Week 6

Question 1

5 specialisations of skeletal muscle

Answer 1

• long cylindrical cells
• many nuclei
• striated
• voluntary
• rapid contractions

Question 2

5 specialisations of cardiac muscle

Answer 2

• branching cells
• one or two nuclei per cell
• striated
• involuntary
• medium speed contractions

Question 3

5 specialisations of smooth muscle

Answer 3

• fusiform cells
• one nucleus
• nonstriated
• involuntary
• slow, wave like contractions

Question 4

what 3 equilibriums exist on the cell membrane

Answer 4

chemical, electrical, osmotic

Question 5

what is an electrical gradient created by

Answer 5

the input of energy to transport ions across a membrane

Question 6

what is the electrochemical gradient

Answer 6

the active transport of positive ions out of the cell creates a chemical gradient, the combination of the chemical and electrical gradient

Question 7

what is the resting membrane potential

Answer 7

the electrical gradient across the cell membrane

Question 8

is the electrical gradient created by active or passive transport

Answer 8

active transport

Question 9

what is the resting membrane potential

Answer 9

-40 to - 90mV

Question 10

what chemical opens Na+ channels

Answer 10

acetylcholine

Question 11

what are the three types of muscle

Answer 11

skeletal, smooth and cardiac muscle

Question 12

what types of muscle forms the majority of muscle tissue in the body

Answer 12

skeletal muscle

Question 13

how is skeletal muscle organised

Answer 13

parallel bundles of long, multinucleated fibres

Question 14

what is the power/stamina of skeletal muscle like

Answer 14

skeletal muscle is capable powerful contractions but can tire very quickly

Question 15

what is an aponeurosis

Answer 15

a thin sheet of connective tissue

Question 16

is skeletal muscle controlled voluntarily or involuntarily

Answer 16

voluntarily but not always

Question 17

where is the muscle belly found

Answer 17

between the origin and insertion

Question 18

what is a muscle fascicle

Answer 18

bundles of muscle fibers

Question 19

what is a muscle fiber

Answer 19

bundles of myofibrils

Question 20

what is a myofibril

Answer 20

bundles of myofilaments

Question 21

what is the endomysium

Answer 21

a thin layer of connective tissue that surrounds each muscle fiber

Question 22

what is the perimysium

Answer 22

a thick layer of connective tissue that surrounds each muscle

Question 23

what is the function of the permysium

Answer 23

to protect the fascicle from damage. it also contains capillaries and nerve fibers

Question 24

what is the epimysium

Answer 24

a sheet of thick connective tissue that surrounds the entirety of a skeletal muscle. it may continue at the end of the muscle belly as a tendon and thus become continous with the periosteum

Question 25

what is the function of the epimysium

Answer 25

to separate the muscle from surrounding tissues and organs

Question 26

what does each skeletal muscle fiber contain

Answer 26

a plasma membrane, cytoplasm, nuclei, sarcoplasmic reticulum and is composed of bundles

Question 27

what is the sarcolemma

Answer 27

the plasma membrane of a muscle fiber. it has invaginations from the T tubules

Question 28

what is the function of the sarcolemma

Answer 28

to receive electrical stimuli and conduct an action potential to the internal structure of the muscle fiber

Question 29

what is the sarcoplasmic reticulum

Answer 29

a special type of smooth ER found only in skeletal muscle cells

Question 30

what is the function of the sarcoplasmic reticulum

Answer 30

stores large, concentrated stores of calcium

Question 31

what is the sarcoplasm

Answer 31

the cytoplasm of muscle cells

Question 32

what is the function of the sarcoplasm

Answer 32

to store large amounts of glycogen and myoglobin - glycogen provides energy during muscle contraction - myoglobin contains stored oxygen

Question 33

what are myofibrils

Answer 33

thread like organelles micro meters in diameter that extend the length of the muscle fiber

Question 34

what are two general types of skeletal muscle fibers

Answer 34

slow twitch (type 1) and fast twitch (type 2)

Question 35

what is the structure of fast twitch muscles

Answer 35

fast twitch muscles are thicker and quicker to contract than slower twitch muscles

Question 36

what is the endurance of slow twitch muscles like

Answer 36

slow twitch muscles have generally more endurance than fast twitch muscles

Question 37

where is cardiac muscle found

Answer 37

the walls of the heart

Question 38

what is special about cardiac muscle

Answer 38

cardiac muscle is resistant to fatigue and contracts without any external stimulation

Question 39

what is word used to describe the nerves that stimulate cardiac muscle

Answer 39

autonomic

Question 40

what does autonomic mean

Answer 40

the control is involuntary

Question 41

where is smooth muscle found

Answer 41

the walls of internal organs, such as organs of the digestive system, walls of blood vessels and the intrinsic muscles of the eye

Question 42

what is the structure of the smooth muscle

Answer 42

smooth muscle is non-striated, it consists of elongated or spindle-shaped fibres

Question 43

what type of contractions are smooth muscles capable of

Answer 43

slow, sustained contractions

Question 44

how is smooth muscle controlled

Answer 44

smooth muscle is able to contract without external stimulation, and is modified by the autonomic nervous system. it is under involuntary control and doesn't fatigue

Question 45

what is the electrical excitability of muscle

Answer 45

the ability of a muscle to respond to stimuli

Question 46

what is the contractility of a muscle

Answer 46

the ability of a muscle to shorten in response to an action potential

Question 47

what is the extensibility of muscle

Answer 47

the ability of a muscle to stretch

Question 48

what is the elasticity of a muscle

Answer 48

the ability of a muscle to recover its original shape after contraction or extension

Question 49

how does muscle contribute to body movement

Answer 49

the contraction and relaxation of muscles produce movement around various joints of the body

Question 50

how does muscle contribute to the stabilisation of joints

Answer 50

regulates the degree of movement possible at each joint

Question 51

how does muscle contribute to the maintenance of body positions

Answer 51

continuous or sporadic contraction of skeletal muscles around the body helps us to maintain our posture and position

Question 52

how does muscle contribute to storage of substances

Answer 52

contraction of smooth and skeletal muscle at specific points within the body enables certain substances to be kept in one place

Question 53

how does muscle contribute to he movement of substances

Answer 53

relaxtion of cardiac and smooth muscle at specific points within the body controls the movement of substances from one place to the other

Question 54

how does muscle contribute to thermogenesis

Answer 54

contracting muscles produce heat as a by-product and this contributes to the maintenance of normal body temperature

Question 55

what is muscle atrophy

Answer 55

the weakening and shrinking of a muscle

Question 56

what is muscle atrophy caused by

Answer 56

immobilisation or loss of neural stimulation

Question 57

what is muscle hypertrophy

Answer 57

the enlargement of a muscle

Question 58

what is muscle hyperplasia

Answer 58

an increase in muscle cell numbers

Question 59

where does excitation contraction coupling take place

Answer 59

the sarcoplasm of a muscle fiber

Question 60

where are a large number of calcium ions stored

Answer 60

the sarcoplasmic reticulum

Question 61

where are the calcium ions released

Answer 61

during contraction to mediate the process by binding to troponin

Question 62

5 key biological roles of calcium

Answer 62

- neuromuscular excitability and maintenance of membrane potential - blood clotting cascade - hormonal secretion - enzymatic regulation - cell signalling

Question 63

what is the normal range of plasma calcium

Answer 63

2.2-2.6 mmol/L

Question 64

why do we measure albumin

Answer 64

because albumin carries calcium in the blood, low albumin can make total calcium look low even when the true active calcium level is normal. measuring both helps interpret calcium accurately. (free and bound calcium)

Question 65

what two key hormones are involved in the metabolic control of calcium

Answer 65

- parathyroid hormone - 1,25dihydroxyvitamin D

Question 66

what four organs are involved in calcium regulation

Answer 66

- parathyroid glands - kidney - gut - bone