FC The Human Muscle System

Questions and Flashcards based on Human Skeletal & Muscle System Notes

What’s the primary function of the muscle?

Responsible for all movement of the body.

How do muscles create movement

Through flexing and extending

What are muscles called as they transform chemical energy into mechanical energy? (from food to movement) and what do they contain and why?

body energy converters and they contain many mitochondria since they have energy demand

How much percent of the body weight is muscle?

50% of body weight is muscle

What is muscle made up of?

water and proteins

Tendons. what are they capable of

• A tough band of fibrous connective tissues that connect bone to muscle or other body structures

• capable of withstanding tension

Ligaments

• The fibrous connective tissues that connect bones to another

• keeps structure stable

Skeletal and smooth muscle are… (shape/size)

elongated

Muscle Cell =

Muscle Fiber

What causes muscle contraction?

The movement of microfilaments (protein fibers) cause muscle contraction

myo and mys refer to..

muscles

sarco refers to..

flesh

Multinucleated

have more than one nucleus

Why are Skeletal Muscles multinucleated?

they’re formed from the fusion of multiple cells

→ ensure muscle fibre produces enough proteins to meet high energy demands

What do the skeletal muscles contain? What do they do?

Many kinds of mitochondria

• produce energy in the form of ATP

Skeletal Muscle are… which means..

Striated = striped/banding

What type of muscle is consciously controlled?

Skeletal Muscle

What are the four functions of skeletal muscle?

1. Produce movement

2. Maintain posture

3. Generate heat

4. Stabilize joints

What is the shape of a cell (fibre) of a skeletal muscle?

• long and cylindrical

What are Myofibrils?

units in the skeletal muscle cells that can contract and shorten

What do Myofibrils contain?

• They contain two protein filaments

  1. Actin

  2. Myosin

What do the things that Myofibrils contain do?

The two filaments (Actin and Myosin):

• overlap and use energy from mitochondria, ATP

• ATP powers the filaments to slide over each other to shorten the myofibril

  • causes muscle contraction

What is sliding filament theory?

The explanation of how muscles contract

What type of muscle tissue lacks striations?

Smooth muscle

Describe the shape of smooth muscle cells.

Spindle shaped with Actin and myosin filaments present (protein fibres)

How many nuclei does a smooth muscle typically have?

one

Are smooth muscle contractions voluntary or involuntary?

Involuntary

Where are smooth muscle cells primarily found in the body?

the walls of hollow organs

How are smooth muscle cells arranged in the walls of hollow organs?

they line the wall of the digestive tract

What is peristalsis, and how is it achieved in the digestive tract?

involuntary tightening or relaxation of the muscles of the intestine

• from alternate contraction of circular and longitudinal muscle in the intestine

What type of muscle tissue is found only in the heart?

Cardiac

What are the characteristics of cardiac muscle cells?

1. short, branched, and interconnected

2. striated

3. usually one nucleus

How does the shape of cardiac muscle cells differ from skeletal muscle cells?

skeletal is spindle shaped

branching cells

What type of muscle is cardiac?

involuntary with rhythmic contractions

How do heart muscle cells behave as a unit?

behave as one unit
all contract and relax together

What is the unique characteristic of heart muscle contractions?

it always contracts to its fullest extent

What is the only type of muscle can carry a nerve impulse?

Cardiac