Muscle (Mace) Flashcards
Why is skeletal muscle striated?
Because the cells have alternating light and dark bands (called striations)
Skeletal muscle tissue is voluntary/involuntary
Voluntary (consciously controlled)
Describe the arrangement of skeletal muscle
Long, unbranched, cylindrical cells (skeletal muscle fibers), arranged in parallel bundles that run the length of the entire muscle
Skeletal muscle cells are/ are not multinucleated
Multinucleated- many nuclei are adjacent to the cell membrane
Where is skeletal muscle tissue?
Attached to bone, skin, surround the distal end of the digestive and urinary tract as sphincters
What does contraction of skeletal muscle do?
Moves bones, causes facial expression, controls defecation and urination
Describe cardiac muscle tissue
Short, branched, striated
One or two centrally located nuclei
Mitochondria rich
Cells closely packed in one direction
What are intercalated discs?
In cardiac muscle tissue, the junction between cells that strengthens attachments between cells and promotes rapid conduction of electrical activity through cardiac cells
What structure is responsible for rapid conduction of electrical activity through cardiac cells?
Intercalated discs
Cardiac muscle tissue is involuntarily/voluntarily controlled
Involuntarily controlled
What is syncytium?
The syncytium of cardiac muscle is important because it allows rapid coordinated contraction of muscles along their entire length. Cardiac action potentials propagate along the surface of the muscle fiber from the point of synaptic contact through intercalated discs.
Describe smooth muscle tissue
Spindle shaped cells
Short, closely packed in one first
Unbranched
Single nuclei that is centrally located
Smooth muscle tissue does/does not have striations
Does not have striations- appears smooth
Where is smooth muscle tissue located?
Walls of digestive, respiratory, and urinary tracts Erector pili in the skin Surround the blood vessels Digestive tract Respiratory tract as sphincters
Smooth muscle tissue is voluntarily/ involuntarily controlled
Involuntarily controlled
What are some functions of smooth muscle tissue?
Moves substances along internal passages (peristalsis) Erects hairs Controls blood flow and blood pressure Regulates air flow in lungs Controls urination and defecation
What are the functions of skeletal muscle?
Muscular contraction moving bone
Maintenance of posture
Protection and support abdominal and pelvic cavity, internal organs, maintain position
Storage and movement of materials- contract and relax sphincters
Heat production- heat is released when muscles contract
Muscle cells are organized into bundles called…
Fascicles
Each muscle contains…
Connective tissue
Blood vessels
Nerves
What are the three concentric layers of connective tissue?
Epimysium
Perimysium
Endomysium
What is the epimysium?
Layer of dense irregular CT, surrounds whole skeletal muscle
What is the perimysium?
Dense irregular CT surrounding the fascicles, contains extensive blood vessels and nerves supplying fibers
What is the endomysium?
Areolar CT, surrounds and electrically insulates each muscle fiber
What type of tissue are tendons?
Dense regular CT
What are the layers of a tendon?
Formed by the three connective tissue layers ?
What do tendons connect?
Muscle to bone
Muscle to skin
Muscle to muscle
(Bone to bone is a ligament)
What is an aponeurosis?
Thin, flattened sheet of tendon with wide area of attachment formed from the three connective tissue layers- holds muscles together for functional enhancement
What is deep fascia?
Additional sheet of dense irregular CT
External to the epimysium
What is the function of deep fascia?
Separates individual muscles
Binds together muscles with similar functions, fills spaces between muscles
What is contained in Deep Fascia?
Contains nerves, blood vessels, and lymph vessels