Run for your life Flashcards
What is an antagonistic pair
when one muscle contracts and the other one relaxes to induce a movement.
What are synovial joints?
- synovial fluid is present between the bones
Wht to tendons do?
connect muscle to bone
what do ligaments do
connect bone to bone
what occurs in arthritis
- swelling of joints - either bone ends rub together and cartilage in thinned (osteoarthritis)
- or bone erosion due to a swollen, inflamed synovial membrane
What are extensors and flexors?
extensors extend the limb
flexors bend the limb
Describe the size by size comparison of a bundle to muscle fibers
bundle of muscle fibers –> one muscle fiber —> myofibrils —> sarcomere
What does a sarcomere contain
a repeated unit of actin and myosin filaments
Describe/define the following terms:
- A Band
- I band
- H zone
- Z disk
- Region with overlapping of myosin and action filaments, including a myosin only area in the middle.
- Actin only area
- Only myosin filaments (in the middle of the A band)
- Z disk links adjacent sarcomeres together, zigzag line with actin molecules on either side, leading to 2 different sarcomeres
describe what happens to the Bands when a muscle contracts
- Z lines move closer together, I band gets smaller.
- A band remains the same
Describe the role of calcium ions in muscle contraction.
- bind to Tropomyosin is moved by troponin
- this exposes the myosin binding sites on actin.
Describe the changes that help muscle contraction occur after Ca2+ ions are bound.
- myosin heads can now bind to binding sides
- this causes the myosin to change shape
- actin filaments pulled over the myosin towards the M line
- sarcomeres therefore shorten.
explain the interaction between Ca2+ ions, Troponin and Tropomyosin
- Ca2+ binds to troponin, which causes it to change shape
- This causes tropomyosin to move away from the myosin binding site.
Describe how the concentration of Ca2+ ions around the myofibrils is controlled
- Ca2+ ions released from sarcoplasmic reticulum
- in response to action potential at neuromuscular junction
- Calcium channels open to allow ions to cross across the membrane
- Ca2+ ions taken back into the sarcoplasmic reticulum by active transport.
Name the 4 stages in order of aerobic respiration
- glycolysis
- link reaction
- Krebs cycle
- oxidative phosphorylation
Describe the cardiac cycle
- blood flows in through the vena cava, into the atria, increasing pressure.
- this opens the AV valves, causing atrial systole to take place.
- blood fills the ventricles, increasing pressure.
- AV valves close, and SL valves open out of the ventricles into the heart.
- diastole takes place.
what does myogenic mean in terms of the heart?
no external signal required to beat, beats on its own.
describe how a heart beat is coordinated.
- cells in the sinoatrial node become depolarised
- depolarisation spreads through the walls of the atria, causing atrial systole.
- Atrio ventricular node detect this depolarisation, sending impulses down the bundle of his (bundle of purkyne fibres) , and then down to the Purkyne fibres.
- after a slight delay (to ensure ventricles contract after the atria), this causes ventricular systole.
- ventricles contract from the apex upwards.
Why can’t the ventricles receive the depolarisation from the SAN?
atria and ventricles separated by a layer of non conducting tissue. (annulus fibrosus)
name 4 factors that effect heart rate
- low pH
- Stretch receptors
- decrease in BP
- Adrenaline
Describe the process of glycolysis
- glucose is phosphorylated to produce 2 pyruvate molecules, 2 ATPs and 2 NADH (end products)
- Glucose is phosphorylated to glucose bisphosphate.
- splits into triose phosphate, and this is oxidised to pyruvate. (NAD is reduced to NADH)
Describe the processes involved in the Link reaction.
- Pyruvate is oxidised (NAD–> NADH)
- simultaneously, it looses a Carbon (due to the coenzymeA)
- this produces CO2 and AcetylCoA and NADH as final products
Describe the processes involved in the krebs cycle
- acetylCoA reacts with a 4C compund to produce a 6C compound. In this process, CoA is reformed and goes back to the link reaction.
- the 6C compund is oxidised to a 5C compound - where NAD is reduced to NADH, and CO2 is produced
- this 5C compund is then resynthesised to the original 4C compound - producing 2NADH, 1FAD, and 1ATP molecule. (CO2 also produced)
Describe the processes involved in oxidative phosphorylation
- the Hydrogen carriers (NADH and FAD) are oxidised, producing electrons and H+ ions
- the electrons go through electron transport proteins, a series of redox reactions.
- the energy released from these reactions is used to actively pump H+ ions into the intermembrane space.
- H+ ions then diffuse back down an electrochemical gradient, through ATP synthase, which simultaneously produces ATP from ADP + Pi
- the H+ ions are accepted by oxygen, forming water.
How is lactate formed?
- when pyruvate accepts a H from NADH
What is substrate level phosphorylation?
- enzymes remove a “high-energy” phosphate from an organic substrate and directly transfer it to ADP to form ATP
describe the process of anaerobic respiration during glycolysis
glucose is converted into
pyruvate by glycolysis
the pyruvate is then further converted into lactate with the help of NADH in a process known as lactate fermentation.
Lactate is then converted back to pyruvate in the liver.
Describe the whole process of the sliding filament theory in muscle contraction.
- Ca2+ ions released from sarcoplasmic reticulum
- Ca2+ ions bind to troponin
- troponin binds to tropomyosin, and moves it aside to expose myosin binding sites
- Myosin heads have ADP attached - which enable them to the binding site on acting and create a cross bridge.
- Myosin heads release their ADP molecules when they slide actin (creating an angle that creates tension)
- ATP molecules bind to myosin heads to dettach the myosin heads.
- the ATPase in the myosin heads hydrolyse ATP.
- this returns myosin heads to their starting positions - ready for another cycle.
What happens to lactate after a period of anaerobic respiration?
- transported back to the liver where it is converted to glucose.
what is the enzyme that catalyses the formation of lactate from pyruvate?
- lactate dehydrogenase.
Describe the benefits of moderate exercise.
- increases NK cell count and activity
- prevents obesity as energy output is happening, preventing risks for hypertension, diabetes etc.
- increased bone density, reducing risk of osteoporosis
- increases vasodilation, lowering BP, decreasing chances of hypertension.
Describe the drawbacks of intense excersise.
- increases the chances of upper respiratory tract infections
- increases risk of joint injuries - torn ligaments, inflammation, damaged cartilage etc.
Name some advantages of keyhole surgery
- less invasive so easier recovery
- less blood loss
- less pain
Define the term doping
- the use of banned performance enhancing drug in sports
Describe the role of the brain in reducing heart rate after exercise
- chemoreceptors detect decrease in blood pH
- thus resulting in impulses being sent to the SAN to decrease heart rate.
Describe how the brain reduces sweat production after the body cools down to its base temp
- thermoreceptors detect decrease in temperature
- thus, less impulses are sent to the sweat glands from the thermoregulatory centre in the hypothalamus.
Describe how thermoregulatory mechanisms are controlled to help marathon runners avoid
heat stress.
- thermoreceptors in the hypothalamus detect change in temperature environment
- thermoregulatory centre in hypothalamus is stimulated.
- The hypothalamus sends impulses to sweat glands to produce more sweat
- vasodilation occurs, increasing blood flow to surface of skin.
Give 2 arguments against doping
- health concerns
- gives athletes who use it an unfair advantage
Explain the role of the nervous system in bringing about the increase in
temperature of the fingertip
- thermoreceptors detect increase in temperature
- thermoregulatory centre in hypothalamus is activated
- impulses sent through sympathetic nervous system
- causes constriction of shunt vessels
- this causes vasodilation
- allowing more blood to flow to the surface of the skin.
Describe how transcription factors work to bring about a change in gene expression
- transcription factors bind to the promoter region, forming a transcription initiation complex with RNA polymerase.
- this results in the synthesis of mRNA.
Where does the repressor bond to on the operon?
the operator region
