Muscles Pre-test/Packet Muscles to Know Coloring Monday - 9/26/16 Question of the Day Agenda What are 3 every day functions that your muscular system allows you to do? Return tests Muscles Pre-test/Packet Muscles to Know Coloring Muscle Notes

Tuesday 9/27/16 Question of the Day Agenda Name the tissues that… Are involuntary? Are striated? Have intercalated disks? Are voluntary? Are attached to bone? Are in the heart? Are not striated? Moves substances along a pathway? 1. Review 2. Microscopic Anatomy of Skeletal Muscle Notes 3. DIY Skeletal Muscle

Thursday - 9/29/16 Thin myofilaments are made of the protein _____. Question of the Day Agenda Thin myofilaments are made of the protein _____. Thick myofilaments are made of the protein _____. 1. Review 2. Notes 3. Work on packet 4. Lab

Friday - 9/30/16 1. Review 2. Finish notes 3. Work on packet Question of the Day Agenda Place these structures of the skeletal muscle in order from largest to smallest 1. fascicle 2. myofilament 3. muscle fiber 4. myofibril 5. sarcomere 1. Review 2. Finish notes 3. Work on packet

Monday - 10/3/16 Question of the Day Agenda Put the steps of the sliding filament theory in the correct order. 1. Another cross bridge is formed 2. Actin cross bridges to myosin 3. Another power stroke slides actin closer to the center of the sarcomere 4. Cross bridge is broken 5. Actin slides past myosin in a short power stroke 1. Review 2. Muscular System Project - due at the beginning of class on Thursday Test is Thursday!

The Muscular System

Comes from the Latin word mus meaning “little mouse” What are “muscles?” Comes from the Latin word mus meaning “little mouse”

Types of muscular tissue What are the 3 types of muscular tissue? (Think back to when we covered histology.)

Types of muscular tissue 1. Skeletal Muscle Tissue 2. Cardiac Muscle Tissue 3. Smooth Muscle Tissue

Types of muscular tissue Skeletal Muscle Tissue – Found attached to bone Striated, multinucleated Voluntary (often reg. by reflexes) Exerts great force but tires easily

Types of muscular tissue Cardiac Muscle Tissue – Found only in the heart (bulk of heart walls) Has striations and intercalated disks Involuntary

Types of muscular tissue Smooth Muscle Tissue – Found in the walls of hollow internal structures No striations Involuntary Propels substances along a definite pathway

Functions of muscular system Movement Maintains posture Regulate organ volume Move substances within the body Produce heat Stabilize joints

What does skeletal muscle tissue look like?

Microscopic Anatomy of Skeletal Muscle Epimysium Surrounds the entire muscle Continuous with tendons (attaches the muscle to the bone)

Microscopic Anatomy of Skeletal Muscle Perimysium Surrounds a bundle of muscle fibers (called fascicles)

Microscopic Anatomy of Skeletal Muscle Endomysium Surrounds each muscle fiber (muscle cell)

What does skeletal muscle look like? Khan Academy Video

Design your own muscle fiber DIY muscle fiber

1. 2. 3. 4. 5.

Microscopic Anatomy of Skeletal Muscle Myofibrils are composed of alternating light (I) and dark (A) bands (called myofilaments) – gives the muscle its striped appearance

What does skeletal muscle look like? Myofibrils (light and dark bands) are divided into compartments known as sarcomeres.

What does skeletal muscle look like? Each sarcomere is divided into sections. A band I band H zone Z disc

What does skeletal muscle look like?

What does skeletal muscle look like? Sarcomeres are arranged into even smaller structures called myofilaments. Myofilaments produce banding pattern by 2 proteins Myosin (thick) Actin (thin)

What does skeletal muscle look like? Thick myofilaments are composed of the protein myosin. Split ATP to generate the power needed for muscle contraction

What does skeletal muscle look like? Thin filaments are composed of the protein actin. Slide toward each other during contraction

Sarcomere coloring

Physiology of skeletal muscle contraction Skeletal muscle requires stimulation from the nervous system in order to contract. Motor neurons are the cells that cause muscle fibers to contract.

Neuromuscular junction Junction between muscle cells

Overview of events at the NMJ Action potential travels down the axon of the motor neuron to the end bulbs (axon terminals) Acetylcholine (Ach) is released into the synaptic cleft (gap)

Overview of events at the NMJ Ach binds to Ach receptors on the motor end plate The binding of Ach to its receptors causes a new action potential to be generated along the muscle cell membrane

Overview of events at NMJ Immediately after it binds to its receptors, Ach will be broken down Prevents continuous contraction of the muscle cell Events at the NMJ

Blocks the release of Ach by the neuron Weakens muscle ~3-4 months Botox Botulinum toxin Blocks the release of Ach by the neuron Weakens muscle ~3-4 months

Physiology of skeletal muscle contraction Myofilament contraction animation

Providing energy for muscle contraction As muscles contract, ATP is broken down to release the needed energy and break cross bridges In order for muscle contraction to continue, ATP must be regenerated (creatine phosphate, anaerobic respiration and aerobic respiration)

No oxygen = No ATP production Myosin/Actin cross bridges do not break Rigor Mortis No oxygen = No ATP production Myosin/Actin cross bridges do not break

Creatine Phosphate At rest, muscle fibers make more ATP than is needed which is then used to make creatine phosphate + ADP When muscle begins to contract, phosphate group is transferred back to ADP forming ATP Enough energy for short bursts (15 sec)

Anaerobic Respiration Glucose broken down into pyruvic acid which is then converted to lactic acid (when oxygen levels are low) = 2 ATP ~ 30 to 40 seconds of maximal muscle activity

Aerobic Respiration In the presence of oxygen, pyruvic acid enters mitochondria where it generates ATP 36 ATP molecules from 1 glucose molecule Lasts more than 10 minutes

Muscle/Body Movements Flexion: decreases the angle of the joint and brings two bones closer together

Muscle/Body Movements Extension: increases the angle between 2 bones or parts of the body Opposite of flexion

Muscle/Body Movements Abduction: moving a limb away from the midline Adduction: movement of limb toward the body midline

Bell Work - 11/18/14 Put the steps of the sliding filament theory of muscle contraction in the correct order. 1. Another cross bridge is formed 2. Actin cross bridges to myosin 3. Another power stroke slides actin closer to the center of the sarcomere 4. Cross bridge is broken 5. Actin slides past myosin in a short power stroke

What causes cramps? Inadequate blood supply Mineral depletion Myosin fibers cannot break free of actin

Nutritional Imbalance Why is my eye twitching? Eye strain Tiredness Too much caffeine Allergies Nutritional Imbalance

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