Body Systems: Musculatory System (Muscle Anatomy)

Question 1

Antagonistic muscles:

Answer 1

-flexor= muscles that bend a limb.
-extensors= muscles that straighten a limb.
-antagonists= muscles that cause movement in opposite.
-ex: contraction of hamstring flexes at knee, but contraction of quadriceps causes leg to extend.

Question 2

Terms: tendons:

Answer 2

Tendons: link muscle to bone

Question 3

Terms: ligament:

Answer 3

Ligament: link bone to bone.

Question 4

Types of muscle: cardiac muscle:

Answer 4

•only in the heart.
•one nucleus.
•tubular, striated, branched.
•involuntarily control.
•controlled by autonomic nervous system (automatic- don’t need to think about it!)

Question 5

Types of muscle: smooth muscle:

Answer 5

•lines blood vessels, tubes and organs.
•ex. Esophagus, stomach.
•non-striated.
•one nucleus.
•involuntary contractions.
•controlled by autonomic nervous system (automatic- don’t need to think about it!)

Question 6

Types of muscles: skeletal muscle:

Answer 6

•all over body.
•aids in locomotion.
•tubular and striated.
•many nuclei.
•very long.
•contraction is voluntary.
•central nervous system.
•supports the body.

Question 7

Components of skeletal muscles:

Answer 7

•muscles are made up of bundles of muscle fibres, which are made up of myofibrils.
•the fibres are enclosed within a membrane called the sarcolemma.
•within the muscle fibres are tiny myofilaments bundled together.
•myofilaments: thread of contractile proteins found within the muscle.

Question 8

Two kinds of myofilaments can be seen:

Answer 8

1. Thin myofilaments composed of actin.
2. Thick myofilaments composed of myosin.
   -they overlap to produce a striated, or striped, appearance.

Question 9

What is the sarcomere?

Answer 9

Basic, repeating unit of a muscle cell.

Question 10

Sarcomere (Z line):

Answer 10

-the length of the muscle fibre that anchor the actin fibres.
-Z line to Z line = 1 sarcomere.

Question 11

Sarcomere (A band):

Answer 11

-full length of the thick myosin filaments including the part that is overlapped with actin filaments (aka dark band).

Question 12

Sarcomere (I band): (i)

Answer 12

-thin actin- filaments (aka light band).

Question 13

Sarcomere (H zone):

Answer 13

-in the middle of A-band where only think filaments are found.

Question 14

Sarcomere (M line):

Answer 14

-Center of the H zone where thick filaments are bound in the centre.

Question 15

Sarcomere (cross bridges):

Answer 15

-spaces where thick and thin overlap and attach to each other.
-myosin heads attach onto actin filaments.

Question 16

Muscle fibre:

Answer 16

-Description: Single muscle cell.
-function: is responsible for muscle contractions.

Question 17

Myoglobin:

Answer 17

-Description: Oxygen-binding pigment (similar to hemoglobin) in a skeletal muscle fibre.
-function: stores oxygen for use during muscle contractions.

Question 18

Sarcolemma:

Answer 18

-description: membrane of a muscle fibre.
-funnction: surrounds the muscle fibre and regulates the entry and exit of materials.

Question 19

Sacroplasm:

Answer 19

-definition: cytoplasm of a muscle fibre.
-function: is the site of metabolic processes for normal cell activities; contains myoglobin and glycogen (which stores energy for muscle contractions).

Question 20

Sarcoplasmic reticulum:

Answer 20

-definition: smooth endoplasmic reticulum in a muscle fibre.
-function: stores calcium ions needed for muscle contractions.

Question 21

Myofibrils:

Answer 21

-definition: organized bundles of myofilaments; cylindrical structures as long as the muscle fibre itself.
-function: contain myofilaments that are responsible for muscle contractions.

Question 22

Thick filament:

Answer 22

-definition: Fine myofilament composed of bundles of protein called myosin (about 11nm (nanometers) in diameter).
-function: binds to actin and causes muscle contractions.

Question 23

Thin filament:

Answer 23

-definition: Fine myofilament composed of strands of protein called actin (about 5nm (nanometers) in diameter.
-function: binds to myosin and causes muscle contractions.