Muscle Tissue

Question 1

Three types of muscle are:

Answer 1

1. Skeletal
2. Cardiac
3. Smooth

Question 2

Typical Skeletal Muscle consists of?

Answer 2

Whole Muscle, connected by
tendons to the skeleton

Question 3

Muscles have what color as an appearance?

Answer 3

reddish appearance duo to high vascularization

Question 4

Tendons are what color?

Answer 4

whitish due to being
minimally vascular, collagen
fibers.

Question 5

Whole muscle is covered in?

Answer 5

a dense connective tissue
called Epimysium

Question 6

Whole muscle is divided into
smaller “bundles” called?

Answer 6

Fascicles which are
covered in connective tissue
called Perimysium

Question 7

Fascicles are divided into
smaller bundles called?

Answer 7

Muscle Fibers which are
covered by connective tissue
called Endomysium

Question 8

Muscle Fibers are the ——-
of muscle?

Answer 8

cells

Question 9

Tendons are a continuous
mass of?

Answer 9

connective tissues
(endomysium, perimysium
and epimysium) that emerge
from muscle at both ends

Question 10

Skeletal Muscles are supplied
with?

Answer 10

nerves and blood

Question 11

Skeletal Muscles are supplied with nerves are called?

Answer 11

Somatic Motor Neurons

Question 12

During embryonic development, muscle fibers arise from?

Answer 12

fusion of hundreds of myoblast cells

Question 13

Each mature Muscle Fiber has how many nuclei?

Answer 13

hundred or more nuclei

Question 14

Action Potentials propagate along?

Answer 14

sarcolemma and down the T tubules into the depths of muscle fiber

Question 15

What is Sarcolemma?

Answer 15

blue covering is the plasma membrane of Muscle Fiber

Question 16

Muscle fibers are composed of multiple skeletal muscle called?

Answer 16

Myofibrils which are contractile
elements of skeletal muscle and extend entire length of muscle fiber

Question 17

Encircling each myofibril are?

Answer 17

calcium-filled sacs called the Sarcoplasmic Reticulum

Question 18

When an Action Potential is carried by the T tubule into the muscle fiber, it
causes the release of?

Answer 18

calcium ions from the sarcoplasmic reticulum

Question 19

Within myofibrils are smaller structures called?

Answer 19

filaments

Question 20

Thin filaments are composed of?

Answer 20

mainly of the protein Actin

Question 21

Thick filaments are composed of?

Answer 21

protein Myosin

Question 22

Filaments are arranged in compartments called?

Answer 22

Sarcomeres

Question 23

Sarcomeres are what basic units?

Answer 23

basic functional units
of muscle contraction

Question 24

Z-discs do what?

Answer 24

separates one sarcomere from
another

Question 25

sarcomere extends from?

Answer 25

one Z disc to the next Z disc

Question 26

A Band extends where?

Answer 26

the entire length of thick filaments

Question 27

I Band contains what?

Answer 27

Thin filaments but no Thick filaments

Question 28

H Band contains?

Answer 28

Thick filaments but no Thin filaments

Question 29

Myofibrils are composed of?

Answer 29

1. Contractile proteins (generate force during contraction) 2. Regulatory proteins (help switch the contractile proteins on and off) 3. Structural Proteins * Keep Thick and Think filaments in proper alignment) * Give the myofibrils elasticity * Link myofibrils to the sarcolemma and extracellular matrix.

Question 30

two Contractile Proteins are?

Answer 30

Myosin (Thick filament) and Actin (Thin filament)

Question 31

Myosin functions as?

Answer 31

“motor” protein

Question 32

Motor proteins do what?

Answer 32

convert ATP’s energy into mechanical energy = production of force

Question 33

About 300 myosin molecules form what?

Answer 33

a single myosin filament

Question 34

Myosin shaped like what?

Answer 34

a twisted golf club

Question 35

Myosin heads have what two binding sites?

Answer 35

1. An Actin-Binding site (A) 2. An ATP Binding site (B)

Question 36

Thin Filaments main component is?

Answer 36

Actin which is twisted into a helix

Question 37

Thin filaments are two “Regulatory proteins” called?

Answer 37

1. Tropomyosin rope-like structure * During relaxation it covers Actin Binding site * This prevents Myosin from binding to Actin 2. Troponin has three binding sites. * During contraction calcium binds to troponin * Result: tropomyosin pulled away from Actin exposing Acting binding sites * Result: myosin can now bind to Actin = muscle contraction

Question 38

Two Structural Proteins are called?

Answer 38

1) Titin *Very elastic can stretch four times in length Anchors Thick filament to both Z disc and M Line * Prevents sarcomere overstretching 2) Myomesin: Molecules form M line which holds Thick filaments in alignment.

Question 39

Skeletal muscles shorten during contraction because?

Answer 39

Thick and Thin filaments slide past one another “Sliding Filament Mechanism”

Question 40

Muscle contraction occurs because?

Answer 40

Myosin heads attach and “walk” along the thin filaments. This “pulls” towards the M line / and pulls both Z discs towards the M line Sarcomere shortens / however the lengths of Thin and Thick filaments do not change.