Exam 3 Flashcards
articulation
where two bones meet
synarthroses joint
immovable joints
ampiarthrises joints
slightly moveable joints
Diarthroses joint
freely moveable joint
fibrous joints
no joint cavity, joins by fibrous tissue
Sutures fibrous joint
“seams” only between bones of skull
syndesmoses fibrous joint
bones connected by a ligament
ex.distal ends of tibia and fibula
gomphoses fibrous joint
“peg in socket”
no movement
ex.teeth
cartilaginous joint
articulating bones connected by cartilage
synchondroses cartilaginous joint
all immovable (synarthrosis)
symphysis cartilaginous joint
articular surfaces of bones are covered with hyaline cartilage which is fused to fibrocartilage
limited movement
synovial joint
do have cavity
monaxial
biaxial
triaxial
synovial joint -articular cartilage
glassy smooth (hyaline) covers opposing bones surfaces
keeps ends of bones from being crushed
synovial joint-articular capsule
2 layered capsule that encloses the joint cavity
external layer(FIBROUS CAPSULE) dense irregular connective tissue -strengthens joint so bones aren’t pulled apart
inner layer (SYNOVIAL MEMBRANE)-covers all internal joint surfaces that aren’t hyaline cartilage
synovial joint-Joint Synovial Cavity
potential space, contains small amount of synovial fluid
synovial joint-synovial fluid
slippery fluid occupies all free spaces within joint capsule
provides weight bearing film that reduces friction
has phagocytes cells that eat debris
synovial joint _reinforcing ligaments
band like ligaments connecting bone to bone
Bursa
“purse”
flattened fibrous sacs lined with synovial membrane containing a thin film of synovial fluid
articular surfaces
determine what movements possible
play minor role in stability
ball and socket
ligaments
the more ligaments, the more stable
muscle tone
tendons (muscles) coming across the joint provide most stability
gliding joint
slight non-axial or multi-axial
ex.acromioclavicular
hinge joint(door)
monaxial
ex.elbow
pivot joint
rotation
monaxial
ex.radio-ulnar joint
condylar joint
biaxial
ex.metacarpals
saddle joint
biaxial
allows for apposition
ball and socket joint
triaxial
ex.hip joint
largest degree of movement
origin
attachment to less moveable bone
insertion
attachment to moveable bone
when does movement occur
when a muscle contracts across joint and insertion moves towards origin
lever
bone
fulcrum
joint
applied force to make lever move
effort
first class lever
has fulcrum in middle between effort and resistance
ex.back of neck
second class lever
resistance between fulcrum and effort
ex.jaw and chin
third class lever
effort between the resistance and the fulcrum
ex.most joints
circumduction
circular motion
rotation
c1 c2
sprains
ligaments are stretched or torn
strains
muscle/tendon are stretched or torn
cartilage injuries
tearing knee menisci
luxation
total dislocation
subluxation
partial dislocation
bursitis
inflammation of bursa
tendinitis
inflammation of tendon
arthritis
inflammatory diseases that damages joints
muscle fiber
myofiber, myocyle
few cm in lengths
lots of nuclei
cytoplasm has contractile proteins called myofibril
cytoplasm of muscle
sacroplasm
cell membrane of muscle
sarcolemma
transverse tubules
sarcolemme has tunnel like unfolding
carry electric current to cell
muscle sarcoplasmic reticulum
store calcium
around myofibril
endomysium
around single muscle fiber
contains myosatallite cells that repair damage
perimysium
around a fascicle
contains blood vessels and nerve supply
epimysium
surrounds fascicles
separates muscle from surrounding tissues
aponeuroses
broad sheet-like structure , not chord like
myofibril
bundles of myofilaments, contain contractile proteins
thick filaments (myosin)
thin filaments (actin)
study organization of sarcomere
A band
produced from overlapping thick and thin filaments
M line
center of A band
H band
on either side of M line, no thin filaments
zone of overlap
contains thick and thin filaments on either side of H band
I band
contains thin filaments only
Z lines
mark boundary
interconnect thin filaments
titian
elastic protein that connects the thick filaments to the Z line , brings it bzck
thick filament (myosin)
shaped like golf club, but with two heads
heads stick out to form cross bridge
thin filament ACTIN
interacts with proteins tropomyosin and troop in
sliding filament theory
shortening of sarcomere
when muscle contracts, it gets smaller
filaments don’t change in length , they overlap
nerve muscle relationships
skeletal muscle must be stimulated by a nerve
somatic motor fibers (terminal end branches supply one muscle fiber
motor unit
each motor neuron and all the muscle fibers it integrates
fine control
small motor units contain as few as 20 muscle fibers per nerve fiber
ex.eye muscles
strength control
gastrocnemius muscle has 1000 fibers per never fiber
Neuromuscular junctions (synapse)
Functional connection between nerve fiber and muscle cell
•Neurotransmitter (acetylcholine/ACh) released from nerve fiber stimulates muscle cell
•Components of synapse (NMJ):
•Synaptic knob is swollen end of nerve fiber (contains ACh)
•Junctional folds region of sarcolemma
•increases surface area for ACh receptors
•contains acetylcholinesterase that breaks down ACh and causes relaxation
•Synaptic cleft = tiny gap between nerve and muscle cells
Electrically Excitable Cells
plasma membrane is polarized or charged
stimulation opens ion gates in membrane
excitation
nerve action potentials lead to action potentials in muscle fiber (create action potential)
excitation-contraction coupling
action potentials on the sarcolemma activate myofilaments
contraction
shortening of muscle fiber
relaxation
return to resting lemgth
Excitation steps 1 and 2
Nerve signal opens voltage-gated calcium channels. Calcium stimulates exocytosis of synaptic vesicles containing ACh = ACh release into synaptic cleft.
excitation steps 3 and 4
Binding of ACh to NICOTONIC ACh receptor proteins opens Na+ and K+ channels resulting in jump in RMP from -90mV to +30 mV forming an end-plate potential (EPP)
excitation step 5
Voltage change in end-plate region (EPP) opens nearby voltage-gated channels producing an action potential
excitation-contraction coupling (steps 6 and 7)
Action potential spreading over sarcolemma enters T tubules – voltage-gated channels open in T tubules causing calcium gates to open in SR
Excitation-Contraction Coupling (steps 8 and 9)
Calcium released by SR binds to troponin
•Troponin-tropomyosin complex changes shape and exposes active sites on actin
Relaxation (steps 14 and 15)
Nerve stimulation ceases and acetylcholinesterase removes ACh from receptors. Stimulation of the muscle cell ceases.
Relaxation (step 16)
Active transport needed to pump calcium back into SR
•ATP is needed for muscle relaxation as well as muscle contraction
Relaxation (steps 17 and 18)
Loss of calcium from sarcoplasm moves troponin-tropomyosin complex over active sites
•stops the production or maintenance of tension
•Muscle fiber returns to its resting length due to recoil of series-elastic components and contraction of antagonistic muscles
Pesticides (cholinesterase inhibitors)
•bind to acetylcholinesterase and prevent it from degrading ACh
•spastic paralysis and possible suffocation
Flaccid paralysis is caused by
toxin of Clostridium (botulinum) bacteria
Flaccid paralysis (limp muscles) due to
due to curare that competes with ACh
•respiratory arrest
Myasthenia Gravis
Autoimmune disease - antibodies attack NMJ and bind ACh receptors in clusters
•receptors removed
•less and less sensitive to ACh
•drooping eyelids and double vision, difficulty swallowing, weakness of the limbs, respiratory failure
•Disease of women between 20 and 40
•Treated with cholinesterase inhibitors, thymus removal, or immunosuppressive agents
Rigor Mortis
Muscles begin to stiffen 3 to 4 hours after death
•Occurs because dying cells have a massive release of ? from the SR which promotes myosin cross bridge binding
•Dead = no more ATP.
•Rigor mortis disappears as muscle proteins break down several hours after death (48 to 60 hours)
M uscle Tension
When sarcomeres contract, they shorten which shortens the muscle fiber
•Muscle fiber shortening causes tension on the connective tissue attached to muscle (tendons).
•The tension produced can vary…
Length-Tension Relationship
Amount of tension generated depends on length of muscle before it was stimulated
•length-tension relationship (see graph next slide)
•Overly contracted (weak contraction results)
•thick filaments too close to Z discs and can’t slide
•Too stretched (weak contraction results)
•little overlap of thin and thick does not allow for very many cross bridges too form
•Optimum resting length produces greatest force when muscle contracts
•central nervous system maintains optimal length producing muscle tone or partial contraction
Recruitment and Stimulus Intensity
Stimulating the whole nerve with higher and higher voltage produces stronger contractions
•More motor units are being recruited
•called multiple motor unit summation
•lift a glass of milk versus a whole gallon of milk
3 Phases of Twitch
Latent period before contraction:
–the action potential moves through sarcolemma
–causing Ca2+ release
2.Contraction phase:
–calcium ions bind
–tension builds to peak
3.Relaxation phase:
–Ca2+ levels fall
–active sites are covered
–tension falls to resting levels
Unfused (incomplete) tetanus
Some relaxation occurs between contractions
·Sustained, fluttering contractions of motor units
·The results are summed into a smooth contraction
·Fused (complete) tetanus
No evidence of relaxation before the following contractions
·The result is an intense, sustained muscle contraction
·Calcium is never reclaimed by the SR
Isometric muscle contraction
develops tension without changing length
•important in postural muscle function and antagonistic muscle joint stabilization
Isotonic muscle contraction
Same tension while shortening = concentric
•Same tension while lengthening = eccentric
anaerobic fermentation
ATP production limited)
•without oxygen, produces lactic acid
aerobic respiration
more ATP produced)
•requires continuous oxygen supply, produces H2O and CO2
Phosphagen system- IMMEDIATE ENEGRRY
myokinase transfers Pi groups
from one ADP to another forming ATP
•creatine kinase transfers Pi groups from creatine phosphate to make ATP
•Result is power enough for 1 minute brisk walk or 6 seconds of sprinting
Glycogen-lactic acid system takes over- SHORT TERM ENERGY
no oxygen
Glycogen-lactic acid system takes over
• produces ATP for 30-40 seconds of maximum activity
•playing basketball or running around baseball diamonds
•muscles obtain glucose from blood and stored glycogen
Long-Term Energy Needs
•Aerobic respiration needed for prolonged exercise
Produces 36 ATPs/glucose molecule
•After 40 seconds of exercise, respiratory and cardiovascular systems must deliver enough oxygen for aerobic respiration
•oxygen consumption rate increases for first 3-4 minutes and then levels off to a steady state
•Limits are set by depletion of glycogen and blood glucose, loss of fluid and electrolytes
Oxygen Debt
Heavy breathing after strenuous exercise
Purposes for extra oxygen
•replace oxygen reserves (myoglobin, blood hemoglobin, in air in the lungs and dissolved in plasma)
•replenishing the phosphagen system
•reconverting lactic acid to glucose (oxidation) in kidneys and liver
•serving the elevated
metabolic rate that occurs as
long as the body temperature
remains elevated by exercise
Slow- Twitch Fibers
Slow oxidative fibers
•Smaller diamter, MORE MITOCHONDRIA, myoglobin and capillaries
•adapted for aerobic respiration and resistant to fatigue
•Slow to contract
•soleus and postural muscles of the back
Fast-Twitch Fibers
Have large diameter, large glycogen reserves, FEW MITOCHONDRIA
•Fast glycolytic, fast-twitch fibers
•rich in enzymes for phosphagen and glycogen-lactic acid systems
•sarcoplasmic reticulum releases calcium quickly so contractions are quicker
•extraocular eye muscles,
gastrocnemius and biceps brachii
•Fatigue quickly
Muscles and Fiber Types
White muscle:
–mostly fast fibers
–pale (e.g., chicken breast)
•Chickens fly in bursts
•Red muscle:
–mostly slow fibers
–dark (e.g., chicken legs)
•Chickens walk a lot
•Most human muscles:
–mixed fibers
–pink
Study Cardiac Muslce page 62
Major Organelles of the Cell Body of Neuron
Large nucleus and nucleolus
•Cytoplasm (perikaryon - around the nucleus)
•Mitochondria – What does this do?
•Nissl Bodies - RER and ribosomes (produce neurotransmitters)
•Cytoskeleton
The Cytoskeleton of neuron
Neurofilaments and neurotubules:
•in place of microfilaments and microtubules
•Neurofibrils:
•bundles of neurofilaments
•support dendrites and axon
Dendrites in Neuron
Highly branched
•Dendritic spines:
•many fine processes
•receive information from other neurons
•80–90% of neuron surface area
Axon in neuron
Only one per neuron
•Carries electrical signal (action potential) to target
•Axon structure is critical to function (much more to come!)
Structures of the Axon in neuron
Axoplasm:
•cytoplasm of axon
•What was the cytoplasm around the nucleus called?
•Perikaryon
•contains neurotubules, neurofibrils, enzymes, organelles
•Axolemma:
•specialized cell membrane
•covers the axoplasm
Structures of the Axon p 2
Axon hillock:
•thick section of cell body
•attaches to initial segment
•Initial segment:
•attaches to axon hillock
Collaterals:
•branches of a single axon
•Telodendria:
•fine extensions of distal axon
•Synaptic terminals:
•tips of axon
Myelin Sheath Of The Axon
Whitish, fatty protein layer (20% protein and 80 % lipid)
•Serves to protect and electrically insulate axon
•Increases the speed of transmission of nerve impulses (up to 150 times faster)
•Only associated with axons, not dendrites
•All myelination completed by late adolescence
CNS- Consists of the Brain AND spinal cord
Functions to integrate, process and coordinate sensory data and motor commands
PNS- Includes neural tissue outside the CNS
Delivers sensory information to the CNS
•Carries motor information from CNS to peripheral tissues and systems
CNS Support Cells (Neuroglia)
·Astrocytes
Abundant, Star-shaped Cells - Form Framework Of CNS
·Contribute To BBB And Regulate Composition Of Brain Tissue Fluid
·Convert Glucose To Lactate To Feed Neurons
·Secrete Nerve Growth Factor Promoting Synapse Formation
·Sclerosis – Damaged Neurons Replace By Hardened Mass Of Astrocytes
CNS Support Cells (Neuroglia)
Microglia
Spider-like phagocytes
·Dispose of debris in areas of infection, trauma or stroke
CNS Support Cells (Neuroglia)
Ependymal cells
Have cilia
·Line cavities of the
brain and spinal cord
·Produce AND circulate
cerebrospinal fluid (CSF)
CNS Support Cells (Neuroglia)
Oligdendrocytes
Produce myelin sheath around nerve fibers in the central nervous system (more on this soon!)
Multiple Sclerosis
Autoimmune
•Oligodendrocytes and myelin sheaths of CNS degenerate
•Replaced by hardened scar tissue
•Between 20-40 years old
•Double vision, blindness, speech defects, neurosis, tremors, numbness
•Variable cycles until bedridden
•No Cure
How Does The Message Get Passed Along?
Information from one neuron flows to another neuron across a synapse…
•a small gap separating neurons that consists of:
•a presynaptic ending that contains neurotransmitters, mitochondria & other organelles
•a postsynaptic ending that contains receptor sites for neurotransmitters
•a synaptic cleft or space between the presynaptic & postsynaptic endings.
Getting the message across(the synapse)
AP signal arrives at the axon terminal
•This causes VOLTAGE GATED Ca2+ channel to open
•Ca2+ diffuses into neuron
•Causes NT vesicles to move to end & fuse with cell membrane
•Through exocytosis, NTs are released into synapse
•NTs diffuse across synapse & bind to NT receptors on another neuron
•Causes LIGAND GATED Na+ channels to open & AP is initiated in next neuron
Types Of Receptors - Ionotropic
Also called a ligand – gated receptor
•They open or close a channel that lets small particles (ions) in.
•No second messenger is involved= Direct effect
Types Of Receptors – Metabotropic 2 Types
Direct coupling- slow process
•Think meta = middle man
Types Of Receptors – Metabotropic 2 Types
. Second messenger system = even slower
What is cAMP and what does it do?
Cyclic AMP is a secondary messenger derived from ATP.
It can open cell membrane channels & can activate enzymes
One example, is by epinephrine binding to the beta-adrenergic receptor (more on this soon), activation of PKA to cause the stimulation of glycogen breakdown.
2 Classes Of Neurotransmitters
Excitatory neurotransmitters:
•cause depolarization of postsynaptic membranes
•promote action potentials
2.Inhibitory neurotransmitters:
•cause hyperpolarization (goes in opposite direction of depolarization) of postsynaptic membranes
•suppress action potentials
