Muscle Fibers
Which muscle fiber type is dark red and built for endurance?
Slow Twitch (Type I)
What molecule is the body’s immediate source of energy for movement?
ATP
Which side of the heart pumps oxygenated blood to the body?
What structure prevents food from entering the trachea?
The epiglottis
Which muscle fiber type produces quick, powerful force but fatigues easily?
Fast Twitch Type IIB (Fast Glycolytic)
Which energy system lasts only 10–15 seconds and uses phosphocreatine (PC)?
ATP-PC system (Anaerobic Alactic)
What is the job of valves in the heart?
To prevent backflow of blood.
What zone filters, warms, and transports air into the lungs?
Conductive Zone
Which muscle fiber can be converted through training?
Type IIB fibers
Why does glycolysis cause a burning sensation during exercise?
Lactic acid is produced when oxygen is not available.
Why is it so beneficial that capillaries are so thin? And how thin are they?
They are 1 cell thick, they allow for nutrient/O2 exchange and waste/CO2 offload
What are the 3 functions of the respiratory system?
Supply oxygen to the blood, Remove carbon dioxide from the blood, & Regulate blood pH level (acid-base balance)
Transports oxygen through the muscle and gives slow-twitch fibers their red color
Why can’t the ATP-PC system last long?
Muscles store only small amounts of phosphocreatine.
What is concentric cardiac remodeling, and what causes it?
Thickening of the left ventricle wall caused by resistance training.
Explain boyles law
As pressure increases volume decreases and vice-versa
Why are fast-twitch fibers more affected by aging than slow-twitch fibers?
Aging causes motor neuron loss, which fast-twitch fibers rely on more heavily.
Why doesn’t the aerobic system work well for activities under 30 seconds?
It requires oxygen and complex pathways that take longer to activate.
Trace the pathway of blood from the right atrium back to the body.
Right atrium → tricuspid valve → right ventricle → pulmonary semilunar valve → pulmonary artery → lungs → pulmonary vein → left atrium → bicuspid valve → left ventricle → aortic semilunar valve → aorta → body.
During inspiration, why does air flow into the lungs?
Muscles contract → chest cavity expands → internal pressure decreases → air moves from high to low pressure.