HS1-1 Introduction to the Musculoskeletal System Flashcards
How many components of the axial skeleton are there, and what are they?
four components: skull vertebral column ribs sternum
How many components of the appendicular skeleton are there, and what are they?
two components:
pectoral girdle
pelvic girdle
What is the pectoral girdle?
incomplete girdle that provides support for upper limbs
What are the two major components of the pectoral girdle?
scapula
clavicle
What is the pelvic girdle?
girdle that transmits weight of trunk to lower limbs and supports lower limbs
What are the four major components of the pelvic girdle?
hip bones (pubis, ischium, ilium) and sacrum
How does cartilage receive its nutrition?
through diffusion, since it is avascular
What are the four major functions of the cartilage?
replaces bone when increased flexibility is needed
provides protection of bone surfaces in joints
provides support of soft tissues
enables bone growth and elongation of long bones
To which skeleton — axial or appendicular — does the sacrum belong?
the sacrum is part of the axial skeleton
What are the three types of joints?
fibrous
cartilaginous
synovial
Describe fibrous joints.
restricted movement
What are the two types of cartilaginous joints?
primary cartilaginous joints
secondary cartilaginous joints
Describe cartilaginous joints.
united by hyaline cartilage or fibrocartilage
Describe primary cartilaginous joints.
temporary joints seen during development
Describe secondary cartilaginous joints.
strong, slightly movable joints united by fibrocartilage.
Describe synovial joints. (2)
fluid-containing joint cavity
most common joint in the body
Describe the articular capsule.
bones are separated by cavity but united by an articular capsule reinforced by ligaments
Describe the synovial membrane.
lines the inner surface of the articular capsule and secretes synovial fluid
What is synovial fluid?
viscous substance that resembles the white of an egg
Describe the articular cartilage.
covers the articulating surfaces of bones within the joint capsule
Describe ligament.
dense fibrous connective tissue that is generally collagenous in substance
Define osteokinematics.
motion of bones relative to the 3 principal planes of the body
Define tendon.
the portion of the muscle that attaches to bone
Define isometric contraction.
occurs when a muscle is producing active force while maintaining a constant length
Define concentric contraction.
occurs as a muscle produces active forces as it shortens
Define eccentric contraction.
occurs when a muscle produces active forces as it increases in length
What is an agonist muscle?
muscle that has primary responsibility for initiating desired movement
What are synergists?
group of muscles sharing the same function
What are antagonists?
group of muscles that have opposite function to prime mover or synergistic muscles
What are fixators?
when prime movers and antagonists contract together, they behave as fixators and stabilize a joint
What is the structural unit of a muscle?
muscle fiber, each of which is innervated by one motor axon
What is the functional unit of a muscle?
motor unit, which consists of the motoneuron and all the muscle fibers it innervates
Which type of muscle contraction is most likely to cause injury?
eccentric
What comprises a motor unit?
motor neuron + muscle fiber
What is the function of a vertebral body?
support weight
What is the function of vertebral arches?
protection
What comprises the vertebral arch?
lamina + pedicles
What is the function of vertebral processes?
muscle/tendon attachment
