Muscles And their close connection to the nervous, skeletal, and respiratory/cardiac systems
Skeletons Hydrostatic Skeletons: Fluid is held underpressure and muscles control movement. Ex. Circular and longitudinal muscles in worms. Hard Skeletons: Hard supporting elements such as bones, plates that are moved by muscles. Ex. Endoskeletons & Exoskeletons
Exoskeletons vs. Endoskeletons Compare and contrast Material Position Mechanism for movement
3 Roles for the Human Skeletal System Protection Movement Blood cell formation Can you think of a bone that is an example of each?
Skeletal and Musclar Systems Interact Be able to distinguish Muscles Bones Tendons Ligaments Joints Cartilage
Muscles contract for movement Antagonistic pairs. One contracts (Flexor) One relaxes (Extensor)
Skeletal Muscle at the microscopic level Note that each muscle cell contains actin and myosin arranged in a specific manner.
Describe a Muscle Contraction Sarcomere: A band: Z lines: H band: I band: M line:
Sliding Filament Theory
Structure Meets Function: How do the heads bind? Role of Ca2+ Role of Tropomyosin Role of Troponin
Control: How nerves control muscles
Similar to threshold Tetanus Action potentials combine together and a series at high frequency leads to a contraction.
Which would have more mitochondria? Fast fibers Quick rapid contractions Need lots of calcium storage “White Meat” Slow Fibers Long sustained contractions require steady energy. Less smooth ER (sarcoplasmic reticulum) “Dark meat” rich blood supply
Goals Review muscles with Campbell’s activities 49C and 49D Observe a frog’s muscles. Use the web and microscopes to observe the structural differences and determine the functions of skeletal, cardiac, and smooth muscle.
Comparison of Muscle Tissue