Chapter 1 - Structure and Function of Body Systems Flashcards
Which of the following substances regulates muscle actions?
a. potassium
b. calcium
c. troponin
d. tropomyosin
b. calcium
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
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
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
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
The section of the sarcomere that corresponds with the alignment of myosin and actin filaments.
A-band
A neurotransmitter released when an action potential arrives at the nerve terminal. This diffuses across the neuromuscular junction causing excitation of the sarcolemma.
acetylcholine
A protein that forms actin myofilaments. These filaments consist of two thin strands about 6nm in diameter arranged in a double helix.
actin
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
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
Pressure inside the alveoli when the glottis is open and no air is flowing into or out of the lungs.
alveolar pressure
The final passages in the respiratory system where gases are exchanged from the lungs.
alveoli
Valve in the heart that prevents backflow of blood from the aorta into the ventricle.
aortic valve
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
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
Smaller branches of the arterial system that deliver blood to the capillaries.
arteriole
Strong tubes that rapidly transport blood from the heart.
artery
Conducts the impulse in the heart to the ventricles
atrioventricular (AV) bundle
Node in the heart that slightly delays the impulse from the SA node.
atrioventricular (AV) node
One-way valves that prevent the backflow of the blood from the ventricles into the atria.
atrioventricular (AV) valves
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
Bones of the skull (cranium), vertebral column (C1-coccyx), ribs, and sternum.
axial skeleton
Joints such as the ankle and wrist that allow movement around two perpendicular axes
biaxial joints
A specialized connective tissue covering all bones. The tendons attach to it
bone periosteum
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