1. The Muscular System
FQ: What is the hierarchal structure of a muscle cell from the tiniest fiber to the largest muscle mass?
ET: Grab a copy of the article from the front of the room? Read and highlight important information from the article

2. The Muscular System Focus Questions
ET: What are the four major roles of muscle tissue in the body? Use book
Focus Questions
FQ: What are the following: endomysium, perimysium, epimysium, tendon, and aponeurosis?
Coloring Sheet
POGIL

3. The Function of Muscles
Four important roles for the body:
Produce movement
Maintain posture
Stabilize joints
Generate Heat

4. Review of Muscle Tissue Types
All muscle cells are elongated, thus we call them fibers
All muscle cells can contract
Myo/Mys (muscle)
Sarco (flesh)

5. Skeletal Muscle Connects muscle to bone Appears striped (striated)
Voluntary
May contract rapidly, and forcefully but tires easily
Structure
Endomysium
Perimysium
epimysium

6. Smooth Muscle No striations
Involuntary, slow and constant contractions
Lines hollow visceral organs – stomach, bladder, intestines
Propels substances along a definite track within the body – food
Double layered Sheet of thin cells running circularly and longitudinally

7. Cardiac Muscle Heart only Striated Slow, constant contractions
Figure-8 shaped bundles that pump blood

8. Microscopic Anatomy of Skeletal Muscle
Sarcolemma – the plasma membrane
Myofibrils – bundles of myosin (thick) and actin (thin) proteins
Sarcoplasmic reticulum – Store and release calcium for muscle contraction

9. Lesson 2 Skeletal Muscle Activity
Muscular System
Lesson 2
Skeletal Muscle Activity

10. Stimulation and Contraction of Muscles
ET: Review anatomy of a skeletal muscle cell using your coloring sheet.
FQ: How do muscles contract/move?

11. Nerve Stimulus and Action Potential
The neurotransmitter Acetylcholine (Ach) is released by Axon terminal.
This rush of positively charged ions creates a concentrations gradient/electrical current called an Action Potential.
This makes the membrane of the muscle fiber (sarcolemma) permeable to sodium ions.

12. Mechanism of Muscle Contraction 1
Mechanism of Muscle Contraction 1. Ca+ ions cause troponin and tropomyosin (regulatory proteins) on the actin filament to change shape and move out of the way so that myosin can bind to it forming a cross bridge 2. using ATP, the myosin head bends toward the center of the sarcomere pulling actin filament (power stroke) 3. Detachment – ATP binds to the myosin head and weakens the cross bridge bond 4. The energy released by ATP reactivates the myosin for another contraction to occur

13. Lesson 3 Providing Energy for Contraction
Muscular System
Lesson 3
Providing Energy for Contraction

14. How does muscle keep up with all the ATP that they need?
3 Pathways
Direct phosphorylation of ADP by creatine phosphate
Aerobic respiration
Lactic acid fermentation

15. Direct phosphorylation of ADP by Creatine Phosphate
Creatine phosphate gives its phosphate to ADP to make ATP
CP stores only last about 20 seconds

16. Aerobic Respiration Requires Oxygen 36 ATP / Glucose
Slow compared to CP
Aerobic Respiration

17. Lactic Acid Fermentation
Does not require oxygen
Quicker than CR (2.5 x faster)
Uses huge amounts of glucose for not a lot of ATP
Good for 30 to 40 seconds of strenuous exercise
Build up of lactic acid causes muscle fatigue and soreness

18. 2 Types of Muscle Contraction
Isometric – when the fibers attach but cannot slide, like when you try and lift something too heavy. The muscle cannot contract, even though you are engaging it to lift something
Isotonic – Normal muscle contraction where the fibers are successful in their sliding motion

19. What is Muscle “TONE”??
Continuous partial contraction that cannot be consciously controlled
The nervous system stimulates these fibers in a systematic way all the time so that you can move when you decide to move

20. How Does Exercise Effect Muscles?
Aerobic exercise causes muscles to become flexible with a greater resistance to fatigue
Blood supply to the cell increases
Mitochondria increase in number
Increases overall body cell metabolism
Strengthens bone
Strengthens and enlarges the heart
Improves gas exchange in the lungs

21. How Does Exercise Effect Muscles?
Resistance training (isometric) causes individual muscle cells to develop more fibers and connective tissue
Increases strength and ability to lift
If you exercise your core you’re a providing stability to your entire body