Lab Exam 4

Name of a contraction unit of a muscle fiber.


Regulatory subunit that calcium ions released from the terminal cisternae binds with


Value of resting membrane potential of the sacrolemma and it's unit

-90 mV

Value of the threshold at which action potential starts and it's uint


Effect of stimulating a single motor neuron on the contraction of the entire muscle

Stimulation of a single motor unit causes weak contraction of the entire muscle

Definition of motor unit

Made up of a motor neuron and the skeletal muscle fibers innervated by that motor neurons axonal terminals

Isometric contraction

No movement in the joints. Joint is static and there's no lengthening or contracting of the muscle fibers and limbs don't move

Range of depolarization needed to trigger an action potential on a muscle membrane

(-55 to -50 mV)

Isotonic contraction versus isometric in relation to moving an object

Isotonic: any contractions in which a muscle shortens to overcome resistance.
-at least on joint moves and body movement occurs
Ex: push ups, squats, lunges and sit-ups.
Isometric: does not involve any movement. Occurs when your muscle push against a fixe

Name of Ca storage compartment in a muscle cells

Sacroplasmic membrane

Value of a muscle cell membrane potential at the point where Na gates are closed


What muscle can and cannot do

They can pull but can't push

Identify the following muscle types using their respective structural features

a. cardiac muscle: straited, involuntary, uninucleated
b. Skeletal muscle: straited, voluntary, multinucleated
c. Smooth muscle: non-straited, involuntary, uninucleated

Components of the muscle fiber triad

Sacroplasmic reticulum, sacrolemma, T-tubules

Name of the structure used in attaching

a. Muscle to bones:Tendon
b. Muscles to muscles: ligament


Study of tissue
In depth: study of the microscope structure of biological material and ways in which individuals component are structural and functionally related

Individual muscle making the following muscle groups

a. hamstrings: Biceps femoris, semitendinosus, semimembranosus
b. Quadriceps: rectus femoris, Vastus lateralis, vastus medialis, vatus intermedius
c. Mastication: temporalis, Masseter, and pterygoid muscle

Matching the following muscle names with the criteria used to name them

a. Deltoid: shape ( triangle)
b. Rhomboid: shape (diamond)
c. Rectus femoris: direction of fibers (fibers run straight) femur
d. Occipital: Bone (location); occipital bone
e. Extensor digitorum: action of muscles extends (muscle in arm)

Cells responsible of myelination of axons in the peripheral nervous system

Shawn cells (glial cells)