lec 7 skeletons, muscle and movement Flashcards
what are 3 challenges faced by humans (multicellular) that are not faced by bacteria/ameobas
- after reproduction, multicellular organisms must undergo development
2.must have transport system for sending materials to other cells
- cells must coordinate+communicate activities w/ other cells
t/f cells in multicellular organisms are specialized
true
explain the difference between a single-celled organism and multicellular organism in terms of cell functions.
single-celled: all fxns of life occur in single cell
multicellular: cells specialized to perform one fxn
t/f specialized cells can survive as individuals
false
for multicellular organisms, what is an advantage of having specialized cells?
more control over env. where cells reside
what are organs?
collection of specialized cells that perform shared fxn.
what are organs made of?
tissue
what is tissue made of?
specific cell types
what are the 4 basic tissue types in animals?
epithelial
connective
muscle
nerve
what type of cell is epithelial tissue made of? what are 2 fxns of them?
epithelial cells
-form the surface of animals
-line body cavities
what type of cell is connective tissue made of? what is their fxn?
connective cells
-connect+support other cells
what type of cell is muscle tissue made of? what is their fxn?
muscle cells
-contract to give animals ability to move
what type of cell is nerve tissue made of? what is their fxn?
nerve cells
-transmit nerve signals thru body
what is the purpose of a skeleton?
-supports body
-gives it shape
what is a major component in the skeleton?
bone tissue
what is bone tissue made of?
connective cells surrounded by calcium+collegen matrix
what is the purpose of calcium minerals in bones?
provide rigidity+strength
what is the purpose of collegen in bones?
provides resistance to tension
reduces brittleness
what produces collegen in the bone?
connective cells called osteocytes (bone cell)
what is the purpose of marrow in the bone?
source of blood cells + other important cells (osteocytes)
what is bone remodelling? what are 2 reasons it occurs?
bone changes in thickness
response to: exercise, hormones (estrogen)
how much calcium do adults require for remodelling?
large amt
1000mg/day
what is cartilage? what is it’s main fxn?
-cells that prod. collegen
-support+supplement bone
t/f cartilage is more flexible than bone
true
where are 3 places in the body where cartilage is found?
nose
ears
rib cage
what are ligiments? what is the main fxn?
-flexible sheets of tissue
-join bone to bone
what are hydrostatic skeletons?
use fluid pressure to become rigid
where is hydrostatic skeleton used in humans? what other animals use it?
-tounge
-soft bodied animals (worms, jellyfish)
what part of our skeleton allows us to move?
joints-bends and breaks in the skeleton
what do tendons do?
connect bone to muscle
what do cartliage discs do?
shock absorbers
what are synovial sacs?
provide lubrication to joints
what is Osteoarthritis?
progressive degenerative condition that wears down cartilage
give example of ligiment injury, and why it occurs
ACL tear- football player quickly changing direction while running
torsion on ligaments in knee, under high pressure, ligament will snap
what is an ACL tear?
femur (thigh) twists one way and tibia/fibula (calve) twist another way
-Results in a torn ligament
what are the 5 components of muscle tissue?
muscle fibers
myofibrils (iniv. cylinders)
sarcomere (contractile unit)
actin
myosin
explain how sacomeres work when contracting a muscle
-myosin heads attatch/detatch (‘walk’) along actin filaments
-this pulls z discs (ends of sarcomere) closer together
-sarcomere and therefore, muscle gets shorter
what happens to sarcomeres when a muscle relaxes?
myosic completely released from actin, sarcomere elongates again
