Chapter 07--Muscular System-2

What are the functions of skeletal muscle tissue?

Movement of the skeleton, posture maintenance, respiration and heartbeat, support for soft tissues, control of organ volume via sphincters, and heat production.

How is muscle tissue organized at the tissue level?

Connective Tissue

Blood Vessels

Nerves

Skeletal muscle fibers

What are the structural components of a sarcomere?

z-discs

actin (thin filaments)

Myosin (thick filaments)

troponin

tropomyosin

A-band

I-band

H-zone

M-line

What are the key steps in skeletal muscle contraction starting at the neuromuscular junction?

Acetylcholine release → Na+ influx → action potential → Ca2+ release from sarcoplasmic reticulum → troponin binds Ca2+ → tropomyosin moves → myosin binds actin → ATP-driven cross-bridge cycling → contraction.

What are the different types of muscle contractions?

Isometric

isotonic

What is Isometric

no change in muscle length

What is Isotonic

muscle length changes, including concentric and eccentric contractions

How do muscles obtain energy for contractions?

ATP production through aerobic respiration, anaerobic respiration, creatine phosphate breakdown, and ADP-to-ATP conversion.

How do muscle fiber types affect performance?

Slow-twitch fibers support endurance (aerobic), fast-twitch fibers enable short bursts of power (anaerobic).

What is skeletal Muscle

striated, voluntary

What is Cardiac muscle

striated, involuntary, with intercalated discs;

What is smooth muscle?

non-striated, involuntary, found in organs.

How do muscle names indicate their location, appearance, or function?

Names are based on location, size, shape, number of origins, fiber direction, and function (e.g., rectus abdominis means "straight muscle of the abdomen").

What are the main axial muscles

Temporalis , masseter , sternocleidomastoid, diaphragm , rectus abdominis.

What is Temporalis action

Chewing

What is Masseter Action

Jaw movement

What is Sternocleidomastoid Action

head rotation

What is the diaphragm action

Breathing

What is the rectus abdominis action

abdominal compression

What are the main appendicular muscles

Deltoid, biceps brachii, quadriceps, hamstrings, gastrocnemius

What is the Deltoid Action

Shoulder abduction

What is the biceps brachii Action

Elbow flexion

What is the quadriceps action

Knee extension

What is the hamstrings action

knee flexion

what is the gastrocnemius

foot flexion

What are the effects of aging on muscle tissue?

Muscle fibers shrink, elasticity decreases, flexibility and reflexes slow, and recovery ability declines.

Rectus

Parallel to midline

Transverse

Perpendicular to midline

Oblique

diagonal to midline

Maximus

largest

minimus

smallest

longus

longest

latissimus

widest

longissimus

longest

magnus

large

major

larger

minor

smaller

vastus

great

deltoid

Triangular

Trapezius

trapezoid

Serratus

saw-toothed

Rhomboid

Diamond-shaped

Orbicularis

Circular

Pectinate

comblike

piriformis

pear-shaped

platys

flat

Quadratus

Square

Gracilis

Slender

Flexor

Decreases Joint Angle

extensor

increases joint angle

Abductor

Moves bone away from midline

Adductor

Moves bone closer to midline

Levator

Produces superior movement

Depressor

Produces inferior movement

Supinator

Turns palm anteriorly

Pronator

Turns palm posteriorly

Sphincter

Decreases size of opening

Tensor

Makes a body part rigid

Biceps

Two orgins

Triceps

three origins

Quadriceps

Four origins