Muscle Tissues

Question 1

What are the 3 types of muscle?

Answer 1

skeletal, cardiac and smooth

Question 2

what is muscle tissue specialised for?

Answer 2

contraction/relaxation

Question 3

what is the structure of skeletal muscle and what type of control is it under

Answer 3

striated and under voluntary control (somatic)

Question 4

what is the structure of cardiac muscle and what control is it under?

Answer 4

striated and under involuntary control (autonomic)

Question 5

what is the structure of smooth muscle and what control is it under?

Answer 5

non-striated and under involuntary control (autonomic)

Question 6

what is skeletal muscle tissue like?

Answer 6

elongated cylindrical cells (muscle fibres)

Question 7

where are the nuclei located on skeletal muscle tissue?

Answer 7

multiple nuclei peripherally located

Question 8

where is skeletal muscle found?

Answer 8

attached to the skeleton

Question 9

what is the function of skeletal muscle?

Answer 9

voluntary movement of skeleton, subconscious movement e.g. balance/posture

Question 10

what are skeletal muscles composed of?

Answer 10

skeletal muscle tissue, nervous tissue, blood vessels and connective tissues

Question 11

what do the blood vessels in skeletal muscle do?

Answer 11

deliver metabolites

Question 12

what do connective tissues in skeletal muscle do?

Answer 12

add strength and support and help contraction of muscle

Question 13

what is an epimysium?

Answer 13

dense connective tissue surround the whole muscle

Question 14

what separates individual skeletal muscle fibres?

Answer 14

endomysium

Question 15

what are groups of skeletal muscle cells grouped together in?

Answer 15

fasciculi

Question 16

what is each fasciculi surround by?

Answer 16

loose connective tissue called perimysium

Question 17

what surrounds the entire skeletal muscle?

Answer 17

dense connective tissues caled epimysium

Question 18

what is each skeletal muscle cell packed full of?

Answer 18

myofibrils

Question 19

why do skeletal muscle fibres appear striated?

Answer 19

the arrangement of myofibrils

Question 20

what are myofilaments?

Answer 20

myofibrils composed of repeating protein units

Question 21

histologically what are the dark bands seen in skeletal muscle?

Answer 21

myosin

Question 22

histologically what are the light bands seen in skeletal muscle?

Answer 22

actin

Question 23

what are sarcomeres?

Answer 23

contractile units of skeletal muscle

Question 24

how do sarcomeres contract?

Answer 24

sliding filament mechanism - a conformational change causes the filaments to slide over each other causing the sarcomere to contract

Question 25

what innervates skeletal muscle?

Answer 25

somatic motor neurons

Question 26

what is a motor unit?

Answer 26

a single motor neuron together with all the muscle fibres

Question 27

what do individual motor neurons do?

Answer 27

innervate several muscle fibres

Question 28

what happens when somatic motor neurons innervate skeletal muscle?

Answer 28

neuronal action potential is converted to chemical messenger (acetylcholine) at neuromuscular junction. detected by receptors on muscle fibres. stimulates action potential in muscle fibres

Question 29

what is a sarcolemma?

Answer 29

specialised plasma membrane only in muscle cells

Question 30

what does a sarcolemma do?

Answer 30

invaginates into sarcoplasm to form membranous T tubules

Question 31

what do T tubules do?

Answer 31

interact with sarcoplasmic reticulum and wraps around myofibrils within the muscle cell

Question 32

how are muscular action potentials regulated?

Answer 32

the release of calcium by motor neuron stimulation

Question 33

what is the joint function of the sarcolemma and sarcoplasmic reticulum?

Answer 33

support synchronous contraction of sarcomeres

Question 34

where is cardiac muscle found?

Answer 34

in the heart

Question 35

what is the function of cardiac muscle?

Answer 35

specialised for continuous autonomous contractions. pump blood through the cardiovascular system

Question 36

what is the structure of cardiac muscle?

Answer 36

elongated branched cylindrical cells

Question 37

comment on the location of the nuclei in cardiac muscle

Answer 37

one or two centrally located nuclei

Question 38

what is the appearance of cardiac muscle?

Answer 38

striated

Question 39

what are the 3 layers of the heart wall?

Answer 39

pericardium, myocardium and endocardium

Question 40

what is the pericardium?

Answer 40

outer supporting tissue layer

Question 41

what is the myocardium?

Answer 41

cardiac muscle tissue

Question 42

what is the endocardium?

Answer 42

single layer of endothelial cells

Question 43

what are individual cardiac muscle fibres surrounded by?

Answer 43

retivular connective tissues

Question 44

comment on the vascularity of cardiac muscle

Answer 44

there is a rich capillary network

Question 45

what are intercalated discs and what do they do?

Answer 45

specialised intercellular junctions that anchor adjacent cells together

Question 46

in what ways is cardiac muscle similar to skeletal muscle?

Answer 46

Identical arrangement of sarcomeres. Contain T tubules and sarcoplasmic reticulum. Numerous mitochondria. Glycogen and lipid granules. Contraction by sliding-filament mechanism.

Question 47

in what ways is cardiac muscle different to skeletal muscle?

Answer 47

cardiac muscle contraction is autonomous. SR slowly leaks Ca2+. Cardiac muscle has intercalated discs.

Question 48

what are modified cardiac muscle cells known as?

Answer 48

conducting system

Question 49

what is cardiac muscle modulated by?

Answer 49

external autonomic/hormonal stimuli

Question 50

where is the conducting system of the heart initiated?

Answer 50

the sinoatrial node (pacemaker cells)

Question 51

what does the conducting system do?

Answer 51

directs and conducts action potential within cardiac muscle

Question 52

where does the action potential travel to once it has reached the sinoatrial node?

Answer 52

the atrioventricular node

Question 53

what is the conducting system of the heart regulated by?

Answer 53

nerve cells interacting with every cardiac cell

Question 54

what do intercalated discs do?

Answer 54

help to send nerve signals from cell to cell

Question 55

what is the rate of inherent rhythm in the heart modulated by?

Answer 55

autonomic nervous stimulation and hormonal stimulation

Question 56

where is smooth muscle found?

Answer 56

lining hollow organs

Question 57

what is smooth muscle specialised for?

Answer 57

continuous contractions

Question 58

what is the function of smooth muscLE?

Answer 58

typically to propel lumen contents - peristalsis

Question 59

what is the structure of smooth muscle?

Answer 59

small elongated spindle-shaped cells with tapered ends

Question 60

comment on the location of the nuclei on smooth muscle

Answer 60

single centrally located nuclei

Question 61

are there striations in smooth muscle and why?

Answer 61

no because there are no sarcomeres

Question 62

what is peristalsis

Answer 62

movement of food through the GI tract

Question 63

what does the inner circular layer of smooth muscle do?

Answer 63

constricts lumen diameter

Question 64

what does the outer longitudinal layer of smooth muscle do?

Answer 64

shortens length of muscle

Question 65

what does the parasympathetic nervous system do?

Answer 65

modulate intensity of peristalsis

Question 66

how are actin and mysoin arranged in smooth muscle?

Answer 66

criss-cross lattice

Question 67

what do focal densities do?

Answer 67

anchor actin and myosin in smooth muscle to cytoplasm and cell membrane

Question 68

when relaxed what does a smooth muscle cell look like?

Answer 68

elongated

Question 69

when contraction occurs what does a smooth muscle cell look like?

Answer 69

shortened and globular