Block 2: Skeletal System - Lecture 2.1

Question 1

What are the major structures of the Skeletal System?

Answer 1

• Bones, Cartilage, Ligaments, Epithelial Tissue, and Nervous Tissue
  a. *mostly cartilage
• Other Connective Tissues
  a. Blood CT, Dense Regular CT, and Dense Irregular CT

Question 2

What are the major functions of the Skeletal System?

Answer 2

• Support
  a. rigidity
• Protection
• Movement
  a. muscles pull on bones
• Storage of Fats and Minerals
  a. fat: deep in bone as yellow or red marrow
  b. mineral: calcium
• Blood Cell Production
  a. occurs all the time!

Question 3

Each individual bone is an organ that contains what?

Answer 3

• Bone Connective Tissue
• Blood & Lymph Vessels
• Nerves
• Cartilage Connective Tissue
• Connective Tissue Coverings
  a. provide sensory input

Question 4

What is a major characteristic of the Skeletal System?

Answer 4

The Skeletal System is very dynamic, which means it can change easily!

Question 5

What types of Connective Tissues are Ligaments composed of?

Answer 5

• Dense Regular CT
• Dense Irregular CT
• Tendons

Question 6

What are some characteristics of Cartilage in bones?

Answer 6

• Characteristics
  a. precursor to bone or “cartilage before bone”
  b. protection
  c. more flexible than bone itself
• Functions
  a. connects bones together (articulations)
  b. provides range of motion for bones
• Types of Cartilage Found in Bones
  a. Hyaline
  b. Elastic
  c. Fibrocartilage

Question 7

Where can Hyaline Cartilage be found in the Skeletal System?

Answer 7

• Ends of Bones
• Attaching Ribs to Sternum
• Thyroid Gland
• Nasal Cavity
  a. between hyaline cartilage and elastic cartilage

Question 8

Where can Elastic Cartilage be found in the Skeletal System?

Answer 8

• External Ear
• Epiglottis
• Nasal Cavity
  a. between hyaline cartilage and elastic cartilage

Question 9

What are the two anatomical classifications of the Skeletal System?

Answer 9

• Axial
• Appendicular

Question 10

Where can Fibrocartilage be found in the Skeletal System?

Answer 10

• Meniscus
  a. pad-like cartilage in the knee joint
• Between Vertebrae

Question 11

What are some characteristics of the Axial skeleton?

Answer 11

• Functions
  a. creates the vertical axis of the body
  b. houses vital organs for protection
• 80 Bones
  a. skull - 22 bones
  b. hyoid - 1 bone
  c. auditory ossicles - 6 bones, 3 for each ear
  d. vertebral column - 26 bones
  e. thoracic cage - 25 bones

Question 12

What are some characteristics of the Appendicular skeleton?

Answer 12

• Functions
  a. allows for mobility
  b. attached to the axial skeleton
• 126 Total Bones
  a. pectoral girdle - 4 bones, 2 for each shoulder
  b. arms/upper limbs - 60 bones, 30 for each arm
  c. pelvic girdle - 2 bones, 1 for each hip
  d. legs/lower limbs - 60 bones, 30 for each leg

Question 13

How many bones are in the body?

Answer 13

• Full Grown Adult = 206 Bones
• Newborn Infant = 270 Bones

*Some individuals have more, some have less

Question 14

What are the Bone Classification Shape types?

Answer 14

• Long Bones
  a. structure: longer than they are wide
  b. examples: humerus and femur
• Short Bones
  a. structure: almost cube shaped
  b. examples: wrist and ankle bones
• Flat Bones
  a. structure: thinner than long and short bones and typically curved
  b. examples: ribs, sternum, and cranial bones
• Irregular Bones
  a. structure: complex shape that doesn’t fit into the three categories above
  b. examples: vertebrae
• Sesamoid Bones
  a. structure: shaped like a sesame seed and forms at high friction points
  b. typically form where two bones articulate
  c. examples: patella - protects patellar tendon
• Sutural Bones
  a. structure: bones that form between cranial bone sutures called Wormian Bones
  b. examples: varies between individuals

Question 15

What are the typical components of the Gross Anatomy of bone?

Answer 15

• Compact (Dense) Bone
  a. outer layer of bone that contains osteons
• Spongy (Trabecular) Bone
  a. inner (medullary) cavity of bone
  b. location: between compact bone and middle of long bones

Question 16

What are the components of the Gross Anatomy of Short, Irregular, Flat, Sutural, and Sesamoid Bones?

Answer 16

• Sandwich
  a. compact bone –> spongy bone –> compact bone
• Example: Diploë
  a. spongy bone within the cranial bones
  b. allows for trauma to spread so the impact is all over the bone instead of over one area

Question 17

What are the components of the Gross Anatomy of Long Bones?

Answer 17

• Epiphysis: ends of long bones
  a. 2 per bone
• Diaphysis: middle section of long bones
  a. 1 per bone
• Metaphysis/Epiphyseal Plate/Line: connects epiphysis and diaphysis
  a. 2 per bone
• Layers of Long Bones (Superficial to Deep): integrate with muscle attachment
  a. periosteum
  b. compact bone
  c. spongy bone
  d. endosteum (connective tissue)
  e. medullary cavity (fat & mineral storage and where red & yellow marrow are located)

Question 18

What are some characteristics of the Periosteum?

Answer 18

• Location:
  a. connective tissue on outer surface layer of long and living bone
• Contains arteries to carry nutrients and perforating collagen fibers
• Functions
  a. isolates and protects bone (very strong)
  b. supports blood vessels & nerves
  c. connects to fascial layers of muscles
  d. allows for bone growth and repair through the osteogenic layer, which contains osteogenic
  cells or bone stem cells