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