muscles

Question 1

what are the three types of muscles

Answer 1

cardiac
smooth
skeletal

Question 2

where is smooth muscle found

Answer 2

walls of the blood vessels and the gut

Question 3

are smooth and cardiac muscle contraction under conscious control

Answer 3

no

Question 4

which is thinner actin or myosin

Answer 4

actin

Question 5

what are the two types of skeletal muscle fibres

Answer 5

slow twitch and fast twitch

Question 6

what are properties of a slow twitch fibre

Answer 6

• higher concentration of myoglobin
• contract slowly
• • slow to fatigue
    lots of mitochondria to provide lots of ATP
• lots of blood vessels to reduce diffusion pathway
• slow release of energy

Question 7

what are properties of fast twitch fibres

Answer 7

• low concentration myoglobin #
• contract quickly
  =energy is released quickly
• few mitochondria and blood vessels
• quick to fatigue

Question 8

what is contained in the sarcoplasmic reticulum

Answer 8

Ca2+ needed for muscular contraction

Question 9

what is the sarcoplasm

Answer 9

cytoplasm

Question 10

what is the sarcolemma

Answer 10

the cell membrane

Question 11

what are adaptations of skeletal muscle

Answer 11

• multinucleate
• ## lots of mitochondria for release of ATP needed for muscular contraction

Question 12

what is a sarcomere

Answer 12

short repeating units that make up the myofibril

Question 13

what is the order of letter in the sarcomere

Answer 13

IAI
ZHZ

Question 14

WHY IS THE A BAND DARK

Answer 14

because it contains both actin and myosin

Question 15

why is the I band light

Answer 15

because it only contains actin

Question 16

what is the M line in the sarcomere

Answer 16

middle of the H zone which only contains myosin

Question 17

how does a muscle contract

Answer 17

an action potential from a motor neurone will depolarise the sarcolemma.
- this depolarisation will travel down the T-tubule to the sarcoplasmic reticulum
- this will stimulate Ca2+ ions to be rekeased into the sarcoplasm
- this influx of Ca2+ is what stimulates muscular contraction

• Ca2+ is needed to move the tropomyosin to expose the actin binding sites to the myosin heads to slide past each oyther and for the muscle to contract