Module 6 B141

Front 1

The delicate connective tissue that surrounds the skeletal muscle fibers and ties adjacent muscle fibers together is the......

Back 1

Endomysium (endo as in minecraft endodragon ties all the games plot together)

Front 2

When acetylcholine binds to receptors at the motor end plate, the end plate membrane becomes more permeable to ______ ions

Back 2

Sodium (Na+)

Front 3

This ion is more concentrated inside the cell than outside?

Back 3

Potassium (K+)

Front 4

_____ encircles each sarcomere

Back 4

Transverse Tubules. Extends into the sarcoplasm from sarcolemma.

Front 5

The _______ forms a tubular network around each myofibril

Back 5

Sarcoplasmic reticulum

Front 6

The sarcoplasmic reticulum forms expanded Chambers on either side of the transverse tubule called::::

Back 6

Terminal cisternae

Front 7

The sarcoplasmic reticulum contains pumps that move ______ from sarcoplasm to sarcoplasmic reticulum

Back 7

Calcium

Front 8

What are the Thin and Thick filaments

Back 8

Thin: actin. Thick: myosin.

Front 9

What is troponin and it's three subunits it turns into

Back 9

1) binds to tropomyosin and forms a complex

2) binds to G actin (maintains position on Actin)

3) binds two calcium ions (for activation during contraction)

Front 10

What does tropomyosin do?

Back 10

Covers active sites and prevents actin-myosin interactions. Also attaches to troponin

Front 11

The myosin molecule has three properties. What are they

Back 11

1) has a long tail bound other myosin in molecules

2) connection between head and tail allows pivot motion

3)Forms cross Bridges with actin during contraction.

Front 12

Sliding occurs in all circumstances of a myofibril causing so contraction occurs

Back 12

The myofibril get shorter which means the muscle cell gets shorter

Front 13

Skeletal muscles are stimulated by motor neurons of the _______ nervous system

Back 13

Somatic

Front 14

Neuro- muscular Junction consists of

Back 14

1) Synaptic terminal of neuron which has vesicles filled with neurotransmitter acetylcholine

2) motor end plate of muscle fiber which has junctional folds and contains acetylcholine esterase, an enzyme

3) the synaptic cleft which is the space between the neuron and the muscle fiber

Front 15

Activities at the neuromuscular junction starting with electrical impulse...

Back 15

First electrical impulses at the synaptic terminal cause voltage-gated calcium channels to open and calcium ions diffuse into the terminal.

Second vesicles of ACH fuses with the neuron plasma membrane, causing exocytosis of ACH into synaptic cleft.

Third ACH diffuses across the synaptic cleft and binds to ligands gated receptors on motor end plate. ACh binding allows Na+ to diffuse into the cell.

4th: Depolarizing stimulus generates action potential

5th: AChE and activate receptors by quickly removing acetylcholine from synaptic cleft

Front 16

Describe excitation-contraction coupling related to the final contraction of a muscle

Back 16

An action potential is generated at motor end plate and sweeps across the sarcolemma.

The action potential sweeps down the T tubules and causes calcium to be released from SR to sarcomeres causing muscle contraction

Front 17

Excitation contraction coupling steps: (4)

Back 17

1. an action potential produced at the motor end plate in the NMJ is propagated along the sarcolemma of the skeletal muscle. The depolarization also spreads along the membranes of the T tubules.

2. The depolarization of the T tubules causes gated calcium two channels in the SR to open which causes an increase in the permeability of the SR to calcium two ions specially in the terminal cisternae. Calcium ions then diffuse from the SR into the sarcoplasm.

3. Calcium ions released from the SR bind to troponin molecules the troponin molecules are released causing tropomyosin to move exposing the active sites on G actin

4. Once active sites are exposed the heads of the myosin myofilaments bind to them to form cross Bridges

Front 18

Steps of muscle fiber contraction cycle (6)

Back 18

Contraction cycle begins, Active- site exposure, cross Bridge formation, myosin head pivoting (power stroke), cross Bridges attachment, myosin reactivation

Front 19

What are the two factors that determine the amount of tension produced by skeletal muscle

Back 19

The amount of tension produced by each muscle which is dependent on stimulation frequency, and the total number of muscle fibers stimulated AKA recruitment

Front 20

Groups of muscle fibers that are controlled by one motor neuron are called....

Back 20

Motor units

Front 21

What term means :"motor units are activated on a rotating basis to maintain a sustained contraction"

Back 21

Asynchronous motor unit summation

Front 22

A variable number of motor units that are always active to produce low-level tension

Back 22

Muscle tone or tonus

Front 23

This occurs in the sarcoplasm and produces two ATP and two pyruvate molecules for each glucose

Back 23

Glycolysis

Front 24

This provides 95% of ATP demands of resting muscle cells and requires oxygen unlike glycolysis. It occurs in the mitochindria and produces 17 ATP for each pyruvate

Back 24

Aerobic metabolism or cellular respiration

Front 25

Muscle store few high-energy molecules such as _______ and _______ because most energy is stored as _________

Back 25

Atp and creatine phosphate ,

Glycogen, which allows long periods of muscle contractions