Unit 3 Anatomy and physiology

Skeletal muscle is ___ by or connected to and controlled by ___

Innervated, motor neurons

Conductivity

Involves electrical change that travels along the plasma membrane of the skeletal cell.

Excitability

The ability of skeletal muscle cells to respond to stimulation by the nervous system

Sacroiliac

The cytoplasm of s skeletal muscle cell

True/False: Your biceps brachii muscle in your arm is technically an organ.

True. Organs are made of 2/+ tissues and muscles contain muscle tissue, nervous tissue, and connective tissue

Epimysium

Upon muscle; dense irregular connective tissue that surrounds whole skeletal muscle

Skeletal muscle is ___ by an extensive network of blood vessels

Vascularized

Muscle cells are said to have what characteristic because they can respond to stimulation from the nervous system?

Excitability

What percentage of your body weight is skeletal muscle?

40-50%

Axon

A long extension that branches off the terminal end of motor neurons

Deep fascia

Additional sheet of dense irregular connective tissue external to epimysium. Separates individual muscles, binds similar muscles, and fills spaces between muscles. Has nerves, blood vessels, and lymph vessels.

Functions of skeletal muscles

Body movement, maintenance of posture, protection and support, storage and movement of materials, heat production

Fascicles

Bundles of many muscle fibers

A muscle fiber is what level of organization in the body?

Cellular

Sphincter

Circular muscle bands that contract and relax to regulate the passage of material

Superficial Fascia

Composed of areolar connective tissue and adipose connective tissue that separates muscle from skin

The shortening of muscle cells results in either a pull on bones of the skeleton or the movement of specific body parts. The process of shortening muscle cells is called ____

Contraction

Describe the skeletal muscle function of posture.

Contraction of specific skeletal muscles stabilizes joints.

Transverse Tubules

Deep invagination of the sacrolemma that extend into the sacroplasm of skeletal muscle fibers as a network of narrow membranous tubules

Aponeurosis

Derivation from tendon. Thin, flat sheet of dense irregular tissue

Elasticity

Due to specialized protein fibers within skeletal muscle cells that act like compressed coils when a muscle contracts

Skeletal muscle is composed of muscle that exhibits these characteristics

Excitability, conductivity, contractility, elasticity, and extensibility

Contractility

Exhibited when contractile proteins within skeletal muscle cells slide past one another, causing skeletal muscle cells to shorten

Motor neurons

Extend from the brain and spinal cord to skeletal muscle fibers

Extensibility

Lengthening of a muscle cell

Neurons that stimulate muscle contraction are called ___

Motor neurons

Describe body movement.

Muscles contract and pull on tendons that attach the muscles to the bones.

Endplate potential

Occurs when the inside which was once negative is now positive

Orifices

Openings

The skeletal muscles arranged in layers along the walls of the abdominal cavity and the floor of the pelvic cavity perform what functions?

Protection, compression, contraction, and support

T tubules are sandwiched by ___, which are reservoirs storing the calcium ions required for muscle contraction

Terminal cisternae

During development of skeletal muscle cells, some myoblasts do not fuse and instead become ____ cells

Satellite

Perimysium

Surrounds fascicles; contains blood vessels and nerves that branch to supply muscle fibers in each fasicle

Endomysium

The innermost layer, areolar connective tissue, surrounds and insulates each muscle fiber

Neuromuscular Junction

The junction between the axon and muscle fiber

The superficial fascia is also known as ___

The subcutaneous layer

What are the functions of blood vessels in skeletal muscle?

They deliver oxygen and nutrients to muscle fibers and remove waste products.

Tendon

Thick, cordlike structure made of dense regular connective tissue, that attach muscle to bone, skin, and other muscles

How far does the axon extend?

Through all 3 connective tissue layers to almost a muscle fiber (small gap between motor neurons and muscle fibers)

If the sacroplasm of a muscle cell is flooded with calcium ions which protein will bind to them?

Troponin

Proteins found in thin filament

Troponin, tropomyosin, actin