Muscular System

Muscles and Muscle Tissue

Muscle Review Questions

ADD THESE TO YOUR PACKET ON BACK! 1. What are the three types of muscle tissue? What

are their functions? Where are they located in the body? Voluntary? Striated?

2. What are the four functions of muscle? 3. What are striations and why are they important to

the muscle fibers/whole body?’ 4. What are the 5 different sized stringlike structures

that make up muscle? (Macroscopic to microscopic) 5. What is the name of the two myofilaments? What

are the myofilament’s function in the body?

Microscopic Anatomy of a Skeletal Muscle Fiber PG 282-onwards!

Investigate the microanatomy of a muscle cell with your group.

1. Determine what a “sarcomere” is. How big is it? What function does it serve in the muscle cell?

2. Where are actin and myosin in the sarcomere? What filaments are “thick? Which filaments are “thin?”

3. What are A bands? I Bands? 4. What are H zones? Z Discs? M lines? 5. How do all of these bands and zones and discs

change when muscle contracts? (pg 289)

Agenda Welcome back! I missed you guys, had some

good food and rest over break in Minnesota, but it’s time to get back to education. :-D

3 Weeks left in the semester! Now is the time to give it everything you’ve got!

Be gritty, passionate, and persistent and finish this semester strong, no matter where your grade is at.

Agenda

Finish Introduction to Muscular System Exit Ticket (1st and 5th period), Review all

other periods. Notes 1pg on Muscles Video on Muscles Poke-a-muscle game!

Some Muscle Terminology

Myology: the scientific study of muscle

muscle fibers = muscle cells

myo, mys & sarco: word roots referring to muscle

Introduction

All movements require muscle which are organs using chemical energy to contract

Three Types of Muscle

Skeletal muscleCardiac muscleSmooth muscle

Skeletal Muscle

Most are attached by tendons to bones Cells are multinucleate Striated—have visible banding Voluntary—subject to conscious control Sites of muscle attachment

– Bones– Cartilages– Connective tissue coverings

Smooth Muscle

Lacks striations Spindle-shaped cells Single nucleus Involuntary—no conscious control Found mainly in the walls of hollow organs

Cardiac Muscle

Striations Usually has a single nucleus Branching cells Joined to another muscle cell at an

intercalated disc Involuntary Found only in the heart

Functions of Muscle Tissue

Motion: external (walking, running, talking, looking) and internal (heartbeat, blood pressure, digestion, elimination) body part movements

Posture: maintain body posture

Stabilization: stabilize joints – muscles have tone even at rest

Thermogenesis: generating heat by normal contractions and by shivering

Functional Characteristics

Excitability (irritability) – the ability to receive and respond to a stimulus

(chemical signal molecules) Contractility

– ability of muscle tissue to shorten Extensibility

– the ability to be stretched without damage– most muscles are arranged in functionally opposing pairs –

as one contracts, the other relaxes, which permits the relaxing muscle to be stretched back

Elasticity – the ability to return to its original shape

Conductivity (impulse transmission)– the ability to conduct excitation over length of muscle

Microscopic Anatomy of Skeletal Muscle

• Myofibrils—long organelles inside muscle cell

• Myofibrils complex organelle composed of bundles of myofilaments

• Sarcomeres segment (portion) of the myofibirls. – CONTRACTILE UNIT between 2

Z disks

• Myofilaments proteins that are within one sacromere

Anatomy of Skeletal Muscle Fiber = Muscle cell

Myofilaments

There are two types of Myofilaments:Thin filaments: made of actin

– I bands are the thin filamentsThick filaments: made of myosin

–H zone consists of only thick filaments A bands are made up of overlapping thick and thin filaments

Label the following muscles on the anterior body!

1. Biceps brachii 2. Wrist Flexors 3. Deltoid 4. Pectoralis Major 5. Serratus Anterior 6. External Obliques 7. Rectus Abdominis 8. Tensor Fascia Latae 9. Gastrocnemius* 10. Quadriceps

11. Sartorious 12. Tibialis Anterior 13. Adductors 14. Trapezius * 15. Frontalis (guess where it is) 16. Masseter (new one) 17. Soleus

* = on back but still visible