The Skeletal System Flashcards
list the functions of the skeletal system
- organ protection
- mineral storage
- body movement
- blood cell production
- body support
describe this skeletal system function: organ protection
bone surrounds and protects vulnerable organs and structures (brain, heart, lungs, etc.)
describe this skeletal system function: mineral storage
- bone serves as a storage location for minerals including calcium and phosphorus (in phosphate)
- Ca2+, PO43+
- calcium and phosphate salt makes the bones hard
- the bones can store and give to blood in a regulated way
describe this skeletal system function: body movement
- bone works with muscles and ligaments to produce body movements
- muscular system produces the force, skeletal system anchors muscles and is what is actually being moved
describe this skeletal system function: blood cell production
- bone houses red bone marrow which gives rise to all blood cells
- all bones have blood cell forming tissue (red bone marrow)
describe this skeletal system function: body support
- bone’s dense makeup is well suited for bearing the body’s weight
- bone is hard and does to bend allowing it to bear weight
- skeletal system is a scaffold: rigid structure that all soft structures can attach to
what are the two part of the skeleton
- axial skeleton
- appendicular skeleton
define axial skeleton
a vertical axis for the system
define appendicular skeleton
bones that form the appendages and the girdles
describe why the hyoid bone is special
it is the only bone that doesn’t connect to any other bone
what important structure originates at the hyoid bone
- tongue muscles
- important for swallowing and talking
what are the parts of the hip
- sacrum
- pubic bone (ilium, ischium, pubis)
what is the term for a single side of the pelvis
os coxa
what is the term for both sides of the pelvis
os coxae
what are the three regions of the pelvis
- ilium
- ischium
- pubis
when do the ilium, ischium, and pubis fuse to form one solid bone
around the age of 10-12
what is the purpose of girdles (pelvic and shoulder)
connect appendages to the axial skeleton
what are the components of the shoulder girdle
- clavicle
- scapula
what is the most often broken bone in the body
clavicle
why is the clavicle the most often broken bone in the body
- it is very superficial
- when you fall on your arms, the clavicle takes a lot of the force
what are the main functions of the skull
- protect the brain
- house organs of special senses
- provide place for intake of food and mastication (teeth, mandible, powerful muscles)
what are the two parts of the skull
- cranium
- facial bones
how many bones are in the cranium and how many are facial bones
- cranium: 8 bones
- facial bones: 14 bones
define skull
collection of bones within the cephalic region
how many bones are in the cephalon
22 bones (not including ossicles)
what is the difference between the cephalon and the cranium
- cephalon: whole head made of 22 bones
- cranium: 8 bones protecting the brain
what are the ossicles
- 6 bones, 3 on each side of the temporal bone
- make up the middle ear
describe the middle ear
- airspace on each side of the temporal bone
- each made of 3 ossicles
- transmits soundwaves from the eardrum to the inner ear
what are the names of the discrete openings in the skull
- foramina
- fissures
- canals
what is the purpose of foramina, fissures, and canals
provide passage for soft tissue structure (nerves, blood vessels)
which is singular and which is plural: foramina, foramen
- foramina: plural
- foramen: singular
describe how you would prepare a view of the floor of the cranium
cut off the skull cap (calvaria)
define calvaria
the skull cap
where do the first 4 cranial nerves all have at least 1 branch that runs through
superior orbital fissure
which cranial nerves run through the acoustic canals
- facial nerve 7
- vestibulocochlear nerve 8
which cranial nerves and structures run through the jugular foramen
- internal jugular vein
- glossopharyngeal nerve 9
- vagus nerve 10
- spinal accessory nerve 11
what structures run through the carotid canal
internal carotid artery
what structure runs through the foramen magnum
spinal cord
is the spinal cord a nerve
no, it is part of the CNS
which foramen run through the sphenoid bone
- spinosum
- rotundum
- ovale
are teeth bones
- no
- they are bone-like structures
- organs
define the nasal concha
- flat plates of bone on both sides of the nasal cavity
- superior, middle, and inferior concha on each side
- lined with mucous membranes
what is the function of the nasal concha
- increase the surface area of the nasal cavity
- allows for more entrapment of particles
- easier to warm and humidify air when inhaling
are there any perfect structures in the human body
no, evolution happens until a structure has more benefits than downsides
describe sinuses
- airspace within the skull
- named after the bone that the sinus in embedded in
what is the function of sinuses
- lightens the front of the head
- resonance chamber for sound
describe the downside of sinuses
- easily infected
- drainage hole for sinuses to the nasal cavity is usually very small
describe what happens when a sinus gets infected
- the drainage hole shrinks allowing less fluid to exit, building pressure
- voice may sound weird because sound cannot resonate through the sinus
explain why the maxillary sinus is weird
it must drain upwards, against the flow of gravity
describe the shape of the spine
- elongated S shape
- the spinal column sits on the dorsal side of the body
- organs sit anterior to the spinal column
why is the S shape of the spine important
the curve centers the weight of the body optimally over the hips
describe how the spine is shaped differently at birth and why it changes
- spine is a C shape when born
- shifts to an S shape when the baby begins walking to match shift in the center of gravity
what is the only vertebrae without a body
C1, atlas
what happens to the size of the body of the vertebrae as you move down the spinal column and why
- the body of the vertebrae gets larger as you move from cervical to thoracic to lumbar vertebrae
- the larger body size is important for the spine to carry the weight above it
what is another name for the first and second cervical vertebrae
- C1, atlas
- C2, axis
how many cervical, thoracic, lumbar, sacral, and coccyx vertebrae are there
- 7 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 4 coccyx
describe how the sacral and coccyx vertebrae are different than other vertebrae
- they are unfused early in life
- they fuse later in life
what does the C1, atlas vertebrae articulate with
- occipital bone
- holds the head
what are the visible bumps on someone’s back
spinous processes of vertebrae
what are the 5 types of bones
- long bones
- flat bones
- irregular bones
- short bones
- sesamoid bones
describe the characteristics of long bones
- longer than they are wide
- most of the length is straight and cylindrical
- have at least 1 bulge at the end of the shaft
examples of long bones
- femur
- humerus
- distal phalanx of pinky
describe the characteristics of flat bones
mostly or completely flat
examples of flat bones
- sternum
- occipital bone
- parietal bones
- ribs
describe the characteristics of irregular bones
- do not fit into any other categories
- no specific geometric shape
examples of irregular bones
- sphenoid bone
- vertebrae
- ischium
- ilium
- pubis
describe the characteristics of short bones
- boxy shaped
- as long as they are wide
examples of short bones
carpals in wrist
describe the characteristics of sesamoid bones
- seed shaped
- all develop within a tendon
examples of sesamoid bones
- patella
- some bones in the hands and feet that are variable in umber between people
describe the characteristic that made sesamoid bones different from short bones
all sesamoid bones develop within a tendon
what is a synonym of compact bone
cortical bone
describe compact/cortical bone
- looks like solid bone
- the outermost layer of bones, the surface you see
- composed of multiple osteons
describe osteons
- cylinders going up and down the diaphyseal wall of compact bone
- anatomical unit of compact bone
- made of concentric rings/lamellae, osteocytes in lacunae, haversian canal
which is singular and which is plural: lamella, lamellae
- singular: lamella
- plural: lamellae
which is singular and which is plural: lacuna, lacunae
- singular: lacuna
- plural: lacunae
define lacunae
- little spaces within an osteon
- each space contains 1 osteocyte
what is the most prevalent bone cell in the living skeleton
osteocyte
define the central/haversian canal
- canal running up and down the diaphyseal wall of bone
- within an osteon
- contains an artery, vein, nerve
- how blood can get to osteocytes
what type of tissue is bone tissue
connective tissue
does bone tissue have more cells or more extracellular matrix
- mostly extracellular matric
- little cells
describe canaliculu
- small canals radiating in all directions from lacunae
- connect to haversian canals
- get nutrients to osteocytes
describe interstitial lamellae
lamellae between the concentric lamellae of osteons
describe circumferential lamellae
- lamellae around the circumference of the bones
- closest to the periosteum
describe the perforating/volkmanns canal
- canals running perpendicular to haversian canals
- start from the periosteum and connect to haversian canals
- how blood vessels and nerves move from outside the bone to the haversian canals inside the bone
- can connect 2 haversian canals to each other
define periosteum
the connective tissue surrounding all living bone
what are the functions of the periosteum
- scaffolding that allows blood vessels and nerves to move through the bone
- creates osteoblasts and houses them on the inner surface of the periosteum
- attachment site for tendons and ligaments
describe bruised bone
- the nerves and blood vessels of the periosteum has been damaged
- not broken bone
what bones have spongy bone in them
all bones
where is spongy bone always located
internal to compact bone
why is it called spongy bone
- looks like a dried out sponge
- dead spongy bone tissues has many holes in it like a sponge
what are synonyms for spongy bone
- cancellous bone
- trabecular bone
define diploe
spongy bone and red bone marrow
define trabecula
single beam/strut in spongy bone
how are trabeculae arranged in non-weight bearing bones
in random directions
how are trabeculae arranged in weight bearing bones
- arranged along the lines of stress
- becomes defined as you get older
what is the point of trabeculae arranging along line of stress in spongy bone
helps the epiphysis become stronger and able to carry weight
what is in the spaces between trabeculae in spongy bone
- red bone marrow
- blood vessels
what is similar between a trabecula (spongy bone) and an osteon (compact bone)
- both are made of rings of lamellae
- both have lacuna containing a single osteocyte
- both have canaliculi radiating from the lacunae
what is different between a trabecula (spongy bone) and an osteon (compact bone)
- trabeculae don’t have a haversian canal
- trabeculae are macroscopic (can be seen with the naked eye) while osteons are microscopic
- trabeculae are covered by a membrane called the endosteum
define endosteum
membrane surrounding the outermost lamellae of a trabecula
what is the function of the endosteum
- scaffolding for blood vessels and nerves to travel down/through the trabeculae
- create osteoblasts
- have osteoclasts
where are osteoclasts and osteoblasts found in trabeculae
within the endosteum lining the trabeculae
define appositional growth in bone
- growth by adding to the free surface of the bone
- accomplished by osteoblasts
describe osteoclasts in spongy bone
- multinucleated
- destroy bone
- exist within the endosteum surrounding trabeculae
describe bone remodeling
- done throughout the day
- osteoblasts and osteoclasts collaborate
- osteoclasts break down bone to give calcium to the blood when needed
- osteoblasts build new bone when calcium is taken in
define hematopoietic tissue
red bone marrow
what is in the medullary cavity of long bones when you are first born and what replaces it as you age
- full of red bone marrow when born
- replaced by yellow bone marrow as you age
what is your skeleton made of as am embryo
hyaline cartilage
what are the 2 ways that hyaline cartilage can grow
- appositionally
- interstitially
what is the 1 way that bone tissue can groq
appositionally
describe appositional growth of hyaline cartilage
- growing from the outside surface
- chondroblasts in the perichondrium build more cartilage
describe interstitial growth of hyaline cartilage
- growing from the inside
- chondrocytes in lacunae go through mitosis
- new chondrocytes move through the gelatinous extracellular matrix
why can’t bones grow interstitially
- the extracellular matrix of bone is calcified
- there would be nowhere for new cells inside the bone to go
define primary ossification
- regulated destruction of diaphyseal cartilage that is replaced by bone
- endochondral ossification (ossification within cartilage)
when does primary ossification occur
fetus at 2-3 months to birth
define secondary ossification
- epiphysis of long bones undergoes ossification
- lengthening and widening of bone at the epiphyseal/growth plate
what type of bone tissue is the majority of the epiphysis and metaphysis of long bones
spongy bone
what happens to the outer layer of cortical bone in the epiphysis
- gets thinner
- still is there
describe the difference between juvenile and adult bones in terms of the epiphyseal plate/line
- juvenile: has a robust epiphyseal plate where the bone is growing
- adult: doesn’t have epiphyseal plate, has epiphyseal line where plate used to be
describe the difference between juvenile and adult bones in terms of how the spongy bone in the epiphysis is arranged
- juvenile: trabeculae are unorganized and go in random directions
- adult: trabeculae are organized along stress lines to be better at weight-bearing
describe the difference between juvenile and adult bones in terms of the contents of the medullary cavity
- juvenile: medullary cavity filled with red bone marrow
- adult: medullary cavity filled with yellow bone marrow
what is special about the medullary cavity of the proximal femur and humerus in adults
the proximal end of the femur and humerus and adults retains some red bone marrow
describe the type of location of bone in the diaphysis of long bones
- mostly compact bone on the outside
- some spongy bone is on the very innermost surface lining the medullary cavity
when does juvenile bone officially become adult bone
when the last epiphyseal plate stops functioning and becomes an epiphyseal line
do all long bones become adult bones at the same time
- no
- different bones have different average ages that they become adult bones
at what average age are all your bones adult bones
- 21-23
- females have all adult bone earlier than males
are osteons visible with the naked eye
no
what are the layers of the periosteum
- inner layer
- outer layer
describe the inner layer of the periosteum
makes osteoblasts
describe the outer later of the periosteum
- thicker layer
- where tendons and ligaments attach
list the 4 types of bone cells
- osteoprogenitors
- osteoblasts
- osteocytes
- osteoclasts
define stem cell
- not yet a functional cell
- destined to become either a particular cell type or to exist as a stem cell
what happens to the daughter cells of stem cells after mitosis
- one becomes a particular cell type
- one stays as a stem cell
describe how osteoprogenitors, osteoblasts, and osteocytes are all connected
- different cell types that originate from each other
- osteoprogenitor becomes osteoblast becomes osteocyte
- 1 cell that transitions through different cell types
define osteoprogenitors
- stem cells for bone
- when the divide, one cell will become an osteoblast
describe the structure of osteoprogenitors
they look flattened
where are osteoprogenitor cells found
at the outer edge of the inner layer of the periosteum or endosteum
where are osteoblasts found
at the inner edge of the inner layer of the periosteum or endosteum
what do osteoblasts secrete/do
- secrete collagen
- secrete organic matrix
- induce formation of inorganic matrix
- form new bone
- remodel existing bone
which is created first: organic or inorganic matrix
organic matrix
where are osteocytes found
in lacunae within bone
what do osteocytes do
stabilize and maintain bone matrix
where are osteoclasts found
in the periosteum and endosteum
describe the structure of osteoclasts
- large cells
- multinucleated
what do osteoclasts do
reabsorb calcified bone matrix
define howships lacuna
the space created between an osteoclast and the bone as the osteoclasts breaks down the bone
describe how osteoclasts are made
- when bone starts producing red bone marrow during early ossification of bone, monocytes are formed
- monocytes fuse together into larger cells that become osteoclasts
describe exocytosis
- cell packages materials within into vesicles
- melds the vesicle to the cell membrane
- dumps contents of vesicle into the interstitial fluid/space
how are most things secreted from cells
exocytosis
what mediates the fusion of the vesicular membrane with the cell membrane in exocytosis
proteins
what are the two types of endocytosis
- phagocytosis
- pinocytosis
describe the cells that are capable of phagocytosis
- few cells are capable
- usually immune cells such as macrophages
describe phagocytosis
- type of endocytosis
- a cells swallows something from the extracellular space and brings it into the cell
- large gulp of interstitial fluid
describe the cells that are capable of pinocytosis
most cells are capable
describe pinocytosis
- type of endocytosis
- very common in cells
- cell takes a small sip of extracellular fluid
what tool must be used to see pinocytosis in action
electron microscope
describe transcytosis
- the linkage between endocytosis and exocytosis
- swallowing something on one side of the cell, moving it across the cell, dumping contents on the other side of the cell
how many red blood cells can fit through a capillary at a time
1 RBC
why is it important for capillaries to be one cell wall thick
to maximize the transfer of nutrients and wastes with the bloodstream and surrounding cells
what type of cells make up the walls of capillaries
endothelium (epithelial cells)
how many cell lengths away do all cells need to be from a capillary to stay alive
8 cells away
what does the cytoskeleton in a cell do
maintains cell shape
what fibers make up the cytoskeleton
- microfilaments
- microtubules
- intermediate filaments
list the fibers in the cytoskeleton in order from smallest to largest
- microfilaments: 8nm
- intermediate filaments: 10nm
- microtubules: 25 nm
which fibers in the cytoskeleton act like human muscles and why
- microfilaments and microtubules
- can rapidly elongate or shorten to generate force
what is another name for microfilaments
actin filaments/strands
what are microfilaments made of
polymers of the protein actin
where are microfilaments usually found
near the internal surface of the cell membrane
describe the function of microfilaments
- rapidly extend and contract
- change the shape of the cell membrane
- creates microvilli in cells
which fiber in the cytoskeleton act like the human skeleton and why
- intermediate filaments
- rigid protein strands that do not contract
what fiber in the cytoskeleton will become keratin in some epidermal cells
intermediate filaments
which cytoskeletal fiber drives mitosis
microtubules
which cytoskeletal fiber do motor proteins move along
microtubules
what do microtubules do during mitosis
- move chromosomes to the center of the cell
- pull apart sister chromatids
describe pump proteins
- transmembrane proteins in all cell membranes
- can move material against the concentration gradient
does the movement of materials against the concentration gradient with protein pumps require energy
yes
describe proton pumps
- transmembrane proteins that pump hydronium ions (H3O+) against the concentration gradient
what are the two ways that hydronium is often written
- H+
- H3O+
what is the equation for pH
pH = -log(H+)
what happens to pH when there is higher H+
higher H+ = lower pH
what happens to pH when there is lower H+
lower H+ = higher pH
describe podocytes
- circular rings of extensions on osteoclasts
- seals the osteoclast to the bone so osteoclasts secretions that dissolve bone don’t go somewhere else
what secretions to osteoclasts produce
- H3O+
- hydrolytic enzymes
why is H3O+ an osteoclast secretion
creates an acidic environment that will dissolve the calcium phosphate salt (hydroxyapatite) of bone
what is the chemical weakness of calcium phosphate salt (hydroxyapatite) in bone
dissolves in high acidity
what components of bone do hydrolytic enzymes secreted by osteoclasts dissolve
organic molecules in bone such as collagen
describe how osteoclasts use transcytosis
- break down calcium in bone on one side
- use endocytosis to take up the calcium
- move the calcium to the other side of the cell facing the extracellular space
- use exocytosis to secrete the calcium into the bloodstream
what type of fiber in the cytoskeleton makes microvilli
actin filaments
why is it important for osteoclasts to have microvilli
increase surface area on the bottom of the osteoclasts so it can secrete more materials to dissolve bone
where are osteocytes found in the bone
within a lacunae that is surrounded by bone matrix
how are osteocytes connected
through canaliculi that connect the lacunae in the bone matrix
describe how canaliculi are formed as osteoblasts become osteocytes
- osteoblasts start laying bone matrix that will surround the cell
- before the matrix a hardened, osteoblast extend their body and meet with extensions of other cells which creates a gap junction
- the space surrounding the extensions fills with interstitial fluid
- the bone matrix hardens around the lacunae and the canaliculi
describe what is inside each canaliculi in bone
- extensions of osteocytes in the canaliculi meet with other cell’s extensions
- a gap junction is created between cells
- the empty space surrounding the cell extensions in filled with interstitial fluid
why are gap junctions important for osteocytes
so the cells can communicate and trade nutrients/wastes/materials
what are the two major components of the extracellular component of bone matrix
- organic matrix
- inorganic matrix
which part of the extracellular bone matrix is produced first by osteoblasts
organic matrix
what is another name for the organic bone matrix
osteoid
what are the components of the organic bone matrix
- ground substance
- extracellular fibers
what are the components of the ground substance of organic bone matrix
- proteoglycan aggregates
- hyaluronic acid
is the ground substance of organic bone matrix fibrous
no
what type of macromolecule is hyaluronic acid
carbohydrate
what does hyaluronic acid do
increases viscosity of extracellular fluid
where is hyaluronic acid found in the body
- ground substance of organic bone matrix
- serous fluid
what are the components of the extracellular fibers of organic bone matrix
mainly type 1 collagen fibers
how many types of collagen fibers are there
20
describe type 1 collagen
- very strong
- gives bone tensile strength
what is the main component of the inorganic bone matrix
hydroxyapatite
what is hydroxyapatite made of
calcium phosphate salt
when is the inorganic bone matrix secreted
after the organic bone matrix
describe how osteoblasts help to create hydroxyapatite
- osteoblasts secrete a material that lowers the solubility of hydroxyapatite which causes precipitation
- once one tiny crystal of hydroxyapatite is formed, it will attract more material to make it grow
what type of feedback is the growth of hydroxyapatite
- positive feedback
- a small crystal is formed causing more and more crystals to form exponentially until there is no more space left for hydroxyapatite to form
how is an authentic human bone in a lab similar/different to a bone in a living human
- similar in shape and geometry
- living bone has organic matrix while nonliving bone does not, nonliving bone only has hydroxyapatite so it weighs less and is more fragile
what types of strength does bone have
- compressive strength
- tensile strength