Chapter 1 - Structure and Function of Body Systems Flashcards by Joshua Murillo

Which of the following substances regulates muscle actions?

a. potassium
b. calcium
c. troponin
d. tropomyosin

b. calcium

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Which of the following substances acts at the neuromuscular junction to excite the muscle fibers of a motor unit?

a. acetylcholine
b. ATP
c. creatine phosphate
d. serotonin

a. acetylcholine

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When throwing a baseball, an athlete’s arm is rapidly stretched just before throwing the ball. Which of the following structures detects and responds to that stretch by reflexively increasing muscle activity?

a. Golgi tendon organ
b. muscle spindle
c. extrafusal muscle
d. Pacinian corpuscle

b. muscle spindle

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From which of the following is the heart’s electrical impulse normally initiated?

a. AV node
b. SA node
c. the brain
d. the sympathetic nervous system

b. SA node

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Which of the following occurs during the QRS complex of a typical ECG?
I. depolarization of the atrium
II. repolarization of the atrium
III. repolarization of the ventricle
IV. depolarization of the ventricle

a. I and III only
b. II and IV only
c. I, II, and III only
d. II, III, and IV only

b. II and IV only

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The section of the sarcomere that corresponds with the alignment of myosin and actin filaments.

A-band

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A neurotransmitter released when an action potential arrives at the nerve terminal. This diffuses across the neuromuscular junction causing excitation of the sarcolemma.

acetylcholine

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A protein that forms actin myofilaments. These filaments consist of two thin strands about 6nm in diameter arranged in a double helix.

actin

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An electrical impulse from a motor nerve that signals the release of calcium from the sarcoplasmic reticulum into the myofibril, causing tension development in the muscle.

action potential

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The phenomenon that a stimulus from the motor neuron will cause all fibers in that motor unit to contract. As such, stronger action potentials do not result in bigger contractions.

all-or-none principle

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Pressure inside the alveoli when the glottis is open and no air is flowing into or out of the lungs.

alveolar pressure

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The final passages in the respiratory system where gases are exchanged from the lungs.

alveoli

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Valve in the heart that prevents backflow of blood from the aorta into the ventricle.

aortic valve

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Bones of the shoulder/pectoral girdle (left and right scapula and clavicle), bones of the arms, wrists, and hands (left and right humerus, radius, ulna, carpals, metacarpals, and phalanges); the pelvic girdle (left and right coxal or innominate bones), and the bones of the legs, ankles, and feet (left and right femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges).

appendicular skeleton

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System of tubes that carries blood away from the heart. Due to the high pressure of the blood from the heart, these tubes have strong walls

arterial system

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Smaller branches of the arterial system that deliver blood to the capillaries.

arteriole

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Strong tubes that rapidly transport blood from the heart.

artery

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Conducts the impulse in the heart to the ventricles

atrioventricular (AV) bundle

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Node in the heart that slightly delays the impulse from the SA node.

atrioventricular (AV) node

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One-way valves that prevent the backflow of the blood from the ventricles into the atria.

atrioventricular (AV) valves

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Chambers of the heart that receive blood and pump it to the ventricles. The left and right chambers pump blood to the left and right ventricle, respectively.

atrium

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Bones of the skull (cranium), vertebral column (C1-coccyx), ribs, and sternum.

axial skeleton

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Joints such as the ankle and wrist that allow movement around two perpendicular axes

biaxial joints

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A specialized connective tissue covering all bones. The tendons attach to it

bone periosteum

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Heart rate less than 60 bpm

bradycardia

Second generation passages in the respiratory system that deliver air to the bronchioles

bronchi

The third generation passages in the lungs that deliver air to the alveoli, where gases are exchanged

bronchiole

Small end-tubes of the arterial system that facilitate exchange of oxygen, fluid, nutrients, and other substances between the blood and other fluids in various body tissues

capillary

joints that allow limited movement - i.e. intervertebral disks

cartilaginous joints

The connections between the globular heads on myosin filaments that bind with actin. The strength of a muscle contraction is directly related to the number of myosin crossbridges bound to actin.

crossbridge depolarization

The reversal of the heart membrane electrical potential and results in contraction of the atria or ventricles in the case of the P-Wave and QRS complex, respectively.

diastole

The simple random motion of molecules moving in opposite directions through the alveolar-capillary membrane

diffusion

The attachment of a limb muscle that is further from the trunk relative to the proximal attachment

distal

Graphic representation of heart electrical activity

electrocardiogram (ECG)

The connective tissue that surrounds each muscle fiber and is contiguous with the muscle fiber membrane known as the sarcolemma

endomysium

The outer layer of fibrous connective tissue covering the body’s more than 430 skeletal muscles. This layer is contiguous with the tendons at the ends of the muscle

epimysium

Normal muscle fibers

extrafusal fibers

Bundles of muscle fibers located under the epimedium. These bundles can consist of up to 150 fibers and each one is individually surrounded by connective tissue called perimysium

fasciculi

The fibers in a specific motor unit that develops force and relaxes rapidly, resulting in a short twitch time. These fibers are further broken into Type IIa fibers and type IIx fibers.

fast-twitch fiber

Joints that allow little to no movement such as the sutures of the skull.

fibrous joints

Proprioceptors located in the tendons attached to extrafusal muscle fibers. These proprioceptors relay information regarding tension in the muscle and are though to protect against the development of excess tension in the muscle

Golgi tendon organ (GTO)

The iron-protein molecule carried by red blood cells. This molecule transports oxygen as well as provides an acid-base buffer in the blood to regulate H+ ion concentration

hemoglobin

The smooth covering on the ends of articulating bones

hyaline cartilage

The area in the center of the sarcomere containing only myosin filaments. This area decreases during muscle contraction as actin slides over the myosin toward the center of the sarcomere

H-zone

The area in two adjacent sarcomeres that contain only actin filaments

I-band

The attachment of a trunk muscle closer to the feet relative to other attachments

inferior

Modified muscle fibers that run parallel to normal extrafusal fibers and relay sensory information concerning muscle length

intrafusal fibers

Fibers in the heart that send the contraction impulse to the left ventricle

left bundle branch

Heart valve that prevents blood flow from the left ventricle to the left atria

mitral valve

The nerve cell responsible for innervating the muscle fibers. Each one can innervate many muscle fibers, sometimes hundreds or even thousands

motor neuron

The motor neuron and the muscle fibers it innervates

motor unit

Joints such and the shoulder and hip ball-and-socket joints that allow movement around all three perpendicular axes that define space

multiaxial joints

Long, cylindrical cells 50 to 100 micrometers in diameter (about the diameter of a human hair). These have many nuclei situated on the periphery of the cell and have a striated appearance

muscle fiber

Proprioceptors that consist of modified muscle fibers enclosed in a sheath of connective tissue. These proprioceptors provide information concerning the muscle length and rate of change in length

muscle spindle

Heart muscle tissue

myocardium

Small fibrils within the muscle fiber that contain the apparatus that contracts the muscle cell

myofibril

small strands of protein, primarily either myosin or actin, that are responsible for muscle contraction

myofilament

a protein that makes up myosin filaments of about 16 nm in diameter. This filament has a globular head, a hinge point, and a fibrous tail. Pairs of these filaments form cross-bridges, which interact with actin to produce muscular contractions

myosin

The junction between the motor neuron and the fibers it innervates

neuromuscular junction

Component of the autonomic nervous system. Stimulation of this nervous state slows heart rate by slowing SA depolarization

parasympathetic nervous system

Connective tissue surrounding each fascicle

perimysium

The membranes that envelope the lungs and lining of the chest walls

pleura

The pressure in the narrow space between the chest wall pleura and the lung pleura

pleural pressure

The pulling action during muscle contraction. This action results from the hydrolysis of adenosine triphosphate (ATP) to adenosine diphosphate (ADP) and phosphate. This reaction is catalyzed by the enzyme myosin adenosine triphosphatase (ATPase)

power stroke

Specialized sensory receptors within joints, muscles, and tendons. These are sensitive to pressure and tension in the muscle and relay information about muscle dynamics to the nervous system. This process allows the CNS to maintain muscle tone and perform coordinated movements

proprioceptor

The attachment of a limb muscle that is closer to the trunk.

proximal

Valve in the heart that prevents blood flow from the pulmonary artery into the right ventricle

pulmonary valve

Fibers in the heart that conduct heartbeat impulse to all parts of the ventricles

Purkinje fibers

Recordings of electrical depolarization in the heart. These recordings are generated by changes in electrical potential within cardiac muscle cells that depolarize the atria, resulting in contraction

P-wave

Recording of depolarization in the heart resulting in ventricular contraction

QRS complex

The major component of blood that contains hemoglobin. These transport oxygen as well as other processes such as catalyzing the reaction that facilitates carbon dioxide removal

red blood cell

The process that occurs as ventricles recover from depolarization

repolarization

Fibers in the heart that send the contraction impulse to the right ventricle

right bundle branch

the membrane surrounding each muscle fiber

sarcolemma

The smallest contractile unit of skeletal muscle. In a relaxed fiber, these average about 2.5 micrometers in diameter and are repeated the entire length of a muscle fiber. Actin and myosin filaments are arranged longitudinally here

sarcomere

the cytoplasm fluid inside the muscle fiber connotation protein filaments, other proteins, stored glycogen, fat particles, enzymes, and specialized organelles such as mitochondria and the sarcoplasmic reticulum

sarcoplasm

An intricate system of tubules that surround each myofibril and terminate as vesicles in the vicinity of the Z-lines. Calcium ions are stored in the vesicles

sarcoplasmic reticulum

Collective term for the aortic and pulmonary valves

semilunar valves

Pacemaker of the heart where electrical impulses are initiated

sinoatrial (SA) node

The theory of muscle contraction that states that actin filaments at the end of each sarcomere slide inwards on myosin filaments, which pulls the Z-lines towards the center of the sarcomere, shortening the muscle fiber. As the actin slides over the myosin, the H-Zone and I-Band shrink. The myosin cross-bridges pull on the actin filaments and are responsible for the movement of the actin filament

sliding-filament theory

Muscle fibers, specifically Type I fibers, with high aerobic efficiency but low maximum force output

slow-twitch fiber

The attachment of a trunk muscle that is closer to the head relative to the other attachments

superior

Component of the autonomic nervous system. Stimulation of this nervous state increases the heart rate by accelerating the depolarization of the sinoatrial node.

sympathetic nervous system

The fluid enclosed inside the joint capsule

synovial fluid

joints that allow considerable movement with low friction and large ranges of motion (i.e elbow and knee). Sport and exercise movements occur mostly around these joints

synovial joints

Ventricular contraction

systole

heart rate above 100 beats/minute

tachycardia

Connective tissue that attaches the muscles to the bone periosteum. Muscle contractions pull on these which in turn pulls on the bone

tendon

The process that occurs when stimuli are delivered at such a high frequency that the muscle twitches fuse, resulting in the maximal amount of force a motor unit can develop

tetanus

The first generation respiratory passage where the air is passed to the bronchi and ultimately the bronchioles for oxygenation by the lungs

trachea

Heart valve preventing blood flow from the right ventricle to the right atrium

tricuspid valve

A protein that runs along the actin filament in the groove of the double helix. When calcium binds with this protein’s base molecule, a shift occurs in it that results in rapid attachments of the actin filament to the myosin cross

tropomyosin

A protein situated at regular intervals along the actin filament and has a high affinity for calcium ions. When calcium is released from the sarcoplasmic reticulum, it binds with the this

troponin

These run perpendicular to the sarcoplasmic reticulum and terminate in the vicinity of the Z-line between to vesicles. These run between outlying myofibrils and are contiguous with the sarcolemma at the cell surface. This results in the action potential reaching all depths of the muscle fiber nearly simultaneously.

T-tubule

Recording of the electrical potential generated during repolarization in ventricular muscle

T-wave

Brief contraction of muscle fibers that occurs when an action potential reaches the neuromuscular junction. To develop force, multiple XXX occur before the complete relaxation of the muscle fiber. When there is resistance (ie from an external weight) to the actin-myosin binding process, multiple XXX will occur back-to-back. The force from the XXX is additive. Multiple back-to-back XXX produce more force than a single twitch.

twitch

Slow-twitch fibers with high efficiency and the ability for aerobic metabolism. These fibers are slower to produce force and have a lower maximum force output, but are incredibly efficient

Type I fiber

Fast-twitch fiber with more endurance than the other fast twitch fiber, slightly less maximum force production, and less endurance than slow twitch fibers.

Type IIa fiber

Fast-twitch fibers that have the greatest ability to rapidly produce force but are the least efficient and least able to use aerobic metabolism compared to the other fiber types

Type IIx fiber

joints such as the elbow that operate as hinges, essentially rotating around only one axis.

uniaxial joints

Tubes that transport blood back to the heart.

vein

System of tubes that returns blood from the muscles to the heart.

venous system

Chambers of the heart that receive blood from the atria and pump it either to the lungs [Right] or the rest of the body [Left]

ventricle

Small tubes that collect blood from the capillaries and converge into the larger veins

venule

vertebral bones separated by flexible disks that allow movement to occur. Vertebrae are grouped in the following: Seven cervical vertebrae (C1-C7), the twelve thoracic vertebrae (T1-T12), five lumbar vertebrae (L1-L5), five sacral vertebrae, which are fused together and make up the pelvis, and the three to five coccygeal vertebrae, which form a vestigial internal tail extending downward front the pelvis.

vertebral column

A thin dark line running longitudinally through the I-band.

Z-line

The reversal of the heart membrane electrical potential and results in contraction of the atria or ventricles in the case of the P-Wave and QRS complex, respectively.

Depolarization