Muscle Types & Functions
What type of muscle is voluntary and striated?
Skeletal muscle
What is the name of the connective tissue that surrounds individual muscle fibers?
Endomysium
What neurotransmitter triggers calcium release at the neuromuscular junction?
Acetylcholine (ACh)
Which division of the nervous system controls voluntary movement?
Somatic nervous system
During elbow flexion, which muscle is the agonist?
Biceps brachii
What type of muscle is ONLY found in the heart?
Cardiac muscle
What structure stores and releases calcium ions in muscle cells?
Sarcoplasmic Reticulum
Which ion binds to troponin to begin the contraction process?
Calcium (Ca²⁺)
Name the sensory receptor that detects muscle length.
Muscle spindles
During knee extension, which muscle group is the antagonist?
Hamstrings
What are the three main functions of muscle tissue? (Name 2 of the 3)
Movement, heat production, support (any two)
This is the smallest functional contractile unit of a muscle.
Sarcomere
During the powerstroke, ATP is broken down into what two components?
ADP + Pi
What type of reflex is automatic, fast, and processed in the spinal cord?
Spinal reflex
Which muscle is the primary agonist during plantar flexion?
Gastrocnemius (or gastrocnemius + soleus)
This type of contraction occurs when muscle length does NOT change, such as holding a plank.
Isometric contraction
Which sarcomere band contains ONLY actin?
I-band
What must bind to myosin in order to detach it from actin?
ATP
Which proprioceptor prevents injury by causing a muscle to relax when tension becomes too high?
Golgi Tendon Organ (GTO)
During a squat, which phase do the quadriceps act concentrically?
Rising phase (standing up)
Name the type of muscle found in hollow organs that contracts slowly but can sustain long contractions.
Smooth muscle
What two proteins form the cross-bridge required for muscle contraction?
Actin + myosin
List the FOUR major steps of the sliding filament process in correct order.
ACh released → Ca²⁺ released
Ca²⁺ binds troponin → tropomyosin shifts
Cross-bridges form → powerstroke
ATP binds → myosin detaches and resets
Name the correct order of the 5 components of a reflex arc.
Receptor → sensory neuron → interneuron → motor neuron → effector
Name an agonist–antagonist pair AND describe the specific movement they produce/counteract.
Agonist: Quadriceps (knee extension)
Antagonist: Hamstrings (knee flexion)