Anatomy Exam 3 Flashcards
Synarthrosis
Immovable e.g skull sutures
Diarthrosis
Freely Moveable (elbow)
Amphiarthrosis
Partially Moveable (Pubic Symphysis)
Fibrous Joints: Collagenous
a) sutures- short fibers
b) syndesmosis- long fibers
c) gomphosis- periodontal ligaments anchor the tooth to the jaw
Cartilaginous Joints
a) synchondrosis-hyaline cartilage- Rib 1 to manubrium
b)symphysis- fibrocartillage
(pubic symphysis)
Synovial (Capsular Joints)
Generally: freely moveable joints of the appendicular skeleton
a) parts of one joint
-articular capsule
-fibrous capsule of dense C.T.
-synovial membrane- secretes joint fluid
-articular cartilage
-ligaments (bone-bone)
-tendons (muscle to bone)
-bursae +tendon sheaths with synovial fluid
Types of synovial joints
-Hinge
-Pivot
-Condylar
-Ball+Socket
Hinge Joint
Synovial
-ulna to humerus
-uniaxial
Pivot Joint
Synovial
-proximal ulna- radius joint
-uniaxial
Condylar Joint
Synovial
-metacarpophalangeal joint
-biaxial
Ball+ Socket Joint
Synovial
-shoulder
-multiaxial
Angular- movement
Flexion v.s. Extention
decreases joint angle- flexion
increases joint angle extension
Angular movement
circumduction
making a cone with the limb
Angular movement
Abduction vs Adductuion
abduction- moving away from the midline
adduction- moving towards midline
rotation
medial or lateral rotation
gliding movement
short bones sliding past each other
special movement
opposition of thumb
touching thumbs to tips of other fingers
special movement
pronation vs supination
pronation- radius crosses ulna
supination- forearm bones become parallel
special movement
dorsiflexion vs plantarflexion
dorsiflexion- lift foot up at ankle (flex foot)
plantarflexion- point foot down, stand on toes (point foot)
special movement
inversion vs eversion
inversion- face sole of the foot medially
eversion- face sole of the foot laterally
special movement
retraction vs protraction
retraction- pull back
protraction- Just forward
Shoulder Joint
diarthrotic, synovial, ball+ socket joint
-most freely moveable joint in the body
–head of the humerus in the glenoid of the scapula
hip joint
diarthrotic, synovial, ball+socket
-femoral head into acetabulum
shoulder joint stabilized by
-stabilizes
–glenoid labrum- fibrocartillage
–capsular ligament- e.g. corahumeral ligaments
–biceps brachii tendon
–rotator cuff tendons from supraspinatois m. infraspinatus m. subscapularis m. teres minor m.
hip joint stabilized by
-acetabular labrum
-ligaments
–iliofemoral, pubofemoral, ischiofemoral
-ligamentum teres
Knee joint
diarthrotic, synovial, hinge
-femoral condyles, tibial condyles
-menisci- fibrocartilage pads on tibial condyles
-patellar facets meet femur’s patellar surface
knee ligaments
ACL: Anterior cruciate ligament
PCL: posterior cruciate ligament
LCL: Lateral collateral ligament to fibula
MCL: Medial collateral ligament to tibia
-Patellar ligaments
Types of muscle tissue
Skeletal muscle
Smooth Muscle
Cardiac muscle
Skeletal muscle
striated, multinucleate, voluntary
Cardiac muscle
Intercalated discs, striated, invountentary, uninucleate
smooth muscle
unstriated, uninucleate, involuntary
Active functional characteristics of muscles
Excitability and Contractility
Excitability
Has impulses (ACTIVE)
Contractility
Actively generates force and shortens (ACTIVE)
Passive functional characteristics of muscles
Extensibility and elasticity
Extensibility
Can be stretched (PASSIVE)
Elasticity
passive recoil to rest length after stretch (PASSIVE)
Muscle Functions
-Movement
–of limbs
–of material in hollow organs
-Posture
-Generate Heats
Connective Tissue Wrappings
Fascia, endomysium, perimysium, epimysium
Endomysium
wraps one cell (fiber)
perimysium
wraps one fascicle
epimysium
wraps one muscle
fascia
around multiple muscles
Attachments
Origins vs insertions
origins- proximal anchor to bone
insertions- distal connection to more moveable bone
Attachments made by
tendons, aponeurosis, direct, fleshy attachments
tendons
rope of dense regular C.T.
aponeurosis
Sheet of C.T.
direct, fleshy attachment
epimysium fuses to periosteum
fascicle
bundles of fibers
fiber=cell has
many nuclei and many mitochondria
sarcolemma
cell membranes
T-tubules
-tunnel from the membrane into deeper parts of the cells
-conduct impulses to the middle of cell
sarcoplasmic reticulum (SR)
smooth ER, houses CA++
myofibrils= big organelles
-make up most of muscle cells
-contain muscle filaments w contractile proteins
thick filaments
-each filament has about 200 myosin molecules
–each myosin has 2 heads and 1 tai;
-heads break down ATP and attach to and pull on actin for contraction
thin filaments
-2 strands of actin
–actin has sockets for myosin heads
-2 ribbons of tropomyosin block actin sockets in a relaxed muscle
-troponin acts as a lock+hinge
-Ca++ is key to start contraction: if binds to troponin, then tropomyosin pulls off actin so myosin binds
Parts of sarcomeres
A-band
I-band
Z-disc
A-band
-dArk stripe of striation
-thick filaments present
-The m line is in the middle: if not contracted, an H-zone straddles M-line
I-Band
light stripe of striation
-no thick filaments
-Z-disk is middle of I-band
Z-disk
Sarcomere- one Z to next Z
The sliding filament model
when muscles contract- sarcomeres shorten as thin filaments slide toward center of the sarcomere
The neuromuscular junction (NMJ)
-synapse where motor neuron meets muscle fiber
–neurons axon terminal meets the fibers end plate
–terminal has vesicles of acetylcholine (Ach); endplate has Ach receptions
A nerve impulse (Nerve action potential) causes
a) volt gated Ca++ channels to open , Ca++ diffuses into neuron
b) exocytosis: Ach released
c) Ach diffuses across cleft
End-Plate Potential (EPP)
a) Ach binds to Ach receptor (AchR) and opens the receptor Na+ channel
b) Na+ entry into the muscle cell= depolarization– cell is less negative that’s the EPP
[Ach Esterase splits Ach to clear the junction so relaxation can eventually happen]
Action Potential (muscle action potential)
-long distance message between sarcolemma and down T-tubules
-involves volt-gated channel for Na+,K+,
-Lasts around 2 msec then quickly reset
Excitation- Contraction Coupling
mAP->Ca++ Release from SR-> sliding filament
The crucial role of Ca++ In excitation-Reaction coupling
-mAP triggers Ca++ channel opening in SR membrane- Ca++ diffuses out of SR and into myofibril
-Some Ca++ binds to troponin
-Troponin pulls tropomyosin blockade off of actin
[Ca++ pumps out of SR starts pulling some Ca++ back into SR]
The cross-bridge cycle of excitation-reaction coupling
i) attachment- myosin head to actin
ii) power stroke- myosin pulls actin to sarcomeres center
iii) detachment- ATP attaches to the myosin head and myosin releases actin
iv) cocking of myosin- ATP split- head moves to high energy position
A motor unit consists of
One motor neuron+ all fibers it innervates (1 neuron controls 5 to 500 fibers)
Motor unit size depends on
How many fibers (5-500)
-muscles with fine control (finger muscles) have small motor neurons
-Muscles with high force outputs (quads) have very large motor neurons
-
The muscle twitch is
response of a muscle to a shock
a) latent: no F change but excitation and Ca++ movement
b) contraction- cross-bridge cycling
c) relaxation: tropomyosin blockade resumes; muscle returns to rest position
Graded muscle responses
wave summation= rate of firing
-multiple stimuli occur in rapid succession
-one twitch builds on last
-when frequency is high a contraction results=tetanus
Graded muscle responses
multiple motor unit summation= recruitment of units
-activate several units simultaneously to generate large forces
-occurs in size order: first just small units (w small fibers) , then small+ large
isotonic vs isometric contractions
-isotonic= “same tension” throughout the movement
–concentric- muscle shortens
–eccentric- muscle lengthens as it contracts
-isometric- no movement
–force generated without length change
isometric contractions
-isometric- no movement
–force generated without length change
isotonic contractions
-isotonic= “same tension” throughout the movement
–concentric- muscle shortens
–eccentric- muscle lengthens as it contracts
How much stored ATP does a muscle have
6 sec worth
ATP replenished by
creatine phosphate
(10-15 sec)
CP+ADP—–(creatine kinase)—>ATP+ creatine
ATP replenished by
glycolysis
-1 glucose –> 2 pyruvates
–makes 2 ATP
–provides 30-60 sec of energy
-occurs in the cytosol; no o2 needed
ATP replenished by
aerobic respiration
-requires o2
-pyruvates reacts with o2 in mitochondria to yield ATP
-can be used for hours
Fatigue
-decreased output due to activity
-“command fatigue” can be neutral
-muscle fatigue can be due to high K+ in T-tubules interfering with excitation-contraction coupling
oxygen debt is
-extra o2 needed to replenish o2 and energy stores n body after strenuous excersise
Force of muscle contraction:
number of muscle fibers stimulated
-recruitment
-more active fibers= greater force
Force of muscle contraction:
size of muscle fibers
fatter cells have more filaments-> more force
Force of muscle contraction:
rate of stimulation
high frequency APs-> build more force
Force of muscle contraction:
length-tension relationship
-rest length+ slightly longer are optimal- there is goof overlap between actin and myosin= more force
Force of muscle contraction:
muscle fiber types
all fibers in a motor unit are of the same type
Red muscle fibers
Speed: Slow
Metabolism: Oxidative
Capilaries+ mitochondria: A lot
Myoglobin: A lot
Glycogen: less
Typical activity: long distance jog
White muscle fibers
Speed: fast
Metabolism: glycolytic
Capilaries+ mitochondria: few
Myoglobin: few
Glycogen: lots
Typical activity: weight lifting
Pink muscle fibers
Speed: fast
Metabolism: oxidative
Capilaries+ mitochondria: Moderate
Myoglobin: Moderate
Glycogen: Moderate
Typical activity: tennis
effect of exercise on muscles
aerobic/ endurance exercise promotes
especially in red fibers
-more capillaries, myoglobin, and mitochondria
effect of exercise on muscles
resistance exercise promotes
especially in white fibers
-greater muscle fiber size, more glycogen stores
microscopic structure of smooth muscle fibers
shape and size
spindle shape
smaller than skeletal muscle
microscopic structure of smooth muscle fibers
arrangement
2 layers
-inner circular layer
-outer longitudinal layer
microscopic structure of smooth muscle fibers
neural wiring
diffuse junction where the autonomic nervous system axons have varicosities where they release neurotransmitter
microscopic structure of smooth muscle fibers
organelles and proteins within
smooth m. cells
-no t-tubules, small SR
-no troponin
-dense bodies: connect contractile filaments to the cell membrane
-contracts myosin pulling actin
mechanism and characteristics of smooth muscle contractions
synchronous
because of gab junction connections between neighbors
-activity spreads quickly
mechanism and characteristics of smooth muscle contractions
smooth m. similarities to skeletal m. contractions
myosin pulls actin
Ca++ is key
ATP is energy
mechanism and characteristics of smooth muscle contractions
smooth m. differences from skeletal m. contractions
-most Ca++ comes from out of the cell
-Ca++ activates calmodulin
-calmodulin activates kinase
-kinate phosphorylates myosin
-phosphorylated myosin pulls actin
-tends to be slow, longer duration, use less ATP
regulation of smooth m. contraction
autonomic nerve ending
can excite or inhibit the smooth m. cell
norepi excites smooth m. in skin vessels but inhibits smooth m. in airways
regulation of smooth m. contraction
hormones and local factors
-epinephrine
-PH, O2, CO2 all influence smooth m. activity
types of smooth muscle
single-unit smooth m.
most common
gap junctions present
types of smooth muscle
multiunit smooth m.
-in some places: allows finer control where units can be recruited
-has more nerve fibers than a single unit smooth m.
action of muscles
agonist
-prime mover
-e.g. triceps brachii for elbow extension
action of muscles
antagonist
-provides a breaking force/apposes action of a muscle
-e.g. biceps brachii for elbow extension
action of muscles
synergist
-cooperate in a supporting role
-e.g. deltoid fixes shoulder in movement restricted to elbow
Whats in a name?
Location
Shape
Size
Fasicle/ muscle fiber arrangement
Number of heads
Location of attachments
Action
Fascicle Arrangement
parallel
sartorius muscle
Fascicle Arrangement
Convergent
pec. major m.
Fascicle Arrangement
Pennate (feather): unipennate
extensor digitorum longus m.
Fascicle Arrangement
Pennate (feather): bipennate
rectus femoris m.
Fascicle Arrangement
Circular
Orbicularis oris m.
Fascicle Arrangement
fusiform
biceps brachii m.
muscle twitch latent phase
a) latent: no F change but excitation and Ca++ movement
muscle twitch contraction phase
b) contraction- cross-bridge cycling
muscle twitch relaxation periods
c) relaxation: tropomyosin blockade resumes; muscle returns to rest position
