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The Muscular System. Section 13.3 page 526. The human body has over 600 muscles!!!. I. Muscle Fuction. A. Muscles move the bones of your skeleton B. Muscles keep your heart beating
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The Muscular System Section 13.3 page 526
I. Muscle Fuction A. Muscles move the bones of your skeleton B. Muscles keep your heart beating C. Muscles perform required functions to keep you alive. (Move your ribcage, move food through your digestive track, etc.)
II. Types of Muscle A. Involuntary Muscle- not under your conscious control.
1. Smooth Muscle- involuntary and works automatically to control many of your body functions like: * churning food in your stomach * squeezing of food in your esophagus and intestines (peristalsis) * pulling the ribcage up and out for breathing
Smooth muscles react slowly and tires slowly… They also have no STRIPES (striations)
2. Cardiac muscle- involuntary and found in your heart. Has stripes (striations) and does not tire. It beats about 72 times per minute for your lifetime.
B.Voluntary Muscle 1. Skeletal muscle *attached to the bones of your skeleton by tendons *has striations *conscious control voluntary *reacts quickly, but tires quickly.
Activity 1- Finger clicking… 1. Prediction:Will trial 1 or 2 have the highest number of clicks. Why? Trial 1:-_____ Trial 2:- _____
2. Outcome: Why did the results come out the way they did? List 3 possible reasons. • a. • b. • c.
3. Prediction: What do you think will happen with your other hand if you repeat the same exercise? Faster/slower and why? Trial 1: _____ 4. Outcome:
III. Muscles at Work 1. Messages from the brain are sent to your muscles 2. The muscle shortens or contracts 3. The attached bone moves
Muscles Work in Pairs (page 529) 1. Since muscle cells can only contract (then relax) they must work in pairs… 2.When one muscle contracts, the other must relax.
3. When you flex your arm…(Use your book to complete the statement)
B. Muscular Strength and Flexibility (page 530) List three key points from each paragraph. Paragraph 1: 1. 2. 3. Paragraph 2: 4. 5. 6.
Activity 2: • With your arm at your side bend you elbow upward at a 90 degree angle • Hold your palm facing up and open. • Balance a textbook in your open palm for 3 minutes • Feel the biceps and triceps muscles. • Which of them feels hard?
Activity 3 • Grasp the book in your hand and hold your arm up over your head. • Bend it at the elbow so the book hangs behind your back. • Slowly straighten your arm about two-thirds of the way and hold the book in that position for 3 minutes. • Which muscle feels hard and tense?
Assessment 13.3 • 1a. Skeletal, smooth and cardiac • 1b. voluntary- under conscious control, tire easily. (skeletal muscle) involuntary- not able to control, don’t tire easily (heart and smooth muscle). • 1C. Person can’t move finger because muscle not connected to the bone.
2a.Attached to the bones of the skeleton ie. Upper arm and thigh. 2b.Bend the arm- biceps contracts pulling the arm up and the triceps relaxes. Straighten the arm- triceps contracts and the biceps relaxes. 2c.Exercising both muscles in a pair will make them grow equally strong.