ch. 38 Flashcards
what is abduction?
when a bone moves away from the midline of the body
What is acetylcholinesterase(AchE)? what does it do?
an enzyme that breaks down ACh into acetyl and choline
what is actin?
globular contractile protein
what do myosin and actin work together to produce?
muscle contractions
what is adduction?
movement of the limbs inward after abduction
what is amphiarthorosis? what does it include?
a joint that allows slight movement; includes syndesmoses and symphyses
when is angular movement produced?
when the angle between the bones of a joint change
what is an appendicular skeleton composed of?
it is composed of the bones of the upper limbs and the lower limbs
what is the function of the bones of the upper limbs in an appendicular skeleton?
they function to grasp and manipulate objects
what do the bones of the upper limbs permit in an appendicular skeleton?
they permit locomotion
what happens during appositional growth?
an increase in the diameter of bones by the addition of bone tissue at the surface of the bones
what is an articulation?
any place where two bones are joined
what does an auditory ossicle do?
transducers sounds from the air into vibrations in the fluid-filled cochlea
what is a hydrostatic skeleton?
skeleton that consists of aqueous fluid held under pressure in a closed body compartment (soft-bodied, fluid filled cavity)
what terrestrial animals have hydrostatic skeletons?
earthworms and slugs
what aquatic animals have hydrostatic skeletons?
jellyfish and squid
what is the advantage of a hydrostatic skeleton?
it is flexible
what are the disadvantages of a hydrostatic skeleton?
drying and squishy
what is an exoskeleton?
a secreted cellular product external skeleton that consists of a hard encasement on the surface of an organism (ridged hard case and muscles attach internally)
what animals have exoskeletons? what makes up the exoskeleton?
arthropods; chitin
what are the advantages of an exoskeleton?
can resist desiccation and good for protection
what are the disadvantages of an exoskeleton?
must molt in order to grow, weighs more, and are vulnerable to predation
what animals have endoskeletons?
echinoderms and vertebrates
what makes up a vertebrate’s endoskeleton?
calcium phosphate (Ca3[PO4]2)
what makes up a echinoderm’s endoskeleton?
calcium carbonate (CaCO3)
what is an endoskeleton?
skeleton of living cells that produces a hard, mineralized tissue located within the soft tissue of organisms
what is the purpose of cartilage in an endoskeleton?
joint movement
what is the purpose of ligaments in an endoskeleton?
joint stability
what is the purpose of tendons in an endoskeleton?
muscle attachment
what are the four functions of an endoskeleton?
- protection’
- muscle attachment
- living tissue
- mineral storage
what minerals does an exoskeleton store?
calcium and phosphate
what does the endoskeleton protect?
organs (heart/lungs)
what is the function of the living tissue of an endoskeleton?
to produce red/white blood cells and remodel from stress
What are the bones of the central axis?
- skull (w/ cranial bones) (including mandible and maxilla)
- sternum
- rib cage
what are the functions of the vertebral column (aka spine)?
surrounds and protects the spinal cord, supports the head, and acts as an attachment point for ribs and muscles of the back and neck
how many cervical vertebrae are there in the vertebral column?
7
how many thoracic vertebrae are there in the vertebral column?
12
how many sacral vertebrae are there in the vertebral column?
5 fused
how many coccyx vertebrae are there in the vertebral column?
4 fused
what types of vertebrae in the vertebral column are fused?
sacral and coccyx
what are the bones of the human limbs?
the pectoral girdle and the pelvic girdle
what is the function of the pectoral girdle?
attaches the upper limbs to the body
what is the function of the pelvic girdle?
attaches the lower limbs to the body
what bones make up the pectoral girdle?
scapula and clavicle
what bones make up the pelvic girdle?
ilium, ischium, and pubis
what bones make up the forelimb?
humerus, ulna, radius, carpels, metacarpals, and phalanges
what bones make up the hindlimb?
femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges
when is a bone considered a “long bone”?
when the length is greater than the width
what is the structure of a long bone?
a shaft (diaphysis) with two ends (epiphyses)
what characterizes short bones?
they are cuboidal and their length is equal to width
examples of long bones?
humerus and femur
examples of short bones?
carpels and tarsals
what are characteristics of flat bones?
- thin and broad
- used for organ protection
what are some examples of flat bones?
sternum and ribs
what is a characteristic of irregular bones?
complex shapes
what are examples of irregular bones?
vertebrae and hip bones
what are characteristics of sesamoid bones?
small and flat
what are characteristics of sutural bones?
irregular, small, and flat
what is an example of a sesamoid bone?
patellae
what are examples of sutural bones?
bones of the skull
what are bones?
organs; collections of tissue
what does a compact bone form?
forms the hard external layer of all bones
what is another name for contact bone?
cortical bone
what is another name for spongy bone?
cancellous bone
what does spongy bone lack?
osteons
what cells does spongy bone form?
blood cells
what surrounds the medullary cavity?
compact bone
what is spongy bone?
is forms the inner layer of all bones
what are trabeculae?
lamellae that are arranged as rods or plates
what do osteoblasts secrete? for what?
they secrete the matrix for bone formation
what do osteoclasts do?
breakdown bone matrix
what are osteoclasts?
large bone cells with up to 50 nuclei (multinucleate cells derived from WBCs), responsible for bone remodeling
what activates osteoclasts?
PTH (parathyroid hormone)
what is an osteoblast?
bone cell responsible for bone formation
what are osteocytes?
mature bone cells and the main cell in bone tissue; trapped osteoblasts; living bone cells
what are lacunae?
tight spaces in the bones that house osteoblasts (space in cartilage and bone that contains living cells)
what are canaliculi?
canals connecting lacunae that allow osteocytes to communicate (microchannel that connects the lacunae and aids diffusion between cells)
what is the haversian canal?
central canal in bones that contains the bone’s blood vessels and nerve fibers (contains blood vessels for osteon
what is ossification?
(aka osteogenesis) process of bone formation by osteoblasts (not calcification!)
what is intramembranous ossification?
process of bone development from fibrous membranes
where does intramembranous ossification start and end?
start: mesenchymal cells
end: flat bones, mandible
what is endochondral ossification?
process of bone development from hyaline cartilage
where does endochondral ossification start and end?
start: chondrocytes
end: all other bones
how is a growth hormone disorder treated?
with injections
what is the epiphyseal plate (aka growth plate)?
region between the diaphysis and epiphysis that is responsible for the lengthwise growth of long bones
what does it mean when the growth plate ossifies?
growth stops
what does a chronic low calcium deficiency mean for the bones?
amt of bone calcium decreases while the risk of fractures increases
what do bones do when exposed to repeated stress?
they remodel, thickening to prevent fractures
what is a fibrous joint?
joint held together by fibrous connective tissue; has no cavity, space, or movement
what is an example of a fibrous joint?
sutures of the skull
what are syndesmoses joints?
joint in which the bones are connected by a band of connective tissue, allowing for more movement than in a suture (no cavity or space, some movement, amt of movement = length of CT)
what are examples of syndesmoses joints?
gomphoses and teeth; tibia and fibia to ankle
what is a cartilaginous joint?
joint in which the bones are connected by cartilage (no cavity or space; very little movement)
what are synchondroses?
bones joined by hyaline cartilage; found in the epiphyseal plates of growing bones in children
what are symphyses?
hyaline cartilage covers the end of the bone, but the connection between bones occurs through fibrocartilage; symphyses are found at the joints between vertebrae
what are synovial joints?
only joint that has a space between the adjoining bones; fluid lubricates joint; ends covered with hyaline
what are the three types of functional joints?
- synarthrosis (immovable)
- amphiarthroses (slight movement)
- diathroses (free movement)
what are the four movement types of functional joints?
- gliding
- angular
- rotational
- special
what kind of joint is the atlas-axis (where skull connects to spine)?
pivot
what kind of joint is the elbow?
hinge
what kind of joint is between the carpals and metacarpals?
saddle
what kind of joint is the ankle?
plane
what kind of joint is between the radius and carpal bones of the wrist?
candyloid
what kind of joint is the hip?
ball and socket
what are the three types of muscle?
skeletal, cardiac, and smooth
what is skeletal muscle tissue?
forms skeletal muscles, which attach to bones and control locomotion and any movement that can be consciously controlled
what are characteristics of skeletal muscle?
voluntary, striated, and multinucleated
what are characteristics of cardiac muscle?
self initiating, striated, uninucleate, and only found in the heart
what are some characteristics of smooth muscle?
involuntary and makes up the walls of organs
what is a sarcomere?
the smallest working subunit of muscular contraction; functional unit of skeletal muscle
what is the process of a neuromuscular synapse?
- acetylcholine released from the axon terminal binds to receptors on the sarcolemma
- an action potential is generated and travels down the T tubule
- CA2+ is released from the sarcophagi cell reticulum in response to change in voltage
- CA2+ binds troponin; cross bridges form between actin and myosin
- acetylcholinesterase removes acetylcholine from the synaptic cleft
- CA2+ is transported back into the sarcoplasmic reticulum
- tropomyosin binds active sites on actin causing the cross-bridge to detach
what is the purpose of tropomyosin?
acts to block myosin binding sites on actin molecules, preventing cross-bridge formation and preventing contraction until a muscle receives a neuron signal (found on actin; blocks binding sites)
what is the function of troponin?
binds to tropomyosin and helps to position it on the actin molecule, and also binds calcium ions (found on actin and TPM; holds actin and TPM)
what does low calcium do to the regulation of muscle contractions?
TPM inhibits cross-bridge, blocks binding site
what does high calcium do to the regulation of muscle contractions?
TPN changes confirmation, exposes binding sites
what is the sliding filament theory?
that the sliding of microfilaments contracts sarcomeres
what is happening in photo 1?
- CA2+ is released from the sarcoplasmic reticulum
- CA2+ in the sarcoplasm binds to troponin and exposes myosin-binding sites on the actin filaments
what is happening in image 2?
myosin heads bind to actin; release of Pi initiates power stroke
what is happening in image 3?
in the power stroke, the myosin head changes conformation; filaments slide past one another (rigor mortis)
what is happening at image 4?
ADP is released at the end of the power stroke; ATP binds to myosin causing it to release actin
what is happening at image 5?
hydrolysis of ATP returns the myosin head to its “cocked” position
what is happening at 6?
if Ca2+ is returned to the sarcoplasmic reticulum, the muscle relaxes
what is happening at 7?
if Ca2+ remains available, the cycle repeats and muscle contraction continues
what ion is important for releasing neurotransmitters and/or causing muscular contraction?
Ca2+
what bone was produced as a result of intramembranous ossification?
mandible
_____ secrete the calcium phosphate that secretes the inorganic hydroxyapatite of bone, while _____ chemically breakdown bone to release calcium and phosphate into the blood.
osteoblasts; osteoclasts
