support and movement Flashcards
Explain the structure of a plant stem(vascular bundles) and how it is a support structure
hollow tubes-stronger than solid tubes-works against gravity/compression eg. xylem
plant stem:
epidermis
cortex-collenchyma, have primary wall with some thickening(corners) flexible TF allows bending
pit-parenchyma, thin cell walls - inc. vol. of vacuole inc. the size
vascular bundle-sclerenchyma(tissue surrounding)-thick secondary cell wall, provides rigidity and elasticity- return to OG shape
pit and cortex work together-pit presses against outer cortex-providing support
Hydroskeleton
Capsule of fluid, Surrounded by 2 layers of muscle-inner circular and outer longitudinal
Fluid filled cavity acts as a rigid column on which muscles act
Circular muscles contract to elongate +narrow the body
Longitudinal muscles contract(pull) shorten+thicken the body
Segmental contraction of muscles and anchorage by bristles drives the body forward-burrowing
Exoskeleton
Exoskeleton evolved from hydrostatic skeleton for protection from compression +injury
Eg. Mollusks, (clams+muscles), arthropods(insects+crabs)
Develop hard outer surface -protection of soft tissue -“armor”
Arthro = joint. Podia=foot
Arthropods-exoskeleton provides strength and mobility
Site for muscle attachment to create movement
Chitin-polysaccharides
Strong and light
In parts Mineralised(calcium) = hard and protective
Thin and flexible at joints
limitations:
Easily crushed
Do not grow in line with body(Malting) ecdysis potential vulnerability until it hardens
Size limiting (exo can’t support weight if they were bigger mass)
Endoskeleton
Endoskeleton provides a rigid system for muscle contraction and protection of vital organs
2 types: cartilaginous and bony
Cartilaginous fish (Chondrichthyes)
Cartilage (may be calcified)-must be thin to allow blood diffusion, Light. Efficient and flexible
bony
Support weight of large animals on land
Rigid support against gravity
Develop from cartilaginous skeleton
Levels which can be moved by muscle
DYNAMIC-respond to physiological loading-becomes lighter and less dense when less mobile(less exercise)
Bone structure(gross+cell)
bony structure(gross structure)
Bones are not solid-central (medullary) cavity
Reduces weight
Strength (resist compression +tension)
Filled with yellow bone marrow-cells similar to pit in plant
microscopic(cellular) structure:
Living cells in a mineralised extracellular matrix
Arranged into columns around an artery=osteon
(Lots of hollow tubes)
describe the functions of the skeletal system
Provides support (gravity)
Determines shape of the body
Function as levers by acting with muscle to facilitate joint movement
Protection of vital organs
Contains red bone marrow-blood cell formation
Mineral store for calcium and phosphates (metabolic processes; hormonal demand)
describe the different types of bones, and relate these to the different components of the skeleton
Long bones-limbs, levers, transmits longitudinal forces
Short bones-support/stability-limited movement
Flat bones-protective-muscle attachment sites
Irregular bones
Sesamoid bones-develops with tendon
describe the function and location of bone cells
Living cells-maintain extra cellular matrix
Bone matrix
Bone cell types:
Osteoblasts
Osteoclasts
Osteocytes
bone matrix-inorganic=67%(minerals-rigidity) + 33%=organic(collagen mostly+other proteins-flexibility)
osteoblasts(bone builders)
Immature bone cells
On bone surface(periosteum and endosteum)
Secrete organic bone matrix=osteoid->bone
osteocytes
mature bone cell
stellate(star shaped)
sense loading-communicate(to other bone cells to build/break down bone cells)
embedded in matrix
osteoclasts
Secrete acids and enzymes that remove bone
Multinucleate cells derived from monocytes
In the endosteum
describe the characteristic internal and external features of bone and explain that they are responsive to mechanical loading
top+bottom=epiphysis
middle(bulk)=diaphysis(shaft)
toward bottom=metaphysis-elongates with growth
very top/bottom:
trabeculae-“spongy” bone-(wolfs law)bone adapts to changes in mechanical load
spongy ends
combact bone walls
outside layer of bone-periosteum: connective tissue, vascular and fibrous (collagen+blood vessels)
lining inside of bone-endosteum:connective tissue; cellular(collagen)
middle-medullary cavity: yellow marrow adipose tissue
describe the different types of joints and the movement produced at them
fibrous joint
No/limited movement
Dense fibrous connective tissue
cartilaginous joint:
Primary-Eg. Sternocostal
Secondary-Eg. Intervertebral disc
(depending on tissue present)
synovial joint:
Freely movable
Ends of bones are covered with articular cartilage
Synovial/joint cavity contains synovial fluid<-lubricates joint
Lubricate secreted by synovial membrane
Enclosed in an elastic joint capsule
Shapes: gliding, pivot, hinge, ball and socket, ellipsoid, saddle
types of skeleton
axial skeleton
Midline; protection and attachment
Skull
Vertebral column
Ribs
Sternum
appendicular skeleton
Movement/locomotion
Similar pattern;evolutionary development
Upper limb-dexterity
Lower limb-support and movement(larger+stronger bones)
vertebral column
Provides flexible support for the head and appendicular skeleton(limbs)
4 curvatures-(7)cervical, (12)thoracic, (5)lumbar, sacral and coccyx
->thoracic skeleton-Attached to thoracic vertebrae
Ribs: 12pairs, 7 true(attach to sternum)+5 false(2floating)attach to ribs above)
skull
Contains and protects the brain, organs of special sense and upper respiratory and alimentary tracts (22 bones)
Describe the principle functions of skeletal muscle and their role in lever systems
Movement of the body and/or its parts
Walking, running, chewing, swallowing etc.
Posture
Postural muscles oppose the action of gravity – e.g. neck – supporting weight of the head
Heat production
Highly metabolically active; generate lots of heat; shivering
Describe the varying shapes of skeletal muscle
Skeletal muscle – Striated, voluntary
Cardiac muscle – Striated, involuntary
Smooth muscle – Non-Striated, involuntary
(banding pattern and micro filaments)
Relate muscle fibre organisation to the strength and range of force produced by a muscle
origin=stationary (or more fixed) end
insertion=more movable end
lever system-muscle attachment relative to joing
1st class-seesaw eg. neck
2nd class-wheelbarrow-going up on tip toes
3rd class(most common)-for speed but not large loads-bicep curls
exceptions
not all muscles run bone to bone
bone to skin-muscles of facial expression
Describe the structure and function of tendons
muscles made out of contractile cells and connective tissue
functional unit
Long multinucleate cells=muscle fibre
Contain myofibrils made up of actin and myosin filaments
muscle(tendon) arrangements
parallel eg. neck
circular eg. face(mouth
convergent eg. on skull
pennate eg. lower arm
(parallel-weak contraction-large range of movement, unipennate-stronger contraction, shorter range, bipennate-v strong vontraction short range, multipennate-strongest and shortest range)
