A&P Exam 3 Flashcards
where does what are joint
site where two or more bones meet
what do joints provide
mobility and helps hold the skeleton together
another name for joint
articulations
how many ways can you classify joints
two ways
functional classification
based on the amount of movement allowed
- synarthrosis
- ampiarthrosis
- diathrosis
synarthrosis
a functional movement classification of joints
it is NO movement allowed
ampiarthrosis
a functional movement classification of joints
only SLIGHTLY moveable joint
diarthrosis
a functional movement classification of bone
freely moveable
structural classification
organization of joints based on materials it’s made of or it’s missing
- fibrous joints
- cartilaginous joints
- synovial joints
fibrous joints
joints are joined by protein fibers, most are synarthrosis
- no joint cavity
- like collagen
- no cartilage
sutures
seams that occur only between bones of the skull
what are bones joined by in sutures
by short protein fibers
what happens to sutures in adulthood
sutures ossify and become bone
-synostoses
syndesmoses
bones are connected by a ligament
- straplike dense irregular connective tissue
- longer protein fibers
what do ligaments do
connect one bone to another bone
what do tendons do
connect a muscle to a bone
gomphoses
joint where one bone is embedded in another bone and also connected by a ligament
example of gomphoses
only example is teeth at the alveolar margins of the mandible and maxilla
cartilaginous joints
bomes are joined using cartilage (no joint cavity)
most are immovable or slightly movable (synarthrotic or ampiarthrotic)
synchondroses
joints contain a thin plate of hyaline cartilage
symphyses
joint uses a thin layer of hyaline cartilage on bone ends and a pad of fibrocartilage in between
what is the fibrocartilage pad like
strong and acts as a shock absorber
joints allow for minor movement
synovial joints
bones are joined using cartilage and a joint cavity
which joints are synovial joints
almost all limb joints
what kind of movement do synovial joints allow
diarthrodial (a lot or free movement)
what is the structure of a synovial joint
it has a 5 distinguishable features
articular cartilage
1 (most important synovial joint feature )
made of hyaline cartilage
covers bone ends contained in the joint
acts as a spongy cushion that protects underlying bone
ground substance of cartilage contains keratin sulfate and chondroitin sulfate
articular capsule
2 synovial joint feature
a dense irregular connective tissue (sac like)
-> surrounds joint space
-> composed of two layers
what are the two lays of the articular capsule
outer most layer is the fibrosis capsule
inner layer is the synovium
fibrosis capsule
outer layer of articular capsule for protection
synovium
AKA synovial membrane
contains cells called synoviocytes
synoviocytes
produce synovial fluid
can affect health of the joint
synovial cavity
3 feature of synovial joint
space between two articulating bones
surrounded by the articular capsule
synovial fluid
4 feature of synovial joint
occupies the free space in the joint cavity
viscous (yellow) fluid
fluid acts as a shock absorber
reduces friction between opposing bone surfaces
filtrate of blood plasma
contains hylauronic acid and lubricin
reinforcing ligaments
#5 feature of synovial joints stabilize the joint (maintains normal range of movements) ligaments do not pass through the joint space
fatty pads
cushioning pad along the articular capsule
where can fatty pads be found
at knee and hip
heavy use joints
bursae
a flattened fibrous sac (lined with synovium and filled w/ synovial fluid)
where can you find bursae
near joints that have a lot of structures
- tendonds, ligaments - bony projections -
what is bursar for
to reduce friction during body movements
what are long bursar called
tendon sheath
examples of bursae
elbows and shoulder, knee and hip
articular discs
aka menisci
discs of fibrocartilage - strong resistant to mechanical stress
discs increase the tightness of fit of a joint
examples of articular discs
knee shoulder hip and jaw
joint stability
joints are constantly stretched and must be stabilized so that articulating bones do not come out of alignment
several factors that contribute to joint stability
ligaments associated tendons (held tight by muscle tone) complementary shapes of articular surfaces (bones at a joint are shaped to fit each other)
sprain
ligaments reinforcing a joint are stretched or torn
ligaments
do not stretch well and will snap under too much strain
heal very slowly due to being poorly vascularized
completely ruptured ligament
may need to be replaced
- ulnar collateral ligament replacement - tommy john surgery -
dislocation
articulating bones at a joint are forced out of alignment
often needs to be realigned or reduced
often accompanied by sprain
repeated dislocations of the same joint is possible
what are dislocations common for
fingers shoulder and jaw
cartilage ingury
soft tissue that can be torn
most involve knee
lose fragments can be removed
damaged fragments can be repaired
how long is a cartilage injury recovery
quick
bursitis
inflammation of bursa
causes fluid to accumulate (joint appears swollen)
what is bursitis caused by
repetitive use
forceful blows to the joint
tendonitis
inflammation of the tendon sheath
where is tendonitis / bursitis often seen
elbow - shoulder - and knee
what are treatments for tendonitis / bursitis
rest - ice - and anti inflammatories
arthritis
describes a variety of conditions
what do all forms of arthritis cause
to some degree they cause pain, stiffness and swelling of the joints
what do all forms of arthritis have as a long term issue
long term inflammatory component
what does inflammation cause to the joint
causes more damage
the more inflammation the faster the damage
what causes cartilage homeostasis
release of pro-inflammatory hormones and the presence of immune cells on the joins
what is the issue when cartilage homeostasis is disrupted
chondrocytes secrete less extracellular material and more MMP’s
what are MMP’s
short for matrix metalloproteinases
which are enzymes that degrade connective tissue
what causes permanent cartilage loss
decreased production and increased breakdown of of extracellular matrix lead to
osteoarthritis
most common type of arthritis
what is osteoarthritis due to
regeneration of joints due to chronic use
breakdown over time
osteoarthritis severity
increases with age but it is a slow progression
is the damage done by osteoarthritis reversible
no
what is osteoarthritis commonly associated with
crepitus
what is crepitus
noisy creaky joints
what are the commonly affected joints in osteoarthritis
knee hip and fingers
rheumatoid arthritis
can be found in kids it is an inflammatory based arthritis autoimmune disease unknown etiology joints can be warm to the touch
what is rheumatoid arthritis linked to
bad genes
body has trouble limiting inflammation
what is R.A. characterized by
flare ups and remissions
what joints does R.A. affect
often pair of joints like elbows or shoulders
synovium becomes overgrown forms a pannus
invades joint cavity and destroys cartilage
it can get anklosis which is complete destruction of the joint s and fusion of the bones
gouty arthritis
nitrogen processing disorder
what does the body accumulate during gouty arthritis
uric acid
uric acid crystals form in the body
crystals ember in the joint capsule and initiate an inflammatory response
what joints does Gouty arthritis affect
the joints on big toe
synovial joint movements
body movements occur when muscles contract across a joint
contraction of a skeletal muscle group
moves bones with respect to one another
in bone movement which is the origin
the less movable bone
in bone movement which is the isertion
the bone that moves more
gliding movements
a flat bone slides over the surface of another flat bone
simplest type of movement allowed
flexion
vs
extension
decrease the angle of the joint (draw closer together)
vs
increase the angle of the joint (move further apart)
hyperextension
joint moves beyond 180 degrees
adduction
vs
abduction
movement of a limb towards the body line
vs
movement of the limb away from the body midline
circumduction
movement of a limb to form a cone in space
which joints perform circumduction movements
coxal joint
glemohumeral joint
metacarpaophalangeal joint
rotation
turning of a bone on its own axis
can rotate at hip and shoulder
medial or lateral rotation
suppination
vs
fronation
palms face forward (forearm bones run parallel)
vs
palms face rear (forearm bones form an x)
inversion
vs
eversion
point foot inward
vs
point foot outward
protraction
vs
retraction
anterior movement of a body structure in a horizontal plane
vs
posterior movement of a body structure in a horizontal plane
(moving mandible back and forth)
elevation
vs
depression
superior movement of a body structure in a vertical plane
vs
inferior movement of a body structure in a vertical plane
(moving mandible or scapulae up and down)
opposition
movement of thumbs to the tips of the other fingers
- at the first carpal metacarpal joint
Fibrocartilage pad
Strong and persistent to mechanical stress
What are articular discs for
Reduces joint wear
smooth muscle structure
most cells are oval shape
cells are uninucleated
tissue is not striated
where can smooth muscle be found
always in walls of hallow organs
- stomach
- salivary glands
- uterus
function of smooth muscle
not under voluntary control
how is smooth muscle used
always for slow sustained contractions
characteristics of slow sustained contractions
not very powerful
does not fatigue
100x more energy efficient than skeletal muscle
AND subconscious nervous system
smooth muscle arrangement
single unit smooth muscle (connected with gap junctions)
cells act together
two overlapping sheets (inner and outer layer)
inner layer
aka circular layer
outer layer
aka longitudinal
cardiac muscle structure
cells are shorter rectangles can ben ranched can be binucleate (or multinucleate) tissue is striated, highly organized and powerful connected by gap junctions
where is cardiac muscle found
only in heart
gap junctions in cardiac muscle
contained in intercalated disc
cardiac muscle function
involuntary
contracts and responds to pacemaker cells
skeletal muscle structure
long rectangles skeletal muscle fibers
multinucleate
tissue is striated
attached to bone
skeletal muscle function
under voluntary control
only contract in response to a motor neuron
very powerful but fatigue rather quickly
fascicle
a membrane band group of muscle cells
each skeletal muscle is made of many
connective tissue sheaths
each whole muscle has several layers of this
endomysium
sheath that surrounds a single muscle cell
peromysium
sheath that surrounds a fascicle
epimysium
sheath that surrounds an entire muscle
muscle attachments
tendon (strap-like dense regular)
aponeurosis (sheet-like dense irregular)
both anchor muscle to another muscle or bone
sacrolemma
plasma membrane of a muscle cell
sacroplasm
cytoplasm of a muscle cell
sacroplasm stores …
large numbers of glycosomes (stores ATP) contains myaglobin (oxygen storing nutrient)
myofibrils
rods of cytoskeleton -> proteins
contractile element of the muscle cell (cell structures that shorten)’parallel to the long axis of a muscle cells
many myofibrils in each muscle cell
sacroplasmic reticulum
modified smooth E.R.
large and branched
hold and releases calcium on demand
t tubules
deep invagination in the sacrolemma
what is the space within the t tubules
continuous with extracellular space (interstitial fluid)
myofibrils dan be divided into small regions called?
sacromeres
sacromere
composed of several distinct parts
a band
dark band in sacromere
I band
light band in sacromere
M line
at center of A band
Z disc
structure at center of the I band
H zone
lighter zone at center of a band
what is a sacromere composed of
a central A Band half an I band on each side M line is at center of a sacromere Z disc at each lateral edge smallest contractile unit of a muscle cell
myofilaments
small proteins located within each myofibril
thick fillaments
composed of myosin
extend across the A head
myosin
protein that has prominent heads
thin filaments
composed of the protein actin
extends across I band and overlaps into A band
elastic filaments
composed of titian
located in Z disc
prevent muscle from over stretching
regulatory proteins
found as part of the thin filament (part of I band)
are troponin and tropomyosin
skeletal muscle cell stimulation
a motor neuron must stimulate a skeletal muscle cell for the muscle to contract
neuromuscular junction
where a motor neuron approaches a skeletal muscle cell
steps 1 in neuromuscular junction
- a wave of electrical current called an action potential arrives at the terminus of the motor neuron
step 2 in neuromuscular junction
- the motor neuron releases neurotransmitter into synaptic cleft (acetylcholine)
step 3 in neuromuscular junction
there are specific receptors for acetylcholine on the skeletal muscle cell
step 4 in neuromuscular junction
the binding of acetylcholine opens a nonspecific cation channel
cations flow through sodium and potassium
step 5 in neuromuscular junction
flow of sodium into skeletal muscle changes voltage
skeletal muscle cell voltage
at rest it is -70mV
as sodium enters, voltage moves towards 0mV
step 6 in neuromuscular junction
an action potential is generated in the muscle cell
strong spike of current
toxemia
toxins in the blood likely from bacteria
botulism toxin
can be eaten in natural foods
it blocks acetylcholine release
botulism effects
causes paralysis limp or flacid
tatnus toxin
can get in to small wounds
toxin stimulates acetylcholine receptors
tatnus toxin effect
muscle groups contract uncontrollably and cause rigid paralysis
myasthenia gravis
autoimmune disease
what happens in myasthenia gravis
body produces and immune response against acetylcholine receptors making antibodies against them and they are destroyed
what are the effects of myasthenia gravis
cause progressive muscle weakness and paralysis
coupling
the conversion of an electrical impulse into muscle contraction
step 1 of coupling
an action potential is produced in the skeletal muscle cell (spreads across all of muscle cell and down t-tubules) allows Ca++ channels to open
step 2 of coupling
Ca++ enters skeletal muscle cell
interacts with SR and opens Ca++ channels
large increase in Sarcoplasmic Ca++
step 3 of coupling
high levels of Ca++ in the sarcoplasm binds to regulatory proteins
regulatory proteins
troponin
tropomyosin
troponin
3 subunits
I = an inhibitory subunit that binds to actin
T = subunit that binds to tropomyosin
C = subunit that binds to Ca++
tropomyosin
physically prevents myosin and actin from interacting
result of calcium
Ca++ binds to regulatory proteins, causing them to change shape
- regulatory proteins move out of the way unmasking myosin and actin
step 4 of coupling
myosin heads binds to actin and the muscle contracts
step 5 of coupling
the muscle cell stops contracting when sacroplasmic Ca++ levels decrease
transport ca++ out of cell to extracellular space
pump ca++ into the SR
na/ca exchanger allows 3 na to enter while 1 ca leaves
cross bridge formation
an energized myosin head binds to newly exposed actin
myosin head is bound to ADP
power stroke
myosin head bends back
pulls actin towards M line
-> ADP is released
cross bridge detachment
a new ATP binds to the myosin head
myosin head releases actin
energizing of myosin head
ATP is hydrolyzed to ADP
released energy is transferred to myosin head
(starting position repeats steps over and over)
result of contraction
sacromere shortens
I bands are pulled towards the M line
H zone disappears
A band does not moved (neighboring A bands are pulled closer together)
skeletal muscle subtypes
there are multiple subtypes of skeletal muscle cells based on contraction characteristics (2 important factor)
what two factors are important in subtypes of skeletal muscle for muscle cells
some skeletal muscle cells contract fast or slow
some skeletal muscle cells fatigue quickly while others do not
muscle cell metabolism
pathways muscle cells can use to produce ATP
Creatine phosphate
energy storing protein
where is creatine phosphate found
only in muscle cells
what does creatine phosphate do
directly transfers a phosphate group to an ADP to produce ATP
what do ATP and creatine phosphate stores provide
about 15 seconds worth of energy
what are the 15 seconds of energy provided by creatine phosphate for
gives enough time to start more complicated metabolism and switch to aerobic or anaerobic
aerobic metabolism
requires O2
where does aerobic metabolism take place
process occurs in mitochondria
what happens in aerobic metabolism
glucose is completely broken down to CO2
When does aerobic metabolism dominate
during light exercise when blood flow is adequate and O2 is available
anaerobic metabolism
does not require 02
energy yield is poor
only uses glycolosis (a type of fermentation)
250% faster than aerobic but much less efficient
what does anaerobic metabolism do
uses glycolisis to partially breakdown glucose to form lactic acid
lactic acid
an organic compound that causes muscle to burn (in anaerobic metabolism)
where does anaerobic metabolism take place
process occurs in the cytosol
when does anaerobic metabolism dominate
during periods of strenuous exercise
blood flow to muscles is inadequate
O2 is not available
skeletal muscle cell types
differentiating between skeletal muscle cell populations
slow oxidative fibers
use aerobic metabolism
small cell diameter (each cell is weaker)
slow to respond to stimulus
muscle cells are not easily fatigued (endurance exercise)
red oxygen0fed muscle fibers (blood fed)
fast glycolytic fibers
anaerobic metabolism
large cell diameter (each cell is stronger)
quick to respond to stimulus
easily fatigued muscle cells (for short powerful movement)
white glycogen-fed muscle fibers (not blood fed)
muscle fatifue
muscle cells are unable to contract even with proper stimulus due to lack of energy (no ATP)
What can muscle fatigue cause
contractions and cramps
rigor mortis
skeletal muscles become stiff and stuck in place after death
reason 1 for rigor mortis
skeletal muscle cells decay and leak Ca++
allows for muscle cell contractions
reason 2 for rigor mortis
with out being able to replenish ATP muscle cells lock in place because there is no cross bridge detachment
