Lecture 12: Muscle - Structure and Function

Question 1

Skeletal muscle is made up of long fibre-like cells called:

Answer 1

myocytes
myofibres
muscle cells
muscle fibres

Question 2

Each myocyte is surrounded by connective tissue called:

Answer 2

Endomysium

Question 3

Myocytes bundle together to form:

Answer 3

Fascicles

Question 4

Fascicles are surrounded by:

Answer 4

Perimysium

Question 5

Several fascicles are bundled together to form the muscle & this is surrounded by the:

Answer 5

epimysuim

Question 6

Inside myocytes their are bundles of:

Answer 6

Myofibrils

Question 7

Each myofibril is made up of proteins called:

Answer 7

Myofilaments

Question 8

There are 2 myofilament types which are:

Answer 8

thick filament - mysin

thin filament - actin

Question 9

What is the sacrolema?

Answer 9

Myocyte membrane

Question 10

What does the perimysium do?

Answer 10

Surrounds fascicles

Question 11

What does the epimysium do?

Answer 11

Surrounds several fascicles which from muscle

Question 12

What are sarcomeres?

Answer 12

myosin & actin are arranged in sarcomeres -the basic contractile unit of the muscle

Question 13

What separates sarcomeres?

Answer 13

z- lines

Question 14

How do muscles shorten?

Answer 14

filaments overlap as z-lines move closer together

Question 15

What does the process of muscle contraction require?

Answer 15

Ca+ ions which are stored in the sarcoplasmic reticulum of muscle fibre
actin & mysin overlap

Question 16

What are the function of skeletal muscle?

Answer 16

Movement - locomotion or movement of parts
Heat production
Posture - continued partial contraction

Question 17

What determines muscle function?

Answer 17

Length of muscle fibres
Number of muscle fibres (CSA)
Arrangement of muscle fibres

Question 18

How does length of muscle fibres affect muscle function?

Answer 18

Longer resting length mens muscle fibres can shorten more, increasing the ROM

Question 19

Muscle fibres can shorten up to ?% of their resting length:

Answer 19

50%

Question 20

How does number of muscle fibres (CSA) affect muscle function?

Answer 20

Muscle tension is proportional to cross sectional area. increased num of fibres, increased CSA, increased tension

Question 21

How does arrangement of muscle fibres affect muscle function?

Answer 21

Pennate muscle fibres have increased CSA compared to parallel muscle fibres.
Pennate increased CSA, decreased shortening and ROM

Question 22

How is our posture maintained?

Answer 22

by muscle tone - the continual partial contraction in a muscle: stabilises & maintains posture