Muscle

Question 1

All cells are capable of some degree of movement, but some cells form multicellular contractile units called… drum roll..

Answer 1

muscles

Question 2

what are the three types of muscles

Answer 2

skeletal, smooth and caridac

Question 3

two words that describe skeletal muscle

Answer 3

striated, voluntary

Question 4

two words that describe smooth muscle

Answer 4

non-striated, involuntary

Question 5

two words that describe cardiac muscle

Answer 5

striated, involuntary

Question 6

what are muscles surrounded by

Answer 6

an elastic lamina

Question 7

what causes contractile forces to develop

Answer 7

contractile forces develop by internal contractile proteins transmitting forces to the external lamina via link proteins in the cell membrane

Question 8

what is the skeletal muscle responsible for the movement of

Answer 8

responsible for the movement of the skeleton and organs like the tongue

Question 9

why is the skeletal muscle referred to as voluntary

Answer 9

because it is capable of conscious control

Question 10

what gives the appearance of striations in skeletal muscle

Answer 10

the arrangement of contractile proteins gives the appearance of cross-striations on light microscopy, so also called striated muscle

Question 11

muscle is made up of highly specialised cells so what is the cytoplasm referred to, what is the endoplasmic reticulum referred to

Answer 11

cytoplasm - sarcoplasm, endoplasmic reticulum - sarcoplasmic reticulum, etc. plasma membrane - sarcolemma

Question 12

what is skeletal muscle composed of in terms of cells

Answer 12

multinucleate contractile cells

Question 13

what is skeletal muscle contraction mainly controlled by

Answer 13

the large motor nerve

Question 14

what is a group of muscle fibres supplied by the same nerve called

Answer 14

a motor unit

Question 15

when a nerve fires a motor unit, what happens

Answer 15

all the fibres in the motor unit contract simultaneously

Question 16

what does the vitality of a skeletal muscle fibre depend on

Answer 16

the nerve supply, so if the supply is damaged, the muscle fibres atrophy

Question 17

what are individual muscle fibres (cells) grouped together in

Answer 17

fasciculi

Question 18

individual muscle fibres are grouped together in fasciculi with delicate supporting tissue called

Answer 18

endomysium

Question 19

what is each fascicle surrounded by

Answer 19

a loose supporting tissue called perimysium

Question 20

*label this diagram of muscle

Answer 20

there

Question 21

a muscle involved in fine controlled movements such as controlling the eye has what sort of structure in terms of fasciculi and perimysium

Answer 21

small fasciucli and lots of perimysium

Question 22

what do muscles involved in gross movements e,g. buttocks have in terms of fasciculi

Answer 22

large fasciculi

Question 23

how would you describe the muscle fibres in skeletal muscle on a stained slide

Answer 23

each fibre is elongated, unbranched and cyclindrical

Question 24

what is the nuclei of skeletal muscle fibres like

Answer 24

numerous flattened nuclei are located at regular intervals just underneath the plasma membrane (sacrolemma)

Question 25

why are there cross striations seen in skeletal muscles

Answer 25

cross striations due to contractile proteins

Question 26

what are the two contractile proteins

Answer 26

actin and myosin

Question 27

in smooth muscle the arrangement of contractile proteins does not give the appearance of

Answer 27

cross striations

Question 28

where can smooth muscle be found

Answer 28

the muscular component of visceral structures such as blood vessels, uterus, GI tract and bladder

Question 29

under what control is smooth muscle

Answer 29

under inherent autonomic and hormonal control so called involuntary muscle

Question 30

what type of contractions does smooth muscle take

Answer 30

specialises in continuous contraction of relatively low force producing diffuse wave like rhythmic movements

Question 31

how does the contraction occur in terms of motor units in smooth muscle

Answer 31

in smooth muscle the whole muscle mass contracts rather than individual motor units

Question 32

how would you describe the cells of smooth muscle under staining

Answer 32

cells relatively small, only a single nucleus. fibres are elongated spindle shaped cells with tapered ends. nucleus is centrally located

Question 33

what is the myocardium

Answer 33

The myocardium is the muscular wall of the heart, or the heart muscle

Question 34

what type of muscle makes up the myocardium

Answer 34

cardiac obvs

Question 35

cardiac muscle is an intermediate between smooth and skeletal. Like skeletal muscle, contractions of cardiac muscle are

Answer 35

strong and utilise much energy

Question 36

cardiac muscle in an intermediate between smooth and skeletal muscle, like smooth muscle, contractions are continuous and initiated by

Answer 36

inherent mechanisms - modulated by nerves and hormones

Question 37

how would you describe cardiac muscle fibres

Answer 37

long and cylindrical, with one or two centrally placed nuclei

Question 38

how would you describe the striations in cardiac muscle

Answer 38

arrangement of contractile proteins similar to skeletal muscle, striations less obvious as myofibrils and cells are more irregularly shaped

Question 39

name a key feature to cardiac cells

Answer 39

they have intercalated discs - Cardiac muscle consists of individual heart muscle cells (cardiomyocytes) connected by intercalated discs to work as a single functional organ or syncytium.

Question 40

contraction of myocardium occurs as a whole in each cardiac cycle, what is it co ordinated by

Answer 40

coordinated by highly modified cardiac cells - purkinje system