Muscle Properties

Question 1

5 Functions of muscles

Answer 1

1. Movement - muscular contraction
2. Posture
3. Heat production - aka thermogenesis maintains normal body temps
4. Storage of substances - glycogen & oxygen
5. Movement of substances

Question 2

4 muscle properties

Answer 2

1. Contractility
2. Excitability - can conduct an electrical impulse/current
3. Extensibility - stretch without damage
4. Elasticity - return to original length

Question 3

What is a striated muscle

Answer 3

Muscles that contain cell fibres that are aligned in parallel bundles which helps to control movement eg skeletal & cardiac muscles

Question 4

What is a non-striated muscle

Answer 4

Contain cells that are randomly arranged eg smooth muscle

Question 5

What is fascia

Answer 5

A dense sheet of connective tissue that organises muscle, secures it to skin and provides stability

Question 6

What are myofibrils

Answer 6

Cylindrical structures formed of bundles of protein filaments within muscle fibre

Question 7

What are the two types of myofilaments

Answer 7

1. Actin - thin filament

2. Myosin - thick filament

Question 8

What is a sarcomere

Answer 8

The basic unit of striated muscle where myofilaments overlap

Question 9

What is endomysium

Answer 9

A thin sheath that surrounds Individual muscle fibres

Question 10

What is perimysium

Answer 10

Bundles of 10-100 muscle fibres that surround fascicles

Question 11

What is epiysium

Answer 11

Attaches the entire muscle to fascia and tendons

Question 12

What is the neuromuscular junction

Answer 12

The meeting point (synapse) where motor neurons meet a muscle fibre

Question 13

What is acetylcholine (ACH)

Answer 13

The neurotransmitting chemical at a junction

Question 14

Describe the process of muscle contraction

Answer 14

Acetylcholine diffuses across the synapse & send nerve impulse across the sarcolemma & transverse tubules of a muscle fibre.
This releases calcium & ATP which cause the actin and myosin filaments to bind and slide over eachother

Question 15

Describe the process of muscle relaxtion

Answer 15

Nerve impulses stop and use magnesium & ATP to break the actin & myosin bond which slide back into their original position

Question 16

What role does magnesium play in muscle fibres

Answer 16

Makes them less excitable & prevents myosin binding with actin

Question 17

What nutrients are essential for effective muscle activity & athletic performance

Answer 17

Calcium,
magnesium,
sodium, 
potassium
iron

Question 18

What hormones promote muscle hypertrophy

Answer 18

Growth hormone
Testosterone
Thyroid hormones

Question 19

What are the two pathways for ATP synthesis

Answer 19

1. Aerobic respiration

2. Anaerobic respiration

Question 20

What are the 3 essential nutrients for ATP production

Answer 20

Glucose
Fatty acids
Amino acids

Question 21

Where does aerobic respiration occur

Answer 21

Within mitochondria (often located next to myoglobin)

Question 22

Where does anaerobic respiration occur

Answer 22

Takes place in the cytoplasm & occurs via glycolysis (breakdown of glucose)

Question 23

What is creatine phosphate

Answer 23

A protein unique to muscles & a storage form of energy

Question 24

Properties of slow oxidative muscles

Answer 24

Dark red - lots of myoglobin & mitochondria
In turn means aerobic respiring muscles
Good for endurance eg postural

Question 25

Properties of fast oxidative glycolytic muscles

Answer 25

White-pink - less myoglobin&mitochondria Aerobically and anaerobically respires Also more resistant to fatigue Good for walking & sprinting

Question 26

Properties of fast glycolytic muscles

Answer 26

White - due to lack of myoblobin & mitochondria Anaerobically respires Fatigues quickly Good for weights eg arms/shoulders

Question 27

What attaches the skeletal muscles to the periosteum of bone

Answer 27

Tendons at muscle attachment points

Question 28

What is a prime mover muscle

Answer 28

The main muscle contracting in a movement

Question 29

What is an antagonist muscle

Answer 29

The muscle acting in opposition to the prime mover

Question 30

What is a synergist muscle

Answer 30

A muscle that assists the prime mover muscle in its action

Question 31

What is a fixator muscle

Answer 31

A muscle that stabilises the origin bone while a prime mover contracts

Question 32

How do intercalated discs assist the myocardium

Answer 32

branching cells joined to end-to-end structures that allow contraction to spread from cells like a wave

Question 33

Does the myocardium rely on aerobic or anaerobic respiration

Answer 33

Aerobic Highly! Lots of mitochondria as requires constant blood supply & deivery of oxygen & nutrients

Question 34

Process of smooth muscle contraction

Answer 34

Similar structure to z disc in sarcomeres, arranged at 90 degree angle Filaments attached to dense bodies are pulled together causing the muscle to shorten & twist like a crokscrew Is slower & longer with clacium movement compared to the other muscles Smooth muscle maintains partial contraction ie important for blood pressure

Question 35

What is a smooth muscle stress-relaxation response

Answer 35

Where organs such as stomach & bladder to expand when filled & a contraction to carry contents

Question 36

What do satellite cells help

Answer 36

They have a limited regeneration process that works to help skeletal muscles regenerate

Question 37

What is the muscle cell membrane called

Answer 37

Sarcollema

Question 38

What is the muscle cell cytoplasm called

Answer 38

Sarcoplasm

Question 39

What does the muscle cells sarcoplasmic reticulum store

Answer 39

Stores calcium which is needed in assisting muscle contraction

Question 40

What is the motor end plate

Answer 40

The location where motor neurons terminate in tiny pads on the muscle fibre

Question 41

What is single unit smooth muscle

Answer 41

Fibres are connected by gap junctions and the cells relax and contract in a single unit Eg walls of vessels

Question 42

What is multi unit smooth muscle

Answer 42

Fibres are stimulated individually & operate independently of one another, contain no gap junctions Eg found in walls of larger arteries & airways, iris & arrector pilli

Question 43

How do muscles contribute to skin homeostasis

Answer 43

Facial expressions | Muscle action increases blood flow to skin

Question 44

How do muscles contribute to nervous system homeostasis

Answer 44

Shivering - generates heat & raises body temperature

Question 45

How do muscles contribute to endocrine gland homeostasis

Answer 45

Exercise can improve action of some hormones eg insulin | Muscle protects some glands

Question 46

How do muscles conrtibute to cardiovascular homeostasis

Answer 46

Cardiac muscle Pumps blood Smooth muscle in blood vessel walls controls blood flow Muscle contraction in legs helps return blood to heart Exercise leads to hypertrophy of cardiac muscle Lactic acid produced in skeletal muscle can be used to make ATP in heart

Question 47

How do muscles contribute to reproductive homeostasis

Answer 47

Skeletal and smooth muscle comtractions eject semen | Contractions propel egg along uterine tubes, control menstrual flow & expel baby from uterus in birth