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HUMAN PHYS EXAM THREE
Questions and Answers (100%
Correct Answers) Already Graded A+
sliding filament theory Ans: overlapping, thick/thin filaments
in each sarcomere slide past each other without changing
© 2026 Assignment
length, propelled by cross-bridge movements
sarcomere Ans: Contractile unit of muscle composed of actin
Guru01 - Stuvia
and myosin
Expert
skeletal muscle Ans: striated and voluntary muscle that is
connected to the skeleton to form part of the mechanical
system that moves the limbs and other parts of the body
smooth muscle Ans: involuntary muscle tissue in which the
contractile fibrils are not highly ordered, occurring in the gut
and other internal organs
cardiac muscle Ans: Involuntary striated muscle tissue found
in the heart
motor neuron Ans: a neuron that sends an impulse to a muscle
or gland, causing the muscle fiber or gland to contract
myosin Ans: contractile protein that makes up thick filaments
of muscle fibers; has ATP and actin binding site on globular
head
actin Ans: A globular protein that links into 2 thin chains
twisted forming microfilaments in muscle and other
, 2
contractile elements in cells; includes troponin and
tropomyosin
excitation-contraction coupling Ans: process that links
electrical signals from nervous system to mechanical
contraction of skeletal muscles; action potential generated
from somatic (voluntary) system, depolarizes muscle fiber -
voltage gated calcium channel (DHPR) detects potential change
- DPHR transmits signal to ryanodine receptor and releases
calcium ions from sarcoplasmic - calcium ions activate
contraction
© 2026 Assignment
skeletal muscle excitation-contraction coupling Ans: 1. AP
Guru01 - Stuvia
travels down cleft and release ACh released on motor endings,
Expert
crosses synaptic cleft, binds to nicotinic ACh receptors (motor
end plate)
2. AP travels down T-tubule (tranverse), L-type calcium
releases into in sarcoplasmic reticulum
3. AP opens voltage gated sodium channels, calcium channels
in reticulum releases into cytoplasm, releasing into sarcomere
4. Calcium binds to troponin on actin, moving tropomyosin
out of way so actin and myosin bind - continues to cross
bridge cycle
5. power stroke: head bends and pulls actin over myosin and
positions it towards sarcomere center, ADP + P released -
muscle contraction
6. new ATP molecule binds to myosin head, detaches from
actin, new ATP split into ADP + P, bends back to OG shape to
bind with more actin and repeat cycle
HUMAN PHYS EXAM THREE
Questions and Answers (100%
Correct Answers) Already Graded A+
sliding filament theory Ans: overlapping, thick/thin filaments
in each sarcomere slide past each other without changing
© 2026 Assignment
length, propelled by cross-bridge movements
sarcomere Ans: Contractile unit of muscle composed of actin
Guru01 - Stuvia
and myosin
Expert
skeletal muscle Ans: striated and voluntary muscle that is
connected to the skeleton to form part of the mechanical
system that moves the limbs and other parts of the body
smooth muscle Ans: involuntary muscle tissue in which the
contractile fibrils are not highly ordered, occurring in the gut
and other internal organs
cardiac muscle Ans: Involuntary striated muscle tissue found
in the heart
motor neuron Ans: a neuron that sends an impulse to a muscle
or gland, causing the muscle fiber or gland to contract
myosin Ans: contractile protein that makes up thick filaments
of muscle fibers; has ATP and actin binding site on globular
head
actin Ans: A globular protein that links into 2 thin chains
twisted forming microfilaments in muscle and other
, 2
contractile elements in cells; includes troponin and
tropomyosin
excitation-contraction coupling Ans: process that links
electrical signals from nervous system to mechanical
contraction of skeletal muscles; action potential generated
from somatic (voluntary) system, depolarizes muscle fiber -
voltage gated calcium channel (DHPR) detects potential change
- DPHR transmits signal to ryanodine receptor and releases
calcium ions from sarcoplasmic - calcium ions activate
contraction
© 2026 Assignment
skeletal muscle excitation-contraction coupling Ans: 1. AP
Guru01 - Stuvia
travels down cleft and release ACh released on motor endings,
Expert
crosses synaptic cleft, binds to nicotinic ACh receptors (motor
end plate)
2. AP travels down T-tubule (tranverse), L-type calcium
releases into in sarcoplasmic reticulum
3. AP opens voltage gated sodium channels, calcium channels
in reticulum releases into cytoplasm, releasing into sarcomere
4. Calcium binds to troponin on actin, moving tropomyosin
out of way so actin and myosin bind - continues to cross
bridge cycle
5. power stroke: head bends and pulls actin over myosin and
positions it towards sarcomere center, ADP + P released -
muscle contraction
6. new ATP molecule binds to myosin head, detaches from
actin, new ATP split into ADP + P, bends back to OG shape to
bind with more actin and repeat cycle
