A&P 3.1 (Muscle gross and microanatomy, contraction)

muscles are responsible for all types of ___ movement

body

The three basic muscle types are

• Skeletal muscle

• Cardiac muscle

• Smooth muscle

muscles are responsible for (hint 5 different things)

1. Moving the body and its appendages

2. Maintaining posture and body position

3. Communicating with facial expressions

4. Moving solids, liquids, and gases into and out of and/or through the body

5. Producing body heat

____ & _____ muscle cells are elongated

Skeletal and smooth

muscle cell =

Muscle fiber

contraction of muscles is due to the movement of _____

Microfilaments

all muscles share some terminology:

• Prefixes ____ and ____ refer to “muscle”

• Prefix ____ refers to “flesh”

myo and mys

sarco

what are the five characteristics of all muscle tissue types? (hint ECCEE)

1. Excitability

2. Conductivity

3. Contractility

4. Extensibility

5. elasticity

Which of the five characteristics of muscle tissue types is this?

muscle tissue response to stimuli from hormones or neurotransmitters and produces electrical signals called action potentials

excitability

Which of the five characteristics of muscle tissue types is this?

this is the ability of a cell to conduct action potential along its plasma membrane

Conductivity

Which of the five characteristics of muscle tissue types is this?

this is the ability of a muscle to shorten and thicken in response to an action potential. This is what creates skeletal muscular contraction.

contractility

Which of the five characteristics of muscle tissue types is this?

all types of muscle tissue can extend and stretch. This allows the muscle in artery walls to stretch and accommodate increased blood flow. It allows cardiac tissue to expand when the chambers filled with blood, and it enables skeletal tissue to stretch when an opposing muscle is being contracted.

extensibility

Which of the five characteristics of muscle tissue types is this?

Allows muscle tissues to return to its original length and shape

elasticity

body location of skeletal muscles

Attached to bones or for some facial muscles to skin

body location of cardiac muscle

Walls of the heart

body location of smooth muscle

Mostly in walls of hollow, the visceral organs, other than the heart

cell shape and appearance of skeletal muscle

Single, very long, cylindrical multi nuclear cells with a very obvious striations

cell shape and appearance of cardiac muscle

Branching chains of cell cells, uninuclear, striations and intercalated disc

cell shape and appearance of smooth muscle

Single, fusiform, uninucleate, no striations

cardiac muscle cells are involuntary due to

Pacemaker, nervous system controls; hormones

smooth muscles are involuntary because of

Nervous system controls; hormones chemicals, stretch

what is the speed of contraction in skeletal muscle, cardiac muscle and smooth muscle

• Slow to fast

• Slow

• Very slow

do skeletal muscle, cardiac muscle or smooth muscle have rhythmic contraction

• No

• Yes

• Only in some

most skeletal muscles are attached by ____ to bones

Tendon

What is the only voluntary muscle type?

Skeletal

smooth muscle have ____ shaped cells

Spindle

cardiac cells are arranged in a ____ formation

Branching

cells are surrounded and bundled by _____

Connective tissue

encloses a single muscle fiber

Endomysium

wraps around a fascicle (bundle) of muscle fibers

perimysium

covers the entire skeletal muscle

epimysium

on the outside of the epimysium

fascia

epimysium blends into a ____ tissue attachment aka a ____

Connective

Tendon

cord like structures

Tendons

made mostly out of collagen fibers and often cross a joint due to toughness and small size

Tendons

Sheet like structures

aponeuroses

attach muscles indirectly to bones cartilage’s or connective tissue coverings

aponeuroses

what are the four sites of muscle attachment? (hint BCC)

Bones

Cartridges

Connective tissue coverings

specialized plasma (cell) membrane of individual muscle cells (below the endomysium)

sarcolemma

Long organelles inside muscle cell made of Actin and myosin and divided into sarcomeres. Surrounded by the sarcoplasmic reticulum.

myofibrils

specialized smooth endoplasmic reticulum (stores and releases Ca++ - ion that initiates muscle contraction)

sarcoplasmic reticulum

(proteins - actin and myosin) are aligned to give distinct bands

Myofibers

I band = ______

• contains only thin filaments aka _____

Light band

actin

A band = _____

• contains the entire length of the thick filaments aka _____

dark band

myosin

contractile unit of a muscle fiber

sarcomere

the sarcomere is organized by __

Myofilaments

The two types of myofilaments are

Thick/myosin

Thin/actin

thick/myosin filaments are composed of the protein ____

myosin

thick/myosin filaments have _____ enzymes

ATPase

thick/myosin filaments have heads known as _____ or ______

Extensions or cross bridges

myosin and actin ____ somewhat

overlap

thin/actin filaments are composed of the protein ____

actin

thin/actin filaments are anchored to the __ disc

Z

A rest there is a ____ zone that lacks ____ filaments called the __ zone

bare

actin

H

stores and releases calcium

sarcoplasmic reticulum

surrounds the myofibril

sarcoplasmic reticulum

responsiveness or irritability =

excitability

initially muscles used stored ____ for energy

ATP

__ Bonds are broken to release ___

ATP

energy

only __-__ seconds worth of ATP is stored by muscles

4-6

after stored ATP is used by the muscles other _____ must be utilized to produce ___

Pathways

ATP

Direct phosphorylation of ADP by ____ _____ (CP)

Creatine phosphate (CP)

creatine phosphate (CP) was a ______ molecule

High energy

after ATP is depleted ____ remains

ADP

creatine phosphate (CP) transfers energy to ____ to regenerate ____

ADP

ATP

creatine phosphate (CP) supplies are exhausted in less than ___ seconds

15

• glucose is broken down to carbon dioxide and water releasing energy (ATP)

• This is a slower reaction that requires continuous oxygen

• A series of metabolic pathways occur in the mitochondria

aerobic respiration

• reaction that breaks down glucose without oxygen

• Glucose is broken down to pyruvic acid to produce some ATP

• Pyruvicacid is converted to lactic acid

Anaerobic glycolysis and lactic acid formation

• require huge amounts of glucose

• Produces muscle fatigue

Anaerobic glycolysis and lactic acid formation

when a muscle is ____ it is unable to contract, even with a ____

Fatigued

Stimulus

common cause for muscle fatigue is _____ _____

Oxygen debt

• Oxygen must be “ repaid” to tissue to remove oxygen deficit

• Oxygen is required to get rid of accumulated lactic acid

Oxygen debt

increasing _____ (from lactic acid) causes the muscle to contract ____

Acidity

Less

other causes of ____ _____ include reduction in the nervous impulse reduction in available fuel (glucose) resulting in less available ATP and accumulation of other metabolic waste products

muscle fatigue

skeletal muscles must be _____ by a _____ neuron (never cell) to contract

stimulated

motor

one motor neuron and all the skeletal muscle cells stimulated by that neuron

motor unit

i order to apply more force, more ____ units are activated; this is called ____

motor

recruitment

association site of a axon terminal of the motor neuron and muscle

neuromuscular junction

gap between nerve and muscle; nerve and muscle don’t make contact; filled with interstitial fluid

synaptic cleft

chemical released by nerve upon arrival of nerve impulse

neurotransmitter

the neurotransmitter for skeletal muscles is _______ (__)

acetylcholine (ACh)

acetylcholine attaches to receptors on the ____

sarcolemma

sarcolemma becomes permeable to ____ (__)

sodium (Na+)

_____ rushes into the cell generating an _____ potential

sodium

action

once started muscle contraction cannot be ____

stopped