Types Of Muscles

Question 1

Muscle Tissue

Answer 1

Function of all three major types of muscle is integral to function of the entire body
All three types of muscle tissue provide the movement necessary for survival
Muscles maintain the body in a relatively stable position

Question 2

Cardiac Muscle

Answer 2

Found only in the heart

Striated involuntary muscle

Unique features related to its function:
- Each cardiac muscle contains parallel myofibrils
- Syncytium: Continuous, electrically coupled mass

Question 3

Smooth muscle

Answer 3

composed of small, tapered cells that have a single nucleus
Ca2+ comes from outside the cell and binds to calmodulin instead of troponin to trigger a contraction
No striations

Question 4

Two types of smooth muscle tissue

Answer 4

Single-unit (visceral) smooth muscle and multi-unit smooth muscle

Question 5

Single-unit (visceral) smooth muscle

Answer 5

• Gap junctions join smooth muscle fibres into large, continuous sheets
• Is autorhythmic and produces peristalsis

Question 6

Multi unit smooth muscle

Answer 6

Composed of many independent single-cell units
Can form thin sheets, such as the walls of large blood vessels

Question 7

Characteristics of skeletal muscle cells

Answer 7

Excitability: ability to be stimulated
Contractility: ability to contract, or shorten, and produce body movement
Extensibility: ability to extend, or stretch, thereby allowing muscles to return to their resting length

Question 8

Muscle Cells

Answer 8

Fibres (due to thread like shape)

Question 9

Sarcolemma

Answer 9

plasma membrane of muscle fibres

Question 10

Sarcoplasmic reticulum

Answer 10

T tubules: network of tubules and sacs found within muscle fibres

Membrane of the sarcoplasmic reticulum continually pumps Ca?+ from the sarcoplasm and stores the ions for later release

Question 11

T tubules

Question 12

Muscle Cell components

Answer 12

Contains many mitochondria and several nuclei. Myofibrils: numerous fine fibres packed close in sarcoplasm.

Question 13

Sarcomere

Answer 13

Contractile unit of muscle fires
Each myofibril consists of many sarcomeres

Question 14

Striated muscle

Answer 14

Dark stripes called A bands; light H band runs across the midsection of each dark A band
Light stripes called I bands; dark Z disk extends across the centre of each light I band

Question 15

Triad

Answer 15

Triplet of tubules; a T tubule sandwiched between two sacs of sarcoplasmic reticulum

Question 16

Myofilaments

Answer 16

Each myofibril contains thousands of thick and thin myofilaments

Question 17

Proteins that make up myofilaments

Question 18

Myosin

Answer 18

Makes up almost all the thick filaments
myosin “heads” are known as cross bridges when attached to actin

Question 19

Actin

Answer 19

globular protein that forms two fibrous strands twisted around each other to form the bulk of the thin filament

Question 20

Tropomyosin

Answer 20

protein that blocks the active sites on in molecules

Question 21

Troponin

Answer 21

protein that holds tropomyosin molecules in place

Question 22

Acetylcholine (ACh)

Answer 22

neurotransmitter released into the synaptic cleft that diffuses across the gap, stimulates the receptors and initiates an impulse in the sarcolemma

Question 23

Rotator cuff

Answer 23

Rotator cuff is a group of muscles and tendons that surround the shoulder joint, keeping the head of your upper arm bone firmly within the shallow socket of the shoulder

Question 24

Isotonic contraction

Answer 24

Tone or tension in a muscle remains the same as the length of the muscle changes

Question 25

Isometric contraction

Answer 25

Muscle length remains the same while muscle tension increases