anatomy exam 2
anterior and posterior cruciate ligaments
"cross"
fused tetanus
(100% wave summation) is the most forceful contraction that can be produced by a muscle
voltage gated k+ channels gate open at
+30mV
voltage-gated na+ channels gate open at
-65mV
number of designation of thumb metacarpal
1
triad made up of
1 t-tubule flanked by 2 terminal cisterns of the sarcoplasmic reticulum
crossbridge cycling steps
1)crossbridge formation •myosin head attaches to exposed binding site on actin 2)power stroke •myosin head pulls thin filament toward center of sarcomere 3) release of myosin head 4) reset myosin head
excitation-contraction coupling
1. action potentials trigger release of ca2+ from the sarcoplasmic reticulum 2. troponin binds ca2+ which triggers crossbridge formation between thin and thick filaments 3. crossbridge cycling leads to sarcomere shortening and muscle cell contraction 4. as the muscle cell shortens, there is a change in sarcomere banding pattern 5. muscle cell relaxation reflects elimination of neurotransmitter at the synapse and clearing of ca2+ from the sarcoplasm
number of false ribs
10
number of thoracic vertebrae
12
number of tarsal bones
14
number of vertebrosternal ribs
14
number of carpal bones
16
number of phalanges in each great toe
2
number of phalanges in one thumb
2
number of phalanges is right thumb
2
number of ribs
24
number of cuneiform bones in each foot
3
number of phalanges in little toe
3
number of phalanges in right index finger
3
number of floating ribs
4
number of rudimentary vertebrae forming the tailbone
4
number of bones forming the instep of each foot
5
number of designation for small toe metatarsal
5
number of lumbar vertebrae
5
number of metacarpal bones in right hang
5
number of metatarsal bones in right foot
5
number of rudimentary vertebrae forming the sacrum
6
number of vertebrochondral ribs
6
number of bones forming tarsus
7
number of cervical vertebrae
7
ligament examples
ACL, UCL
acid base and electrolyte balance
Ca++ released from bone
thyroid hormone
Essential to bone growth; enhances synthesis and effects of growth hormone, but excesses can cause hypercalcemia, increased Ca2+ excretion in urine, and osteoporosis
blood cell formation
RBC and WBC form in the red bone marrow
displaced fracture
The portions of bone are out of anatomical alignment
fascicle
a bundle of muscle fibers within a muscle. supplied by nerves and blood vessels and enclosed in a fibrous perimysium that separates it from neighboring fascicles.
myofibril
a bundle of protein myofilaments within a muscle fiber; myofibrils collectively fill most of the cytoplasm. each surrounded by sarcoplasmic reticulum and mitochondria. has a banded (striated) appearance due to orderly overlap of protein myofilaments.
evidence of sarcomere shortening is observed as
a change in striation pattern
unequal distribution of na+ and k+ by this protein leads to
a charge difference across the plasma membrane
muscle
a contractile organ, usually attached to bones by way of tendons. composed of bundles (fascicles) of tightly packed, long, parallel cells (muscle fibers). supplied with nerves and blood vessels and enclosed in a fibrous epimysium that separates it from neighboring muscles.
tropomyosin
a fibrous, string-like protein associates with the thin filament along its length
despite being hardened tissue, the skeletal system is
a flexible framework for the body
troponin
a globular protein attaches to tropomyosin and will re-position tropomyosin along the thin filament in the presence of ca2+
shaft of long bone surrounds
a medullary cavity - site of yellow marrow in adults, red marrow in young children
motor unit
a motor neuron and all the muscle fibers it controls
nerve connections are severed or poisoned
a muscle is paralyzed
at the same time the bone collar is forming
a primary ossification center develops
sarcomere
a segment of myofibril from one z disc to the next in the fiber's striation pattern. hundreds of sarcomeres end to end compose a myofibril. the functional, contractile unit of the muscle fiber.
muscle fiber
a single muscle cell. slender, elongated, threadlike, enclosed in a specialized plasma membrane (sarcolemma). contains densely packed bundles (myofibrils) of contractile protein filaments, multiple nuclei immediately beneath the sarcolemma, and an extensive network of specialized smooth endoplasmic reticulum (sarcoplasmic reticulum). enclosed in a thin fibrous sleeve called endomysium.
polarization
a state of charge separation across the membrane
resting membrane potential (rmp) is seen in
a waiting excitable cell
the false pelvis is bounded anteriorly by the
abdominal wall
rigor mortis peaks
about 12 hours after death, then diminishes over the next 48 to 60 hours
fossa on coxal bone that articulates w/ femur
acetabulum
fossa on coxal bone that articulates with the femur
acetabulum
in adult skeleton, the embryonic coxal bones meet in the
acetabulum
chemically gated channels are concentrated in the junctional folds at the nmj and will bind
acetylcholine (ach) released by the motor neuron
process on scapula that articulates with clavicle
acromion
process on scapula that articulates with the clavicle
acromion
the scapular spine terminates as the
acromion process
thin filaments
actin, troponin, tropomyosin
opening of voltage-gated ion channels trigger
action potential across the entire cell surface and along the t-tubules
fat pads
adipose tissue between synovial membrane and fibrous capsule, move with joint
junctional folds function
allows for amplified packing of receptor proteins for the neurotransmitter in the muscle cell membrane, means the muscle cell has a great capacity to capture the neurotransmitter when it is released by the neuron, makes for more efficient activation of the muscle cell
small motor units have less than five muscle fibers
allows for precise control of force output (e.g. eye muscles, muscles that control the fingers)
large motor units have thousands of muscle fibers
allows for production of large amount of force (but not precise control, e.g. postural muscles, muscles of lower limbs; gastrocnemius muscle of the calf has 1,000 muscle fibers per neuron)
rapid diffusion of na+ and k+ ions across the membrane through regulated ion channels
allows the muscle cell to activate and trigger internal events that lead to contraction
sternocleidomastoid action
alone: laterally rotates neck to opposite side together: flexes neck
spongy bone develops
along lines of stress to reinforce bone structure
voltage gated ion channels are located
along the entire length of the sarcolemma and the t-tubules and are critical to trigger contraction of the muscle cell
triads are located
along the length of the myofibril; as calcium rains out of the sr....it covers the underlying sarcomeres
isometric muscle contraction
although muscle is producing tension, it is insufficient to overcome resistance (its load), muscle is crossbridge cycling but its length stays the same (e.g., holding a weight while arm doesn't move), important in postural muscle function and antagonistic muscle joint stabilization
sockets of jaw in which teeth lie
alveoli
sockets on the superior margin of the mandible in which teeth lie
alveoli
muscle fibers exhibit a resting membrane potential (rmp)
an electrical charge across the plasma membrane when the cell is at rest; it is also referred to as the resting membrane voltage (charge is measured in volts), this charge makes the muscle cell excitable! electrically charged cells are excitable -they are responsive to and capable of conducting electricity
calcitonin
antagonist of parathyroid hormone
anterior termination of iliac crest
anterior superior spine
bone also grows in width through a process called
appositional growth
bone remodel and thicken along
areas where there is the most stress to provide support
superficial fascia
areolar and adipose tissue, located superficial to deep fascia, separates muscles from skin
cartilage covering epiphyseal surfaces of long bones
articular (hyaline)
heat production by skeletal muscles
as much as 85% of our body heat
growth factors
at least 12 hormone like substances produces in bone itself that stimulate neighboring bone cells, promote collagen
acetylcholine (ach) diffuses across the synaptic cleft and arrives
at the muscle cell membrane where it binds to the ach receptor
the first cervical vertebra is called the
atlas
myosin head has this enzyme action
atp adp + pi
myasthenia gravis
autoimmune disease in which antibodies attack neuromuscular junctions and bind ach receptors together in clusters
cartilage blood supply
avascular - nutrients obtained via diffusion from surrounding tissues
division of the skeleton that lies around the body's center of gravity
axial
pivot
axial
lateral border of the scapula.
axillary
the lateral border of the scapula is the
axillary border
shaft of long bone forms the
axis
the second cervical vertebra is called the
axis
neuron features
axon terminal (synaptic knob) with secretory vesicles containing the neurotransmitter acetylcholine, secretion of acetylcholine into the synaptic cleft is triggered by the arrival of an electrical current, synaptic cleft separates membrane of neuron and muscle cell: enzyme acetylcholinesterase is located within this gap; will degrade acetylcholine
radial collateral ligament
bans of strong flexible tissue attaches the humerus to the ulna
h zone
bare zone of no-overlap in the middle region of the thick filament, m line
the sarcomere
basic functional unit of the myofibril, consists of overlapping array of thin and thick filaments (myofilaments)
ca2+ diffuses out of cisterns and into the sarcoplasm
bathing the underlying sarcomeres within the myofibrils
the muscle cell is back at rest electrically
before it even begins force production - action potential has formed and the cell has returned to resting voltage before cross bridge formation begins
where you activate a nerve cell
begins a pathway of electrical current delivery through the cns and out the pns to the muscle
collagen fibers allow for
bend but not break of bones
condylar
biaxial
movement in two planes of space
biaxial
saddle
biaxial
groove separating tubercles of humerus
bicipital or intertubercular
each head can
bind and hydrolyze (breakdown) atp; so myosin is the protein that uses energy to fuel muscle action
compact bone fibers in ecm
bind inorganic minerals (calcium, phosphorus)
stimulation at the nmj through
binding of acetylcholine to its receptor in the muscle cell membrane
z line
bisects the i band; consists of proteins to which the thin filaments attach; one sarcomere is the area between successive z-lines
the perichondrium is invaded by
blood vessels to bring chondrogenic cells
horizontal portion of mandible forming the chin
body
portion of mandible that forms chin
body
the middle part of the breast bone is the
body (gladiolus)
avulsion fracture
body part is completely severed
bone remodeling is a balance of
bone deposition and bone resorption
osteogenic layer of periosteum
bone forming cells (osteogeneic), gives rise to osteoblasts
complete fracture
bone is broken into two or more pieces
parathyroid hormone controls
bone remodeling by maintaining homeostatic levels of Ca++ in the blood
rotation
bone turns along axis
movement
bones act as levers for muscles
comminuted fracture
bones break into multiple pieces, common fracture in elderly (brittle bones)
cartilaginous joints
bones held together by cartilage
fibrous joints
bones held together by fibrous CT
synovial joints
bones held together via a synovial cavity/membrane
mineral storage
bones store Ca++ and PO4-3
protection
bones surround organs
the bony ring formed by the sacrum, coxae, and coccyx
bony pelvis
each nerve fiber (axon)
branches out to form an association with a number of muscle fibers (cells) within the same muscle
within the cleft is the enzyme acetylcholinesterase (ache)
breaks down ach, allowing for relaxation (it clears the neurotransmitter from the synaptic cleft)....this is critical to permit muscle cell relaxation after a contraction event has occurred
twitch
brief contraction produced in response to a single stimulus
osteogenesis imperfecta
brittle bone - defect in collagen protein leading to a lack of tensile strength, collagen cant be the glue anymore so bones break under stress
triangular (convergent) muscles
broad at one end and narrow at the other
medial (tibial) collateral ligament
broad, flat ligament that prevents medial displacement
depressed fracture
broken portion of bone forms a concavity, as in skull fractures
multipennate
bunches of feathers converge to single point
thick filaments
bundles of many myosin protein molecules (look like golf clubs)
myofibrils consist of
bundles of myofilaments (contractile proteins)
deep fascia
bundles various muscles together within compartments to form working groups, external to epimysium, separates muscles while binding them, contains nerves, blood vessels
action potentials triggered
by binding of acetylcholine (ach) to its receptor
medial and lateral menisci
c shaped fibrocartilage rings that attach in the intercondylar area of tibia, attached via the transverse ligament of knee, lateral meniscus more mobile, stabilize knee during movements; cushion joint and allow proper movement between articular surfaces
troponin
ca2+ binding protein
heel bone
calcaneus
terminal cisterns serve as reservoirs for
calcium ions
inorganic components of bone (hydroxyapatites)
calcium phosphate, calcium carbonate
condyle on humerus that articulates with radius
capitulum
condyle on humerus that articulates with the radius
capitulum
endocondral ossification continues as
cartilage grows during development
zone of calcified cartilage
cartilage matrix becomes calcified
plates of hardened matrix wrap around
central canal (haversian)
cns
central nervous system (brain and spinal cord)
branched spinous process are characteristic of
cervical v
transverse foramina are characteristic of
cervical vertebrae
ion channels are specific
channels that permit na+ to diffuse do not permit k+ to diffuse and vice versa; this means that distinct ions can be moving across the membrane at different times
ion channels
charged ions may diffuse across the muscle cell membrane if a channel created by an integral membrane protein is/are present and is open
zone of proliferation
chondrocytes undergoing mitosis in response to factors like IGF-1
cartilage cell types
chondrogenetic, chondroblasts, chondrocytes
bone joining pectoral girdle to axial skeleton
clavicle
voltage-gated ion channels
closed at one membrane voltage but will trigger (gate) open at another
bursa/tendon sheaths
closed regions of synovial membrane, no real space between layers - only thin layer of serous fluid, reduce friction as structures move over each other, occur between skin and bone beneath deep fascia, over tendons, etc
chemically-gated ion channels
closed until the cell is exposed to a specific chemical compound example below depicts a channel protein that functions as a receptor for a neurotransmitter; when the neuron releases the chemical at the synapse the receptor binds it and opens as a gated ion channel
orbicularis oculi action
closes eye; produces blinking and squinting
skeletal muscle control
cns motor neuron activates muscle (we'll cover this later in the nervous system)...but this is where you determine the movement
the distal bone of the vertebral column
coccyx
the tailbone of the cervical vertebral column is called the
coccyx
sharpey's fibers
collagen fibers that extend from the outer layer of periosteum into the bony matrix
zone of reabsorption
collagen matrix is broken down and new bone is produced
organic componenents of bone
collagen, glycosaminoglycans, proteoglycans
two major types of bones
compact and spongy
flat, irregular, and short bones are composed of
compact bone layers surrounding spongy bone, hyaline cartilage lining areas of articulations
long bones are composed of
compact bone surrounding marrow filled cavity, spongy bone in both ends (red marrow for hematopoises), hyaline cartilage lining areas of articulations
bone tissue types
compact bone, cancellous (spongy) bone
transverse abdominis action
compression of abdomen
rectus abdominis action
compression of abdomen, flexion and rotation of trunk/vertebral column
external oblique action
compression of abdomen: alone: rotation of trunk/vertebral column together: flexion of trunk/vertebral column
internal oblique action
compression of abdomen; alone: rotation of trunk/vertebral column together: flexion of trunk/vertebral column
rounded convex projection that articulates with another bone
condyle
articulations of knee joint
condyles of the femur to condyles of tibia, between the patella and femur
endosteum composition
connective tissue layer with osteogeneic cells
perforating (volkman's) canals
connects medullary cavity to central canal, connect nerves and blood supply from periosteum to central canal
m line
contains proteins that help anchor thick filaments in place
effective contraction of the entire muscle typically requires
contraction of several motor units at once
process on scapula anterior to glenoid fossa
coracoid
lateral (fibular) collateral ligament
cord like ligament that prevents lateral displacement
suture between frontal and parietal bones
coronal
depression on anterior surface at distal end of humerus
coronoid fossa
the anterior proximal process of the ulna is the
coronoid process
cavity encasing the brain
cranial
encases brain
cranium
narrow ridge of bone serving as a site for muscle attachment
crest
superior border of the ilium
crest
perforated bony plates lateral to the crista galli
cribiform plates
upward projecting process of ethmoid bone
crista galli
as long as atp is present and ca2+ is available in the sarcoplasm
crossbridge cycling will continue......and is absolutely necessary to produce full contraction of the cell and the whole muscle
binding between myosin and actin
crossbridge: cycling of crossbridges and filament sliding leads to contraction of the muscle cell
short bone
cube shape
osteoblasts
cuboid shaped cells that produce the matrix, non mitotic, most die once matrix is formed
articular cartilage function
cushioning and stress absorbing
a band
dark, anisotropic region, contains thick filaments and overlapping thin filaments, h zone, makes up central region of sarcomere
flexion
decreases the angle of a joint
osteoclasts function
degrade old bone
osteoclasts invade the area and
degrade the mixed matrix
functional classification of joints based upon
degree of movement allowed
endomysium
delicate connective tissue covering individual muscle cell
the axon of nerve cell
delivers an electrical current to a spinal motor neuron sitting in the spinal cord
the vertical protrusion of the axis is the
dens (odontoid process)
perimysium
dense connective tissue wrapping multiple cells/fibers together into fascicles, carries blood vessels, nerves, and stretch receptors that detect degree of extension of the muscle
epimysium
dense connective tissue wrapping multiple fascicles together to form complete muscle
outer layer of periosteum composition
dense irregular connective tissue
tendon
dense regular connective tissue that connect muscle to bone
growth plate fractures usually heal normally
depend on severity and age, splinting vs surgery
platysma action
depresses lower lip, tenses skin of neck
internal intercostals action
depresses ribs during expiration
curare
derived from a plant and used as a poison by south american native peoples to hunt prey in trees using blowgun darts, binds to ach receptors and blocks ach from binding; induces flaccid paralysis
osteoclasts
derived from bone marrow cells, degrade bony matrix
osteocytes
derived from osteoblasts and maintain tissue environment, many projections that allow communication with other bone cells f
shaft of long bone
diaphysis
major difference in secondary ossification center
diaphysis is hollowed out to form the medullary cavity surrounded by compact bone with spicules, epiphyses are surrounded by compact bone with a spongy center
synovial joint movement
diarthrotic
osteoprogenitor cells
differentiate into osteoblasts which being to lay down bony matrix on cartilage - mixed cartilage/bone matrix now exists
this prevents nutrients from
diffusing and the chondrocytes dying
cartilage obtains nutrients via
diffusion (limited thickness)
terminal cisterns
dilated end-sacs of sr which cross the muscle fiber from one side to the other
hematopoiesis sites
diploe of flat bones in skull, os coxa, etc
muscle fibers of one motor unit are
dispersed throughout muscle...they are not all clustered in a bunch
summary of the nerve-muscle cell relationship
each muscle cell interacts with only one neuron but each neuron interacts with more than one muscle cell
organization of skeletal muscle permits
easy interaction between thin and thick filaments which is necessary for contraction
somatic motor neurons carry
electrical impulses from the spinal cord to multiple muscle cells within the target muscle
masseter action
elevates and protracts mandible
temporalis action
elevates and retracts mandible
epicranius action
elevates eyebrows and wrinkles forehead
external intercostals action
elevates ribs during inspiration
delicate membrane lining the medullary cavity of a long bone
endosteum
inner layer of bone
endosteum
the chondrocytes here
enlarge, vacuolize, and secrete molecules that calcify the matrix (not the same as bone hardening)
ach receptor is a chemically-gated ion channel
entry of na+ ions leads membrane to depolarization at the nmj
raised area on a condyle
epicondyle
muscles of facial expression
epicranius, orbicularis oculi, orbicularis oris, buccinator, zygomaticus, platysma
muscle coverings
epimysium, perimysium, endomysium, deep fascia
region for longitudinal growth in developing long bone
epiphyseal disk
growth plates span
epiphyseal plates of cartilage
ends of bones are called
epiphysis - usually broader for muscle attachment
epiphyseal fracture
epiphysis separates from the diaphysis along the epiphyseal plate
major regulator in bone remodeling
estrogen
bone forming inferior border of anterior portion of the cranium
ethmoid
compact bone replaces
every ~10 years
canal leading to the eardrum and middle ear
external auditory meatus
cartilage in the skeletal system
external ear, intervertebral discs, pubic symphysis, joints (articular cartilage)
muscles of respiration
external intercostals, internal intercostals, diaphragm
midline prominence posterior to the foramen magnum
external occipital protuberance
wormian bone
extra bones usually located between cranial bone (sutural)
parathyroid feedback loop
falling of calcium levels stimulates the release of PTH, parathyroid gland release PTH, osteoclasts degrade bone matrix and release Ca++ into blood, PTH stimulates osteoclasts and inhibits osteoblasts
(t/f) the clavicle articulates with the gladiolus if the sternum
false
(t/f) the head of the radius articulates with the trochela of the humerus
false
(t/f) the scapula articulates with the vertebral column
false
(t/f) the semilunar notch of the ulna articulates with the capitulum of the humerus
false
muscle structure reflects organization of fascicles
fascicle orientation determines how the muscle will do its work
bipennate
fascicles approach tendon from both sides
unipennate
fascicles approach tendon from one side
synovial joint accessory structures
fat pads, bursa/tendon sheaths
pennate muscles
feather shaped - unipennate, bipennate, multipennate, circular muscles
pelvis with larger and more circular inlet
female
the bones of the pelvis are more delicate in
female
largest and heaviest bone of the body
femur
spaces between adjacent vertebral bodies are filled with
fibrocartilage
symphysis
fibrocartilage, slight movement - compression, intervertebral discs, pubic symphysis
solid joints
fibrous and cartilaginous
ligaments
fibrous connective tissue connecting bones together
intramembranous ossification
fibrous membrane replaced by bone tissue, bones of skull and clavicles
tropomyosin
fibrous protein
myofilaments
fibrous protein strands that carry out the contraction process. two types: thick filaments composed mainly of myosin, and thin filaments composed mainly of actin. thick and thin filaments slide over each other to shorten each sarcomere. shortening of end-to-end sarcomeres shortens the entire muscle.
types of structural joints
fibrous, cartilaginous, synovial
lateral bone of the lower leg
fibula
non-weight bearing bone of lower leg
fibula
myofibrils
fill the sarcoplasmic space; contain high density of myofilaments - thick and thin filaments
elastic cartilage
fine collagen fibers with lots of elastic fibers
hairline fracture
fine crack in which sections of bone remain aligned, common in skull
narrow slit-like opening that serves as a nerve passageway
fissure
people whose longitudinal arches have fallen suffer from
flat feet
elbow joint allows for uniaxial movement
flexion and extension
circumduction
flexion, abduction, extension, and adduction, distal end moves, proximal end stationary
unossified membranous area of fetal skull
fontanel
opening though a bone
foramen
large opening in the base of the occipital bone
foramen magnum
opening of occipital surrounding brain stem
foramen magnum
circular muscles (sphincters)
form rings around body openings
multiple cell types are important in _____ and ____ of bone tissue
formation, maintenance
depression along surface where nerve terminal is positioned
forms a sort of basin-like depression that helps capture neurotransmitter when released at the synapse, makes for more efficient activation of the muscle cell
shallow depression that frequently forms a socket for another bone in a joint
fossa
colles fracture
fracture of the distal radius and ulna at the wrist, common in osteoporosis
pott fracture
fracture of the lower end of the fibula, tibia, or both, common sports injury
spiral fracture
fracture spirals around axis of long bone; results from twisting stress, common of abuse - adult grabbing child by the arm
diarthrotic joint
free movement allowed
bone forming anterior superior portion of skull
frontal
bone forming forehead and superior parts of orbits
frontal
bone forming superior anterior portion of the skull
frontal
chemically-gated ion channels
gate open when a chemical is applied to the membrane that is received/bound by a receptor that gates open as an ion channel
voltage-gated ion channels
gate open with a change in charge across the membrane
action potentials triggered at the motor end plate by
gating of the ach receptor channel trigger action potentials in the membrane regions surrounding the nmj by opening of voltage-gated ion channels
when voltage reaches + 30 mv
gating potential for voltage-gated k+ channels; these pop open allowing k+ to rush out of the cell, na+ channels also inactivate therefore na+ ion movement across the membrane stops.
cartilage matrix
gel like composition
fiber at resting length
generates maximum contractile force, optimal overlap of thick and thin filaments
fiber at a shortened length
generates weaker force, filament movement is limited (already close to z disc)
fiber at an extended length
generates weaker force, minimal thick and thin filament overlap for crossbridge formation
smooth area of frontal bone between the eyes
glabella
depression on scapula that articulates with the humerus
glenoid fossa
deep notch just below the posterior inferior spine of the ilium
greater sciatic notch
large process lateral to neck of femur
greater trochanter
large process lateral to the neck of the femus
greater trochanter
rounded lateral process distal to anatomical neck of humerus
greater tubercle
part of sphenoid seen on side of skull
greater wing
advantage of using membranes and cartilage as models
growth and flexibility, tissues form framework accommodate mitosis
major drivers of bone growth in children
growth hormone and thyroid hormone
bone matrix
hardened calcified matrix
mineralization of bone
hardening
rigor mortis
hardening of muscles and stiffening of body beginning 3 to 4 hours after death -deteriorating sarcoplasmic reticulum releases ca^2+, deteriorating sarcolemma allows ca^(2+) to enter cytosol, ca^(2+) activates myosin-actin cross-bridging, muscle contracts, but cannot relax
each head
has a binding site where it can attach to a thin filament
myosin head is in the "cocked" high-energy position
has adp + pi bound to the head, previously bound atp and broke a phosphate bond, energy from the bond allowed the protein to extend at the hinge, in this conformation the binding sites for actin are exposed
sarcolemma (plasma membrane)
has t-tubules (transverse tubules) that extend deep into the cell: these are literally a deep internal extension of the cell surface; they open at the surface as a "pore"; the interior fluid in the tube is actually the extracellular fluid
sarcoplasm (cytoplasm)
has typical organelles including many mitochondria for energy production plus contractile proteins
extension carried on a narrow neck that takes part in the formation of a joint
head
proximal disc-shaped end of radius
head
proximal expanded portion of fibula.
head
proximal expanded portion of the fibula
head
myosin head is in the "cocked" position
head previously bound atp and broke a phosphate bond, adp and pi are currently bound to the head (energy was used to extend the head at the hinge)
actin
helix of 2 fibrous strands of actin
spongy bone is the main site of
hematopoiesis in adults
cartilage ability to withstand tension/compression comes from
high water percentage
bone blood supply
highly vascularized, direct nutrient delivery to tissue
the knee joint
hinge joint allowing flexion and extension of the leg
spongy bone composition
holes/spaces filled with marrow
____ play a significant role in regulating bone growth
hormones
bone growth and remodeling occur under the control os
hormones (feedback loop) and physical/mechanical stressors
zone of reserve cartilage
hyaline cartilage
endochondral ossification uses ____ template for bone development
hyaline cartilage - bone formation chases cartilage growth
endochondral ossification
hyaline cartilage replaced by bone tissue in all bones below base of skull (besides clavicles)
synchodrosis
hyaline cartilage, no movement at rib 1 sternal junction, slight movement at ribs 2-7 sternal junction - synovial joints
cartilage tissue types
hyaline, elastic, fibrocartilage
anteriorly located between mandible and larynx
hyoid
bone located in the throat above the larynx that does no articulate with any other bone
hyoid
weakest layer of cartilage
hypertrophic zone
superior ridge of os coxa
iliac crest
connective tissue coverings located more superficially
important to groups muscles together within regions or into working groups (such as the quadriceps or hamstrings)
wave of excitation
impulse; the impulse is being transmitted along the complete length of the very large muscle cell starting from a pinpoint area, the nmj
the stimulus induces a change in membrane voltage
in the direction of depolarization (toward a less negative value)
greenstick fracture
incomplete break (one side breaks, other bends), common fracture in kids (bones more flexible)
torus (buckle) fracture
incomplete fractures of the shaft of a long bone, most common in children (growing bones), fall on outstretched arm or leg - load absorbed in distal portion of bone
loss of estrogen
increased bone resorption
PTH also
increases phosphate excretion, enhances calcium absorption (and therefore decreases excretion)
hyperextension
increases the angle
curved bones protruding from the lateral walls of the nasal cavities
inferior conchae (turbinates)
curved bone attached to wall of nasal fossa
inferior nasal concha
opening under each o
infraorbital foramen
depolarized state
inside is less negative than it was at the start (now in fact is positive if large amount of na+ entered the cell)
hyperpolarized state
inside is more negative than it was at the start (lost more + charged ions in the intracellular space....)
polarized state
inside is negative relative to outside
sarcoplasmic reticulum (sr)
internal membrane complex similar to smooth endoplasmic reticulum
posterior ridge connecting trochanters of femur
intertrochanteric crest
ridge on the posterior surface of the femur connecting the two trochanters
intertrochanteric crest
the opening in the vertebral column for spinal nerves are the
intervertebral foramina
motor neuron activates and releases neurotransmitter
into the synaptic cleft
sarcolemma and t-tubules
inward projecting narrow tubular extensions of the cell membrane; high density of voltage-gated ion channels along all membrane surfaces
at the beginning of contraction
isometric phase, muscle tension rises but muscle does not shorten
muscle begins to shorten and move the load
isotonic phase
myosin head will release from actin when
it binds a fresh molecule of atp
troponin changes shape when
it binds ca2+; the shape change causes it tug on tropomyosin
when ach binds to the receptor
it gates open as a chemically-gated ion channel
when the neurotransmitter is released by the nerve cell
it has to diffuse a short distance to reach the muscle cell membrane
when voltage reaches - 65 mv
it is the gating voltage for voltage-gated na+ channels in the membrane; these channels pop open quickly and that allows na+ to rush into the cell
in the case of the ach receptor at the nmj
it permits the passage of na+ across the membrane, na+ will diffuse into the muscle cell down the concentration gradient, this will lead to depolarization of the membrane at the motor end plate (the area at the nmj)
since muscles have multiple motor units
it provides an ability to sustain long-term contraction as motor units will take turns contracting (critical for postural muscles)
bones bearing a groove that serves as a passageway for tears
lacrimal
bones forming sides of the cranium
lambdoidal
suture between occipital and parietal bones
lambdoidal
multiple nuclei
large size of cells means that extra nuclei are needed to drive heavy load of transcription and translation of proteins to keep cell alive and functioning
multinucleate
large size requires high rate of protein synthesis supported by high rate of gene transcription
periods of the twitch
latent, contraction, relaxation
eversion
lateral aspect of feet point up
distal lateral articulating process of femur
lateral condyle
raised area above capitulum of humerus
lateral epicondyle
the raises area above the capitulum of the humerus is the
lateral epicondyle
distal process of fibula forming outer prominence of ankle
lateral malleolus
once degraded osteoblasts can
lay down fresh bony matrix
epiphysis composition
layer of compact bone surrounds layer of spongy bones
epiphysis covered by
layer of hyalin cartilage - articular cartilage
small indentation separating ischial spine and tuberosity
lesser sciatic notch
process inferior and medial to neck of femur
lesser trochanter
process inferior and medial to the neck and femur
lesser trochanter
rounded anterior process distal to anatomical neck of humerus
lesser tubercle
rounded anterior process distal to anatomical neck of humerus.
lesser tubercle
bat shaped portion of the sphenoid bone anterior to the sella turcica
lesser wings
i band
light, isotropic region, bisected by z line
osteoprogenitor cells
line both the inner layer of periosteum and the endosteum, give rise to all osteoblasts
endosteum location
lines inner surface of compact bone and trabeculae of spongy bone
hyaline (articular) cartilage
lines the ends of bones facing one another, compression absorbing, also contains synovial fluid, slippery fluid forced out with each compression
contraction coupling
linking release of acetylcholine at the nmj to the release of calcium from the sarcoplasmic reticulum and rapid crossbridge cycling within the large myofibril mass in the muscle cell
somatomedins
liver derived hormones secreted in response to GH (most potent stimulator of cartilage, bone, and skeletal muscle growth)
class of bones having greater length than diameter
long
osteon
long pillars of hardened matrix that run lengthwise along bone, concentric and circumferential lamellae (plates)
bone shape classifications
long, short, flat, irregular
syndesmosis joint
longer collagen fibers attach bones together, amphiarthrosis and synarthrosis
long bone
longer than they are wide, serve as levers for movement
posterior boundary of false pelvis
lumbar vertebrae
stability
maintain posture by preventing unwanted movements, antigravity muscles: prevent us from falling over, stabilize joints by maintaining tension
bone forming lower jaw
mandible
lower jaw bone
mandible
the upper part of the breastbone is the
manubrium
complete thick filament
many heads projecting off the filament from both ends and in all directions around the filament
myosin molecules and thick filaments
many myosin molecules bundled together side-on and end-on to make a thick filament
process posterior to styloid process of temporal bone
mastoid
zone of hypertrophy
maturation, enlargement, blood vessel development (VEGF)
bone forming upper jaw
maxill
bone forming anterior portion of the hard palate
maxilla
bones forming upper jaw bone and parts of orbits
maxillae
canal like passageway
meatus
inversion
medial aspect of feet point up
distal medial articulating process of femur
medial condyle
raised area above trochlea of humerus
medial condyle
distal process of tibia forming inner prominence of ankle
medial malleolus
cavity within the shaft of a long bone
medullary cavity
hyperpolarization
membrane charge moves toward a more negative value
the external and internal surfaces of bone are covered by
membranes
embryonic skeleton begins as
membranes and cartilage
prominent opening on the body of the mandible
mental foramen
metacarpal articulating with proximal phalanx of thumb.
metacarpal I
instep bone articulating with proximal phalanx of little toe
metatarsal v
bones forming the instep of the foot
metatarsals
sarcoplasmic reticulum and terminal cisterns
modified form of endoplasmic reticulum; storage site for ca2+ ions
osteoporosis remodeling balance
more resorption than deposition, mass declines despite normal matrix composition
myofibrils make up
most of the cell's volume
thin filaments consist
mostly of two twisted strands of fibrous actin (f-actin)
fibrocartilage
mostly thick collagen fibers
the motor unit
motor neuron and all of the muscle cells it controls
factors that affect intensity of muscle contractions
motor unit recruitment, temporal summation, length tension relationship
movement
move from place to place; move body parts; move body contents in breathing, circulation, and digestion, in communication: speech, writing, facial expressions and other nonverbal communications
functions of skeletal muscle
movement, stability, control of openings and passageways, heat production, glycemic control
synovial joints permit a wide range of movements
movements occur within planes of space
abduction
moves limb away from midline
adduction
moves limb towards midline
ball and socket
multiaxial
movement in 3 planes of space
multiaxial
the nerve cell
muscle cell relationship and stimulation of the muscle cell
muscle structure: from macro to micro
muscle covering,
eccentric contraction
muscle lengthens as it contracts (e.g., in the biceps brachii when lowering a load)
isotonic muscle contraction
muscle tension overcomes resistance resulting in movement, tone (tension) stays constant, but length changes, concentric contraction muscle shortens as it contracts (e.g., in the biceps brachii when lifting a load)
glycemic control
muscles absorb and store glucose which helps regulate blood sugar concentration within normal range
botulism
muscular paralysis (flaccid paralysis) caused by toxin from clostridium botulinum, prevents release of ach at synaptic knobs, although toxin ingestion can be life-threatening, careful injections of it can treat spasticity (e.g., due to cerebral palsy) or can be used for cosmetic purposes (diminishing wrinkles)
organization of a sarcomere
myofilaments (thin and thick) are arranged in repeating units called sarcomeres
the ach receptor is a chemically gated ion channel that permits
na+ to enter at the nmj and this moves the motor end plate (epp) to threshold (-65mv)
bones forming upper part of the bridge of nose
nasal
constriction distal to head of radius
neck
constriction distal to the head of the radius
neck
§fluid inside cell is ____ compared to fluid outside cell
negative
icf
negative relative to the ecf
irregular bones
no distinct shape to fit into other categories
synarthrotic joint
no movement allowed
no movement
nonaxial
plane/gliding
nonaxial
rich supply of blood vessels and nerves enter through
nutrient foramen
direction of fracture
oblique (on an angle), transverse (across), spiral (twisting)
large opening in inferior region of coxal bone
obturator foramen
large opening in the inferior region of the coxal bone
obturator foramen
bone forming floor and lower rear wall of cranium
occipital
bone forming posterior inferior portion of the skull
occipital
the atlas articulates superiorly with the
occipital
rounded projections lateral to the foramen magnum that articulate with the first cervical vertebra
occipital condyles
oblique fracture
occurs at an angle across the bone
posterior process on proximal end of ulna forming point of elbow
olecranon
depression on posterior surface at distal end of humerus
olecranon fossa
posterior projection on proximal end of the ulna forming the point of the elbow
olecranon process
impacted fracture
one bone fragment is firmly driven into the marrow cavity or spongy bone of the other
each muscle fiber is supplied by
only one motor neuron
action potentials are being generated all along the sarcolemma as voltage-gated channels trigger
open in response to changes in voltage in the neighboring region of the cell
fracture classification
open vs closed, complete vs incomplete, displaced vs nondisplaced, direction
openings in the sphenoid though which optic nerves enter the orbits
optic foramina
compact bone extracellular matrix secreted by
osteoblasts
matrix is secreted by
osteoblasts
specific molecules control mineralization and prevent inappropriate mineralization, inhibited by
osteoblasts
mineralization of bone process
osteoblasts secrete collagen - minerals deposit on collagen and begin to harden matrix - kickstart so more calcium and phosphates are recruited and matrix solidifies
mature bone cells
osteocytes
chondrogenic cells differentiate into
osteogenic cells -> osteoblasts
inner layer of periosteum
osteogenic layer
structural unit of compact bone is the
osteon
decline in estrogen levels is highly correlated to
osteoporosis development
girth increases due to activity of
osteoprogenitor cells in the periosteum
bone cell types
osteoprogenitors (osteogenic), osteoblasts, osteocytes
collar of long bone
outer dense layer of compact bone
the relationship between nerve cells and muscle cells is a determinant of
overall force and level of fine tuning of force that can be produced by that muscle
bone forming posterior third of hard palate
palatine
bone forming the posterior portion of the hard palate
palatine
bone forming lateral wall of cranial vault
parietal bone
incomplete fracture
partial fracture extends only partway across the bone, pieces remain joined
central canal
passageway for blood vessels and nerves
the sesamoid bone located in front of the knee joint
patella
the superior opening os the true pelvis
pelvic inlet
protects viscera in abdominopelvic cavity
pelvis
initially the outer layer of the hyaline cartilage is surrounded by the
perichondrium
cartilage is surrounded by
perichondrium - dense irregular connective tissue layer
gomphosis joint
peridontal ligaments, collagen fibers locking tooth into socket, synarthrosis
covering of bone surface
periosteum
outer membrane of bone
periosteum
osteoblasts convert the perichondrium to the
periosteum -> forms the bone collar
pns
peripheral nervous system (peripheral nerves)
gated ion channels
permit ions passage across the membrane; this movement is electrical current and stimulates contraction of the cell
downward extending process of ethmoid
perpendicular plate
plantar flexion
phalanges point inferiorly
dorsiflexion
phalanges point superiorly
structural classifications based upon
physical structure of the joint (how they join/associate)
joint between radius and ulna allows for uniaxial movement too
pivot joint- pronation and supination
neuromuscular junction (nmj)
point of close association between the motor neuron and the muscle cell
sharpey's fibers very thick at
points of tendon/ligament attachment
other risk factors for osteoporosis
poor diet, vitamin D deficiency (low vitamin C - increased PTH), smoking, sedentary lifestyles (bone homeostasis require tension - weight bearing)
high risk for osteoporosis
post menopausal women
hyaline cartilage
primarily fine collagen fibers
diaphragm action
prime driver of inspiration
compact bone matrix
proteoglycans, collagen, etc.
organic components of bone function
provide flexibility
inorganic components of bone function
provide structure
atp should always be available in the cell
provided that it is alive and metabolism is occurring properly
zygomatic (major and minor) action
pulls corners of mouth posteriorly and superiorly (smile)
orbicularis oris action
purses and protrudes lips; puckering- kissing motion
muscle relaxation requires
qatp, and atp production is no longer produced after death, fibers remain contracted until myofilaments begin to decay
junctional folds
qinvaginations of the muscle cell membrane that serve to increase surface area at the nmj
action potential
quick event observed in a stimulated cell resulting from rapid movements of na+ and k+ across the membrane
lateral depression on ulna articulating with head of radius
radial notch
lateral bone of forearm
radius
the myosin head extends at the hinge (re-energizes)
re-positioning the actin binding sites so that another crossbridge can form with the thin filament
motor unit recruitment
recruit just a few motor units to lift a pencil, recruit many motor units to lift a suitcase, if doing external stimulation, above a certain voltage, all units are recruited, and so maximum contraction occurs (regardless of how much higher the voltage is elevated)
muscles of the abdomen
rectus abdominis, external oblique, internal oblique, transversus abdominis
marrow carrying out hematopoiesis
red
openings in spongy bone are filled with
red marrow
synovial fluid purpose
reduce friction, provide nutrients, removes waste
high mitochondrial density
reflects high metabolic demand
the neuromuscular junction (nmj)
region of close association between motor neuron and skeletal muscle cell
troponin and tropomyosin
regulatory proteins of the thin filament
ligaments
reinforce the capsule
total bone mass is
relatively constant in younger adults, areas of bone are remodeled at various rates
collagen fibers of the matrix run in opposite directions in order to
resist twisting
cartilage layers
resting zone, proliferation zone, hypertrophic zone, calcification zone, ossification zone
extension
returns the angle to baseline angle
the rapid loss of + charged k+ ions from the cell
reverses the depolarized membrane potential (back toward a more negative value and a return to a normal polarized state) - repolarization
rapid accumulation of + charged na+ ions in the cell
reverses the membrane potential (depolarization)
the pubic angle of the female pelvis is
right or obtuse
compact bone is composed of
rings of hardened matrix
spongy bone is arranged as
rods
acl
runs from anterior intercondylar area to posterior of femur lateral (intercondylar fossa), prevents anterior displacement
pcl
runs from posterior intercondylar area) to posterior of femur lateral (medial intercondylar fossa), prevents posterior displacement
the curvature formed by the sacrum and the coccyx is the
sacral
collagen fiber flexibility from
sacrificial bonds
articulation between pelvic girdle and axial skeleton
sacroiliac crest
the coxal bone articulates posteriorly with
sacrum
suture between parietal bones
sagittal
membranes and cartilage form
scaffolds for bone development
at or around the time of birth
secondary ossification centers form in the epiphyses of the bone
C cells (parafollicular cells)
secrete calcitonin, inhibits osteoclasts and promotes Ca++ excretion
osteoblasts function
secrete fresh matrix
sharpey's fibers function
secure periosteum to bone
small depression in sphenoid midline in which pituitary glands reside
sella turcica
binding sites on the actin globules for myosin heads are exposed
setting the stage for interaction between the thin and thick filaments
working muscles are an organization of many muscle cells together
several different connective tissue coverings protect and wrap cells together to form muscles and organize muscles into groups
at puberty
sex hormones induce rapid growth of bone (growth spurt)
after puberty
sex hormones slow down growth at the epiphyseal plates -> become epiphyseal lines and longitudinal growth tops
muscle cell features
shallow depression along synaptic surface captures acetylcholine which enhances likely activation of the muscle cell, large number of acetylcholine receptors packed into the muscle cell membrane at the synaptic surface, junctional folds enhance overall membrane surface and thus increase density of receptors at the synapse
synovial joints are classified based on
shape and range of motion
shin splints
sharpey's fibers pull away from matrix
suture joint
short interlocking ct fibers (sharpey's fibers), synarthrosis
denervation atrophy
shrinkage of paralyzed muscle when nerve remains disconnected
secondary ossification center
similar events occur - blood vessels invade, matrix laid down, degraded, laid down again
single twitch
single stimulation is applied, single twitch is produced, small level of force is generated
elbow joint
single synovial cavity protected by fibrous membrane and surrounded by supporting ligaments
cavity contained within skull bone
sinus
cavity within a bone
sinus
lined with mucous membrane
sinus
articulations
sites where two bones come together
structural support
skeleton is the framework of the body
open fracture (compound)
skin is broken, bone protrudes through skin, wound extends to fractured bone
closed fracture (simple)
skin is not broken
as cross bridge cycling proceeds
sliding of the thin filaments inward by the pulling action of the thick filaments leads to shortening of the sarcomere
amphiarthrotic joint
slight movement allowed
compact bone is rings of hardened matrix connected by
small passageways
canaliculi
small passageways fulled with tissue fluid and extensions of osteocytes, osteocytes connected by gap junctions
compact bone composition
smooth, homogenous, solid
ion channels are regulated
sometimes they are closed and no diffusion is permitted and sometimes they are open and the ion is moving across the membrane down its gradient, these channels are referred to as gated channels - to gate means to open
joint cavity
space between bones containing synovial fluid
tetanus
spastic paralysis caused by toxin from clostridium tetani, blocks release of inhibitory neurotransmitter in spinal cord, resulting in overstimulation of muscles, vaccination prevents this life-threatening condition
cartilage and bone are
specialized connective tissue that function in structure and support of the body
gated ion channels are
specific and regulated
control of openings and passageways
sphincters: internal muscular rings that control the movement of food, blood, and other materials within body
spongy bone structure
spicules and trabeculae, lined with endosteum, spaces filled with red marrow, no osteon structure but lamellar matrix
vertebral column encloses the
spinal cord
prominent ridge running horizontally across posterior surface of scapula
spine
sharp, slender projection that serves as the site of muscle attachment
spine
type of bone most affected by osteoporosis
spongy
type of bone composed of small spicules of bone and lots of open spaces
spongy (cancellous)
action potentials next start here and then
spread along the entire muscle cell membrane: this is a transmission of electricity across and deep into the interior of the cell
starting from the nmj, action potentials
spread outward along entire membrane surface
suture between temporal and parietal bones
squamous
sarcoplasmic reticulum (sr) and myofibrils
sr forms a loose network around each myofibril (like a loosely woven sweater sleeve)
muscle of head and neck movement
sternocleidomastoid
ribs articulate anteriorly with the
sternum
the breastbone is the
sternum
growth hormone
stimulated bone elongation and cartilage proliferation at epiphyseal plates
skeletal muscle never contracts unless
stimulated by a nerve
testosterone
stimulated osteoblasts and promotes protein synthesis promoting adolescent growth and epiphyseal closure
insulin
stimulates bone formation, significant bone loss occurs in untreated diabetes mellitus
estrogen
stimulates osteoblasts and adolescent growth, prevents osteoporosis
estrogen role in bone remodeling
stimulates osteoblasts, inhibits osteoclasts
fused tetanus process
stimuli arrive so frequently that there is no evidence of relaxation, crossbridge cycling peaks with maximum sarcomere shortening, muscle will fatigue as cell cannot produce sufficient atp to maintain intensity of crossbridge cycling for extended period of time at 100% wave summation, as atp stores are depleted, cell will lose tension
close association of sr with the myofibrils
stored calcium is surrounding all of the contractile protein components
bone remodeling along lines of
stress
the skeletal system performs multiple functions
structural support, movement, protection, blood cell formation, mineral storage, acid base and electrolyte balance, fat storage
pointed medial projection at distal end of ulna
styloid process
groove or furrow
sulcus
the superior and vertebral borders the scapula join at the
superior angle
bone function
support, resist compressive and pulling forces (stessors)
cartilage function
support, resist compressive forces (stressors)
opening above each orbit
supraorbital foramen
bone remodeling occurs at
surface of periosteum and endosteum
common site of arm fractures
surgical neck
cranial articulation
suture
axon terminal
swollen end of nerve fiber, contains synaptic vesicles with acetylcholine (ach)
the articulation joining the two pubic bones is the
symphysis pubic
nerve cell terminal end
synaptic knob ("enlarged foot")
types of functional joints
synarthrotic, amphiarthrotic, diarthrotoc
an action potential propagates down the length of the entire cell membrane
t-tubules as well so the entire cell from outside to inside becomes electrified
tarsal bone between tibia and calcaneus
talus
hyaline cartilage and fibrous membranes serve as
templates for bone formation
bone inferior to the parietal bone
temporal
forms movable joint with mandible
temporal
muscles of mastication
temporalis, masseter
only movable joint in the skull
temporomandibular joint
key regulator of bone remodeling
tension
contributor to the density of bone
tension (weight bearing)
muscle tension
tension is the force generated when a muscle is stimulated to contract, lab experiments measure tension and graph it (myogram)
when tension overcomes resistance of the load
tension levels off
relaxation requires
termination of nerve cell stimulation and a return to resting conditions inside the muscle cell
relaxation process
termination of nerve signal and ach release from motor neuron (no more neurotransmitter release) hydrolysis (degradation) of ach by acetylcholinesterase located in the synaptic cleft; enzyme clears the chemical quickly from the extracellular space....... closure of ach receptor causes cessation of end plate potential so no further action potential generation in the muscle cell closure of ca2+channels in sarcoplasmic reticulum and ca2+will be taken back up by the sarcoplasmic reticulum by active ca2+ transporters (calcium is cleared out of the sarcoplasm) as ca2+ levels decline in the sarcoplasm, troponin changes shape and re-positions tropomyosin back along the thin filament blocking the myosin binding sites; cross bridge cycles stop muscle returns to resting state
each channel type gates at a different voltage
that means different ions move directionally across the membrane at different times under different conditions
resting membrane potential (rmp) created by
the action of the na+/k+ atpase
muscles produce tension/force when they contract
the amount of force produced can be varied based upon the demand placed on the muscle
neuromuscular junction
the area where the enlarged terminal end of the neuron comes in close association with the sarcolemma of the muscle cell
the border of each sarcomere
the border of each sarcomere
major articulation points in the elbow joint
the capitulum of the humerus and head of the radius, the trochela of the humerus and trochlear notch of the ulna, the head of the radius and the radial notch of the ulna
chemically-gated ion channel will stay open as long as
the chemical remains present in the synaptic cleft
calcitonin aids in
the control of bone remodeling by maintaining homeostatic levels of Ca++ in the blood, decrease blood Ca++ levels
initial stimulus
the delivery of acetylcholine to the muscle cell membrane and how it moves the membrane toward threshold to trigger an action potential
myosin head degrades atp (breaks a phosphate bond) and produces adp + pi
the energy released is use to change shape at the hinge
if these channels are gating open to induce an action potential in this region
the flow of ions across the membrane here will move the neighboring membrane area to threshold and that will trigger these voltage gated ions channels in this area to gate open
linear fracture
the fracture is parallel to the long axis of the bone
transverse fracture
the fracture is perpendicular to the long axis of the bone
temporal (wave) summation
the frequency of stimulation can influence tension development by a muscle fiber, repetitive stimulation of a fiber produces contractions of longer duration and greater tension than a single twitch
the trigger that opens the channel is called
the gating stimulus
myosin changes shape at the hinge
the head flexes inducing the power stroke
immediately upon binding to actin, myosin changes shape at the hinge
the head flexes relative to the tail, since it is gripping the thin filament this means it pulls the thin filament toward the midline of the thick filament (the thin filament slides inward), this movement is called the power stroke, the myosin head releases adp and pi when it completes the power stroke
repolarization
the membrane has returned to a state of polarization following a depolarization event
acetylcholine binds to its receptor on
the muscle cell membrane
as sarcomeres shorten
the myofibrils will shorten...and the muscle cell shortens
in the presence of atp
the myosin head will quickly release from actin
rmp is generated primarily by
the na+/k+ atpase pumps
eventually the na+ and k+ channels close
the na+/k+ atpase returns the na+ and k+ ion gradients to rest conditions. this means the cell is quickly primed to fire another action potential ....within milliseconds.
synaptic cleft
the narrow gap between axon terminal and sarcolemma
chemically gated ion channels are concentrated at
the neuromuscular junction and are critical for the nerve cell to activate the muscle cell
strength of a muscle and the direction of its pull are determined partly by
the orientation of its fascicles
nondisplaced fracture
the portions of bone are still in correct anatomical alignment
the banding pattern of the sarcomere
the positions of thin and thick filaments give rise to alternating i-bands and a-bands
the striations of skeletal muscle are due to
the precise organization of thin and thick filaments (called myofilaments) in the myofibrils, a pattern that is repeated over and over again along the length of the entire cell
blood vessels invade
the primary ossification center and bring osteopregenitor cells
if threshold is reached for gating of fast voltage-gated na+ channels
the regional membrane will fire an action potential and that will trigger activation of electrical impulse transmission across the entire muscle cell
motor neuron releases acetylcholine at
the synapse
length-tension relationship
the tension a muscle produces depends on its length at the time of stimulation
the myofibril is comprised of many sarcomeres in a series
the z-discs connect each neighboring sarcomere along the entire length
depolarization
there has been a change in charge inside the cell toward a less negative (or more positive value)
action potentials shoot down the t-tubules
these electrical impulses shock the flanking sarcoplasmic reticulum (terminal cisterns)
each strand is a necklace of hundreds of actin globules
they link together to create f-actin; two f-actin strands twist together to form the base of the thin filament
troponin and tropomyosin function
they regulate the interaction between thin and thick filaments and therefore control the transition between the at-rest and contractile state of the muscle cell
narrowing (or disappearance) of h zone and i band
thick and thin filaments remain the same length but slide past each other
fusiform muscles
thick in the middle and tapered at each end
a sarcomere is a precise overlapping array of
thin and thick filaments
binding of myosin head to actin is a crossbridge
thin and thick filaments are attached (thick is gripping thin)
flat bone (sesamoid)
thin and usually curved, forms in tendon
epiphyseal line
thin plate of compact bone in adults, remnant of epiphyseal plate, disc of hyaline cartilage that allows bone to grow during childhood
bone growth from
thin plates of cartilage called epiphyseal plates
stimulation of the muscle cell will trigger release of calcium from the sarcoplasmic reticulum
this is the trigger for interaction of thin and thick filaments
a single cross-bridge cycle is not sufficient to produce a robust contraction of the muscle
this process has to repeat many times over to get shortening of the muscle
binding site for myosin is covered in
this thin filament
facets for articulation with the ribs are found on the f
thoracic vertebrae
cone shaped enclosure forming shield protecting heart and lungs
thorax
ulnar collateral ligament
three band of strong flexible tissue attach the humerus to the ulna - anterior band (strongest), posterior band, transverse band
femur articulates distally with
tibia
medial bone of the lower leg
tibia
the fibula articulates proximally with
tibia
midline projection anterior and inferior to tibial condyles
tibial tuberosity
mineralization of bone is a
tightly regulated process involving multiple organ systems
latent period
time after stimulus but before contraction begins, no change in tension; ca2+ levels are still low in the sarcoplasm
relaxation period
time when tension is decreasing to baseline, begins with release of crossbridges, no more action potentials; ca2+ is being removed from sarcoplasm, generally lasts a little longer than contraction period
contraction period
time when tension is increasing; action potentials have triggered release of ca2+, begins as power strokes pull thin filaments; tension rises quickly as crossbridge cycling proceeds
tropomyosin is pulled
to a slightly different position
rapid diffusion of na+ and k+ ions across the membrane through regulated ion channels allows the muscle cell
to activate and trigger internal events that lead to contraction
trabeculae arrangement
to resist stress and compression
spongy bone lattice of rods
trabeculae
the axon of the spinal motor neuron
transmits an electrical signal to muscle cells located within the target muscle
terminal cisterns combine in twos with central t-tubule to form
triads
voltage-gated ca2+ channels
trigger open
ca2+ interacts with myofilaments
triggering contraction
the myosin head binds a fresh molecule of atp
triggers its release from actin
very large, usually irregularly shaped pricess
trochanter
condyle on humerus that articulates with the ulna
trochela
condyle on humerus that articulates with ulna
trochlea
calcium is bound by
troponin in the thin filament
(t/f) the clavicle articulates with the acromion process of the scapula
true
(t/f) the cuboid is a tarsal bone
true
(t/f) the hamate is a carpal bone
true
(t/f) the head of the humerus articulated with the glenoid cavity of the scapula
true
(t/f) the proximal phalanx of the thumb articulates with metatarsal I
true
(t/f) the radius articulates with the ulna
true
small rounded process serving for muscle attachment
tubercle
midline projection from anterior surface just below tibial condyles
tuberosity
t tubule
tubular extension of the cell membrane that runs directly into the interior of the large muscle cell
supination
turn palm anteriorly
protonation
turn palm posteriorly
impacts capable to breaking bone
twisting or blunt force
each myosin molecule has
two heads and two intertwined tails
joint capsule
two layered covering for the joint, fibrous layer of dense irregular ct, synovial layer of loose ct produces synovial fluid
wave summation
two stimulations are applied in close succession, the cell begins to contract after stimulus #1 but does not get to fully relax before stimulus #2 hits the cell, the force produced by stimulus #2 adds on to the force from stimulus #1 and reaches a higher value, higher force reflects higher level of ca2+ in the sarcoplasm....too little time to clear it all when stimulations come close together in time
triad
two terminal cisterns flanking one t-tubule: one triad is located at each a-i band junction; carries electrical current deep into muscle fiber
the muscle cell is electrically charged at rest due to
unequal pumping of positively charged ions across its membrane even at rest
hinge
uniaxial
movement in one plane of space
uniaxial
parallel muscles
uniform width and parallel fascicles
net diffusion direction of the ion moving through the channel depends
upon the concentration gradient only for that ion; so na+ will move directionally according to its gradient only, k+ according to its gradient, etc.
myasthenia gravis details
usually occurs in women between 20 and 40, muscle fibers remove receptor clusters from the sarcolemma by endocytosis, fiber becomes less and less sensitive to ach, effects usually first appear in facial muscles, drooping eyelids and double vision, difficulty swallowing, and weakness of the limbs, strabismus: inability to fixate on the same point with both eyes
encases spinal cord
vertebrae
center opening in each vertebra is the
vertebral foramen
bone tissue is
very metabolically active and is continuously remodeling
as membrane potential moves toward threshold at the nmj
voltage gated na+ channels in the region will open at -65 mv and an action potential will be triggered in the surrounding membrane region
when the membrane reaches -65mv
voltage-gated na+ channels open in the nmj and action potentials form radiating outward from the nmj along the sarcolemma and down the t tubules
bone forming posterior and inferior nasal septum
vomer
thin bone on median line in nasal cavity
vomer
unpaired face bone in nasal cavity
vomer
mineralization occurs and osteoblasts are
walled off into lacunae and become osteocytes
stressors
weight bearing or muscle pull
since the muscle fibers are spread out within the muscle and all contract together
when the motor neuron activates the motor unit will produce a weak general contraction over wide area
the muscle fibers of the same motor unit
will all contract in unison
chemically-gated ion channel is specific
will permit a particular ion to diffuse across the membrane
incidental bones developing in the sutures of the skull
wormian
to get maximum force production from muscle
would want 100% motor unit recruitment
the lower part of the breastbone is the
xiphoid process
adipose tissue stored in a medullary cavity
yellow marrow
fat storage
yellow marrow
bone forming inferior lateral surface of eye orbit
zygomatic
bone forming prominence of cheek
zygomatic
bones commonly called cheekbones
zygomatic
rmp in skeletal muscle cells
~ -90 m
spongy bone replaces every
~3-4 years
bone grows in length throughout life until
~puberty
each actin globule (bead) has a myosin binding site
§to which myosin heads attach during contraction (the myosin heads will attach to the actin beads of the thin filament during muscle contraction)
heads are
•angled off of the tails and can bend at a hinge location (similar to the way you can bend your closed fist toward your forearm when your arm is extended...)