intro anatomy and physiology ch 8

Muscular system

skeletal muscles aka “red meat”

skeletal muscle

volunatary muscle that creates movement of the body

cardiac muscle

Flashcard: Cardiac Muscle

• Only in heart

• Involuntary

• Striated

• Rhythmically pumps blood

• Resistant to fatigue

intercalated disk

involuntary muscle, Where the plasma membranes of adjacent cardiac fibers contact each other

smooth muscle

Involuntary, moves blood through hollow organs 

3 muscle fibers

• Skeletal, cardiac, and smooth

skeletal muscle

Type of muscle responsible for voluntary movement;

contracts and relaxes to generate force and movement in the body.

fascia

• The loose connective tissue outside the muscle organs that form a flexible, sticky, “packing material” between muscles, bones and the skin

Origin

• The muscle attachment to the more stationary bone 

Muscle Insertion

• Attachment to the more moveable bone 

Body of the muscle

• Remainder of the muscle other then the 2 ends 

Tendons

• Anchor muscles firmly to bones 

• made of dense, fibrous connective tissue that extends from the muscle “wrappers” 

Bursae

• Small fluid-filled sacs

• Lie between some tendons and the bones beneath them

Flashcard: "Synovial Membrane"

Thin layer of connective tissue that lines the inner surface of joint capsules, secreting synovial fluid to lubricate and nourish the joint.

- Tendon Sheaths

Protective coverings that surround tendons, reducing friction during movement.

Muscle fibers

Long, slender cells that make up muscles. They can contract and relax, allowing for movement.

myofilaments

Thin and thick protein structures within muscle cells responsible for contraction.

Flashcard: Sarcomere

composed of overlapping actin and myosin filaments, slide past each other during muscle contraction

responsible for generating the force required for muscle movement.

- Contraction of Muscle Fibers

Contraction of Muscle Fibers: Shortening of muscle fibers due to the activation of myosin and actin filaments, resulting in muscle movement and force generation.

- Myoglobin

Protein responsible for storing and transporting oxygen in muscle cells. Aids in oxygen delivery during periods of low oxygen availability, such as during exercise.

- Movement of skeletal muscle

Voluntary contraction and relaxation of skeletal muscles, responsible for body movement and maintaining posture.

Synergist muscles

muscles that aide in movement

Prime movers

the muscle mainly responsible for producing the movement of skeletal muscle

Antagonist Muscles

produce oppisite movement of synergist and prime muscles

Tonic contraction 

muscle tone: what makes maintaining body position possible

Hypothermia 

when body tempature is any degree below normal

Fatigue 

• Muscle fibers are stimulated without adequate rest, the strength of the muscle contractions decrease

Oxygen debt 

continually increasing metabolism that must occur in a cell to remove the excess lactic acid that accumulates during prolonged exercise

Paralysis

Nervous system disorder that shuts off impulses to certain skeletal muscles 

Multiple sclerosis (MS)

a chronic disease of the central nervous system

may lose the ability to see clearly, write, speak, or walk.

Motor neuron 

allows for both voluntary and involuntary movements through the innervation of effector muscles and glands

Neuromuscular junction (NMJ)

Point of contact between the nerve ending and the muscle fiber

nuerotransmitters

signal chemicals

Acetylcholine (ACh)

• Type of neurotransmitter operating each NMJ

Twitch

A single pulse applied to muscle tissue will result in a single contraction or twitch

tetanic contractions

As pulse frequency increases the twitches become more frequent until they merge into a sustained contraction known as tetanic contraction or spasm.

Isotonic Contraction

• when the muscle contracts but no movement occurs

Disuse atrophy 

• During prolonged inactivity muscles usually shrink in mass

Hypertrophy

• Exercise on the other handy cause an increase in muscle sizes 

Angular Movements

flexion, extension, abduction, abbuction,

flexion

• Movement that decreases the angle between two bones at their joint 

  • Bending movement

extension

• Increase the angle between two bones and their joints 

• Straightening or stretching 

abduction

• Moving a part away from the midline of the body 

  • Ex. Moving arm away from side 

abbuction

• Moving a part of the body towards the midline of the body 

  • Bringing arms down to your side 

circular movements

rotation, circumduction, supination, pronation

rotation

• Moving around a longitude axis 

  • Ex. Rotating head and neck by moving side to side

Circumduction

• Moves a part of your body that its distal end moves in a circle 

  • ex. Pitcher winds up arm to throw a ball

supination

• When palm is turned anterior 

pronation

• When palm is facing posterior 

Special Movements

Dorsiflexion and Plantar flexion inversion and eversion

Dorsiflexion

• • The dorsum or top of the foot is elevated with toes pointing up

Plantar flexion 

• • Bottom of foot is directed down 

Cross bridge sequence

1. myosin heads split ATP and become reoriented and energized

2. myosin heads bind to actin forming crossbridges

3. myosin heads rotate towards center of the sarcomere

4. as myosin heads bind ATP the cross bridge detach from actin

Frontal muscle 

• Raise eyebrows furrow skin of forehead

Orbicularis oris

aka kissing muscle

Zygomaticus

elevates the corners of the mouth and lips

mastication

chewing muscle

masseters

elevates the manible and the temporal

sternocleidomastoid

2 muscles located on the exterior of the neck

originate in the sternum

trapezius

trianglular shaped

the line from each shoulder to the neck on its posterior side

pectorals major

covers the upper chest

flexor of the arm

Latissumus dorsi

structures over lower back

extensor of arm

deltoid

shoulder muscle

Biceps brachii

primary flexor of the forearm

Tricep brachii

extensor of the elbow

preforms straighting function

muscles of the trunk

• 3 layers with the fibers in each layer

  • Outermost layer external oblique 

  • Middle layer internal oblique 

  • Innermost layer transverses abdominis

Rectus abdominis

runs down the midline of the abdomen from the thorax to the pubis

Gluteus Maximus

• Forms much of the buttock 

  • Extensor of thigh 

  • Supports torso in erect postion

Hamstring muscles 

• Flexor of the legs 

Quadriceps femoris 

• Covers the upper thigh 

• Four thigh muscles 

  • Rectus femoris 

  • Three vastus muscle 

• Extend the leg 

Gastrocnemius 

• Primary calf muscle 

  • Responsible for plantar flexion 

Fibulas group or peroneus group 

• Three muscles 

• Found along the sides of legs 

• fibularis longus 

  • Muscle tendon 

    • Forms support arch for the foot