Muscle Tissue

Question 1

Muscle tissue is characterized by

Answer 1

• properties that allow movement

Question 2

muscle cells

Answer 2

• excitable
• respond to stimulus
• contractile: they can shorten and generate pulling force
• when attached between two moveable objects (bones contractions of muscles cause the bones to move)
• some muscle movement is voluntary (under conscious control)
• some are involuntary (not under conscious control)

Question 3

muscle tissue is classified into 3 types

Answer 3

1 skeletal
2 cardiac
3 smooth

Question 4

Skeletal histology

Answer 4

• long cylindrical fiber, striated, many peripherally located nuclei

Question 5

skeletal function

Answer 5

voluntary movement, produces heat, protects organs

Question 6

skeletal location

Answer 6

• attached to bones and around entrance points to body (mouth, anus)

Question 7

cardiac histology

Answer 7

• short, branched, striated, single central nucleus

Question 8

cardiac function

Answer 8

• contracts to pump blood

Question 9

cardiac location

Answer 9

heart

Question 10

smooth histology

Answer 10

• short, spindle-shaped, no evident striation, single nucleus in each fiber

Question 11

smooth function

Answer 11

• involuntary movement moves food, involuntary control of respiration, moves secretion, regulates flow of blood in arteries by contraction

Question 12

smooth location

Answer 12

• walls of major organs and passageways

Question 13

skeletal muscles

Answer 13

• attached to bones
• contraction makes possible locomotion, facial expressions, posture and other voluntary movements of the body
• 40% of body mass is made up of skeletal muscle
• generate heat as byproduct of their contraction and thus participate in thermal homeostasis
• myocyte (muscle cell): develops from myoblasts derived from mesoderm, myocytes and their numbers remain relatively constant throughout life
• skeletal muscle tissue is arranged in bundles surrounded by connective tissue
• striation: due to regular alternation of contractile proteins actin and myosin
• along w structural proteins that couple contractile proteins to connective tissues
• cells are multinucleated as result of fusion of the many myoblasts that fuse to form each long muscle fiber

Question 14

cardiac muscle

Answer 14

• forms contractile walls of the heart
• cells of cardiac muscle are called cardiomyocytes: striated under microscope, single cells, contracton their own intrinsic rhythms without any external stimulation, attach to one another with specialized cells junctions called inercalated discs
• attaching cells form long, branching cardiac muscle fibers that are essentially mechanical and electrochemical syncytium allowing the cells to synchronize their actions
• cardiac muscle pumps blood through the body and is under involuntary control
• attachment junctions hold adjacent cells together across the dynamic pressures changes the cardiac cycle

Question 15

intercalated discs

Answer 15

• have both anchoring junctions and gap junctions
• specialized cell junctions

Question 16

smooth muscle tissue contraction

Answer 16

• responsible for involuntary movements in internal organs
• it forms the contractile of the digestive, urinary, and reproductive systems as well as the airways and arteries
• each cell is spindle shaped with single nucleus and no visible striations