Skeletal System
What are the 4 types of cells found in bone? Describe them.
●osteogenic cells – stem cells
●osteoblasts – bone-forming cells
• osteocytes – mature bone cells
• osteoclasts – these are large cells that resorb/break down the bone matrix
What 2 ways are joints classified?
Structural: based on what type of material is present (Fibrous, cartilaginous, synovial)
Functional: How much movement is allowed (Synarthrotic, amphiarthrotic, diarthrotic)<- what do these mean?
What is sarcolemma?
How about sarcoplasm?
Sarcolemma is the membrane of a muscle cell.
Sarcoplasm is the cytoplasm of a muscle cell.
What are the 4 functional characteristics of muscle tissue?
TRIPLE E-C
• Extensibility – the ability to be stretched or extended
• Elasticity – the ability to recoil and resume the original resting length
• Excitability– the ability to receive and respond to stimuli
• Contractility – the ability to shorten forcibly
What are the 6 functions of bones?
Support, protection, movement, mineral storage, blood cell formation, fat storage
What type of synovial joint are the hip joints and shoulders examples of?
Ball-and-socket joint. VERY MOVEABLE!!!
Which is stronger: The hamstring muscle group or the quadricep muscle group?
The quads
What are the 2 regulatory proteins found in actin?
Troponin- binds calcium ions.
Tropomyosin- Stiffen and stabilize actin
What are the 3 types of cartilage that we look at and where can they be found?
Elastic- Ear and epiglottis
Hyaline- ends of long bones, nose, and costal region of ribs
Fibrocartilage- Knee and intervertebral discs
What is a Bursa?
A bursa is flattened, fibrous sac lined with synovial membranes. Provide cushion and resistance
What is the structural organization of muscle from the organ level to the macromolecule structure?
Muscle -> Fassicle -> Muscle Fiber/Cell -> Myofibril -> Sarcomere -> Myofilament
What substances are required for muscles to contract? What does muscle contraction produce?
ATP and creatine phosphate are required for muscles to contract. Muscle contraction produces lactic acid.
What is the structure of a long bone? What can be found in the different regions?
A proximal and distal epiphyses with an outer layer of compact bone and inner layer of spongy bone.
A middle diaphysis made of compact bone that surrounds yellow bone marrow (fat)
What are some types of movement allowed by synovial joints?
•Flexion — bending movement; joint angle decreases
•Extension — reverse of flexion; joint angle increases
•Abduction — movement away from the midline
•Adduction — movement toward the midline
•Circumduction — movement describes a cone
•Rotation – movement describes turning of a bone
What is the structure of a myosin molecule?
A myosin filament has one rod-like tail and two globular heads.
What steps are required for skeletal muscle contraction?
• stimulation by a nerve ending
• propagation of a nerve impulse along sarcolemma
• rise in intracellular calcium levels
What is Wolff’s Law (Think structure fits functions).
Wolff’s Law states that a bone grows or remodels in response to the forces or demands placed upon it.
Ex: Curved bones are thickest where they are most likely to buckle!
What is a sprain?
What is tendonitis?
A sprain occurs when the ligaments reinforcing a joint are stretched or torn.
Tendonitis occurs when the tendon sheaths become inflamed due to overuse.
What are the 2 filaments found in muscle? How does their organization relate to A bands and I bands?
Actin (thin blue) filaments and Myosin (thick red) filaments overlap to create dark (A) bands. The section in which actin filaments do not overlap with the myosin filaments are called light (I) bands.
What is the difference between isometric contraction and isotonic contraction?
•Isometric contraction – increasing muscle tension (muscle does not shorten during contraction)
•Isotonic contraction – decreasing muscle length (muscle shortens during contraction)