Module 3 chapters 10 and 11 A&P

What are the five main functions of muscle tissue

Movement, stability, control of openings and passages, heat production, and glycemic control.

Movement

Allows movement of body parts, walking, breathing, and communication.

Stability

Maintains posture and stabilizes joints.

Control of body openings and passages

Uses ring-shaped sphincter muscles to control intake and expulsion of materials.

Heat production

Generates 20–30% of body heat at rest and up to 85% during exercise.

Hormone secretion

Muscles release hormones that regulate glucose and fat metabolism.

Glycemic control

Muscles absorb and store glucose to stabilize blood sugar levels.

Voluntary muscles

Muscles under conscious control responsible for body movements.

Myology

Study of the muscular system.

Endomysium

Thin connective tissue surrounding each muscle fiber allowing room for capillaries and nerves.

Perimysium

Connective tissue wrapping bundles of muscle fibers called fascicles.

Fascicles

Bundles of muscle fibers carrying nerves, blood vessels, and stretch receptors.

Epimysium

Sheath of dense connective tissue covering the entire muscle.

Fascia

Connective tissue separating or binding muscles into groups.

Hypodermis

Subcutaneous layer of areolar and adipose tissue beneath the skin storing triglycerides and providing insulation.

Tendons

Cordlike extensions of connective tissue connecting muscle to bone.

Aponeurosis

Flat sheet-like tendon connecting muscles to bones or other muscles.

Direct muscle attachment

Muscle connects directly to bone with minimal separation.

Indirect muscle attachment

Muscle connected to bone via tendons or aponeuroses.

Origin

Attachment site of a muscle on the stationary bone.

Insertion

Attachment site of a muscle on the moving bone.

Belly

Thick, central part of a muscle.

Reverse muscle action

Ability of a muscle to switch origin and insertion depending on movement.

Fusiform muscles

Spindle-shaped muscles with parallel fascicles ending in short tendons.

Parallel muscles

Muscle fibers running parallel to the long axis, such as abdominal muscles.

Triangular (convergent) muscles

Fan-shaped muscles with a single thick tendon, like pectoralis major.

Unipennate muscles

Fascicles arranged on one side of the tendon.

Bipennate muscles

Fascicles arranged on both sides of a central tendon.

Multipennate muscles

Fascicles attached to multiple tendons in various directions.

Circular (sphincter) muscles

Ring-shaped muscles controlling openings, such as around the mouth or anus.

Intrinsic muscles

Muscles fully contained within one region of the body.

Extrinsic muscles

Muscles located in one region but act on another.

Prime mover (agonist)

Muscle responsible for the main movement.

Antagonist

Muscle opposing the action of the prime mover.

Synergist

Muscle assisting the prime mover by reducing unnecessary movement.

Fixator

Muscle that stabilizes the origin of the prime mover.

Orientation

Direction of muscle fibers relative to the body midline.

Size

Relative size of a muscle, such as maximus, medius, longus, or brevis.

Shape

Muscle shape used for naming, such as deltoid (triangle).

Action

Principal movement performed by a muscle such as flexion or extension.

Number of tendons

Number of origins a muscle has, such as biceps (two tendons).

Location

Site of the muscle, such as temporalis near the temporal bone.

Origin and insertion

Specific attachment points used for naming muscles.

Occipitofrontalis

Moves the scalp forward and backward.

Zygomaticus major

Elevates the mouth upward and laterally.

Zygomaticus minor

Raises the upper lip.

Buccinator

Compresses cheeks for blowing, whistling, and chewing.

Risorius

Draws the mouth laterally.

Suprahyoid muscles

Elevate the hyoid bone and floor of the mouth, and depress the mandible.

Infrahyoid muscles

Depress the hyoid bone and assist in swallowing.

Sternothyroid

Depresses the thyroid cartilage and larynx.

Sternocleidomastoid (SCM)

Flexes and rotates the head; forms anterior and posterior neck triangles.

Capitis muscles

Extend, flex, and rotate the head.

Diaphragm

Prime mover of inspiration.

Abdominal muscles

Support abdominal organs and assist in posture and breathing.

Flexor muscles of the forearm

Biceps brachii, brachialis, and brachioradialis.

Extensor muscles of the forearm

Triceps brachii and anconeus.

Anterior forearm compartment

Responsible for flexion; includes superficial and deep layers.

Posterior forearm compartment

Responsible for extension; includes superficial and deep layers.

Extrinsic hand muscles

Originate in the forearm and insert in the hand.

Intrinsic hand muscles

Located entirely within the hand for fine finger movement.

Thenar muscles

Control thumb movements.

Hypothenar muscles

Control little finger movements.

Midpalmar (intermediate) muscles

Control movements of the middle three fingers.

Iliopsoas muscle

Flexes the hip; composed of psoas major and iliacus.

Gluteus maximus

Extends and rotates the thigh laterally.

Gluteus medius

Abducts and medially rotates the thigh.

Tensor fasciae latae

Stabilizes the hip and knee.

Adductor muscles

Adduct and rotate the femur.

Thigh anterior compartment

Extends the leg and flexes the thigh.

Thigh posterior compartment

Flexes the leg and extends the thigh.

Thigh medial compartment

Adducts the femur.

Gracilis

Medially rotates the thigh and flexes the knee.

Leg anterior compartment

Extends toes and dorsiflexes the foot.

Leg posterior compartment

Flexes toes and plantarflexes the foot.

Leg lateral compartment

Everts the foot and assists with ankle stability.

Dorsal foot muscles

Located on the top of the foot.

Ventral foot muscles

Located on the bottom of the foot.

Types of muscle tissue

Skeletal, cardiac, and smooth.

Skeletal muscle

Striated, voluntary muscle attached to bones for body movement.

Cardiac muscle

Striated, involuntary muscle found only in the heart.

Smooth muscle

Non-striated, involuntary muscle found in walls of hollow organs and vessels.

Muscle fiber

Single muscle cell specialized for contraction.

Striations

Alternating light and dark bands visible under the microscope.

Voluntary control

Conscious regulation of skeletal muscle contraction.

Involuntary control

Automatic function without conscious control, seen in cardiac and smooth muscle.

Somatic nervous system

Controls skeletal muscle movement.

Autonomic nervous system

Controls cardiac and smooth muscle activity.

Autorhythmic fibers

Cardiac muscle cells that generate their own electrical impulses.

Autorhythmicity

Built-in rhythm allowing the heart to beat automatically.

Excitability

Ability of muscle tissue to respond to electrical or chemical stimuli.

Conductivity

Ability to transmit an electrical impulse through the muscle fiber.

Contractility

Ability to shorten and generate force when stimulated.

Extensibility

Ability to stretch without being damaged.

Elasticity

Ability to return to original shape after being stretched or contracted.

Sarcolemma

Plasma membrane of a muscle fiber.

Transverse tubules (T-tubules)

Extensions of the sarcolemma that carry electrical impulses deep into the cell.

Sarcoplasm

Cytoplasm of a muscle fiber containing glycogen and myoglobin.

Myoglobin

Oxygen-binding protein in muscle tissue.

Myofibrils

Long, contractile organelles within muscle fibers responsible for striations and movement.