Chapter 7

The anatomical system of a species that allows it to move. The muscular system in vertebrates is controlled through the

nervous system, although some muscles are (such as the cardiac

muscle) can be completely autonomous.

The Muscular System

Overview of Muscular System Types of Muscle Tissue

Under voluntary control Skeletal muscles

Under involuntary controlCardiac muscleSmooth muscle

visceral organs

Overview of Muscular SystemSkeletal muscles attach to bones directly or indirectly

Perform five functionsProduce movement of skeletonMaintain posture and body position

Support soft tissuesGuard entrances and exitsMaintain body temperature

Anatomy of Skeletal MusclesGross Anatomy

Connective tissue organizationEpimysium

Fibrous covering of whole musclePerimysium

Fibrous covering of fascicleEndomysium

Fibrous covering of a single cell (a muscle fiber)

Tendons (or aponeurosis)- at each end of the muscle, the collagen fibers of all three layers come together to form either a bundle or a broad sheet.

Anatomy of Skeletal MusclesThe Organization of a Skeletal MuscleThe Organization of a Skeletal Muscle

Figure 7-1

Anatomy of a Muscle Fiber

Anatomy of a Muscle FiberMicroanatomy of a Muscle Fiber

SarcolemmaPlasma membrane

Sarcoplasmcytoplasm

Sarcoplasmic reticulum (SR)Like smooth ER

Transverse tubules (T tubules)Myofibrils (contraction organelle)Sarcomeres

Inside a single fiber

Anatomy of Skeletal Muscles

Sarcomere—Repeating structural unit of the myofibrilComponents of a sarcomere

MyofilamentsThin filaments (mostly actin)Thick filaments (mostly myosin)

Z lines at each endAnchor for thin filaments

Anatomy of a Muscle Fiber

Figure 7-2(a)

Anatomy of a Muscle Fiber

The Organization of aThe Organization of aSingle Muscle FiberSingle Muscle Fiber

Figure 7-2(b)

Anatomy of Skeletal MusclesThe Organization of a Single Muscle FiberThe Organization of a Single Muscle Fiber

Figure 7-2(cde)

Anatomy of Skeletal Muscles

Changes in the Changes in the Appearance of a Appearance of a Sarcomere Sarcomere During During Contraction of a Contraction of a Skeletal Muscle Skeletal Muscle FiberFiber

Figure 7-3 (1 of 2)

Anatomy of Skeletal Muscles

Changes in the Changes in the Appearance of a Appearance of a Sarcomere Sarcomere During During Contraction of a Contraction of a Skeletal Muscle Skeletal Muscle FiberFiber

Figure 7-3 (2 of 2)