Chapter 1-Structure and Function of body systems Flashcards
(36 cards)
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