Do Now

1. Do Now • What happened one year ago today? • During the height of the Boston Marathon, two homemade bombs were planted. Each was a pressure cooker filled with nails and screws. To cause maximum harm to people. • It went off at 2:48 April 15th 2013 killing 3 (including a young boy) and seriously injured hundreds.

2. Homework • Due Today: Find two sources (bring in the web sites) for each point you covered in your introductory paragraph. No Wikipedia • Pull that out now • Due Friday: Read pages 935 – 938. Read and summarize each section. For example: Integumentary system functions. • Look up on your lab write up when we add the herbicide to the plants. Know this for next class • Essay – see handout

3. What is plagiarism? • How would you define it? • What is a citation? • A method to acknowledge someone’s work • This is stating you are using the work, but crediting the person(s) that wrote it. • Properly acknowledging someone else’s work that you are using (borrowing). It also lets the author know that this piece of work can be trusted

4. Trust & Fact checking • For example: • http://www.dhmo.org/facts.html • Trust – meaning how do you know what is accurate and what is made what up?

6. One more plagiarism situation • Re-cycling a paper and claiming it is “new work” • Several seniors did this in the winter. We took it as an opportunity to teach now so problems do not happen later. • In college it follows under “Academic Dishonesty”

7. Plagiarism • What is the difference between plagiarism, paraphrasing and direction quotation? • Plagiarism – is essentially taking work that someone else created and calling it your own word (the cut & paste method) • Paraphrasing – acknowledges that this is not your own work simply used but given credit. • Direct quotation is writing down something that someone said in the past.

8. Muscular System • Cardiac muscle – is somewhat a combination of smooth & skeletal. • Smooth because the person has no control over them. • Like skeletal because it is very strong and fibrous (striation). • The heart can never stop beating or tire. • It has its own impulse to beat known as a pacemaker. Some people have an external pace because their heart does not beat on its own.

9. Muscular Contraction • What is a muscle contraction? • It occurs in the body when movement is necessary. It is when muscle is shortened. • Skeletal muscles are filled with bundles of filaments called myofibrils. • Myo means muscle • Each myofibril contains a layer of protein called myosin (thick layered) and a thin layer of protein called actin

10. Muscular Contraction • These thick & thin layered fibers are weaved together or overlaid which produced what looks like stripes. • The thin actin filaments are arranged in Z- lines. • Two Z-lines and the filament between them form a sacromere

11. Muscular Contraction • During a contraction, myosin filaments form a cross-bridge with the actin filaments. • These cross bridges change shape and pull the actin filaments to the center of the sacromere. • Then it detaches and then it repeats. As they slide the muscle shortens or contracts. • The process is known as the sliding filament theory

12. Muscular Contraction • A motor neuron (where the impulse to contract travels) meets with a skeletal muscle at a junction (synapse) called a neurotransmitter junction. • When stimulated, the axon end or terminals release acetylcholine and cross the synapse to produce an impulse. This will cause the release of calcium in the muscle fibers. They regulate proteins to allow myosin cross bridges to bind with actin.

13. Muscular Contraction • As long as acetylcholine is present the muscle will continue to contract. • Does your body know the difference between lifting something heavy and something light? • Yes, doing things over and over your brain matches the weight with the necessary contractions to lift the object. • Your body can lift, push or pull through a contraction.

14. Muscular Contraction • As long as acetylcholine is present the muscle will continue to contract. • Does your body know the difference between lifting something heavy and something light? • Yes, doing things over and over your brain matches the weight with the necessary contractions to lift the object. • Your body can lift, push or pull through a contraction. • Muscles typically have opposing pairs, meaning while one contracts the other is at rest.

15. Muscular Contraction • Muscle fiber types: Red versus white • Red muscles are aka slow twitch muscles which means they contain many mitochondria. They are deep red due to the supply of oxygen rich blood. • These type of muscles are designed for endurance (long lasting activities) such as marathons. • White fibers are fast twitch muscles. These white fibers can create a great deal of force but tire quickly (compared to red or dark muscles). Fewer mitochondria are found in White Fibers. A sprinter would want to have more white (Fast Twitch) and a marathoner would want slow twitch

16. Muscular Contraction • Aerobic (make use of oxygen and are activities such as running) exercises help to strengthen the heart & lungs. Which is why athletes have a lower heart rate, their body is more efficient. • It also strengthens bones as well as connective tissue. • Following a ligament sprain, a physical therapist would focus development on strengthen the muscles to support the ligament.