1
Q
What are muscle tissues?
A
specialised types of connective tissues, responsible for movement and support of the body
2
Q
Types of muscle tissue? (3)
A
- Skeletal
- Cardiac
- Smooth
3
Q
Skeletal muscles? (4)
A
- Attach bone to muscle via tendons
- Responsible for voluntary muscle movements (Under conscious control)
- Striation
- Made up of long multinucleated muscle fibres
4
Q
Cardiac muscle (3)
A
- only in the heart the cardiac muscle is found it’s for pumping blood out of the heart
- Striation, nucleus, intercalated discs at the end of the fibre to help contract
- High density of mitochondria
5
Q
Smooth muscle (4)
A
- Non-striated muscle
- The wall of the organs
- Arranged in bundles and a multi layered
- Contracts involuntary to regulate digestion, respiratory and circulation
6
Q
Properties of muscle tissue (4)
A
- Excitability (Ability to respond to a stimuli)
- Contractility (Ability to shorten and generate a force)
- Extendibility (Ability to stretch)
- Elasticity (Ability to return to original shape)
7
Q
Characteristics common and muscle tissues (5)
A
- Contract ability – ability of muscle cells to Forcefully shorten
- Extendibility – ability of muscles to lengthen
- Elasticity – ability of muscles to return to normal size
- Atrophy – wasting of muscle tissue
- Hypertrophy – increased size of muscle tissue
8
Q
Types of muscle contraction (4)
A
- isometric
- Isotonic concentric
- Isotonic eccentric
- Isokinetic
9
Q
isometric
A
muscles generate force without length change e.g. a plank, wall sit
10
Q
Isotonic concentric
A
muscle shortens to generate a force e.g. curling a dumbbell
11
Q
Isotonic eccentric
A
muscle lengths while generating a force e.g. lowering the dumbbell
12
Q
Isokinetic
A
– muscle changes length at constant speed varying the resistance e.g. leg extension
13
Q
Structure of skeletal muscle
A
- Epimysium:
- Perimysium:
- Endomysium:
- Muscle fiber:
- Myofibril:
- Myofilaments
14
Q
- Epimysium:
A
The outer connective tissue that surrounds an entire muscle, holding it together.
15
Q
- Endomysium:
A
delicate connective tissue surrounding individual muscle fibers, providing support, facilitating nutrient exchange,
16
Q
- Perimysium:
A
The perimysium is connective tissue in muscle that surrounds and bundles muscle fibers, facilitating their coordinated contraction and transmitting neural signals.
17
Q
- Muscle fiber:
A
An individual muscle cell
18
Q
- Myofibril:
A
The contraction element of skeletal muscle.
19
Q
- Myofilaments
A
are protein filaments, including actin and myosin, found within myofibrils
20
Q
- Sarcomere:
A
The basic functional unit of a myofibril.
21
Q
- Actin:
A
A thin protein filament that acts with myosin filaments to produce muscle action.
22
Q
- Myosin:
A
One of the proteins that form filaments that produce muscle action.
23
Q
Neurones?
A
are the fundamental units of the nervous system.
24
Q
Nucleus -
A
a membrane enclosed organelle contains the cell genetic material
25
Axon -
long fibre of a nerve cell, sends electrical impulses from the cell body though the axon to target cells
26
Dendrites -
brings info to cell body
27
Motor end plate -
neuromuscular junction is the synapse of the axon terminal where a muscle cell communicates with a target cell
28
Synapse -
the small junction across where a nerve impulse passes from one cell to another
29
Neuromuscular junction -
motor units work together to make skeletal movement
30
Action potential -
conduction of the impulse down the motor neurone via the axon
31
Neurotransmitter
- Chemicals that transmit signals across a synapse from one neurone to another
32
Acetylcholine -
primary neurotransmitter for motor neurone that supply neurone for the skeletal muscles (to contract muscles)
33
Cholinesterase -
enzymes that catalyses the hydrolysis of the neurotransmitter acetylcholine into choline and acetic acid, a reaction that is necessary to allow a neutron to return to its resting state after activation (to relax the muscles)
34
Property of antagonist muscle pairs? (8)
Contraction time
resistance to fatigue
force production
energy systems
mitochondrial density
capillary density
oxidative capacity
size of motor neuron
35
SFT?
Myosin filaments slide in and out between each other to form a muscle contraction
36
Tropomyosin =
an actin-binding protein that regulates muscle contaction
37
T tubule =
transverse tubule is an extension of the sarcolemma which goes inside the muscle fiber
38
Troponin =
complex of 3 proteins attached to tropomyosin needed to move tropomyosin from the binding site
39
Sarcoplasmic reticulum =
regulates calcium ions
40
Sarcolemma =
fine transparent tubular sheath covering the muscle fiber
41
Process of the SFT?
1. Nerve impulse arrive at the muscular junction and releases a chemical called ACH
- this causes sodium ions to enter the muscle and modify the myofibril
- causes the calcium to be released from the sarcoplasmic reticulum
1. Calcium binds to the troponin - allowing tropmyosin to move away from the myosin binding site on the actin
2. myosin filaments attach to actin forming a cross bridge
3. A power stoke takes place - the myosin pulls the actin inwards to shorten the muscle
4. Z line gets closer together and the H zone gets smaller
5. When a new ATP molecule binds to the myosin head, myosin detaches from the actin and the cross bridge is broken
6. The ATP is broken down so the myosin head can attach to the actin binding site again (repeaters the power stroke)
7. This process of muscular contraction can last for as long as there is ATP and Ca stores
- ACH is removed by cholinesterase
- Calcium is pumped back into the sarcoplasmic reticulum and the myosin heads can move back to their resting position (away form actin) so the muscle can relax and lengthen
42
Injury?
is defined as a reduction or loss of bodily function or structure
- Injury can negatively affect a person’s motivation and ability to exercise; for athletes, it can impact competition, ranking, sponsorships, and team opportunities.
43
trauma in sport science
refers to pain, discomfort, or loss of function experienced during exercise (e.g., feeling a muscle pull and pain).
44
Classifications of human tissue that can be affected by sports injuries (4)
1. **Nervous tissue:** Nerve impingement from a herniated disc.
2. **Epithelial tissue:** Skin abrasions.
3. **Muscle tissue:** Strains or tears.
4. **Connective tissue:** Ligament sprains or tendinopathies.
45
Main types of injury onsets and provide examples of each (3)
1. Acute injuries: Occur suddenly due to trauma, e.g., ligament sprain or bone fracture.
2. Sudden-onset repetitive injuries: Result from repetitive stress not conditioned for, e.g., stress fractures.
3. Gradual-onset repetitive injuries: Develop slowly over time, e.g., tendinopathy from overuse
46
5 stages of likelihood of risk
- almost certian
- likely
- possible
- unlikely
- rare
47
5 stages of severity of risk
- negligible
- minor
- moderate
- major
- extreme
48
Internal risk factors -
are those relating to the person exercising or participating in physical activity. These are athlete or participant dependent.
49
Internal risk factors (9) examples
- Age
- Gender
- Psychological
- Pregnancy
- Training effects
- Congenital (from birth)
- Postural Defects
- Fitness Levels
- Previous injury
50
External risk factors -
relate to outside the exercising person, for example, the environmental conditions or the playing surface.
51
7 examples of external risk factors?
- Protective equipment
- Position
- Playing surface (turf = abrasions, grass = slips, court = sprains)
- Poor Coaching (Faulty techniques instructed)
- Fitness levels (lower fitness, higher injury)
- Skill level (more skill, higher injury)
- Somatotype (body composition) (Endomorphs (higher mass) = joint strain, Mesomorphs (higher muscle mass) = greater force, chance of more severe injury), Ectomorphs (higher slenderness) = stress fractures)
