Quiz 1 Flashcards
biology is the study of…
living things
mechanics is the study of…
motions and the applied loads that cause them
biomechanics is thus defined as the study of…
the motions experienced by living things in response to applied loads
da Vinci was interested in…
human flight (he studied how birds fly), an early example of mankind attempting to base the design of engineered systems on nature’s way of doing the same thing
mankind attempting to base the design of engineered systems on nature’s way of doing the same thing is called…
bionics
Galileo was interested in…
bone strength, and how the structure of bones contributes to their strength
Galileo (mistakenly) proposed that bones could be _________, which would improve the strength-to-weight ratio
hollow
Julius Wolff put forth the idea (and eventually the Law) of…
form follows function
following Wolff’s ideas, Wilhelm Roux put forth the concept of…
a quantitative self-regulating mechanism that results in functional adaptation of living things
list some reasons the 1960s were big for biomechanics
development of the computer, space race necessitating research into how bodies would react in space, advancement of numerical methods like FEM, birth of modern biology following identification of protein and DNA structures in the 50s
compared to classical physics, modern physics enables important diagnostic tools such as…
CAT scans and MRI
statistical mechanics attempt to describe the ________ behavior of the ___________
statistical (mean), individual molecules
continuum mechanics consider a _______________ behavior that is independent of the _________________
volume-averaged mean, individual molecules
the continuum assumption is reasonable when characteristic length of the microstructure / characteristic length of the physical problem of interest is («_space;or»_space;) 1
«_space;1 (basically, when the scale of the overall problem is way bigger than the scale of the individual particles)
“cell,” a term coined by ______, comes from the Latin cellulea, meaning ____________
coined by Hook, meaning “little rooms” (that’s so cute)
primary function of the nucleus is…
to archive and replicate genetic code as needed to direct cellular activity
all cells in a given organism contain the same ____________, but do not all ________ the same genes
genotype, express
the genes which are expressed determine a cell’s…
phenotype
the mitochondria…
provides a cell with energy by oxidizing foodstuffs to make ATP
the rough ER…
synthesizes proteins
ribosomes…
carry RNA
the smooth ER…
packages proteins and synthesizes lipids and steroids
the Golgi apparatus…
synthesizes polysaccharides and modifies, packages, and transports various macromolecules
lysosomes, with an internal pH of 5, …
digest proteins, carbs, and fats with enzymes like nucleases, proteases, and lipases
peroxisomes…
generate and degrade hydrogen peroxide (a cytotoxin) and assist in detoxifying other compounds
the cytoplasm includes…
all organelles other than the nucleus, the cytoskeleton, and the cytosol
the cytosol is about ______ of the total cell volume and consists primarily of _______
1/2, water
the cytoskeleton is made up of three classes of filamentous proteins that collectively give the cell much of its internal structure. list the three types of proteins
actin, microtubules, and intermediate filaments (vimentin, lamins, and keratins)
what is the additional intracellular constituent present in striated muscle?
the myofibril
myofibrils are made up of…
sarcomeres
sarcomeres consist of…
thin (actin) and thick (myosin) filaments that attach, detach, and reattach to each other to produce muscle contraction
integrins are transmembrane proteins that bind to other proteins - they consist of…
two noncovalently associated glycoproteins, called alpha and beta units
what are the three types of cell interconnections?
occluding (or tight), anchoring, and communicating (or gap)
what do growth factors do?
GFs are special proteins that bind to specific receptors on the membrane and encourage cell division
common classes of growth factors are…
platelet-derived (PDGFs), fibroblast (FGFs), and transforming (TGFs)
____________ and __________ can increase the secretion of growth factors
mechanical stresses and injuries
the ECM consists primarily of…
proteins, glycosaminoglycans (GAGs), and bound and unbound water
GAGs are often bound to…
protein cores, forming proteoglycans
_________ is the most abundant protein in the body (25-30%)
collagen
collagen types I and III…
form fibers and provide structural support in tension, abundant in ligaments, tendons, and bones
collagen type II…
occurs as fibrils, found largely in cartilage
collagen type IV…
forms as a porous network (basement membrane) that acts as a scaffold for epithelial and endothelial cells, has extensive disulfide bonds
collagen types V and VI…
associate with smooth muscle cells
collagen type VIII…
associates with endothelial cells
the collagen molecule consists of…
3 polypeptide alpha chains, organized into a central triple-helix motif repeating AA residues (G-X-Y)
what type of cells synthesize type IV collagen?
endothelial
what type of cells synthesize types I and III collagen?
fibroblasts and smooth muscle cells
the degree of cross-linking (increases/decreases) with age, resulting in…
increases, resulting in stiffening
the primary responsibility of fibroblasts is…
regulation of the collagen-rich ECM
cells that can change their gene expression in response to mechanical stimuli are called…
mechanocytes
what two junctions connect cells to the ECM?
hemidesmosomes and focal adhesions
what two junctions connect cells to cells?
desmosomes and adherent junctions
ligaments attach…
bone to bone (guides movement)
tendons attach..
bone to muscle (transmits force)
the most common type of cartilage is…
hyaline (lots of bound water)
