Muscular System

http://www.youtube.com/watch?v=Ry9IcQMFiz8&feature=fvw

How many muscles do we have?

• Our over 650 muscles fall into three categories –

• 1. skeletal,

• 2. cardiac &

• 3. smooth.

Fun Facts• There are 50 muscles in your face alone.• It takes 17 muscles to smile and 40 muscles to

frown.• Your heart muscle NEVER gets any rest neither

do the muscles of your intestines!• The most active muscles are those in your eyes.

They move more than 100,000 times a day!

Biggest, Strongest, and Hardest Working

• The gluteus maximus is the largest muscle in the human body.

• The strongest muscle in your body is the masseter, located on each side of your mouth. These muscles help you bite down with 150 pounds of force!

• The hardest working muscle is the heart. Every day the heart pumps at least 2,500 gallons of blood.

In one day, your blood travels nearly 12,000 miles.

Three Types of Muscle Cells

• Skeletal

• Cardiac

• Smooth

1. Skeletal Muscle a.k.a. striated muscle

Nuclei are on the periphery of the cells

2. Smooth Muscle

3. Cardiac Muscle

Do Now!

4. Lines hollow organs (C, Sm, Sk?)

5. Makes up the heart walls (C, Sm, Sk?)

6. Connected to bone (C, Sm, Sk?)

7. Involuntary (C, Sm, Sk?)

8. Used to push substances along internal passageways. (C, Sm, Sk?)

9. Voluntary (C, Sm, Sk?)

10. Moves bones (C, Sm, Sk?)

1. What kind of muscle?

2. What kind of muscle?

3. What kind of muscle?

(C, Sm, Sk?)

(C, Sm, Sk?)

(C, Sm, Sk?)

                                                                      

1. Identify the type of tissue.A) Dense regular connective tissueB) Smooth muscleC) Cardiac muscleD) Skeletal muscle

2. In question 1, above, what was the most distinctive identifying feature?

A) StriationsB) Branched fibersC) Peripheral nucleiD) A and CE) A, B, and C

 

Practice Practical Muscle Quiz

                                                              

       3. Identify this tissue:A) Dense regular connective tissueB) Smooth muscleC) Cardiac muscleD) Skeletal muscle

4. In question 3, above, what was the most distinctive identifying feature?A) StriationsB) Branched fibersC) Central nucleiD) A and CE) A, B, and C

                                                                                                            

5. This specialized junction separates cells in:A) Cardiac muscleB) Skeletal muscleC) Smooth muscleD) Tendons

6. Identify this tissue.

A) Dense regular connective tissue

B) Smooth muscle

C) Cardiac muscle

D) Skeletal muscle

E) Dense irregular connective tissue

 7. Identify this tissue.A) Dense regular connective tissueB) Smooth muscleC) Cardiac muscleD) Skeletal muscleE) Dense irregular connective tissue

                                                                         8. Identify this tissue:A) Dense regular connective tissueB) Smooth muscleC) Cardiac muscleD) Skeletal muscleE) Dense irregular connective tissue

9. In question 8, above, what was the most distinctive identifying feature?A) StriationsB) Branched fibersC) Peripheral nucleiD) A and CE) A, B, and C

                                                                           

10. Identify the name of the connective tissue around each fiber:A) epimysiumB) endomysiumC) perimysiumD) meromysiumE) sarcomysium

                                                                        

11. Identify the structures noted by the arrows:A) striationsB) sarcomeresC) Intercalated discsD) Sarcoplasmic reticulumE) endomysium

• Connect to bones• Forms the smoother contours of the body• Very long and cylindrical in shape• Multinucleated• Largest of the 3 muscle types• A.K.A. Striated muscles• Only muscle type under voluntary control• Can also be activated by automatic

reflexes

How can they be so strong?• Each fiber is wrapped in

connective tissue called endomysium.

• Several fibers are then wrapped in a courser membrane called a perimysium to form a fascicle.

• The fascicle is bound together by an even tougher cover called an epimysium.

Endomysium

• The epimysium (outer layer) can blend into strong cordlike tendons or

• Into sheet-like aponeuroses (fascia) which attach muscle indirectly to bone, cartilages, or other connective tissue coverings.

Label this skeletal muscle using the diagram on the next slide

What do you remember?

Origin vs. Insertion

• The muscles origin is attached to the immovable bone.

• At its other end, the insertion is attached to the movable bone.

You’ll need this for lab!

The endomysium can be further

divided.

The myofilaments of a myofibril are arranged in a regular fashion so that their ends are all lined up.

This is what gives the muscle its striated appearance.

The contractile units of the cells are called sarcomeres.

Sarcomere The myofibrils have distinct, repeating microanatomical units, termed sarcomeres.

The sarcomere is composed of thick and thin filaments – myosin and actin, respectively.

Chemical and physical interactions between the actin and myosin cause the sarcomere length to shorten (contract).

The interactions between actin and myosin serve as the basis for the sliding filament theory of muscle contraction.

Sliding Filament Theory

• The sliding filament theory is the basic summary of the process of skeletal muscle contraction.

• Myosin moves along the filament by repeating a binding and releasing sequence that causes the thick filament to move over the thinner filament.

• This progresses in sequential stages. By progressing through this sequence the filaments slide and the skeletal muscles contract and release.

Naming Skeletal Muscles

• Named based on structural or functional characteristics.

1. Direction of fibers: Rectus (straight or parallel to an imaginary line) or oblique (at a slant)

Naming Skeletal Muscles

2. Size of muscle:

Maximus (largest),

Minimus (smallest) and

Longus (long)

Naming Skeletal Muscles3. Location of the Muscle

Some are named for the bone they attach are associated with.

Ex. The temporalis muscle lays over the temporal bones of the skull.

Naming Skeletal Muscles4. Number of Origins

Ex. Bicep muscle has two heads, triceps have three and quadriceps have four.

Naming Skeletal Muscles

5. Location of Muscle’s origin and insertion.

• Ex. Sternocleidomastoid has its origin on the sternum (sterno), and clavicle (cleido) and inserts on the mastoid process of the temporal bone.

Naming Skeletal Muscles

6. Shape of the Muscle

If a muscle has a definitive shape, it is used to help identify them.

Ex. Deltoid (triangular)

Naming Skeletal Muscles

Flexor: Closes a joint Bending movement that

decreases the angle between two parts. For ex. bending the elbow, or clenching a hand into a fist

Extensor: opens a joint a straightening movement that increases the angle between body parts

Adductor: A motion that pulls a structure or part towards the midline of the body, or towards the midline of a limb

7. Action of the Muscle

Abductor: moves away from midline

Four functions of skeletal muscles.• Maintain posture• Stabilize joints• Generate heat• Produce movement

Aging and Muscles

• After 30, your muscle mass dwindles some 3-8 percent each decade. Once you hit 60, these losses accelerate even more quickly.

• Decreased muscle mass means you'll burn far fewer calories.

• Muscles require a lot of calories to maintain. (Think of them as a bunch of high-strung, active family members visiting your home. They're always up, moving around. As a result, they're hungry and require a lot of food.)

• The strength of your muscles is related to the strength of your bones. When your muscles are weak, your bones are more likely to be weak. (This is esp. important for women who have higher risk of osteoporosis.)

• Muscles are usually in (Antagonistic) pairs. When one muscle contracts, the other extends.

• Adrenaline allows your muscles to use 4 to 6 times more oxygen than usual thus creating a huge amount of energy.

• Extreme strength: http://www.youtube.com/watch?v=Q9wRTIZIByk&NR=1

• Two man strength performance: http://www.youtube.com/watch?v=JWK5mfRGkiE&feature=related

Muscle Pairs

Disorders of the Muscular System

1. Muscular Dystrophy: Occurs when a particular gene on the X chromosome:

a. fails to make the protein dystrophin. b. makes low amounts of dystrophin.

the membranes around muscle cells become weak and tear easily, eventually leading to the death of muscle fibers.

• More common in males.

Types of MD A. When one of these

proteins, dystrophin, is absent, the result is Duchene’s muscular dystrophy.

B. Poor or inadequate dystrophin results in Becker’s muscular dystrophy.

DMD

Animation: http://www.youtube.com/watch?v=6wLnR7GJakYA family’s story: http://www.youtube.com/watch?v=dSEc5zvGTbc

Disorders of the Muscular System2. ALS: Amyotrophic lateral sclerosis: disease of

the nerve cells in the brain and spinal cord that control voluntary muscle movement.

• AKA Lou Gehrig's disease. • The symptoms usually do not develop until after

age fifty. • Persons with this disease have a loss of muscle

strength and coordination that eventually gets worse.

• Breathing or swallowing muscles may be the first muscles affected. As the disease gets worse, more muscle groups develop problems.

• Life expectancy of an ALS patient averages about two to five years from the time of diagnosis.

• Amyotrophic lateral sclerosis (ALS) is caused by the degeneration and death of motor neurons in the spinal cord and brain. These neurons convey electrical messages from the brain to the muscles to stimulate movement in the arms, legs, trunk, neck, and head. As motor neurons degenerate, the muscles are weakened and cannot move as effectively, leading to muscle wasting.

http://www.youtube.com/watch?v=tKRWUZr4gBg

Fans, for the past two weeks you have been reading about the bad break. Today I consider myself the luckiest man on the face of this earth. That I might have been given a bad break, but I have an awful lot to live for. Thank you.

His record for most career grand slam home runs (23) still stands today (Alex Rodriguez has 22, Manny Ramirez has 21)

Disorders of the Muscular System

3. Myasthenia gravis: is caused by a defect in the transmission of nerve impulses to muscles.

• Its a disease in which the immune system attacks the body's own tissues ("autoimmune" disease);

• Causes a weakness of voluntary muscles without pain that gets worse with repeated or sustained use of the muscle (fatigued muscle weakness).

• In two thirds of patients with MG, the first muscles to be affected are those controlling eye movements (causing double vision) and those holding the eyelids up (causing drooping of the eyelids).

• There are medications to treat the disorder. It is not fatal.

4. Chronic Fatigue Syndrome: Symptoms of chronic fatigue syndrome include loss of memory, difficulty concentrating, fatigue, random muscle pain, headaches, unrefreshing sleep and sore throats.

5. Fibromyalgia: results in widespread pain throughout every muscle in a person's body. Approximately 2% of the entire US population is affected by fibromyalgia. Symptoms of fibromyalgia include joint tenderness, fatigue problems, and sleep disturbances. No cure.

• 6. Cerebral Palsy:

• Cerebral palsy is condition that can involve brain and nervous system functions such as movement, learning, hearing, seeing, and thinking.

• There are several different types of cerebral palsy.

• Cerebral palsy is caused by injuries or abnormalities of the brain.

• Most of these problems occur as the baby grows in the womb, but they can happen at any time during the first 2 years of life, while the baby's brain is still developing.

Botulism & Botox

• Botulism is a rare but serious condition caused by toxins from bacteria called Clostridium botulinum.

• can be fatal• A weakened botulinum toxin (BOTOX)

has been used to reduce facial wrinkles by paralyzing muscles beneath the skin, and for medical conditions, such as eyelid spasms and severe underarm sweating.

• Difficulty swallowing or speaking

• Facial weakness on both sides of the face

• Blurred vision • Drooping

eyelids • Trouble

breathing • Nausea,

vomiting and abdominal cramps (only in food-borne botulism)

• Paralysis

• Botulism: What is this toxin? http://video.google.com/videosearch?q=botulinum+toxin&www_google_domain=www.google.com&hl=en&emb=0&aq=3&oq=botu#

• Botulism: Cerebral Palsy treatment and Botox

• http://www.youtube.com/watch?v=RI7FVOBKTXM

Poisons vs. Venom

• Terms are often used interchangeably, but they actually have very different meanings.

• It is the delivery method that distinguishes one from the other.

• Poison is absorbed or ingested; Ex. Toxin in skin or organs. (frogs, puffer fish, poison ivy)

• Venom is always injected. Ex. Stab with tails. Slash with spines. Pierce with fangs. Spike with spurs. Shoot with harpoons. Chew with teeth. (snakes, spiders, bees)

Poisons (venom)

Effects of snake venom: • Part 3: Rattlesnake Compartment

Syndrome http://dsc.discovery.com/videos/discovery-channel-snakebite-stories/

• Part 2:Symptoms of the Bite• http://dsc.discovery.com/videos/

discovery-channel-snakebite-stories/

• • Part 1: Bitten By a Rattler• http://dsc.discovery.com/videos/

discovery-channel-snakebite-stories/

Stiletto Snake bite:

Part 1 : Envenomation

Part 2: http://dsc.discovery.com/videos/i-was-bitten-stiletto-snakebite-symptoms.html

Part 3: surgery

Part 3 automatically plays first so select Part 1

Two Types of Venom and What They Do To The Body

1. Neurotoxin acts on the victim's nervous system, causing excitation (cramps, vomiting, convulsions) or depression (paralysis, respiratory or cardiac depression or arrest). •Black Widow Spider•Cobra•Coral Snakes•Gila monster •Puffer fish •Short-tailed shrew•Kraits

Two Types of Venom and What They Do To The Body

2. Hemotoxin ("blood poison") breaks down the victim's tissues, usually by an acid or a toxin that prevents or causes blood clotting, or destroys red or white blood cells. Venom usually contains both types, but one dominates.

•scorpion

•Copperhead

•Rattlesnakes

•Water Moccasin/Cottonmouth

You are 9X more likely to die by lightening strike than getting bit by a venomous snake.

Hey You!

Label my muscles!

Steroids anyone?• http://www.youtube.com/watch?

v=gp11d7qDQSg

Steroid use: 15minutes (some bad lang.)

Part 3: http://www.youtube.com/watch?v=ITG-IbHEYEE&feature=related

Part 4: http://www.youtube.com/watch?v=U0dmXRAKieQ&NR=1

Tyra: Greg Today: http://www.youtube.com/watch?v=vwcL6mOcPF4

Muscle System Test

• 3 types of muscles: chara. of each one, and ID a picture.(matching description with muscle type)

• Four functions of skeletal muscles.– Produce movement– Maintain posture– Stabilize joints– Generate heat

• Basic Microscopic Anatomy/sliding filament theory. Label muscle cell.

• 7 ways to name muscles & ex of each.• Name the main anterior and posterior muscles.• Disorders/diseases (M.D., cerebral palsy, ALS,

myasthenia gravis, botulism, snake venom) : treatment: Botox

The anatomy of a sarcomere• The entire array of thick and thin filaments between the Z disks is called a

sarcomere. • The thick filaments produce the dark A band. • The thin filaments extend in each direction from the Z disk. Where they do

not overlap the thick filaments, they create the light I band. • The H zone is that portion of the A band where the thick and thin filaments

do not overlap. • The M line runs through the exact center of the sarcomere. Molecules of

the giant protein, titin, extend from the M line to the Z disk. One of its functions is to provide a scaffold for the assembly of a precise number of myosin molecules in the thick filament (294 in one case). It may also dictate the number of actin molecules in the thin filaments.

• Shortening of the sarcomeres in a myofibril produces the shortening of the myofibril and, in turn, of the muscle fiber of which it is a part.

•[This electron micrograph of a single sarcomere was kindly provided by Dr.

H. E. Huxley.]

Actin & Myosin

Actin & Myosin

Sliding Filament Theory1.

http://msjensen.cehd.umn.edu/1135/Links/Animations/Flash/0008-swf_sarcomere_shor.swf

2. http://www.youtube.com/watch?v=ren_IQPOhJc

7 stages of the Sliding Filament Theory

•First Stage: The first stage is when the impulse gets to the unit. The impulse travels along the axon and enters the muscle through the neuromuscular junction. This causes full two to regulate and calcium channels in the axon membrane to then open. Calcium ions come from extra cellular fluid and move into the axon terminal causing synaptic vessels to fuse with pre synaptic membranes. This causes the release of acetylcholine (a substance that works as a transmitter) within the synaptic cleft. As acetylcholine is released it defuses across the gap and attaches itself to the receptors along the sarcolemma and spreads along the muscle fiber.

Second Stage: The second stage is for the impulse spreads along the sarcolemma. The action potential spreads quickly along the sarcolemma once it has been generated. This action continues to move deep inside the muscle fiber down to the T tubules and the action potential triggers the release of calcium ions from the sarcoplasmic reticulum.

Third Stage: During the third stage calcium is released from the sarcoplasmic reticulum and actin sites are activated. Calcium ions once released begin binding to Troponin. Tropomyosin blocking the binding of actin is what causes the chain of events that lead to muscle contraction. As calcium ions bind to the Troponin it changes shape which removes the blocking action of Tropomyosin (thin strands of protein that are wrapped around the actin filaments). Actin active sites are then exposed and allow myosin heads to attach to the site.

Fourth Stage: The fourth stage then begins in which myosin heads attach to actin and form cross bridges, ATP is also broken down during this stage. Myosin binds at this point to the exposed binding sites and through the sliding filament mechanism the muscles contract.

Fifth Stage: During the fifth stage the myosin head pulls the Actin filament and ADP and inorganic Phosphate are released. ATP binding allows the myosin to detach and ATP hydrolysis occurs during this time. This recharges the myosin head and then the series starts over again.

Stage Six: Cross bridges detach while new ATP molecules are attaching to the myosin head while the myosin head is in the low-energy configuration. Cross bridge detachment occurs while new ATP attaches itself to the myosin head. New ATP attaches itself to the myosin head during this process.

Stage Seven: During stage seven the ATP is broken down and used as energy for the other areas including new cross bridge formation. Then the final stage (stage 8) begins and a drop in stimulus causes the calcium concentrate and this decreases the muscle relaxation.

•

Read more: http://wiki.answers.com/Q/How_does_the_sliding_filament_theory_work#ixzz1JDtbSisM

Resting and Action Potential• Neurons send messages electrochemically. This means that chemicals

cause an electrical signal. • The important ions in the nervous system are sodium and potassium (both

have 1 positive charge, +), calcium (has 2 positive charges, ++) and chloride (has a negative charge, -).

Resting Membrane Potential• When a neuron is not sending a signal, it is "at rest.“

Action Potential• An action potential occurs when a neuron sends information down

an axon, away from the cell body. Neuroscientists use other words, such as a "spike" or an "impulse" for the action potential.

• The action potential is an explosion of electrical activity that is created by some event (a stimulus).

• There are no big or small action potentials in one nerve cell - all action potentials are the same size. Therefore, the neuron either does not reach the threshold or a full action potential is fired - this is the "ALL OR NONE" principle.

• This is in reference to an individual muscle cell not the whole muscle therefore there can be a graded response in the muscle contraction.

Neuromuscular Junction• A skeletal muscle cannot contact

unless stimulated by a motor nerve.• This junction between a nerve fiber

(axon) and muscle cell is called a neuromuscular junction.

• http://video.google.com/videosearch?hl=en&rlz=1T4HPND_enUS310US240&resnum=0&q=botulism&um=1&ie=UTF-8&sa=N&tab=wv#q=motorneuron+junction&hl=en&emb=0

• Watch it using flash player:• http://www.galaxygoo.org/

biochem/neuro/nmj_flash.html

Acetylcholine

• When acetylcholine is released from an axon terminal, it moves across the synaptic cleft to bind to a receptor on the other side of the synapse (on the post-synaptic membrane).

• In the peripheral nervous system, acetylcholine is located at the "neuromuscular junction" where it acts to control muscular contraction.

Extra Credit

• 1. How does adrenaline make you stronger?• 2. Muscles are usually in antagonistic pairs.

What does that mean and give an example of a pair?