Joints
What are the three ways to classify joints structurally? Functionally?
Structurally: fibrous, cartilaginous, synovial
Funcitonally: amphiarthrotic, diarthrotic, synarthrotic
What makes up the thin and thick filaments in the sarcomere?
Thin: actin, troponin, tropomyosin, structural proteins
Thick: myosin and titin
What activates a chemically gated channel, leak channel, voltage gated, and mechanically gated channel?
Chemical: NTs
Leak: always open (no activator)
Voltage: change in transmembrane potential
Mechanical: physical touch
What is the first step in fracture repair called?
Fracture Hematoma
What the two cartilaginous joints and list examples of each
Sychondrosis (hyaline) first rib to sternum, symphysis (fibrocartilage) intervertebral discs
What surrounds whole muscle, what surrounds fascicles, and what surrounds muscle cells?
Muscle – epimysium
Fascicle – permimysium
Myofiber - endomysium
How does calcium get into the SR?
Calcium pumps pump calcium into the SR (NOT mechanically gated channels). This is active as calcium is going against the concentration gradient
What effect does exercise have on our bones? What about gender?
Exercise increases bone density; the earlier it is introduced, the greater bone density will be. Men always have greater bone density than women (even between a woman who exercises and a man who does not)
What are the joints in the vertebrae?
Intervertebral discs –symphysis
Articular facets – gliding
SI joint – gliding
Atlantoaxial -pivot
What are three organelles specific to muscle cells?
Sarcolemma
Sarcoplasm
Sarcoplasmic reticulum
What is the next step in the process after calcium is released from the SR?
Calcium binds to troponin which moves tropomyosin off of the actin active sites
What does calcitonin do and how?
“Tones down calcium”
It inhibits osteoclast activity and increases calcium loss through waste
What is the most inferior articulation between the appendicular and axial skeleton?
SI joint
What is a triad and what is its purpose?
A triad is the combination of 2 SRs and a t-tubule (t-tubule is in the middle). The voltage gated channels on the t-tubule pull open the mechanically gated channels on the SR.
Define transmembrane potential and resting membrane potential.
Transmembrane potential is the difference in the charges across the cell membrane. Resting membrane potential is the potential across the membrane when the cell is not undergoing an AP.
What are two hormones that increase blood calcium?
Parathyroid – increases osteoclast actvity
Calcitriol – increases calcium absorption in the GI tract
What are 2 examples of a synchondrosis joint?
First rib to sternum
Epiphyseal plates
What are all the parts of a sarcomere and how do they change length during a contraction?
A band – ALL of the thick filament
I band – Just thin filament (no overlap)
H zone – just thick filament (no overlap)
M-line – middle of sarcomere
Z –disc – ends of sarcomere
H zone and I band shorten, A band stays the same
Describe the process of an action potential from the nerve to the effect calcium has on the sarcomere.
AP travels down the neuron, synaptic vesicles fuse with the nerve membrane, NTs are released into the synaptic cleft, NTs bind to receptors on the chemically gated channels. Chemically gated channels open and sodium rushes into the cell. The increase in the transmembrane potential opens the voltage gated channel. Voltage gated channels on the t-tubule pull open the mechanically gated channels on the SR. Calcium flows out of the SR and binds to troponin which moves tropomyosin so myosin can bind to actin.
What are the function of osteoclasts in fracture repair?
Break down debris made during the fracture as well as remodel lamallae from irregular lamallae into osteons