Muscle Structure
The most basic functional unit of a muscle fiber
Sarcomere
This ion binds to troponin in order to shift tropomyosin away from binding sites on actin
Ca2+
In this type of contraction, muscle does not change length and the tension produced never exceeds the load
This posterior arm muscle has three heads
Triceps brachii
This muscle originates on the subscapular fossa
Subscapularis
The two primary myofilaments present in muscle fibers
Actin and myosin
This concept explains muscle contraction by the movement of thick and thin myofilaments past one another to shorten the muscle
Sliding filament theory
Activity of this organelle is the ultimate source of energy for skeletal muscles
Mitochondria
This muscle is the most superficial in the abdominal region
External oblique
What is the primary action of the extensor digit minimi muscle
Extension of the 5th digit
Wrist and elbow extension to a lesser degree
The sheath of tissue that houses fascicles
This neurotransmitter alters membrane permeability to Na+ ions
Acetylcholine (ACh)
Concentric and eccentric contractions are both examples of this type of contraction
Isotonic contractions
This muscle originates from the spinous processes of T7-T12, thoracolumbar fascia, and dorsal ¼ of iliac crest
Latissimus dorsi
This major anterior upper arm muscle has no attachments on the humerus
Biceps brachii
Originates on the scapula (both heads) and inserts on the radius
Troponin and Tropomyosin
Which enzyme leads to the closure of the ACh-receptor membrane channels
Acetylcholinesterase
Excess pyruvate production from glycolysis during high intensity exercise is converted which molecule
Lactate
These three muscles in the gluteal region are collectively known as the triceps coxae
Superior gemellus, obturator internus, inferior gemellus
This muscle is considered the "landmark" of the gluteal region
Piriformis m.
The BLANK of a muscle fiber carries an uneven charge distribution. Reversal of this charge is an element of the initial steps of muscular contraction.
The sarcolemma
What are the three components of a Neuromuscular Junction (NMJ)
Axon terminal of a motor neuron, a motor end plate, and a synaptic cleft,
The amount of oxygen required to restore typical resting conditions in muscle cells following exercise is known as what?
Oxygen debt or excess post exercise oxygen consumption (EPOC)
The primary actions of these two paired posterior axio-appendicular muscles are:
Scapular retraction and downward rotation of the glenoid fossa
Rhomboids major and minor
What are the four muscles that are collectively known as the rotator cuff
Supraspinatus m.
Infraspinatus m.
Teres minor m.
Subscapularis m.