muscles

Question 1

Skeletal muscle tissue

Answer 1

attached to bones- or for face muscles skin.
-packaged in skeletal muscle that attach and cover bony skeleton
-has striations
-controlled voluterily
contracts rapidally but tires easliy
extremely adaptable, can exart force 0.001 to 30kg

Question 2

Sooth muscle tissue

Answer 2

Mostly in walls of visceral organs.

• maintains blood pressure
• propels substances (food, faaeces) through internal pathways
• not striated
• involuntery

Question 3

cardiac muscle tissue

Answer 3

walls of heart.

• contracts at steady rate
• neural control allows heart to respond to bodies needs
• pumps blood through body
• some striated
• involuntary

Question 4

Structure of muscle tissue (all 3 tissue type sum up)

Answer 4

Each muscle is a discrete organ composed of muscle tissue, blood vessels nerve fibres and connective tissue

Question 5

Endomysium

Answer 5

First layer - fine sheath of connective tissue composed of reticular fibres surrounding each muscle cell….en-side-inner most layer

Question 6

Perimysium

Answer 6

Second layer- fibrous connective tissue that surrounds groups of muscle cells called fascicles

Question 7

Epimysium

Answer 7

3rd layer- an overcoat of dense regular connective tissue that surrounds the entire muscle.

Question 8

Sacromere

Answer 8

Is the smallest contractile unit of muscle- it is the region of myofibril between two successive Z disks- it is made up of myofilaments and contractile protiens.

Question 9

microscopic structure of skeletal muscle structure

Answer 9

myofibrilis- densely packed rod organelles within muscle cell

• arrangement of myofibrilis is perfectly aligned- dark A bands and light I bands repeat
• This banding occurs because of thick (myosin) and thin (actin) protien filaments within a myofibril.
• Thick and thin myofibril attach to Z disk
• A single segment of thick and thin filament and inbetween Z discs is called a sacromere
• Sacromeres are arranged in a series along the length of skeletal muscle.

Question 10

Neuromuscular Junction= somatic motor neuron

Answer 10

the region where the motor neuron comes into close contact with a skeletal muscle cell—– equivalent of a synapse in nerve cell

Question 11

Motor Unit

Answer 11

A motor neuron and all the cells attached to it is called a motor unit.
Small- motor unit only connected to to a few muscle cells, for fine movement
Large-motor unit connected to many muscle fibres-generates higher forces.

Question 12

Sliding Filament theory

Answer 12

• Thin filaments slide past thick filaments so that actin and myosin filaments overlap more.
• In a relaxed state only overlap slightly
• Upon stimulation myosin heads bind to actin and sliding begins
• Each myosin heads binds and detaches throughout contraction, this acts as a ratchet to generate tension and propel the thin filaments to the center of the sacrome.
• As this event occurs throughout the sacromes the muscle shortens.

Question 13

Flexion

Answer 13

Decrease angle of joint, brings 2 bones closer together

Question 14

Abduction

Answer 14

movement away from midline

Question 15

circumduction

Answer 15

combination of flexion adduction and abbduction

Question 16

order of muscle structure

Answer 16

muscle fibre> enclosed in endomysium> bunch of muscle fibres> enclosed in Perimysium> this is called a fasicle> a group of fasicles is enclosed in epimysium

Question 17

crossbridge

Answer 17

myosin head attached to an actin is called a crossbridge- the more crossbridges the heavier strain the muscle can endure.

Question 18

why skeletal cells are multinuclenated

Answer 18

because cells are so big

Question 19

sacrolemma

Answer 19

plasma membrane of muscle cells

Question 20

myofibrils

Answer 20

bundles of myofilaments

Question 21

myofilaments

Answer 21

actin and myosin

Question 22

very short muscle length compared to stretched muscle

Answer 22

short- lots of actin-actin crossover so not to many places myosin can attach. Long- muscles so stretched myosin heads may pop up but can not always attach

Question 23

what does a striped muscle pattern mean

Answer 23

very organised- skeletal muscles…… cardiac kind of organised……..smooth not very organised

Question 24

isotonic and isometric

Answer 24

isometric- muscle stays the same

isotonic- muscle shorTens