Test 1 Flashcards
How many bones are in the body?
206
The skeletal system provides ____ and ____
Support and protection
The skeletal system is pulled by ______ to allow the body to ______ or ____ against _____ _____
Muscles
Push or pull
External objects
Axial skeleton
Middle bones
Appendicular skeleton
Appendages
Junctions of the bones
Joint
Joint which allows virtually no movement
Fibrous joint
Joints which allow limited movement
Cartilaginous joints
Example of fibrous joints
Sutures of the skull
Example of cartilaginous joints
Intervertebral joints
Joints which allow considerable movement
Synovial joints
Examples of synovial joints
Elbows and knees
Types of synovial joints
Uniaxial
Biaxial
Multiaxial
Synovial joint which operates as a hinge/rotates about 1 axis
Uniaxial
Examples of uniaxial joints
Elbows and fingers
Synovial joints which operate in two perpendicular axes
Biaxial
Examples of biaxial joints are
Ankle and wrists
Synovial joints which allow movement on 3 axes
Multiaxial
Examples of multiaxial joints
Shoulders or hips
Movement in multiaxial joints an sometimes cause issues with
Stability
The vertebral column is made up of
Vertebrae and flexible discs
What allows movement in the vertebral column
Flexible discs between the bones
Muscle to bone
Tendon
Bone to bone
Ligament
Bundle or a bundle of muscle fibers
Fasciculus
What are muscle fibers made of?
Actin and myosin
What does a motor unit consist of?
Motor neuron and the muscle fibers which it innervates
How many muscle fibers are in a single motor unit?
Typically several hundred
A muscular contraction will not happen without
Calcium
Control of a contraction depends on what?
The number of muscle fibers in the motor unit
More control of a contraction means
Fewer fibers
Once an action potential is release what will happen
A contraction
What is the all or none principle?
Either an entire unit contracts or nothing happens
Brief muscle contraction
Twitch
Would a second twitch be stronger or weaker than the first?
Stronger
A second stimulus has to occur when?
Before relaxation of the first stimulus