing connective
tissue in one of two ways
- Intramembranous bones
- Endochondral bones
Fetus at 14 weeks of development shows growth of both
intramembranous and endochondral bones
- Intramembranous Ossification:
- Flat skull bones, clavicles, sternum and some facial bones
- Bones form between sheets of primitive connective tissue
- Endochondral Ossification:
- Long bones and most of skeleton
- Bones form from hyaline cartilage models
Osteoclasts
break down calcified matrix
Osteoblasts
then invade, replacing cartilage with bone
tissue
Growth at the Epiphyseal Plate
- Bone can continue to grow in length, as long as cartilage
cells of epiphyseal plate remain active - When ossification centers meet, and epiphyseal plate
ossifies, bone can no longer grow in length - Bone can thicken by depositing compact bone on outside,
under periosteum
What are the Factors Affecting Bone Development,
Growth, and Repair?
Nutrition, sunlight exposure, hormone levels, and physical
exercise all affect bone development, growth, and repair
Vitamin D
calcium absorption; deficiency causes rickets,
osteomalacia
Vitamin A
osteoblast and osteoclast activity; deficiency
retards bone development
Vitamin C
collagen synthesis; deficiency results in
slender, fragile bones
Growth Hormone
stimulates cartilage cell division
* Insufficiency in a child can result in pituitary dwarfism
* Excess causes gigantism in child, acromegaly in adult
How many bones are in the adult skeleton?
206
Some people have extra bones, while others lack certain
bones
Division of the Skeleton is…?
Axial Skeleton - 80 Bones
Appendicular Skeleton - 126 Bones
Axial Skeleton - 80 Bones and their functions
- Skull: Cranium and facial bones
- Middle ear bones: Move sound to receptors in inner ear
- Hyoid bone: Supports tongue and is muscle attachment site
- Vertebral column: Forms central axis of skeleton
- Thoracic cage: Ribs and sternum; protects organs
Appendicular Skeleton - 126 Bones and their fucntions
- Pectoral girdle: Scapula and clavicle; upper limb movement
- Upper limbs: Humerus, radius, ulna, hand
- Pelvic girdle: Hip bones; lower limb movement; forms pelvis
- Lower limbs: Femur, tibia, fibula, patella, foot
What are the Characteristics of Infantile Skull?
- Incompletely developed at birth
- Small face, large orbits, prominent forehead
- Small nasal cavity and jaw
- Sinuses are not completely formed
- Bones are thin and flexible
Fontanels (soft spots):
- Fibrous membranes that connect cranial bones, where
intramembranous ossification is incomplete - Allow skull to change shape slightly during birth
- Four major fontanels close between 2 months and 2 years of age
Vertebral Column facts
- Forms vertical axis of skeleton
- Consists of many vertebrae separated by cartilaginous
intervertebral discs, and connected by ligaments - Supports head and trunk, permits several types of
movements - Protects spinal cord in vertebral canal
- 33 separate bones in infant, 26 in adult
What are the Vertebral Column differences between infants and adults?
- 33 separate bones in infant, 26 in adult
4 Curvatures of Vertebral Column:
- Cervical curvature (secondary)
- Thoracic curvature (primary)
- Lumbar curvature (secondary)
- Sacral curvature (primary)
Vertebral Column consists of:
- 7 cervical vertebrae
- 12 thoracic vertebrae
- 5 lumbar vertebrae
- 5 fused sacral vertebrae form sacrum
- 4 fused coccygeal vertebrae form coccyx
Thoracic cage:
- Includes ribs, thoracic
vertebrae, sternum,
and costal cartilages
that attach the ribs to
the sternum - Supports pectoral
girdle and upper
limbs - Protects thoracic and
upper abdominal
viscera - Role in breathing
How many pairs of Ribs do humans have?
12
True Ribs
Vertebrosternal, 7 pairs, connect directly to
sternum
False Ribs (5 pairs)
- Vertebrochondral ribs: Upper 3 pairs, costal cartilages connect to
Cartilage #7 - Floating ribs: Vertebral, lower 2 pairs, no connection to sternum
What is the Structure of a Rib?
- Shaft: main portion; long and slender
- Head: posterior end; articulates with vertebrae
- Tubercle: articulates with vertebra
- Costal cartilage: hyaline cartilage, connects rib to sternum
Sternum (breastbone):
- Along midline of anterior thoracic cage
- 3 parts:
- Manubrium: Upper part
- Body: Middle and largest part
- Xiphoid process: Lower part
- Articulates with costal cartilages of ribs, and clavicles
Pectoral (shoulder) girdle:
- Consists of 2 clavicles and 2 scapulae:
- Clavicles = collarbones; anterior portions
- Scapulae = shoulder blades; posterior portions
- Forms incomplete ring; open in back
- Supports upper limbs
- Attachment site for muscles that move upper limbs
Upper Limb Bones:
- Form framework of upper arm, forearm, hand
- Provide muscle attachments, and work with muscles for
limb movement
What are the bones of the Upper Limb?
- Humerus
- Radius
- Ulna
- Carpals
- Metacarpals
- Phalanges
Each hand consists of the…?
wrist, palm, and fingers (digits)
- Carpal (wrist) bones (8 ):
- Scaphoid
- Lunate
- Triquetrum
- Pisiform
- Hamate
- Capitate
- Trapezoid
- Trapezium
Matacarpal (hand) has how many bones?
5
- Phalanges (finger bones, 14):
- Proximal phalanx
- Middle phalanx
- Distal phalan
Pelvic Girdle
consists of 2 hip (coxal, pelvic, or innominate)
bone
- Supports trunk of body
- Protects viscera, such as urinary bladder
- Transmits weight to lower limbs
- Provides attachment for lower limbs
Pelvis =…?
pelvic girdle + sacrum + coccyx
Each hip bone consists of 3 fused bones which are…?
Ilium, Ischium, and Pubis
- Ilium (largest, most superior part):
- Iliac crest
- Iliac spines
- Greater sciatic notch
- Ischium (L-shaped, lowest part):
- Supports weight while sitting
- Ischial spines
- Ischial tuberosity
- Pubis (anterior portion):
- Pubic symphysis
- Pubic arch
Acetabulum
Depression for head of femur
Obturator Foramen
Opening between pubis and ischium
Female pelvis facts
- Functions as birth canal
- Iliac bones more flared
- Broader hips than male
- Pelvic cavity wider than male
- Pubic arch angle greater
- More distance between ischial spines and ischial tuberosities
- Sacral curvature shorter and flatter
- Lighter in weight
Male Pelvis
Less flared, heavier in weight
the Lower Limb Bones form…?
framework of each thigh, leg, and foot
What are the Bones of the lower limb?
- Femur
- Patella
- Tibia
- Fibula
- Tarsals
- Metatarsals
- Phalanges
Patella (Kneecap):
- Flat sesamoid bone located in the quadriceps tendon
- Anterior surface of knee joint
- Helps with lever actions with movement of lower limbs
Tarsal (Ankle) Bones (7):
- Calcaneus: Heel bone
- Talus: Articulates with tibia
- Navicular
- Cuboid
- Lateral cuneiform
- Intermediate cuneiform
- Medial cuneiform
How many bones are in the Metatarsal (Foot)?
5
Phalanges (Toe Bones, 14 ):
- Proximal
- Middle
- Distal
Life-Span Changes
- Decrease in height begins at about age 30
- Calcium levels fall
- Bones become brittle and more prone to fracture
- Osteoclasts outnumber osteoblasts
- Spongy bone weakens before compact bone
- Bone loss rapid in menopausal women
- Hip fractures common
- Vertebral compression fractures common
