Chapter 1: Structure and Function of Body Systems Flashcards
dark band that is the length of the myosin filaments, NEVER CHANGES LENGTH
A band
primary neurotransmitter that acts at the neuromuscular junction, excites the muscle fibers in the motor unit
acetylcholine
thin protein myofilament
actin
electrical nerve impulse
action potential
all muscle fibers in the motor unit contract and develop force at the same time
all or none principle
pressure inside the alveoli when the glottis is open and no air is flowing into or out of the lungs
alveolar pressure
where gases are exchanged in respiration
alveoli
valve that prevents backflow of blood from the aortic artery into the ventricle during ventricular relaxation
aortic valve
small branches of arteries that act as control vessels through which blood enters the capillaries
arteriole
sends signals to the ventricles
AV bundle
where the impulse is delayed slightly before passing into the ventricles
AV node
valves that prevent the flow of blood from the ventricles back into the atria during ventricular contraction
AV valves
joints that allow movement around 2 perpendicular axis
biaxial joints
specialized connective tissue covering all bones, where tendon attaches
bone periosteum
fewer than 60 bpm
bradycardia
second generation respiratory passage
bronchi
third generation respiratory passage
bronchiole
facilitate the exchange of oxygen, fluid, nutrients, electrolytes, hormones, and other substances between the blood and interstitial fluid in various tissues of the body, have thin permeable walls
capillary
joints that allow little movement
cartilaginous joints
formed by myosin heads attaching to actin filaments
crossbridge
“contraction,” reversal of the membrane electrical potential
depolarization
ventricular relaxation
diastole
process that allows oxygen and carbon dioxide to move through the alveolar capillary membrane
diffusion
graphic representation of the electrical activity of the heart
electrocardiogram (ECG)
fibrous connective tissue that surrounds each individual muscle fiber
endomysium
fibrous connective tissue that surrounds the entire muscle belly
epimysium
a bundle of muscle fibers grouped by fiber type
fascicle
motor unit that develops force and relaxes rapidly, has a short twitch time
fast twitch fibers
joints that allow virtually no movement
fibrous joints
proprioceptors located in series near the myotendinous junction, SENSE MUSCLE CONTRACTION + CAUSE MUSCLE INHIBITION
golgi tendon organ (GTO)
iron protein molecule carried by the red blood cells that transports oxygen, also an acid-base buffer
hemoglobin
type of smooth cartilage that covers the articulating ends of bones
hyaline cartilage
area in the center of the sarcomere where only myosin is present, shortens with contraction
H zone
corresponds with the areas in two adjacent sarcomeres that contain only actin filaments, shorten with muscle contraction
I band
two types of modified muscle fibers within the muscle spindle
intrafusal and extrafusal fibers
valve that prevents the back flow of blood from the left ventricle back into the left atrium during ventricular contraction
mitral valve
nerve cell
motor neuron
motor neuron + muscle fibers it innervates
motor unit
joints that allow movement around 3 axis
multiaxial joints
muscle cells made of myofibrils
muscle fiber
prorpioceptors that consist of several modified muscle fibers enclosed in a sheath of connective tissue, SENSE MUSCLE STRETCH + CAUSE MUSCLE CONTRACTION
muscle spindle
heart muscle
myocardium
contain what contracts the muscle (myofilaments)
myofibril
protein filaments of myofibrils in muscle cells
myofilament
thick protein myofilament
myosin
junction between a motor neuron and the muscle fiber it innervates
neuromuscular junction
fibrous connective tissue that surrounds one bundle of muscle fibers (fascicle)
perimysium
membranes enveloping the lungs and lining the chest walls
pleura
pressure in the narrow space between the lung pleura and the chest wall pleura, normally slightly negative
pleural pressure
pulling action of myosin on actin
power stroke
specialized sensory receptors located within joints, muscles, and tendons that send kinesthetic information to the brain
proprioceptors
valve that prevents back flow of blood from the pulmonary artery into the ventricle during ventricular relaxation
pulmonary valve
further divides and conducts impulses to all parts of the ventricles
purkinje fibers
atrial depolarization
P wave
ventricular depolarization + atrial repolarization
QRS complex
major cell components of blood that facilitate carbon dioxide removal
red blood cell
“filling” or “relaxation,” occurs shortly after depolarization to allow the ventricles to recover
repolarization
muscle fiber membrane
sarcolemma
smallest contractile unit of skeletal muscle, contain actin and myosin
sarcomere
cytoplasm of muscle fiber
sarcoplasm
system of tubules surrounding each myofibril, stores calcium
sarcoplasmic reticulum
valves that prevent backflow of blood from the aorta and pulmonary arteries into the ventricles during ventricular relaxation
semilunar valves
pacemaker of the heart, where the rhythmic electrical impulses are normally initiated
SA node
theory that states that the actin filaments at each end of the sarcomere slide inward on myosin filaments, pulling the Z lines toward the center of the sarcomere and thus shortening the muscle fiber
sliding filament theory
motor unit that develops force and relaxes slowly, has a long twitch time
slow twitch fiber
joints that allow the most movement
synovial joints
ventricular contraction
systole
more than 100 bpm
tachycardia
maximal amount of force that motor unit can develop, twitches begin to merge and eventually completely fuse together
tetanus
first generation respiratory passage
trachea
valve that prevents the back flow of blood from the right ventricle back into the right atrium during ventricular contraction
tricuspid valve
protein molecule that is roped around the actin filament, covers and uncovers actin binding site
tropomyosin
protein molecule that is situated at regular intervals along the actin filament and has a high affinity for calcium ions
troponin
tubes that run perpendicular to the sarcoplasmic reticulum
T tubule
ventricular repolarization
T wave
short period of activation of the muscle fibers within the motor unit
twitch
slow twitch oxidative fiber type, efficient and fatigue resistant, and have a high capacity for aerobic energy supply but a limited potential for rapid force development (endurance athletes)
type I muscle fiber
fast twitch (mixed) fiber type, inefficient and fatiguable, have a low aerobic power and high anaerobic power, and rapid force development (power athletes)
type IIa muscle fiber
fast twitch glycolytic fiber type, show less resistance to fatigue (1-5 RM)
type IIx muscle fiber
hinge joints that rotate around one axis
uniaxial joints
collect blood from capillaries
venule
the walls of the sarcomere, dark line in the middle of the I band
Z line
dictated by the number of crossbridges that are formed between actin and myosin at any instant in time
muscle force production
the discharge of an action potential from a motor nerve signals the release of calcium from the sarcoplasmic reticulum into the myofibril, causing what to develop in the muscle
tension
what two things are necessary for cross bridge cycling with actin and myosin filaments?
calcium and ATP
motor units are composed of muscle fibers with specific morphological and physiological characteristics that determine their what?
functional capacity
varies through change in the frequency of activation of individual motor units or change in the number of activated motor units
force output of a muscle
primary function of the respiratory system
basic exchange of oxygen and carbon dioxide
information concerning kinesthetic sense, or conscious appreciation of the position of body parts with respect to gravity (processed at subconscious levels)
proprioception
the assistance that contracting muscles provide to the circulatory system (veins) to help blood return to the heart, rather than pooling in the lower extremities
skeletal muscle pump