Bio K103 Chapter 40: Protection, Support, and Movement- Skeletal System

what is the primary function of the human skeletal system?

locomotion and movement (with muscles)

muscles and the skeleton work ___ ___ with each other

in opposition

what is the secondary function of the human skeletal system?

support and protection

what are the types of skeletons?

hydrostatic, muscular (hydrostat), exoskeleton, endoskeleton

what is a hydrostatic skeleton?

a fluid-filled body compartment

what is a muscular hydrostat?

fluid within tissue

what is an exoskeleton?

epithelium secretes, covers epithelium, cuticle on body surface

what is an endoskeleton?

skeletal tissue is covered by another tissue

how does a hydrostatic skeleton work?

muscle contracts on compartment, fluid moves within compartment, constant volume

what organisms have a hydrostatic skeleton?

invertebrates and some vertebrates

how does a muscular hydrostat work?

constant volume

what organisms have a muscular hydrostat?

invertebrates and vertebrates

how does an exoskeleton work?

muscle attached to it; contraction causes skeleton to move, may or may not grow with animal

what organisms have an exoskeleton?

invertebrates

how does an endoskeleton work?

muscle attached to it; contraction causes skeleton to move

what organisms have an endoskeleton?

chordates (notochord or bone) and echinoderms (ossicles)

what are the functions of vertebrate skeletons?

support, protection, movement, storage (ex. minerals like calcium and phosphate), blood cell formation, energy through lipid storage (yellow bone marrow)

what are examples of hydrostatic skeletons?

a gastrovascular cavity and coelom

describe the gastrovascular cavity in cnidarians

closed on one end and open on the other, have contractile proteins (epidermal or endodermal contraction) that work in antagonistic fashion against fluid-filled gastrovascular cavity

what is epidermal contraction?

shortening

what is endodermal contraction?

lengthening

describe the gastrovascular cavity of platyhelminthes

lots of muscle so they are able to do a variety of different movements

describe the gastrovascular cavity of nematodes

have a fluid-filled pseudocoelom, muscle contracts against it

describe the coelom in annelida

fluid-filled coelom divided by septa, muscles contract on coelom, movement is compartmentalized and allows for different parts to move different ways, coelom is partitioned and can act independently

give examples of muscular hydrostats

elephant's trunk, mammalian and reptilian's tongues, spider legs, octopus arms

what is the definition of an exoskeleton?

secreted by and covers epithelium

what is the exoskeleton composed of in bivalves?

calcium carbonate

what is the exoskeleton composed of in arthropods?

chitin

what organisms have exoskeletons that continually grow?

anthozoans and mollusks

how do some exoskeletons continuously grow?

continual secretion of calcium carbonate

what organisms must molt their exoskeleton?

ecdysozoa (arthropods and nematodes)

how are arthropods attached to their exoskeleton?

tendons attach muscles to the inner surface of the exoskeleton

describe the exoskeleton of arthropods

cuticle containing chitin, thin and flexible at joints

describe the endoskeleton of poriferans

spicules in mesophyll

what is the difference between a muscular hydrostat and a hydrostatic skeleton?

muscular hydrostat involves compression upon fluid inside tissue (muscle), while a hydrostatic skeleton involves compression upon tissue within a confined space

describe the endoskeleton of echinoderms

calcified spines and plates beneath epidermis, where the tube feet extend

what is the composition of a vertebrate skeleton?

ossified bone in most, and cartilage (chondrichthyes)

what is the tetrapod skeleton composed of?

two forelimbs and two hind limbs

what are the vertebrate skeleton divisions?

axial skeleton and appendicular skeleton

what is the axial skeleton?

the central axis

what is the appendicular skeleton?

limb bones and connections

what are the divisions of the appendicular skeleton?

pectoral gridle and pelvic girdle

what is the pectoral girdle?

connected to upper limbs (shoulder)

what is the pelvic girdle?

connected to lower limbs (pelvis)

which girdle is more securely attached to the axial skeleton?

pelvic girdle

what are the classifications of bone?

dense (compact) and spongy (trabecular)

what animals have a tetrapod skeleton?

birds, amphibians, reptiles, and mammals

what is dense/compact bone?

mineralized, outer "hard" bone, encloses spongy bone and marrow cavity, muscle tendons attach to it

what do tendons attach to?

membrane surrounding dense bone

what are the components of the dense bone osteon system?

osteons, osteocytes, lacunae, lamellae, canaliculi, haversian/osteon canal

what is an osteon?

a single isolated unit of dense bone

what happens if you break a bone?

it bleeds, lots of blood vessels so blood rich

what are osteocytes?

mature bone cells

what are lacunae?

small cavities where osteocytes reside

what are lamellae?

nonconcentric circles, give strength and support

what are canaliculi?

small channels between lacunae that allow for diffusion between cells

what is the haversian/osteon canal?

central channel in osteons that contains blood vessels, runs longitudinally

where is spongy bone found?

inside dense bone

where is a place you would find spongy bone?

the ends of long bones

what is found within spongy bone?

red bone marrow

what is formed in red bone marrow?

all blood cells (red and white) and platelets

where is marrow located?

in marrow cavity and between trabeculae

what happens to our bone marrow as we age?

red marrow gets replaced with yellow marrow

what is yellow marrow?

fatty connective tissue that can be used for energy storage

what parts of the body is red marrow found in (in adults)?

the pelvis and sternum

what are the bone classifications based upon shape?

long bones, short bones, flat bones, irregular bones, and sesamoid bones

describe the shape of long bones

longer than they are wide

describe the shape of short bones

cuboidal shaped

describe the shape of flat bones

bones that are somewhat put together like a sandwich (layers)

describe the shape of irregular bones

no real shape to them, lot of projections and contours

what bones are examples of long bones?

humerus, femur, fingers

what bones are examples of short bones?

wrist bones (carpals) and ankle bones (tarsals)

what is an example of a flat bone?

sternum

what is an example of an irregular bone?

vertebrae

what are examples of sesamoid bones?

patellae and hyoid

what are the bone coverings of long bones?

periosteum and endosteum

what is the periosteum?

covers dense bone outside surfaces, attachment site for tendons and ligaments

what is the endosteum?

covers dense bone inside surface

what are the anatomical regions of a long bone?

epiphysis, diaphysis, metaphysis

what is the epiphysis?

end of a long bone, area where joint is formed with another bone, bone growth happens here

what is the diaphysis?

the center/shaft/body of the long bone

what is the metaphysis?

area between epiphysis and diaphysis, where joint between two pieces of bone occurs

what is the epiphyseal plate?

growth plate, cartilage that extends the length of the bone on both ends, evetually calcifies

what is the epiphyseal line?

present when growth ends, is calcified, looks like a line on x-rays

what are the kinds of bone development?

endochondral and intramembranous

how do long bones develop?

endochondral bone development

what is endochondral bone formation?

in utero, bones develop from cartilage templates, blood supply grows into shaft and ends, shaft opens in middle and must remodel bone

what is intramembranous bone development?

bone growth from connective tissue that happens without a cartilaginous skeleton,

what kinds of bones have intramembranous development?

those without synovial joints

what is a joint?

a junction between two or more bones?

what is the function of joints?

allow flexibility and movement between most bones

how are the surfaces of joints protected?

bone surfaces coming into contact with one another are covered by articulate (hyaline) cartilage

what are the types of joints?

synovial, fibrous, cartilaginous

what are synovial joints?

encapsulated, fluid filled, reinforced with ligaments

what are fibrous joints?

bones joined by fibrous, connective tissue

what are cartilaginous joints?

made of cartilage, example is in pelvis and between vertebral discs

describe the movement of synovial joints

freely moveable, very flexible

describe the movement of fibrous joints

synarthrosis (sutures) or amphiarthrosis (ligament connection)

describe the movement of cartilaginous joints

amphiarthrosis (cartilage connection), more moveable than fibrous, less moveable that synovial

what does synarthrosis mean?

fixed, immoveable