Chapter 1-Structure and Function of body systems Flashcards
Axial skeleton
Appendicular skeleton
skull, vertebral column, ribs and sternum
shoulder girdle; bones of the arms, wrists and hands; pelvic girdle; and bones of the legs, ankles and feet
Fibrous joints
Cartilaginous joints
Synovial joints
allow virtually no movement (sutures of the skull)
allow limited movement (intervertebral discs)
allow considerable movement (elbow and knee)
low friction and large range of motion
Hyaline cartilage
most common type, smooth with a glassy appearance; covers the ends of articulating bones and is found in the ribs, nose, larynx and trachea
Synovial fluid
entire joints are enclosed in a capsule filled with SF whose main role is to reduce the friction between the articular cartilage of the joints
Uniaxial joints
Biaxial joints
Multiaxial joints
operate as hinges rotating about one axis (elbow)
allow movement about two perpendicular axes (wrist and ankle)
allow movement about all three perpendicular axes that define space (shoulder and hip)
Vertebral column
7 cervical vertebrae
12 thoracic vertebrae
5 lumbar vertebrae (lower back)
5 sacral vertebrae (fused together to make up rear pelvis)
3-5 coccygeal vertebrae (vestigial internal tail)
Skeletal muscle
organ containing muscle tissue, connective tissue, nerves, and blood vessels
more than 430 muscles
Epimysium
Perimysium
Endomysium
fibrous connective tissue contiguous with the tendons at the ends of the muscle
connective tissue surrounding the fasciculi
connective tissue surrounding each individual muscle fiber
Bone periosteum
specialized connective tissue covering all bones and attached to the tendon
Limb muscles–2 attachments
Trunk muscles–2 attachments
proximal–closer to the trunk
distal–farther from the trunk
superior–closer to the head
inferior–closer to the feet
Muscle fibers
long, cylindrical muscle cells about the diameter of a hair
Fasciculus
groups of up to 150 muscle fibers grouped together and bound by perimysium
Sarcolemma
transparent sheath that encircles and is contiguous with the fiber’s membrane
Neuromuscular junction
junction between a motor neuron and the muscle fiber it innervates
each muscle cell only has 1 neuromuscular junction, but a single motor neuron innervates many muscle fibers
Motor unit
the motor neuron and the muscle
Sarcoplasm
Myofibril
cytoplasm of muscle fiber containing contractile components
contains the apparatus that contracts the muscle cell, primarily the myofilaments myosin and actin
Myosin
Actin
Sarcomere
thick filament composed of a globular head, hinge point and a fibrous tail
thin filament consisting of two strands arranged in a double helix
smallest contractile unit of muscle where the myosin and actin filaments are organized longitudinally
A-band
I-band
Z-line
H-zone
dark due to the alignment of the myosin
light due to adjacent sarcomeres containing only actin
in the middle of the I-band and appears as a thin, dark line running longitudinally through it
center of the sarcomere where only myosin filaments are present
Action potential
electrical nerve impulse
the discharge of an action potential from a motor nerve signals the release of calcium from the sarcoplasmic reticulum into the myofibril, causing tension development in muscle
Sliding filament theory
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 shortening the muscle fiber
Troponin
Tropomyosin
protein that is situated at regular intervals along the actin filament and has a high affinity for calcium
protein molecule that runs along the length of the actin filament in the groove of the double helix
At any instance in time the number of crossbridges that are formed between actin and myosin
dictate the force production of muscle
What two things are necessary for crossbridge cycling with actin and myosin filaments
Calcium and ATP
all-or-none principle
once a sufficient amount of acetylcholine diffuses across the neuromuscular junction, it generates an action potential along the sarcolemma and contracts all of the fibers
tetanus
maximal amount of force the motor unit can develop
slow-twitch fibers (Type I)
fast-twitch fibers (Type IIa and Type IIx)
develop force and relax slowly and have a long twitch time; efficient and fatigue resistant with a high capacity for aerobic energy supply
develop force and relax rapidly and have a short twitch time; inefficient and fatiguable with low aerobic power, rapid force development, high myosin ATPase activity, and high anaerobic power
recruitment
process of increasing muscle force through varying the number of motor units activated
Proprioceptors
specialized sensory receptors located within joints, muscles, and tendons that are sensitive to pressure and tension, and relay info concerning muscle dynamics to the conscious and subconscious parts of the CNS
Muscle spindles
proprioceptors consisting of several modified muscle fibers enclosed in a sheath of connective tissue
provide info concerning muscle length and rate of change in length
facilitate activation of the muscle
Golgi tendon organs
proprioceptors located in the tendons that are activated when the tendon attached to an active muscle is stretched
inhibit muscle activation
ability of the motor cortex to override the GTO’s inhibition may be one of the fundamental adaptations to heavy resistance training
Cardiovascular system
responsible for the exchange of oxygen, transportation of nutrients throughout the body and removal of waste from the cells
regulates body’s acid-base system, fluids, and temperature
Heart chambers
top chambers-atria
bottom chambers-ventricles
right side receives blood from the body and pumps it to the lungs for oxygenation
left side receives oxygenated blood from the lungs and pumps it out to the body
Atrioventricular valves
Semilunar valves
tricuspid and bicuspid
prevent the blood from reentering the atria from the ventricles during systole
aortic and pulmonary
prevent the backflow of blood from the arteries into the ventricles during diastole
Electrical impulse conduction
SA node
AV node
AV bundle
Purkinje fibers
sinoatrial node–starting place of the electrical impulse and the pacemaker
atrioventricular node–delays the impulse before sending it to the AV bundle
AV bundle–location where the impulse is prepared to be conducted to the ventricles
Once prepared, the impulse is sent to the left and right bundle branches of the heart
impulse divides and is conducted into the Purkinje fibers allowing both ventricles to receive the impulse
bradycardia
tachycardia
HR fewer than 60 beats/min
HR higher than 100 beats/min
Depolarization
Repolarization
negative potential inside the membrane becomes positive
P-wave and QRS wave
ventricles restore homeostasis
T-wave
QRS complex–repolarization of the atrium is masked by depolarization of the ventricle
