responsible for all locomotion

acetocholine is the only neurotransmitter used to talk to it because it only needs one message to tell muscles to contract.  Has 1 nerves talking to a bundle of muscle cells.

Is responsible for overall body motility

(move body)

voluntarily

are stimulated by motor neurons

helps maintain blood pressure,

: use 2 neurotransmitters.

These must be antagonist.

They must send the opposite message.

Blood vessels intestine and stomach all covered in ____________- only have two oppositions (constrict or dilate) make the lumen smaller or bigger.

Epinephrine (constrict) and acetocholine (dilate) (antagonist) 1 nerve talking to a bunch of muscle cells.

is not striated.

always partially constricted

Forces food and other substances through internal body channels

move substance through the body

is responsible for coursing the blood through the body

use 2 neurotransmitters. These must be antagonist. They must send the opposite message. (heart/ speed up or slow down) epinephron  and acetocholine (antagonist

Contracts at a fairly steady rate set by the heart’s pacemaker

move blood through body

- cytoplasm of a muscle cell

have numerous glycosomes and a unique oxygen binding protein calleb myoglobin

Functional characteristics:of skeletal muscle

Functional characteristics: also maintain posture, stabilize joints, and generate heat

• Extensibility

• Elasticity

 – the ability to recoil and resume the original resting length

Skeletal muscle sheaths

1 Endomysium 2 Perimysium 3 Epimysium

Endomysium

 – fine sheath of connective tissue composed of reticular fibers surrounding each muscle fiber

3 Epimysium

– an overcoat of dense regular connective tissue that surrounds the entire muscle

 How do we store glucose and oxygen in our muscles?”

 in the form of glycosomes and myoglobin

 myoglobin stores oxygen in our muscles

glycosomes- granules of stored glucogon that provide glucose during periods of muscle cell activity

Destruction prevents continued muscle fiber contraction in the absence of additional stimulation

ACh is enzymatically destroyed

          Acetylcholinesterase

action potential

(an electrical current)

The ionic concentration of the resting state is restored

to put ions back where they belong to regain ionic balance

“How do we store calcium in the muscle?”

• Ca²⁺ is removed into the SR, tropomyosin blockage is restored, and the muscle fiber relaxes
• Removal of Ca+2 by active transport
• tropomyosin blockage restored; contraction ends

• - A muscle twitch

a few msec

 Onset of stimulus

                        ii. No measured contractile activity

                        iii. Excitation-contraction coupling

10-100 msec)

                        i. Onset of shortening to peak contraction

                        ii. If pull greater than load, muscle shortens

      cross bridges form; muscle shortens

Ca²⁺ reabsorbed; muscle tension goes to zero

(10-100 msec)

                        i. Re-entry of Ca²⁺ into SR

                        ii. Muscle tension gradually returns to zero

Graded muscle responses are:

a.       Variations in the degree of muscle contraction

b.      Required for proper control of skeletal movement

Changing the frequency of stimulation

     Changing the strength of the stimulus

• Twitch-Wave summation-Incomplete tetanus - Complete tetanus

• Wave summation-

Frequently delivered stimuli (muscle does not have time to completely relax) increases contractile force

Strength of contraction increases with successive stimuli

ii. Muscles that are already contracted, contract further with additional Ca²⁺

iii. If stimulation is delivered prior to relaxation, contraction s are summed

muscle contracts more vigorously as stimulus strength is increased, force of contraction is precisely controlled by multiple motor unit summation, brings more and more muscle fibers into play

 Force of contraction is precisely controlled by multiple motor unit summation

Multiple motor unit summation

• the purpose is to warm you up.

• Staircase – increased contraction in response to multiple stimuli of the same strength
• force of contraction increases during response to stimuli at the same strength

              a. Result of increasing Ca²⁺ availability

              b. Heat created during contraction increases efficiency of muscle enzymes

                          i. Warming up prior to athletic activity

Muscle tone

The outside of an average cell is -70.

- Is the constant, slightly contracted state of all muscles, which does not produce active movements

Keeps the muscles firm, healthy, and ready to respond to stimulus

where muscles stay partially contracted @ all times. Most of the muscles in the legs, back, and abdomen take turns contracting and relaxing.  Which allows you stand and sit up.

“What is the purpose of the warm-up?”

Stimulate and relax muscles repeatedly until we plateu and end up having the maximum contractions that allow you to be ready to engage in exercising. (until you warm up the enzymes until theresenough calcium ions floating around to pop the troponin top. Training the muscles to let the calcium out faster out of the cisternae. Get muscles warmed up for peak contraction abilities.

Doing the work while you have shortening the muscle

raising of a weight during a bicep curl.

• aerobic respiration

“What factors affect the force of muscle contraction?”

The bigger the bundle the muscles 

 The larger the muscle fiber 

 The stretched out muscles have more

Size of muscles gives you more

Size of fibers gives you more

prodominance of fast glycolitic fibers 

• Slow oxidative fibers contract slowly, have slow acting myosin ATPases, and are fatigue resistant
• Fast oxidative fibers contract quickly, have fast myosin ATPases, and have moderate resistance to fatigue
• Fast glycolytic fibers contract quickly, have fast myosin ATPases, and are easily fatigued

 results in an increase of:

•  
  • Muscle capillaries
  • Number of mitochondria
  • Myoglobin synthesis

there is an increase in the # of capillaries surrounding the muscle fibers and in the # of mitochondria w/ in them and the fibers synthesize more myoglobin

Act as pacemakers and set the contractile pace for whole sheets of muscle

•  
  • Are self-excitatory and depolarize without external stimuli

§  Unique characteristics of smooth muscle include:

§  Smooth muscle tone

§  Slow, prolonged contractile activity

§  Low energy requirements

§  Response to stretch

• Hyperplasia-

 Certain smooth muscles can divide and increase their numbers by undergoing this

This is shown by estrogen’s effect on the uterus

At puberty, estrogen stimulates the synthesis of more smooth muscle, causing the uterus to grow to adult size

During pregnancy, estrogen stimulates uterine growth to accommodate the increasing size of the growing fetus

“Where do you find single unit smooth muscle?”

found in the viscera

“Where do you find multi-unit smooth muscle?”

“What are some differences between skeletal and smooth muscle?”

skele- multinucleate cells

smooth- uninucleate

skele- epimysium, endomysium and perimysium

smooth- endomysium

skeletal presence of myofibrils compossed of sarcomeres

smooth- no but actin and myosin filaments are present throughout; dense bodies anchor actin filaments

skeletal- presence of t-tubule; two in each sarcomere @ a i juctions

smooth-no; only caveolae

skeletal: elaborate sarcoplasmic recticulum

smooth. equivalent to cardiac muscle; some SR contacts the sarcolemma

stimulates the clustering of ACh receptors at newly forming motor end plates

“How did skeletal muscle become multi-nucleate?

skeletal muscle fuses as a fetus to be stronger to move the body

When they were still lil myoblasts they fused together and they kept their own individidual nuclei

Cardiac and smooth muscle don’t fuse

Which muscle tissue is mitotic?  Which is amitotic?

“What is meant by: muscular development reflects neuromuscular coordination?”

 Development occurs head-to-toe, and proximal-to-distal

§

Babies start having more coordination in face 1^st.  get coordination from head to foot. From medial to lateral.

• With more muscle mass, men are generally stronger than women. Women’s skeletal muscle makes up 36% of their body mass
• Men’s skeletal muscle makes up 42% of their body mass

“Why are men considered stronger than women?”

is the degenerative loss of skeletal muscle mass and strength associated with aging.

 . Exercise can reverse that.

By age 80, 50% of muscle mass is lost

Nerve impulse (afferent signal) from motor neuron generates action potential in nerve cell

            a. AP propagated along sarcolemma and down T tubules

b. Tetanus:

Isotonic and Isometric contractions

            a. Terms:

  i. Muscle tension—force of contracting muscle on an object

                        ii. Load—reciprocal force exerted by the object

Aerobic respiration

a. 95% of ATP during light exercise

b. In presence of oxygen, products of glycolysis are broken down entirely with the generation of significant amounts of ATP

 is the source of glucose for both aerobic and anaerobic metabolism

The motor end plate of a muscle, which is a specific part of the sarcolemma that contains ACh receptors and helps form the

- when u touch, eat or smell something whole body reacts. All the basophils, mast cells,  histamines are released. When histamines are released makes blood vessels dialate which makes blood pressure go down so far that the heart stops. Doctor will give you a stick of the epipen which has epinephron in it and makes your heart speed up.

What do you want your blood vessels to do after you had a big meal?

Open up

What do you want your blood vessels around your stomach to do when you want all the blood to go to your arms and leg?

Close down

What do you want your heart to do after eating a meal?

Slow down

What do you want your heart to do when you are in a car accident?

Speed up.

What do you want your bronchioles to do when you need to run?

Open up.

What do you want your bronchioles to do when you need to sleep?

Get smaller.

We grow more trabeculae in an area where the bone is more stressed then it becomes compact bone. When you stress your muscles you will grow more capillaries, myoglobin and glycosomes. When you stress your bones you get more trabeculae and more compact bone.

What happens when you stress a bone? What do you grow more of?

not making as much ATP as you are using up. Ionic imbalance. Sodium and potassium aren’t where theyre suppose to be.

Oxygen debt- took out all the oxygen stored in myoglobin as well as all the oxygen stored in capillaries so now need a double dose of oxygen to get back to normal. Have to replenish the storage. Glycogens stores must be replaced. And have to resynthesize all the ATP and creatine phosphate your gonna use.

• aerobic respiration

the more muscles you have the higher your metabolism is because the more muscles you havethe more heat you generate. The more heat you generate the more efficiently you use the food youre eating. The less muscle mass the less efficient you use your food.

 Essentially have the same actin and myosin but work in a different way.

 comes in 2 layers circular that surrounds the lumen and a longitudinal which goes down the length. Together they do peristalisis.

Does not have the same bouton as skeletal. Just have thickenings along the axon- varacosities.

No t-tubules, have pouch like cavelolae, calcium is cequestered near the calvolae, no sarcomere, no tropnin complex, no z disc, actin and myosin are put together in a zigzag manner.

out of the ventral nerve (red) going through muscle. Ones going into brain and spinal cord are sensory nerves (afferent/ blue) come in on the dorsal side.

complete tetanus

the force of contraction is controlled more precisely by this

delivered by delivering increased voltage to the muscle