Intrinsic factors that affect meat quality (Dr Pamela)

Question 1

Name the Intrinsic factors that affect meat quality

Answer 1

1. Muscle and muscle fibre types
2. Anatomical position
3. Connective tissues content:
4. Carcass and muscle fat
5. Juiciness
6. Colour

Question 2

What does tenderness include?

Answer 2

1. Texture
2. Initial ease of penetration of meat by teeth
3. Ease with which meat breaks into fragments
4. Amount of residue after chewing

Question 3

Name the ways we can measure meat tenderness

Answer 3

1. Blunt jaws
2. Warner-Brarzler shear
3. Armour-type tenderometer
4. Electric meat grinder
5. Instron test for tensile properies
6. Meat glued onto clamp

Question 4

Why do we have variation in meat tenderness?

Answer 4

1. Exists either at slaughter
2. Created during post-mortem storage
3. During meat preparation
4. Or a combination of the above

Question 5

Texture is a function of the ordered arrangement of what?

Answer 5

– fasciculi (bundles of fibres)
– fibres (large cells)
– fibrils (organelles) and
– filaments (protein filaments)

Question 6

Name the 3 muscle membranes?

Answer 6

1. Epimysium
2. Perimysium
3. Endomysium

Question 7

Define Epimysium

Answer 7

Connective tissue that surrounds the entire muscle

Question 8

Define Perimysium

Answer 8

Layer beneath epimysium, divides the muscle fibers into small groups, or fasciculi. Primary bundles, secondary bundles and tertiary bundles

Question 9

Define Endomysium

Answer 9

Layer beneath perimysium, surrounds muscle fibers individually.

Question 10

What factors influence the size of fasciculi?

Answer 10

1. Muscles engaged in lighter activities
2. Muscle for finely adjusted movements (eye muscle)
3. Muscle performing grosser movements (Biceps)

Question 11

What is the smallest contractile elements of muscle?

Answer 11

Sarcomeres

Question 12

What is the fluid surrounding the sarcomeres called?

Answer 12

Sarcoplasm

Question 13

What does the Sarcoplasm contain?

Answer 13

1. Sarcoplasmic proteins
2. Glycolytic enzymes
3. Proteolytic enzymes
4. Cell elements

Question 14

What factors determines the diameter of muscle fiber?

Answer 14

– Age
– Plane of nutrition
– Degree of post-natal development
– Oestradiol administration

Question 15

What is a Sarcolemma?

Answer 15

Excitable membrane that contains electric (voltage) gated channels
Extends into cell to form transverse tubules, or T-tubules

Question 16

What is the physical properties of Sarcoplasmic reticulum (SR)

Answer 16

• Modified endoplasmic reticulum
• Network of horizontal tubules
• Wrap around the myofibrils
• Fuse at each end to form a vertical tubule called the terminal cisterna

Question 17

What is the function of Sarcoplasmic reticulum (SR)?

Answer 17

Regulates ionic calcium by ATP calcium ion pumps

Question 18

What does the thin Actin filaments of myofibrils consist of?

Answer 18

1. Actin protein
2. Associated protein troponin
3. Associated protein tropomyosin

Question 19

What does the thick Myosin filaments of Myofibrils consist of?

Answer 19

molecules of myosin containing a head (cross-bridge) region and tail region

Question 20

What is the function of Myosin?

Answer 20

Myosin binds ATP that serves as energy for movement of cross-bridge which results in shortening of sarcomere (muscle contraction)

Question 21

Name the different transverse structures of myofibril

Answer 21

1. A-bands
2. H-bands
3. M-line
4. I-bands
5. Sarcomere

Question 22

Define A-bands

Answer 22

Dark regions consisting mostly of the thick filaments and the overlapping portions of the thin filaments

Question 23

Define H-bands

Answer 23

Light region in middle of A-band

Question 24

Define M-line

Answer 24

Line in middle of H-zone

Question 25

Define I-bands

Answer 25

Light regions consisting mostly of the thin filaments and their associated Z-discs

Question 26

Define Sarcomere

Answer 26

Region of the myofibril which is defined as the unit of contraction. Region from middle of each I-band, the Z-discs (lines) to next Z-disc; thus includes an A-Band

Question 27

What does the Neuromuscular Junction (Synapse) consist of?

Answer 27

A. Axon terminals
B. Synaptic cleft
C. Motor end plate