Muscle tissue

Why is skeletal muscle rich in blood vessels and innervation?

• Skeletal muscles need to bring in a lot of oxygen and nutrients and quickly remove wastes to function properly. Nerves allow us to control contraction consciously.

   

• Nutrients and extra oxygen from the blood in the skeletal muscles diffuses to ‘feed’ the epithelial layers above the muscle are not vascularized or innervated.

• The blood vessel and nerves supply each other with oxygen and electrical signaling, this then stimulates the muscles to contract.

• Blood vessels bring in the blood to be filtered by the skeletal muscles and send the purified blood back out. The nerves analyze the blood and make sure it’s being filtered efficiently.

What is the I band of the sarcomere?

• The area from one Z disc to the next Z disc.

• Actin filaments, Z discs, and connectin – but no overlap with thick filaments.

• The regions where actin and myosin filaments overlap.

• The thick filaments made up of myosin (may overlap with actin filaments).

Most parts of the sarcomere shorten during contraction, but what part of the sarcomere stays the same size during contraction?

• Sarcomere length

• H zone

• I Band

• A Band

What is the ‘neuro’ part of the neuromuscular junction?

• It’s the proprioceptor that tells the central nervous system where the muscle is located in the body.

• It’s the sensory receptor that tells the central nervous system if the muscle is contracted.

• It’s the reflex that acts before the signal gets back to the CNS.

• It’s the axon terminal of a motor neuron that contacts the muscle cell.

What protein will you find in thick filaments?

• actin

• calcineurin

• connectin

• myosin

Below is a graph of a muscle twitch. During the relaxation period, calcium is being moved back into the sarcoplasmic reticulum and cross-bridge cycling stops. Click on the part of the graph that shows the relaxation period.

• Section D

• Seection B

• Section A

• Section C

What do you know to be true for "slow oxidative fibers"?

• They have the fast ATPase, so they contract quickly.

• They use aerobic respiration to make ATP, are a darker red color because they have myoglobin, and usually have slower contractions than fast fibers.

• They use glycolysis for their main means of making ATP, so they make it quickly and have powerful contractions.

• They lack myoglobin and are pink-to-white in color.

Tags

NGSS.HS-LS2-3

Of the three systems that make energy for muscle cells, which one uses oxygen and makes the most ATP?

• Artificial respiration

• Phosphagen system

• Glycolysis

• Aerobic cellular respiration

Tags

NGSS.HS-LS1-7

NGSS.HS-LS2-3

Reorder the followingPut the steps of cross-bridge cycling in the order they occur, starting with formation of cross-bridges between myosin and actin.

• Myosin head pulls and slides actin filament,myosin releases ADP and ...

• Cross-bridge formation(myosion binds to actin)

• Myosin head resets as it breaks down ATP and releases from actin.

• Myosin head binds ATP and releases from actin

What does the sarcoplasmic reticulum do in muscle cells?

• It is continuous with the sarcolemma.

• Stores calcium and releases it when the action potential travels into the T tubule.

• Produces ATP for contraction.

• Creates another source of oxygen.