Muscle Functions and Types

14 Questions

What is the primary function of the Gluteus Maximus and Medius muscles?

Extension of the hip and external rotation of legs

What type of muscle is the hamstring during flexion of the knee?

Agonist

What is the term for a decrease in muscle cell diameter due to neglect?

Atrophy

What is the site of attachment that moves during a contraction?

Insertion

What is the term for a muscle that contracts during a contraction?

Agonist

What is the primary function of the Iliopsoas muscle?

Flexion of the hip

Which type of muscle tissue is responsible for creating the actions that pump blood?

Cardiac Muscles

What type of muscle contraction occurs when the load is greater than the force, resulting in muscle fibers lengthening?

Eccentric

Which muscle is responsible for flexion of the shoulder and adduction of the humerus?

Pictorialist Major

What type of muscle fibers are found in smooth muscles?

Non-striated

Which muscle is responsible for extension of the elbow and pronation of the forearm?

Triceps Brachii

What type of muscle contraction occurs when the load is equal to the force, resulting in no movement?

Isometric

Which muscle is responsible for flexion of the lumbar spine and creation of intra-abdominal pressure?

Rectus Abdominus

What type of muscle tissue is attached to bones by tendons and is controlled by nerve fibers?

Skeletal Muscles

Study Notes

Muscle Functions

Maintain posture (neck, lower back)
Enable locomotion (bony movement and body functions)
Regulate heat (muscles release heat as a by-product of reactions)

Types of Muscle Tissues

Smooth Muscles: Involuntary, located around internal organs, no striations, contract and relax slowly
Cardiac Muscles: Involuntary, found in the heart, responsible for pumping blood, controlled by the autonomic neural system
Skeletal Muscles: Voluntary, attached to bones by tendons, controlled by nerve fibers, striated, with slow and fast twitch types

Types of Muscle Contractions

Concentric: muscle fibers shorten, load < force, angle between joints decreases
Eccentric: muscle fibers lengthen, load > force, angle between joints increases
Isometric/Static: muscle fibers stay the same length, load = force, no movement

Major Muscles

Pectoralist Major: superficial part of the chest, flexion of shoulder and adduction of humerus
Trapezius: neck and upper back, elevation and depression of scapula
Latissimus Dorsi: superficial part of the back, extension of shoulder and abduction of humerus
Deltoid: superficial part of the shoulders, flexion and extension of shoulder
Biceps Brachii: anterior part of the upper arm, flexion of elbow and supination of forearm
Triceps Brachii: posterior part of the lower arm, extension of elbow and pronation of forearm
Rectus Abdominus: superficial part of the stomach, flexion of lumbar spine and creation of intra-abdominal pressure
Quadriceps Femoris: anterior part of the femur, extension of the knee and flexion of the hip
Hamstrings: posterior part of the femur, flexion of the knee and extension of the hip
Gluteus Maximus/Medius: posterior side of the pelvis, extension of hip and external rotation of legs
Iliopsoas: anterior side of the pelvis, flexion of the hip
Gastrocnemius: posterior part of the shin, plantar flexion of foot
Tibialis Anterior: anterior part of the shin, dorsiflexion of foot

Agonist vs. Antagonist Muscle Pairs

Agonist: muscle that contracts during a contraction
Antagonist: muscle that lengthens during a contraction and counteracts the movement of the agonist muscle

Muscle Origin vs. Insertion

Origin: site of attachment that does not move during a contraction (proximal)
Insertion: site of attachment that moves during a contraction (distal)

Atrophy vs. Hypertrophy

Atrophy: decrease in muscle cell diameter/loss of muscle tissue due to neglect
Hypertrophy: increase in muscle cell diameter/gain of muscle tissue due to stimulation