1C Flashcards
Skeletal System
System of the body, which forms a solid framework around which the body is built.
What is the skeletal system composed of?
Bones and cartilage.
Functions of the skeletal system.
A. Support of the body.
B. Attachment for skeletal muscles (origin, insertion).
C. Protection of certain vital organs (ex. brain by skull; heart by thoracic cage).
D. Manufacture certain blood cells: hemopoiesis (bone marrow).
E. Storage of certain chemical substances (ex. calcium, phosphate).
Types of bones in the skeletal system.
Long bone, short bone, flat bone, and irregular bone
Long Bone
A bone in which the length exceeds the width, and is characterized by having a medullary (marrow) canal.
Example: humerous
Short Bone
A bone in which the length equals the width.
Example: Carpal Bones
Flat Bone
A bone expanded into 1 plane.
Example: Scapula
Irregular Bone
A bone that does not fit into any of the other 3 categories.
Example: Vertebrae
Divisions of the Skeleton.
Axial and appendicular
Axial Skeleton
Part of the skeleton that occupies the central axis of the body.
Bones of the Axial Skeleton.
- Skull and hyoid (23)
- Vertebral Column (7 cervical, 12 thoracic, 5 lumbar, sacrum, and coccyx=26)
- Ribs and Sternum (12 pairs of ribs + sternum=25)
- Bones of middle ear (3 per side=6)
Total: 80 Axial Skeleton Bones
Appendicular Skeleton
Part of the skeleton that compromises the appendages.
Two limbs of the appendicular skeleton.
Upper Limb and Lower Limb.
Bones of the Upper Limb
- Clavicle: collar bone
- Scapula: shoulder blade
- Humerus: arm
- Ulna and Radius: forearm
- Eight Carpal Bones: wrist
- Five Metacarpal Bones: palm
- Fourteen Phalanges: fingers
Total: 64 Upper Limb Bones
Bones of the Lower Limb
- Hip Bone
- Femur: thigh
- Patella
- Tibia and Fibula: Leg
- Seven Tarsal Bones: Ankle
- Five Metatarsal Bones: Foot
- Fourteen Phalanges: toes
Total: 62 Lower Limb Bones
How many bones are in the appendicular skeleton?
206
Sesamoid Bone
Bone located in the tendons; not counted in the 206.
Ectopic Bone
Pathological bone formation; not counted in the 206.
What is the long bone composed of?
- Epiphysis
- Diaphysis
- Compact Bone
- Spongy Bone
- Periosteum
- Endosteum
- Medullary Cavity
- Articular Cartilage
- Articular Capsule
- Epiphyseal Disc
- Metaphysis
Epiphysis
The two ends of the long bone, which are wider than the shaft and take part in the formation of a joint.
Diaphysis
Shaft of long bone.
Compact Bone
Bone laid down in concentric layers making it appear solid.
This type of bone forms the outer surface of all bones.
It is thicker in the diaphysis and thinner in the epiphysis.
Spongy Bone
Composed of very thin plates of bone that meet other plates of bone at various angles, leaving spaces between them.
Found in the epiphysis.
Periosteum
Connective tissue sheath composed of 2 layers:
Outer Layer: tough fibrous layer that serves as a place of insertion for muscle tendons.
Inner Layer: Delicate cellular layer responsible for producing growth in the diameter of the bone.
Endosteum
Thin, cellular layer found lining the medullary cavity and the cavities of spongy bone.
Its primary function is to destroy, thus allowing for growth in the diameter of the marrow cavity, which prevents bone from becoming solid and heavy as it increases in size.
Medullary (marrow) Cavity
Cavity running the length of the diaphysis that contains either red marrow (which actively forms blood cells), yellow marrow (where fat cells are stored), or combinations of the two.
Articular Cartilage
Thin layer of hyaline cartilage covering the articular surface of the epiphysis.
Resiliency of this material cushions the joint during movement.
Articular Capsule
Connects together the 2 bones and completely encircles the joint, thus enclosing a cavity that is called the joint cavity or synovial cavity.
Composed of 2 layers:
- Outer Fibrous Layer: continuous with the periosteum
- Inner Layer (Synovial Membrane): lines the inside of the fibrous layer; quite vascular and produces synovial fluid that fills the joint cavity, lubricates the joint, and nourishes the articular cartilage.
Epiphyseal Disc
In embryo of a growing child, it is a cartilaginous plate located at the junction of epiphysis and diaphysis that allows for growth in the length of the bone.
This disc is not present when growth is complete.
Metaphysis
Spongy bone tissue located at the junction of diaphysis and the epiphyseal disc.
In the adult, the bony tissue of the metaphysis is continuous with the epiphysis.
Cartilage
A tough connective tissue, which is composed of cells embedded in a firm, gel-like intercellular substance.
Characteristics of Cartilage
- It is not as hard as bone, and exhibits some degree of flexibility.
- It is called gristle by laymen.
- It lacks nerves.
- It lacks blood vessels; nutrients diffuse through the intercellular substance.
- The entire embryo skeleton is initially cartilage, but it is replaced by bone during growth (ossification).
- The classification of cartilage is via the histologic appearance of the intercellular matrix.
Three Types of Cartilage
Hyaline, Fibrocartilage, and Elastic.
Hyaline Cartilage
Has a glassy, translucent appearance.
- Embryo
- Epiphyseal Discs
- Articular Cartilages
- Costal Cartilages (b/w ribs and sternum)
- Larynx, trachea, and bronchi (respiratory system)
- Nasal Cartilages
Fibrocartilage
- Interpubic disc (symphysis pubis)
- Intervertebral discs (b/w adjacent vertebrae)
Elastic Cartilage
- Auricle (part of external ear)
- Auditory tube (connects ear and pharynx)
- Epiglottis (flap that keeps food from entering lungs)
how many total bone(s) in the middle ear in the body?
a. 3
b. 1
c. 0
d. 6
e. none of the above
D
A bone in which it’s width equals it’s length is:
a. long bone
b. short bone
c. wedge bone
d. irregular bone
e. flat bone
B
Ectopic bone refers to
a. Anatomy of a bone
b. Is a pelvic structure in females
c. Pathological bone formation
d. Apex of the bone
e. None of the above
C
All of the following are functions of the skeletal system EXCEPT:
a. Attachments for muscles
b. movement of upper and lower appendages
c. Provides protection for vital organs
d. Supports the body
e. all of the above
B
Which bone is characterized by a marrow canal?
a. Humerus
b. carpal bones
c. scapula
d. vertebrae
A
Choose the statement(s) that is/are not considered a function of the skeletal system.
A. storage of certain chemical substances B. protection of underlying organs C. attachment for smooth muscles D. protection of the brain E. hemopoiesis
C
Choose the statement that best describes the articular capsule.
Select one:
A. the inner layer is continuous with the periosteum of bone
B. produces synovial fluid that lubricates the joint and nourishes the articular cartilage
C. connects together the two bones and partially encircles the joint
D. it is avascular
E. all of the above
B
This is considered a pathological bone formation.
A. irregular bone B. hyoid bone C. ectopic bone D. metaphysic E. sesamoid bone
C
How many bones can be found in the vertebral column?
A. 24 B. 12 C. 62 D. 31 E. none of the above
E
Which of the following option(s) are/is related to cartilage? (i.e. characteristics, examples, etc)
A. glossy, translucent appearance B. elastic C. intervertebral discs D. larynx, trachea, bronchi E. all of the above
E