CSCS Chapter One Key Terms

a-band

The region of a sarcomere that contains thick myofilaments (myosin) and appears darker under a microscope. It is involved in muscle contraction.

acetylcholine

A neurotransmitter that transmits signals across the neuromuscular junction, facilitating muscle contraction.

actin

A protein that forms thin myofilaments in muscle fibers and plays a crucial role in muscle contraction by interacting with myosin.

action potential

a rapid, temporary change in electrical voltage across a cell membrane that neurons use to send signals

all-or-none principle

a neuron or muscle fiber will fire a complete action potential at full strength if a stimulus reaches the required threshold, and will not fire at all if the stimulus stays below that threshold

alveolar pressure

Alveolar pressure is is the pressure of the air inside the alveoli (tiny air sacs) inside the lungs

alveoli

tiny, balloon-like air sacs at the very end of your lung's breathing tubes where your body trades fresh oxygen for waste carbon dioxide

anatomical dead space

the volume of air in the conducting airways that does not take part in gas exchange, around 150ml in an adult

aortic valve

a one-way gate in the heart located between the left ventricle and the main artery, called the aorta

appendicular skeleton

consists of bones that form upper and lower limbs, the shoulders and pelvic girdles.

arterial system

a branching network of strong muscular tubes that carry oxygen rich blood from the heart to every organ and tissue in the body

arteriole

a very small blood vessel that branches out from an artery and leads directly into smaller capillaries

artery

a major blood vessel that carries blood away from the heart to tissues and or organs throughout the body

arteriovenous oxygen difference

the difference in oxygen content between arterial and venous blood. (a-vO2 difference) indicates cell oxygen extraction and metabolic demands

atrioventricular (av) bundle

Known as bundle of his, group of specialized heart muscle fibers. carry electrical signals from av node to lower chambers of the heart

atriventricular (av) node

a group of specialized cells in the heart that acts as electrical connector between upper (atria) and lower (ventricle chambers.

atrioventricular (av) valves

one way flaps of tissue that sit between the upper and lower chambers of the heart. Consists of mitral valve on left, tricuspid valve on the right

atrium

the two upper chambers of the heart that collect blood returning from the body and lungs

axial skeleton

formed of 80 bones that include the skull, vertebral column, and thorax.

biaxial joints

a freely movable synovial joint that allows movements around two distinct axes and two anatomical planes. example is knuckle joints

bone periostium

a dense fibrous membrane that covers the outer surface of almost all bones. Attachment point for tendons and ligaments

bradychardia

condition where resting heart rate drops below 60 bpm. Due to aging, medications, heart problems or high levels of cardiovascular health

bronchi

large air passageways that branch off from the windpipe (trachea) and lead into the lungs

bronchiole

tiny air passageways in the lungs that branch off from bronchi to deliver air to alveoli

capillary

smallest blood vessel, enables transfusion of oxygen, nutrients and waste to pass between blood and tissues

cardiac output

the total volume of blood your heart pumps through your body every minute. Cardiac output = stroke volume x heart rate (bpm)

cartilaginous joints

a connection between bones where the surfaces are entirely joined by cartilage, a tough yet flexible connective tissue

cross bridge

when the globular head of a thick filament (myosin) binds with active site on thin filament (actin)

cross bridge cycling

the repetitive molecular process where myosin head groups bind to, pull on, and detach from actin fillaments to generate muscle force and shortening

depolorization

rapid change in muscle or nerve cell membrane potetnial from a negative to a positive state. triggering an action potential that leads to muscle contraction

diastole

relaxation and filling phase of the cardiac cycle when the heart ventricles refill with blood between contractions

diastolic blood pressure

the lowest arterial pressure during the relaxation phase of the cardiac cycle between heart beats.

diffusion

passive movement of gas molecules (ie oxygen/co2) from areas of varying pressure. occurs passively.

distal

located further from the center of the body/trunk.

double product

also called rate pressure product (rpp), a direct measure of the workload and energy demand placed on heart. formula: rrp = HR x Systolic Blood Pressure

ejection fraction

the percentage of blood pumped out of the hearts main pumping chamber (left ventricle) with each heart beat. EF = (SV/EDV) x 100 edv=end-diastolic volume

electrocardiogram

a diagnostic procedure that records the hearts electrical activity via electrodes while an individual performs activity on a treadmill or cycle

end-diastolic volume

the maximum amount of blood in the ventricles right before the heart contracts. Marks the end of diastole (filling phase)

endomysium

the innermost layer of loose connective tissue surrounding and enclosing each individual muscle fiber

epimysium

dense layer of fibrous connectiove tissue that wraps around an entire skeletal muscle

extrafusal fibers

the standard skeletal msucle fibers that generate the force and tension needed for body movements and posture

fasciculi

bundles of individual skeletal muscle fibers. contained by the perimysium

fast twitch fiber

skeletal muscle cells optimized for rapid, high force, and explosive contraction using anaerobic metabolism

fibrous joints

fixed connections between bones that are united by dense collagen fibers, lack joint cavity (skull sutures)

fick equation

vo2 - Q x (a-v)O2 difference. Math rule that shows how much oxygen your body uses when you exercise by multiplying how much blood your heart pups by how much oxygen your muscles use.

frank starling mechanism

the hearts built in ability to pump harder when more blood fills it (like a rubber band)

fused tetanic contraction

smooth, continuous, maximal muscle contraction caused by a very high frequency of nerve signals

golgi tendon organ

a sensory receptor located where the muscle meets its tendon. it measures muscle tension and triggers relaxation to prevent injury

heart rate

the number of times your heart beats per minute. direct measure of cardiovascular work

hemoglobin

iron-rich protein in red blood cells, carrying oxygen from the lungs to working muscles during exercise

hyaline cartilage

specialized tissue covering ends of bones where they articulate, act as shock absorber and smooths joint movements

h-zone

central region of muscle fiber subunit (sarcomere). Contains only thick filaments (myosin)

i-band

light colored zone inside a msucle fiber that shortens when your muscle contracts

inferior

situated toward the feet relative to another part of the body

intrafusal fibers

specialized muscle fibers found inside a muscle spindle, detects muscle stretch and rate of stretch

left bundle branch

electrical pathway in the heart that carries signals to the lower-left chamber (left ventricle), causes ventricles to contract.

maximal heart rate

the maximum amount of bpm your heart can beat during extreme effort

maximal oxygen uptake

Vo2 max, the highest amount of oxygen your body can absorb, transport and use during extreme exercise

mean arterial pressure

(the average blood pressure in a persons arteries during a single heartbeat. MAP = diastolic pressure + 1/3 (pulse pressure).

metabolic equivalent (MET)

1 MET: the amount of energy (and oxygen) your body uses at rest. Measurement of work during physical activity. 3 = light, 3-6 moderate, 6> vigorous

minute ventilation

the total volume of air you breath in and out of your lungs in one minute. Tidal volume x Respiratory Rate

mitral valve

one way valve between left atrium and ventrical. preents blood flow back into atrium

motor neuron

specialized nerve cell (and the muscle fibers it innervates) which carries electrical impulses from the brain and nervous system to skeletal muscles.

motor unit

a single nerve cell (motor neuron) and all the muscle fibers it controls

multiaxial joints

a freely movable synovial joint that allows movement in three different directions or planes of motion

muscle fiber

a single cylindrical muscle cell that contracts to create movement.

muscle spindle

a tiny sensory receptor inside a muscle belly that detects muscle length and speed of stretch. composed of intrafusal fibers

myocardium

the msucular middle layer of the heart that contracts and pumps blood

myofiber

a single complete muscle cell

myofibril

cylindircal fiber running the length of a muscle cell, made up of sarcomeres

Myofilament

microscopic thread-like protein strands of actin or myosin. building blocks of sarcomeres

myosin

microscopic protein, thick filament, tiny motor myosin heads latch to actin binding sites

Myosin adenosine triphosphate (ATP)

the chemical energy source and reaction that powers muscle contraction. the energy currency of muscle cells.

neuromuscular junctions

the chemical connection point where a motor neuron meets skeletal muscle fiber to signal movement

oxygen uptake

the amount of oxygen the body takes in, delivers and uses to create energy for muscles during exercise

parasympathetic nervous system

bodys rest and digest braking system: lowers HR, reduces blood pressure, restores metabolic balance after physical activity

perimysium

layer of connective tissue that groups individual muscle fibers into bundles called fascicles

physiological dead space

the total volume of inhaled air that does not take part in O2/CO2 exchange with blood

pleura

two-layer fluid filled membrane that surrounds the lungs and lines the chest cavity

pleural pressure

the pressure in the thin, fluid filled space between the lungs and the chest wall, prevents lungs from collapsing

power stroke

moment when muscle cell generats force to cause muscle contraction. myosin heads latch and pull on actin filaments

proprioceptor

specialized sensory receptor in your muscles, tendons, and joints that aid in body awareness, balance and control

proximal

indicates a body part that is close to the center of the body or the point where a limb attaches

pulmonary valve

a one way valve that enables blood flow from the right ventricle to the pulmonary arteries

purkinje fibers

specialized electrical conducting cells located in the inner walls of the hearts ventricles. maximizes cardiac output, increases hr, prevents backflow

P-wave

initial upward bump on an ecg/ekg, shows the electrical activation and contraction of the atria

qrs complex

spike on ecg, indicates depolorization, contraction and repolarization of the hearts ventricles during contraction

rate pressure product

simple n