MUSCULAR SYSTEM <3

Midterm reviewer for Anaphy exam

Muscular System

are responsible for all types of body movement - they contract or shorten and are the machine of the body.

Skeletal Muscles

Attach to the skeleton are responsible for voluntary body movements.

Smooth Muscles

• Occur mainly in blood vessels and tubular organs of the GI tract, reproductive, urinary and respiratory systems.

• The muscle fibers are unstriated and contain a single nucleus.

Cardiac Muscle

• It is found only in the wall of the heart and has the unique property of auto rhythmicity.

• Its contractions are involuntary and have an intrinsic rhythm.

600 muscles

The body has more than _____ skeletal muscles.

Movement

The primary function of skeletal muscle system.

Body Heat Production

Physiologically this is one of the principles of homeostasis - the body’s ability to regulate its functions.

Posture and Support of body

• The skeletal system provides a framework for body support but the muscles do all the heavy lifting.

• Skeletal muscles maintain___________ , stabilize the joints and support the viscera (internal organ).

Irritability (Electrical Excitability)

Muscle responds to electrical stimulation from nerve impulses.

Contractility

Muscle responds to stimuli by contracting lengthwise, or shortening.

Extensibility

it is capable of being stretched beyond its resting length by the contraction of an opposing muscle.

Elasticity

Muscle fibers, after being stretched, have a tendency to recoil to their original resting length.

Tendons

• These are dense connective tissue that attaches the muscle to bone.

• When a muscle contracts, it shortens and puts tension on the ________ and the bone.

Origin

• The less moveable attachment of the muscle is called the ______

• At the girdles and appendages, the most proximal muscle attachment is the ____

Origin. Insertion

• Movement of the bone at the synovial joint causes one of the attached bones to move more than the other.

• The more moveable bony attachment of the muscle is called the ____

Belly

The fleshy thick part of the muscle. It is also called the gaster. Aponeuroses: It is a flattened sheet like tendon.

Retinaculum

It is a strong band of connective tissue that covers entire groups of tendons and keeps the tendons from bowing during muscle contraction.

Endomysium (Associated Connective Tissue)

• The outer covering of individual muscle fibers.

• It binds individual fibers together and supports capillaries and nerve endings serving the muscle.

Perimysium (Associated Connective Tissue)

• Another sheath covering that binds groups of muscle fibers together into bundles called fasciculi.

• m supports the nerves and blood vessels that serve the surrounding fasciculi.

Epimysium (Associated Connective Tissue)

The entire muscle is covered by a sheath called the ______, which in turn is part of a tendon

Fascia

It is a fibrous connective tissue that covers the muscle and attaches to the skin.

Superficial fascia

• It is securing skin to the underlying structures.

• In areas such as the abdomen, buttocks the fascia is thick and is laced with adipose tissue.

Deep fascia

It is an extension of the superficial fascia to deeper surfaces. It lacks adipose tissue and blends with the epimysium.

Subserous fascia

It extends between deep fascia and serous membranes. It is composed of loose connective tissue.

Synergistic

• Muscle groups that contract together to accomplish a particular movement.

Prime movers (Synergistic)

Muscles that are primarily responsible for a movement are called ______

Fixators (Synergistic)

Muscles that aid and allow prime movers to act efficiently by stabilizing the joint to prevent unwanted movements.

Antagonistic

Muscles that have opposing actions and are located on opposite sides of a joint.

Parallel (Longitudinal)

• It is a strap-like long excursion, contracted over a long distance

• Good endurance (stamina), not especially strong

Convergent (Radiate)

• Fan shaped, force of contraction focused on a single point of attachment.

• Stronger th

Sphincteral (Circular)

Fibers concentrically arranged around an orfice.

Pennate (feather)

• In this type one or more tendons run through the body of the muscle.

• ______ muscles contain more fibers than parallel types and are capable of generating more tension (are stronger).

Unipennate

It has one extended tendon. All the muscle fibers are found on the same side of the tendon.

Bipennate

It has 2 tendons.

Multipennate

It has more than 2 tendons that branch within the muscle.

Motor (efferent) neurons and Sensory (afferent) neurons

What are the 2 neural pathways for each muscle fiber

Motor (efferent) neurons

It is a nerve cell that conducts impulses to the muscle fiber, stimulating it to contract.

Sensory (afferent) neurons

Nerve cells that conduct impulses away from the muscle to the CNS, which responds to the activity of the muscle fiber.

Sarcolemma (Structure of Skeletal Muscle Fiber)

Cell membrane of the muscle fiber

Sarcoplasmic reticulum (Structure of Skeletal Muscle Fiber)

- It is a network of membranous channels that extends through the cytoplasm of the cell

T tubules (transverse tubules) (Structure of Skeletal Muscle Fiber)

It is a system of tubules that run perpendicular to the sarcoplasmic reticulum.

Myofibrils (Structure of Skeletal Muscle Fiber)

It is a contractile element of the skeletal muscles. They are 1-2 μm in diameter

i) Thin filament ii) Thick filament iii) Elastic filament

What are the three smaller structures which are known as myofilament?

Contraction of Muscles

It is well described by a sliding filament model.

Relaxation of muscles

Ca +2 is the main mediator for muscles contraction

Muscles of Facial Expression

The muscles in this group provide humans with the ability to express a wide variety of emotions, including surprise, fear and happiness.

Occipitofrontalis muscle (Face Muscle)

is a muscle which covers parts of the skull

It consists of two parts or bellies:

• Occipital belly & Frontal Belly

Orbicularis oris (Face Muscle)

• It is situated at a corner of the mouth.

• Its closed lips, compresses lips against teeth and gives shapes during speech to the lips.

Orbicularis oculi (Face Muscle)

• It is present around the palpebral fissure.

• Its contraction closes the eyelids.

Zygomaticus (Face Muscle)

• Insert in skin at angle of mouth and orbicularis oris.

• It pulls the corner of the mouth upward and outward as in smiling and laughing.

Levator labii superioris (Face Muscle)

• It helps for the elevation of the upper lips.

Depressor labii inferioris (Face Muscle)

It is present in the skin of lower lips and It depresses (lowers) lower lips.

Buccinator (Face Muscle)

It is situated in the chick and It contracts the chicks.

Mentalis (Face Muscle)

It is present in the skin of the chin. It elevates and protrudes lower lips and pulls the skin of chin up as in pouting.

Platysma (Face Muscle)

These are present around the angle of mouth and skin of the lower face. Draws outer parts of the lip inferiorly and posteriorly as in pouting.

Risorious (Face Muscle)

Present in skin at an angle of mouth. Draws angle of mouth laterally as in tenseness.

Corrugator supercilii (Face Muscle)

It is present in the skin of the eyebrow. It draws an eyebrow inferiorly as in frowning.

Levator palpebrae superioris (Face Muscle)

It is present in the skin of upper eyelids. It elevates upper eyelids (open eye).

Muscles that move the Mandible (Lower Jaw)

are also known as muscles of mastication because they are involved in biting and chewing.

Masseter (Lower Jaw)

It is situated between the process and external surface of the corner of the lower jaw.

Temporalis (Lower Jaw)

It is present in the temporal part. It raises (moves up) the lower jaw.

Medial pterygoid (Lower Jaw)

Elevate and moves mandible side to side

Lateral pterygoid (Lower Jaw)

It protracts (prolong or extend) and moves side to side mandible and open mouth.

Extrinsic muscles (Eye Muscle)

It originates outside the eyeballs and inserts on their outer surface.

Intrinsic muscles (Eye Muscle)

It originates and inserts within the eyeball.

Superior rectus (Eye Muscle)

It is present in the superior and central part of the eyeball. It rolls the eyeball superiorly.

Inferior rectus (Eye Muscle)

It is present in the inferior and central part of the eyeball. Rolls eyeball inferiorly.

Lateral Rectus (Eye Muscle)

It is present in the lateral side of the eyeball. Rolls eyeball laterally.

Medial Rectus (Eye Muscle)

It is present in the medial side of the eyeball. It rolls the eyeball medially.

Superior oblique (Eye Muscle)

It is present in the eyeball between superior and lateral recti. It rotates the eyeball on its axis.

It directs the cornea inferiorly and laterally.

Inferior oblique (Eye Muscle)

It is located between inferior and lateral recti. It rotates the eyeball on its axis.

It directs the cornea superiorly and laterally.

Extrinsic muscles (Tongue Muscle)

• It originates outside the tongue and is inserted into it.

• They move the entire tongue anteriorly, posteriorly and laterally.

Intrinsic muscles (Tongue Muscle)

• It originates and is inserted within the tongue.

• These muscles alter the shape of the tongue rather than moving the entire tongue.

Genioglossus (Tongue Muscle)

• It is the present undersurface of the tongue and hyoid bone.

• It depresses (lower) tongue and thrusts (pushes) it anteriorly.

Styloglossus (Tongue Muscle)

• It is the present side and undersurface of the tongue.

• Elevates tongue and draws it posteriorly.

Palatoglossus (Tongue Muscle)

• It is present inside the tongue.

• It elevates the tongue posteriorly and draws a soft palate inferiorly on the tongue

Hyoglossus (Tongue Muscle)

• It is present inside the tongue.

• It depresses the tongue and draws its sides inferiorly.

Digastric (Oral Cavity Muscle)

Elevate hyoid bone and depresses the mandible as in opening the mouth.

Stylohyoid (Oral Cavity Muscle)

Elevates hyoid bones and draws it posteriorly.

Mylohyoid (Oral Cavity Muscle)

Elevates hyoid bone and floor of mouth and depresses mandible.

Geniohyoideus (Oral Cavity Muscle)

Elevates hyoid bone and draws hyoid bones and tongue anteriorly and depresses mandible.

Anterolateral abdominal wall (Muscle on Abdominal Walls)

composed of skin, fascia and four pairs of flat and sheet like muscles: ➔ Rectus abdomens ➔ External oblique ➔ Internal oblique ➔ Transversus abdominis

• It compresses the abdomen and provides help in urination, forced expiration and childbirth.

Posterior abdominal wall (Muscle on Abdominal Walls)

• is formed by lumbar vertebrae, hip bone, and quadratus lumborum muscles.

• Quadratus lumborum muscles give help in forceful expiration and deep inspiration.

Muscles used in Breathing

• These muscles are attached to the ribs

• Their contraction and relaxation alter the size of the thoracic cavity during breathing.

Muscles that move the Shoulder

These muscles depress, rotate or elevate the clavicle or scapula

Anterior (Muscles that move the Shoulder)

It consist

• Subclavius

• Pectoralis minor

• Serratus anterior

Posterior (Muscles that move the Shoulder)

It consist

• Trapezius Levator

• scapulae

• Rhomboideus major

• Rhomboideus minor

Axials Muscles (Muscles that move the Arm (Humerus))

Consist of

• Pectoralis major

• Latissimus dorsi

Scapular muscles are (Muscles that move the Arm (Humerus))

Consist of

• Deltoid

• Subscapularis

• Supraspinatus

• Infraspinatus

• Teres major

• Coracobrachialis

Flexor (Muscles that move the Radius and Ulna (Forearm))

It consist

• Biceps brachii

• Brachialis

• Brachioradialis

Extensors (Muscles that move the Radius and Ulna (Forearm))

It consists

• Triceps brachii

• Anconeus

• It flexes and extends forearm

Anterior compartment muscles (Muscles that move the Wrist, Hand and Finger)

• It originates on the humerus and inserts on the carpals, metacarpals and phalanges.

• Anterior compartment muscles are flexors.

Posterior compartment muscles (Muscles that move the Wrist, Hand and Finger)

• It is raised on the humerus and inserts on the metacarpals and phalanges.

• It is further divided into superficial and deep muscles.

Anterior compartment muscles (Flexors)

Consist of: Superficial

• Flexor carpi radialis

• Palmaris longus

• Flexor carpi ulnaris

• Flexor digitorum superficialis

  Deep

• Flexor digitorum profundus.

• Flexor pollicis longus.

Posterior compartment muscles (Extensor):

Consist of: Superficial

• Extensor carpi radialis longus

• Extensor carpi radialis brevis

• Extensor digitorum

• Extensor digiti minimi

• Extensor carpi ulnaris

  Deep

• Abductor pollicis longus

• Extensor pollicis brevi

• Extensor pollicis longus

• Extensor indicis

Muscle of Palm

Consist of:

• Thenar

• Hypothenar

• Intermediate

Anterior (extensor) compartment (Muscles of Thigh)

• These muscles extend the leg and some also flex the thigh.

• It is innervated by the femoral nerve.

Quadriceps femoris (Muscles of Thigh)

These muscles provide help in extension of leg and flexion of thigh.

Consist of:

• Rectus Femoris

• Vastus Lateralis

• Vastus Intermedius

• Vastus medialis

Sartorius muscles (Muscles of Thigh)

• It is the longest muscle of the body.

• It flexes the thigh and leg.

Posterior (flexor) muscles (Muscles of Thigh)

• It mostly flexes the leg but sometimes extends the thigh.

• It is innervated by a branch of the sciatic nerve.