Wk 3: Muscle Tissue

Question 1

Does striated muscle or non striated (smooth) muscle contain sarcomeres

Answer 1

Striated muscle contains sarcomeres

Question 2

Morphological & Functional classification of skeletal muscle

Answer 2

Striated & voluntary

Question 3

Morphological & Functional classification of cardiac muscle

Answer 3

Striated & involuntary

Question 4

Morphological & Functional classification of smooth muscle

Answer 4

Non striated & involuntary

Question 5

6 functions of skeletal muscle

Answer 5

1. Produces movement
2. Maintain posture
3. Support viscera (soft internal organs of body)
4. Guards entrances & exits
5. Maintains body temp
6. Stores nutrients

Question 6

Skeletal muscle is composed of what specialised cells & what is their purpose

Answer 6

• Muscle fibres
• Their function is contractability

Question 7

What are the 3 layers of CT surrounding the skeletal muscles

Answer 7

1. Epimysium
2. Perimysium
3. Endomysium

Question 8

What type of CT is the epimysium

Answer 8

Dense irregular CT

Question 9

Function of epimysium (2)

Answer 9

• Maintains structural integrity
• Projects inwards & divides muscle into compartments of muscle fibre bundles (fasciculi)

Question 10

Function of the perimysium (1)

Answer 10

Surrounds each fasciculus

Question 11

What is the endomysium composed of

Answer 11

CT layer of collagen & reticular fibres

Question 12

Function of endomysium

Answer 12

Encases each muscle fibre within a fascicle

Question 13

What is a myocyte (muscle fibre)

Answer 13

A muscle cell

Question 14

What is the sarcolemma

Answer 14

The plasma membrane

Question 15

What is the sarcoplasm

Answer 15

The cytoplasm

Question 16

What is the sarcoplasmic reticulum

Answer 16

Smooth ER

Question 17

What is the sarcosome

Answer 17

The mitochondria

Question 18

What is the sarcomere

Answer 18

FUnctional unit of muscle

Question 19

What does the sarcomere contain

Answer 19

• COntractile myofilaments
• Thin filament = actin
• Thick filament = myosin

Question 20

Myofilaments + _______ = sarcomere

Answer 20

Regulatory proteins - troponin & tropomyosin

Question 21

Where does actin project from & to

Answer 21

Actin & troponin-tropomyosin complex projects from Z discs towards centre of sarcomere

Question 22

Where does myosin project from & to

Answer 22

Myosin strands project from centre of sarcomere towards Z-discs (thick filaments)

Question 23

What happens to the filaments when the muscle is relaxed

Answer 23

• Thick filaments don’t extend entire length of sarcomere
• Thin filaments don’t meet in the middle

Question 24

What is the I band of the sarcomere

Answer 24

Adjacent portion of 2 sucessive sarcomeres

Question 25

What is the A band of the sarcomere

Answer 25

Encompasses entire length of thick filaments (myosin)

Question 26

What is the H band of the sarcomere & what is it bisected by

Answer 26

• The H band is the zone in the middle of the A band, devoid of thin filaments
• H band is bisected by M line

Question 27

What happens to the 2 filaments during muscle contraction

Answer 27

• Thick & thin filaments do not shorten
• Z discs are brought closer together as thin filaments slide past thick filaments

Question 28

Where is smooth muscle found

Answer 28

Found in walls of hollow organs:
* Urinary bladder
* Uterus
* Stomach
* Intestines
And in walls of passageways
* Arteries & veins
* Tracts of resp, urinary, reproductive systems

Question 29

How does smooth muscle contract

Answer 29

• Calcium calmodulin complex activates myosin kinase which activates the myosin heads via phosphorylation
• Heads attach to actin binding sites & pull on thin filaments
• Thin filaments are anchored to dense bodies
• The thin filaments pull on dense bodies

Question 30

Function of cardiac muscle (myocardium)

Answer 30

pump blood in circulatory system

Question 31

What cells coordinate the contraction of myocarium tissue

Answer 31

Pacemaker cells