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,Define the sagittal plane. What movements occur within - Divides the body along the midline into left and right halves
this plane?
- flexion/extension
Define the frontal plane. What movement occurs within - Separates the body into anterior (front) and posterior (back) portions
this plane? - abduction/adduction & side flexion
Define the transverse plane. What movement occurs - Separates the body into superior (toward the head/upper body) and inferior
within this plane? (away from the head) portions
- internal/external rotation & horizontal flexion/extension & supination/pronation
Define supination Lying face up
Define pronation Lying face down
Functions of skeletal system - provide form, structure and movement of body
- protection of internal organs
- attachment point for muscles
- RBC's produced in bone marrow
- warehouse for calcium, iron, and energy (fat)
How many bones in skeletal system? 206
What is the axial and appendicular skeleton? Axial Skeleton: runs along body's midline axis (skull, ribs, vertebral column)
Appendicular Skeleton: the limbs, pelvic girdle, and shoulder girdle
What are the 5 classifications of bones? What are some 1) Long Bones
characteristics of each? - grow the most throughout life; hollow medullary cavity for bone marrow
2) Short Bones
- as long as they are wide (ie. carpal bones in wrist)
3) Flat Bones
- very thin in one direction, no medullary cavity (ie. skull bones, hip bones)
4) Irregular Bones
- no regular shape (ie. vertebrae, sacrum, coccyx)
5) Sesamoid Bones
- formed after birth inside tendons; help protect from strains at the joint (ie.
patella)
Types of joints and their characteristics: 1) Synovial Joints:
- most common, have a fluid-filled gap between bones allowing for free ROM &
lubrication
2) Fibrous Joints:
- where bones are very tightly joined; little to no movement (ie. teeth into sockets)
3) Cartilaginous Joints:
- where two bones meet cartilage; provide small flexibility due to gel-like cartilage
How many muscles are there in the human body? ~700 named
What are the three types of muscle? Are the voluntary or - smooth and cardiac muscle: involuntary
involuntary?
- skeletal muscle: voluntary
What is the sarcolemma? What is it's function? - the cell membrane of a muscle fibre
- conducts electrochemical signals that stimulate muscle cells
, What is the function of transverse tubules (T-tubules)? Help carry electrochemical signals into the middle of the muscle fiber
What are myofibrils? What are they made up of? The contractile structures of a muscle fiber
- made up of protein fibers arranged into sarcomeres (functional unit of a muscle
fiber)
What are thick and thin filaments composed of? Thick: bonded units of myosin protein
Thin: three proteins - actin, tropomyosin, and troponin
What is the Sliding Filament Model? Actin filaments interact with myosin filaments appearing to "slide" over each other
- results in shortening of sarcomere and hence contraction of the muscle fiber
What is a motor unit? A single motor neuron and the muscle fibers it innervates
- the less muscle fibers a motor neuron innervates, the more fine motor control
that region has
Difference between ligaments and tendons? Ligaments: fibrous connective tissue connecting bone to bone
Tendons: tough fibrous connective tissue connective muscle to bone
What are the two main phases of contraction? 1) Isometric Contraction
- no visible shortening of muscle, tension is increasing
- sarcomere is shortening but elastic components parallel to muscle fibre are
stretching
2) Isotonic Contraction
- visible shortening of muscle, tension remains constant
What is Bowditch's Law? (The "all-or-nothing" law) MU's are either activated all the way or not at all
- stimulus threshold
What is the Henneman size principle? Number of MU's activated is proportional to stimulus received
- smaller MU's activated first moving to larger MU's at highest threshold
Characteristics of Slow-Twitch Oxidative Fibers (Type 1) - Structure: small diameter, high capillary density, large amount of mitochondria
Metabolic:
- depend on aerobic cellular respiration (lots of ATP but slower because of length
of oxidative pathway)
- Slowest contraction speed b/c of decreased myosin ATPase activity
- high myoglobin levels
- store energy as triglycerides
- Function: endurance (very fatigue resistant), postural muscles (low stimulation
threshold), lowest power production
Characteristics of Fast Oxidative fibers (Type 2a) - Structure: largest diameter, high capillary density, LOTS of mitochondria,
moderate amount of stored glycogen
Metabolic:
- depends on aerobic conditions (uses glucose +oxygen) but can switch to
anaerobic (PCr)
- fast contractility due to high myosin ATPase activity
- myoglobin density relatively high
Function:
- second fiber type recruited; moderate power production
- walking muscles (moderately fatigue resistant ~<30 mins)
- high intensity (ie. sprinting) but for no longer than 1 min.