The Muscular System Flashcards
The three muscle tissues types
Skeletal, smooth, cardiac
Skeletal Muscle
Voluntary control, striated appearance.
Attached to bones and is responsible for voluntary movements.
Cardiac Muscle
Involuntary control, striated but with intercalated discs.
Found in the heart, responsible for pumping blood.
Smooth Muscle
Involuntary control, non-striated.
Found in walls of organs and vessels, responsible for involuntary movements like digestion.
Sarcomere
the fundamental unit of muscle that’s responsible for contraction.
Z-discs
Boundary of the sarcomere; anchor thin filaments.
I band
Region with only thin filaments; shortens during contraction.
A band
Region containing the entire length of thick filaments; remains unchanged during contraction.
H zone
Central region of A band with only thick filaments; shortens during contraction.
M line
Middle of the sarcomere; stabilizes thick filaments
Thin Filaments
made of actin
Actin
Actin is the protein that forms the thin filaments and provides the binding sites for myosin during muscle contraction.
Tropomyosin
Tropomyosin is a protein that covers actin’s myosin-binding sites, preventing contraction until activated.
Troponin
Troponin is a protein that binds calcium ions, causing tropomyosin to move and expose actin’s binding sites for myosin.
Thick filaments
Made of myosin
Myosin
Structured with a head, neck and tail. Binds to actin and uses ATP to pull actin filaments toward the center of the sarcomere and contract the muscle
ATP
adenosine triphosphate; energy!!!!!
CA2++
calcium
Role of calcium
binds to troponin, allowing myosin to bind actin and begin the contraction process
Neuromuscular Junction (NMJ)
a specialized synapse (a structure that allows a neuron to pass a signal to another neuron) that allows the nervous system to transmit electrical impulses to muscles, causing them to contract
Lever
a rigid bar that rotates around a fixed point (the fulcrum).
Levers in the body
the bones act as levers, the joints serve as fulcrums, and muscles provide the force to move the bones.
3 types of levers in the body
first class, second class, third class
First-class lever
Fulcrum in the middle (e.g., neck movement).
Second-class lever
Resistance in the middle (e.g., standing on tiptoes).
Third-class lever
Effort in the middle (e.g., bending the arm).
Origin Point
The attachment site of the muscle on the bone that remains still during contraction.
Example: The biceps brachii muscle originates at the scapula.
Insertion Point
The point where the muscle attaches to the bone that moves during contraction.
Example: The insertion of the biceps is at the radius.
Action
The specific movement that the muscle causes when it contracts.
Example: The action of the biceps is flexion of the elbow joint.
Prime Mover (Agonist)
The muscle primarily responsible for a specific movement.
Example: The biceps brachii is the prime mover during elbow flexion.
Synergist
Muscles that assist the prime mover in creating a movement.
Example: The brachialis muscle assists the biceps in elbow flexion.
Antagonist
The muscle that opposes the action of the prime mover, producing the opposite movement.
Ab-
Away from
Ad-
To or towards
6 Criteria for naming muscles
- Shape
- Size
- Fiber direction
- Location
- Number of origins
- Action
Lateralis
Lateral, or away from midline
Medialis
Center or towards midline
Maximus or Major
Largest
Medius
Medium
Minimus or minor
Small or smallest
Brevis
Short
Longus
Long
Rectus
Straight
Bi-
Two
Tri-
Three
Flexor
Decrease angle at the joint
Extensor
Increases angle at the joint
