Biology chapter 11 mcat

skeltal muscle

striated, polynucleated, voluntary,

red fibers

slow twitch fibers, carry out oxidative phosphorylation

white fibers

fast twitch, rely on anaerobic respiration

smooth muscle

nonstriated, involuntary control, uninucleated, can display myogenic activity

myogenic activity

contraction without neural input

cardiac muscle

striated, uninucleated, involuntary, can display myogenic activity. cells are connected with intercalated discs that contain gap junctions

sarcomeres

basic contractile unit of striated muscle

troponin and tropomyosin

in the thin filament and regulate actin-myosin interactions

z-lines

boundaries of each sarcomere

m line

located in the middle of a sarcomere

i band

contains only the thin filament

h zone

consists of only thick filament

a band

contains thick filaments in their entirety. It is the only part of the sarcomere that maintains a constant size during contraction

myofibrils

sarcomeres attached end to end

sarcoplasmic reticulum

a calcium containing modified ER

sarcolemma

cell membrane of a myocyte(muscle cell)

neuromuscular junction

where muscle contraction begins. the motor neuron releases acetylcholine that binds to receptors on the sarcolemma causing depolarization

creatine phosphate

can transfer a phosphate group to adp forming atp

myoglobin

heme containing protein that is a muscular oxygen reserve

oxygen debt

the difference between the amount of oxygen needed and the amount of oxygen present

endoskeletons

internal skeletons

exoskeletons

external skeletons (crabs and bugs)

axial skeleton

consists of midline structures (skull spine, rib cage and hyoid bone)

appendicular skeleton

consists of bones from the limbs(pectoral, girdle and pelvis)

compact bone

provides strength and is dense

spongy/cancellous bone

has a lattice like structure consisting of bony spicules known as trabeculae

trabeculae

cavities filled with bone marrow

epiphyseal plate

causes linear growth to bones

tendons

bone to muscle

ligaments

bone to bone

osteoblasts

build bone

osteoclasts

chew bone

vitamin D

increases reabsorption of bone, leading to increased turnover and the production of stronger bone

chondrocytes

secretes cartilage

cartilage

found in spaces that require more flexibility and cushioning. Avascular tissue that is non innervated

endochondral ossification

how bones form from cartilage in fetal life

intramembranous ossification

bones form directly from undifferentiated tissue (bones in the skull)

synovial fluid

aids in motion by lubricating the joint, secreted by the synovium

articular cartilage

each bone in the joint is coated in this to aid in movement and provide cushioning