Class notes
Skeletal System Summary [Essential of Human Anatomy and Physiology]
- Course
- Nursing
- Institution
- Trent University (TrentU )
Skeletal System Summary [Essential of Human Anatomy and Physiology]
[Show more]
Connected book
Book Title:
Author(s):
- Edition:
- ISBN:
- Edition:
Seller
Follow
Content preview
SKELETAL SYSTEM c. Bone substance – EM and cells§ It consists of the bone, cartilage, tendons and
ligaments. Histology of Bone
§ Skeleton; dried (Greek) Osteoblasts – bone-forming cells; repair and remodeling
of bone
Functions (S2PMB)
1. Support Osteocytes – bone cells located between the lamellae
2. Protection (thins sheets of EM)
3. Movement
4. Storage Lacunae – spaces within the lamellae
5. Blood cell production
Canaliculi – tiny canals within the lamellae
Extracellular Matrix
§ Composed of connective tissues Types of Bone Tissue
a. Compact bone
Collagen – tough ropelike protein § Forms most of the diaphysis of long bones
§ Central Canal / Haversian Canal – concentric
Proteoglycans – large molecules consisting of rings that contains blood vessels; ‘bull’s eye’
polysaccharides attached to core proteins § Osteon / Haversian System – central canal +
lamellae + osteocytes
Tendons & Ligaments – large amounts of collagen fiber
b. Spongy bone
Cartilage – contains collagen & proteoglycans § Located mainly in the epiphyses of long bones
§ Forms the interior of all other bones
Bone – contains collagen and minerals (Calcium & § Consists of trabeculae (interconnecting rods,
Phosphate) plates of bone) without central canals
Hydroxyapatite – calcium phosphate crystals Bone Ossification
Ossification – formation of bone by osteoblasts
General Features of Bone
§ Long bones; upper and lower limbs Types of Ossification
§ Short bones; wrist and ankle a. Intramembranous ossification – osteoblasts
§ begin to produce bone in connective tissue
§ Irregular bones; vertebrae and facial bones Ø Ossification centers – where
intramembranous ossification begins
Long Bones
a) Diaphysis – central shaft b. Endochondral ossification – bone formation
b) Epiphysis – ends occurs inside the cartilage; bones at the base of
c) Epiphyseal plates – growth plate; where the the skull and remaining skeletal system are
bone grows in length formed
Ø Chondrocytes – cartilage cells; increase
Articular cartilage – covers the ends of the epiphyses in no., enlarge, and die
Epiphyseal line – bone growth stops and the epiphyseal Primary ossification center – where bone first begins to
plate is replaced by bone appear
Medullary Cavity – large cavity in the diaphysis; Osteoclasts – cells that remove calcified cartilage matrix
contains the marrow
Secondary ossification center – form in the epiphyses
Marrow – soft tissue within the cavity
Bone Growth
Yellow Marrow – consists of adipose tissue (fat) § Deposition of new bone lamellae onto existing
bone
Red Marrow – consists of bone forming cells; site of § Bone elongation occurs at the epiphyseal plate;
blood formation leads to increase in height (endochondral
ossification)
Layers of a Bone § Chondrocytes proliferate, enlarge, die, and are
a. Periosteum – outermost layer; surround the replaced by bone
diaphysis; contain blood vessels, nerves,
osteoblasts Appositional growth – increase in bone width or
diameter
b. Endosteum – innermost layer; lines the
medullary cavity (thinner connective tissue)
M o r a n o , M . A .
, Bone Remodeling AXIAL SKELETON
§ Removal of existing bone by osteoclasts § Composed of the skull, vertebral column, and
§ Deposition of new bone by osteoblasts thoracic cage
§ Responsible for change in bone shape, bone § Form the longitudinal axis of the body
adjustment, repair, and calcium ion regulation
I. Skull
Bone Repair § 22 bones
§ Clot is formed in the damaged area
§ Blood vessels and cells invade the clot and form Braincase
a callus (network of fibers and islets of cartilage) § 8 bones
§ Osteoblasts enter the callus and from a spongy § Covers and protects the fragile brain tissue
bone
§ Bone is slowly remodeled to compact bone 1. Frontal Bone – forehead, bony projections
under the eyebrow, part of the eye’s orbit
Bone and Calcium Homeostasis
§ Osteoclasts remove calcium = blood calcium 2 - 3. Parietal Bone (paired) – the superior and
levels increases lateral walls of the cranium; coronal suture
§ Osteoblasts deposit calcium = blood calcium
levels decrease 4 - 5. Temporal Bone (paired) – lies inferior to
the parietal bone; squamous suture
Hormones that maintain Calcium Homeostasis Ø External Auditory Meatus (EAM) – a
1. Parathyroid hormone (PTH) canal that leads to the eardrum and the
§ Parathyroid gland; middle ear
§ Increase bone breakdown & increase blood Ø Styloid process – a sharp, needlelike
calcium levels; structure located inferior to the EAM
§ Stimulates the kidneys to from active vitamin D Ø Zygomatic process – a bridge of bone
that joins with the cheekbone anteriorly
2. Calcitonin Ø Mastoid Process – a rough projection
§ Thyroid gland posterior and inferior to the EAM
§ Decrease bone breakdown and decrease blood
calcium levels 6. Occipital Bone – inferior and posterior bone
of the cranium; lambdoid suture
General Considerations of Bone Anatomy Ø Foramen magnum – where the spinal
§ 206 bones = adult cord joins the brain
§ 276 bones = newborn baby Ø Occipital condyles –rests on the first
vertebra of the vertebral column
Foramen – hole in a bone Ø Foramen ovale – allows the fiber of
cranial nerve 5 to pass
Canal / Meatus – elongated hole in a tunnel like body
7. Sphenoid Bone – butterfly-shaped bone that
Fossa – depression in a bone spans the width of the skull
Ø Sella Turtica – saddle-shaped structure
Tubercle / Tuberosity – lump on a bone at the central region; contains the
pituitary gand
Process – projection from a bone
8. Ethmoid Bone –
irregularly shaped bone that
Condyle – end of a bine that forms a joint with another lies anterior to the sphenoid bone
bone
Facial bones
Facet – small flattened articular surface § 14 bones; 13 solidly connected, 1 movable
(mandible)
Crest – prominent ridge § Holds the facial muscles in place
§ Joined together by sutures (interlocking,
Trochanter – tuberosity found only on proximal femur immovable)
Fissure – cleft 1-2. Maxillae – main bones of the face; carries
the upper teeth
Sinus – cavity
3-4. Palatine Bones – lies posterior to the
Suture – a joint uniting the bones of the skull palatine processes of the maxilla
5-6. Zygomatic Bones – cheekbones
M o r a n o , M . A .
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller rarereads. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for CA$11.79. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
56326 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now