Chapter 8: The Muscular System

Role Of Calcium In Muscle Contraction

* Calcium unblocks sites where cross-bridges can form between actin and myosin filaments to begin muscle contraction. * Troponin and tropomyosin cover binding sites where cross-bridges can form between actin and myosin. * Calcium shifts troponin and tropomyosin away from binding sites so cross-bridges can form

Gluteus Maximus

* Forms the fleshy part of the buttocks * Extends the thight and is important in walking and running

Smooth Muscle

* Hollow body organs, blood vessels, and respiratory pathways make up smooth muscles * Cell Characteristics - Tapered at each end and have a single, central nucleus - No striations, or visible bands * Control Action - Contracts involuntarily and produces wavelike motions called peristalsis - Contracts and relaxes slowly and can remain contracted for a long time

Skeletal Muscles

* Location * Cell Characteristics - Long and cylindrical - Multiple nuclei per cell * Control Action - Nervous system stimulates skeletal muscles to contract - Tissue usually contracts and relaxes rapidly VOLUNTARY

Cardiac Muscles

* Location: Found in the walls of the heart * Cell Characteristics - Striated - 1 nucleus per cell and branching interconnections * Control Action - Specialized membranes between cells are designed to allow electric impulses to travel readily through - Can be modified by nervous stimuli and hormones

Structure Of The Sliding Filament Mechanism

* Muscle contractions depend on interaction of actin and myosin filaments within the cell * When a muscle is relaxed, there is no contact between the actin and myosin filaments * When a muscle fiber contracts, cross-bridges form and actin filaments are moved closer together * When the muscle returns back to its original position, the cross-bridge turns back into its original form

Abductor Muscles

* Muscles that are located on the medical thigh; * They press the thights together, as in grasping a saddle between the knees when riding a horse * Include the abductor

Hamstring muscles

* The ________ muscles' job is to flex the leg at the knee as in kneeling, and extend and rotate the thight at the hip. They are located in the posterior thigh

Serratus Anterior

* The _________ is a muscle that is located on either side of the superior chest that moves the scapula forward when one is pushing something, and also aids in raising the arm above horizontal level * Elevates surfaces of ribs 1-8

External Oblique

* The ___________ outermost part of the abdominal wall. There are THREE parts to the abdominal wall- the external oblique, internal oblique, and transversus abdomens

Action Potential Of A Muscle Cell

* The neuromuscular junction (NMJ) is the point at which a nerve fiber contacts a muscle cell, its job includes releasing neurotransmitters into the synaptic cleft, the tiny space attached to the synapse * Neurotransmitters attach to receptors in the motor end plate, the muscle cell's receiving membrane, whose folds increase in surface area to allow as many receptors as possible

Saromere

...

troponin;tropomyosin

2 proteins called _________, which represents the yellow dot, and _________, which represents the green dot, are designed to block the sites on actin filaments where cross-bridges can form while the muscles are supposed to be at rest.

anaerobic glycosis

A compound that breaks down glucose without oxygen

Sarcomere

A contracting subunit of a skeletal muscle that is made up of myosin filaments and actin filaments on each side

Diaphragm

A dome-shaped muscle that forms division between the thoracic cavity above and the abdominal cavity below; * Diaphgram contacts ----------- dome-shaped is pulled downward --------- thoracic cavity enlarges

concentric

A muscle as a whole shortens to produce movement, without changing in tension or tone, during a __________ contraction. This type of contraction may occur while lifting a heavy dumbbell off the ground. ISOTONIC SUBCATEGORY

Skeletal Muscle

A muscle that is attached to the bones of the skeleton and provides the force that moves the bones. It exerts VOLUNTARY control

Gluteus Medius

A muscle that is partially covered by the gluteus maximus and abducts the thigh

Orbicularis Oculi

A muscle that surrounds the eye

Orbicularis Oris

A muscle that surrounds the lips

Structure Of A Muscle Cell Filament

Actin makes up the light band and myosin makes up the dark band. The dark line in the actin band marks points where actin filaments are held together. A sarcomere is a subunit of a skeletal muscle. The sarcoplasmic reticulum is the ER of the muscle cells.

creatine phosphate

An anaerobic compound that is used to make ATP for muscle contraction. It generates very rapidly, but the supply is limited

Rectus Abdominus

Connective tissue that extends anteriorally and encloses a vertical wall

Sternocleidomastoid

Contraction of one side: laterally flexes neck, rotates head to opposite side; Contraction of both sides together: flexes neck

Quadriceps Femoris

Covers the anterior and lateral femur, and has 4 heads orf origin

contracted

Cross-bridges form and actin filaments are moved closer together while a muscle is ___________. When the muscle returns back to its original position, the cross-bridge turns back into its original form

Isometric Contractions

During _____________ contractions, tone and tension changes but muscle tone does not. Trying to lift an immoveable object off the ground produces a contraction of this sort.

Gracilis

Extends from the pubic bone to the medial surface of the tibia, adducts the thigh at the hip and flexes the leg at the knee

anterior

Front of body

Smooth Muscles

Hollow body organs, blood vessels, and respiratory pathways are where _________ muscles take place

sternocleidomastoid

In torticollis, a condition in which the head leans to one side because the neck muscles on that side are contracted, pertains to issues with the __________ muscle

Pectoralis Major

Located on either side of the superior chest; This muscle flexes and adducts the arm, pulling it across the chest

third-class

Most levers in the skeletal system are __________-class levers

Structure Of A Skeletal Muscle

Muscles are held together by a layer of connective tissue. These layers merge to form the tendon that attaches a muscle to a bone

eccentric

Muscles lengthen as they extert force during a _____________ contraction. This may occur while lowering a dumbbell back towards the ground. ISOTONIC SUBCATEGORY

bottom;top

Of the 2 middle layers of the quadricep femurs, the vastus medialis is the ________ layer, and the vastus lateralis is the _______ layer.

Perineum

Otherwise known as the pelvic diaphragm

Intercostal Muscles

Respiratory muscles that are attached to and fill the spaces between the ribs; Contractions of these muscles elevate the ribs and enlarge the thoracic cavity

obicularis

Ring-shaped muscles around the eyes and lips that are used in facial expressions are known as the ________ muscles.

...

Tendons attach muscles to bones. The stable point is the origin. The moveable point is the insertion.

Myoglobin;glycogen;fatty acid

The 3 main storage compounds are ________, __________, and ______________

...

The 4 pairs of chewing muscles are the temporalis, masseter, intrinsic and extrinsic muscles of the tongue

Transversus Abdominus

The _______ innermost part of the abdominal wall

temporalis; masseter

The _______ is a chewing muscle that is slightly above the ears, and _________ is another chewing muscle located at the angle of the jaw.

Deltoid

The _______ is a muscle in the arm/shoulder area that is responsible for the roundness of the upper arm just inferior to the shoulder. It abducts the arm and rotates the shoulder.

Rotator Cuff

The _______ is a supporting structure of the shoulder consisting of the muscles and tendons that attach the arm to the shoulder joint and enable the arm to move

sartorius

The _______ is the muscle that crosses the front of the thigh and stems from the iliac spine. It is situated below the iliopsoas, but above the gracilis.

Sartorius

The ________ is a long, narrow muscle across the anterior thigh; Used in crossing the legs, begins at the iliac spine

Trapezius

The ________ is a triangular muscle in the shoulder/arm area that enables people to raise their shoulders and pull them back

Iliopsoas

The _________ are muscles that cross the anterior hip joint that flex the thighs and help keep the trunk from falling backwards when one is standing erect. They arise from the lumbar vertebrae.

Levator Ani

The _________ is a principle muscle of the pelvic diaphragm that acts on the rectum and aides in defecation

Linea Alba

The _________ is the midline meeting of fibrous tissue, marked by a whitish area in the abdomen.

smooth muscle

The _________ muscle cells are tapered at each end and have a single, central nucleus, and no striations

NMJ

The _________ of a neuron, the point at which any given nerve fiber contacts a muscle cell, is what releases neurotransmitters into the synaptic cleft.

Biceps Branchii

The __________ are located in the front of the upper arm and assisting in bending the arm

Triceps Branchii

The __________ is a muscle that is located in the posterior arm that is used to straighten the arm, as in lowering a weight from an arm curl, and pushing because it converts arm and forearm into a sturdy rod

Endomysium; Perimysium; Epimysium

The __________ is the deepest layer of the connective tissue and surrounds the individual fibers in a fascicle; _________ tissue that layers around each fascicle, and the ___________ surrounds the entire fiber

iliopsoas

The __________ is the leg muscle that crosses the front of the hip joint to the femur and is furthest away from the pelvis

motor end plate

The __________ is the part of the muscle cell that contains receptors on which neurotransmitters attach to and become absorbed within.

Brachialis

The __________ muscle is the one that lies deep within the biceps branchii and inserts distally over the anterior elblow joint. It flexes the forearm forcefully in all positions, sustains flexion, and steadies the forearm's slow extension.

intrinsic;extrinsic

The __________ muscles of the tongue are located entirely within it, while the ______ muscles are located outside the tongue.

Flexor Carpi;Extensor Carpi;Flexor Digitorum; Extensor Digitorum

The ___________ and __________ are muscles in the forearm/hand area that are responsible for many hand movements, while the ___________ and __________ are responsible for finger movements

Vastus Intermedius

The ___________ is the bottom layer of the quadriceps femoris

Sliding Filament Mechanism

The ____________ is the name of the process of muscle fiber contraction, where it becomes shorter and thicker, by enabling the filaments, or threads, to repeatedly overlap and slide together

above;below

The adductor longus is positioned _________ the gracilis and the adductor magnus is positioned __________ the gracilis

sarcoplasmic reticulum

The job of the _____________ during muscle contraction is to release calcium into the cytoplasm. While the muscles are at rest, the __________ keeps the calcium in storage.

orbiculari oculi

The levetator palpebrae superioris is a muscle that lifs the upper eyelids, and is an antagonist to the _________ muscle.

Internal Oblique

The middle part of the abdominal wall

antagonists

The obicularis muscles are __________ because they perform the opposite action of its pairing muscle

Rectus Femoris

The outermost layer of the quadricep femoris; There are 4- the rectus femurs, vast us medial is/vastus lateralis, and the vastus intermedius

further

The serratus anterior is ________ from the chest than the pectoralis major

origin;insertion

The stable point of attachment between the muscle and bone is called the ________, while the moveable part is called the _______________.

Myosin

The threads, or filaments, of a skeletal muscle cell that make up the dark band is made out of the protein ______.

Actin

The threads, or filaments, of a skeletal muscle cell that make up the light band is made out of the protein ______.

Latissimus Dorsi

The wide muscle of the back and lateral trunk; Extends the arm, bringing it down forcibly as in swimming

relaxed

There is no contact between the actin and myosin filaments while a muscle is ___________.

Structure of the Abdominal Wall

Thin layers of muscle tissue with fibers running in different directions give strength to the abdominal wall.

Skeletal

_________ muscle cells are long and cylindrical, and have multiple nuclei per cell because during development, pre-cells, or myoblasts, form large multinucleated cells

Troponin;tropomyosin

___________ and ___________ are the name of the proteins that block the sites on actin filaments while the muscles are at rest

Cardiac Muscle

___________ muscles are found in the walls of the heart

Buccinator

____________ are used in whistling and blowing, and are considered one of the largest muscles of facial expressions in the part of the cheek

Cardiac muscles

____________ muscle cells are striated, and have 1 nucleus per cell with branching interconnections

Fatty Acids

_____________ are stored as triglycerides that form into fat droplets, which are able to be broken down into fatty acids when needed by the muscle cells.

Glycogen

_____________ stores a form of glucose called a polysaccharide, which is made up of multiple glucose molecultes that can be broken down into glucose when needed by the cell

Myoglobin

_____________ stores additional oxygen. It is similar to the hemoglobin in blood, but is located specifically in muscle cells

Isotonic contractions

of or involving muscular contraction in which tension is constant while length changes, involves 2 subcategories, concentric contractions and eccentric contractions

Lateral

sideways

Medial

the middle