T7 - Run for your life Flashcards
Define a joint
- the physical point of connection between 2 bones
- the point at which 2 or more bones articulate
What is a ligament
- connect bone to bone and help stabilize joints they surround
- composed of long, collagen fibres
- that create bands of tough, fibrous connective tissue
- slightly elastic, increasing flexibility
- can become overstretched
What is a tendon
- tough and inelastic bands of fibrous tissue that attach skeletal muscles to bone
What is cartilage
- firm, flexible tissue that acts as a shock absorber and reduces friction
What does the flexor muscle do
- bends a joint (decreases angle between 2 bones)
What does the extensor muscle do
- straightens a joint (increases angle between 2 bones)
Define antagonistic muscles
- when two muscles work in a pair, one contracts as the other one relaxes to allow movement
- e.g. bicep and tricep
Examples of joints
- ball and socket joints - shoulders and hips
- pivot joints - neck
- hinge joints - knee and elbow
Why are muscle cells multinucleated
- for sufficient mRNA and so that mRNA is in the right place for translation into proteins
- proteins can be synthesised close to the site of function so less need for transport over large distances
- more efficient
Where are the mitochondria located in a muscle cell
right beside / under the sarcolemma
Why are the mitochondria not located within the myofibrils?
- they would be in the way of the contracting microfibril
- it takes longer for blood to reach the microfibril
Properties of fast twitch muscles
- fast speed of contraction + short bursts of movement
- strong power of contraction
- a short length of contraction
- adapted for activities that require power and speed
- white in colour
Properties of slow twitch muscles
- slow speed of contraction + gently
- weak power of contraction
- long lengths of contraction
- adapted for endurance activities
- dark red in colour
Why are chicken breasts white in colour
- they are fast twitch muscles
- they don’t need much myoglobin and oxygen
- as they respire anaerobically
- few blood vessels
Why is duck meat dark red in colour
- they are slow twitch muscles
- they need lots of myoglobin and oxygen
- as they respire aerobically
- lots of blood vessels
Why do fast twitch muscles have fewer mitochondria
- it has a bigger store of glycogen than glucose
- energy from the hydrolysis of glycogen is used instead of ATP from mitochondrial
- respire anaerobically
- it uses creatine phosphate to produce ATP from ADP for energy
Why do slow twitch muscles have more mitochondria
- it has a bigger store of glucose than glycogen
- ATP from aerobic respiration is used as energy
In muscles cells, is actin thick or thin
Thin
In muscles cells, is myosin thick or thin
Thick
A band in muscle cells contains what
Both myosin and actin
I band in muscle cells contains what
Only actin and Z line
What is rigor mortis and how is it caused?
- stiffening of the joints and muscles of a body a few hours after death
- because there is no aerobic respiration after death ATP is not made
- as there is no ATP to detach the myosin heads, the muscles remain contracted
Sliding filament theory process
- An action potential arrives at the neuromuscular junction
- Calcium ions (Ca2+) are released from the sarcoplasmic reticulum
- Calcium ions bind to troponin molecules, stimulating them to change shape
- This causes troponin and tropomyosin proteins to change position on the actin filaments
- Myosin binding sites are exposed on the actin
- The globular heads on the myosin molecules bind with these sites, forming cross-bridges between them
- The formation of the cross-bridges causes the myosin heads to bend
- Releasing ADP and Pi, pulling the actin filaments towards the centre of the sarcomere
- ATP binds to the myosin heads producing a change in shape that causes the myosin heads to release from the actin filaments
- The enzyme ATPase hydrolyses ATP into ADP and Pi which causes the myosin heads to move back to their original positions, known as the recovery stroke
- The myosin heads can now bind to new binding sites on the actin, closer to the Z line
- The myosin heads move again, pulling the actin filaments closer to the centre of the sarcomere.
Ethical reasons why the use of drugs should be banned from sport
- it can be a health risk to the athletes
- not fair to other athletes who do not use drugs
- pool role model to young kids
Benefits of keyhole surgery
- less damage to the tissue so less scarring
- short recovery time
- quick surgery so more patients can be treated
- cheaper than invasive surgery
- less anaesthetic needed
Benefits of prosthetics
- both cartilage and bone can be replaced
- allowing people with damaged bones to live a normal life and continue playing sport
How does working out too little lead to CVD
- reduces the muscles’ ability to pull oxygen out of the blood, increasing the need for the heart to pump more blood to the muscles
- increases stress hormones
- decreases HDL so increased risk of atherosclerosis and high blood pressure
How does working out too little lead to obesity
- increases the fat percentage as there is an energy imbalance
- energy that isn’t lost/used gets turned into fat
How does working out too little lead to diabetes
- lack of exercise can cause muscle cells to lose their sensitivity to insulin, which controls levels of sugar in the blood.
- increased blood sugar as muscle cells and liver do not need to use sugar from the blood
Disadvantages of exercising too much
- wear and tear of joints because of overuse
- reduction in the activity of immune cells (weaker immune system)
- releases hormones which can cause an inflammatory response, suppressing the immune system
- increased risk of infection
What is negative feedback
The reversing of a change in the internal environment to restore the optimum conditions.
What is positive feedback
Increases original change detected by receptors.
What does the body do to keep warm
- Shivering
- Vasoconstriction
- Hairs stand on end
What does the body do to cool down
- Sweat
- Vasodilation
- Hairs lay flat
Process to lose heat
- Thermoreceptors in hypothalamus detect increase in core temp/temp of blood
- Heat loss centre stimulated.
- Sweat glands release more sweat removing heat energy by evaporation.
- VASODILATION of arterioles
- SHUNT VESSELS CONSTRICT
- Arterioles dilate so more blood flows to skin surface (capillaries) / heat loss by RADIATION
How does sweating help
Sweat evaporates from the surface of the skin carrying heat away from the body by radiation
Process to gain heat
- Thermoreceptors in hypothalamus detect decrease in core temp/temp of blood
- Heat gain centre stimulated.
- Sweat glands release less sweat removing less heat energy form skin.
- VASOCONSTRICTION of arterioles
- SHUNT VESSELS DILATE
- Arterioles constrict so less blood flows to skin surface (capillaries)
Cardiac cycle
- An electrical impulse from the SA node spreads across both atria, causing them to contract together. ATRIAL SYSTOLE
- The blood leaves the atria through the AV-valves into the ventricles (which have a lower pressure).
- After a DELAY. The AV node then sends electrical impulses down the bundle of His, which is made up of Purkyne fibres to the hearts apex.
- The impulses spread up through the ventricle walls causing contraction from the apex upwards.
- Blood is squeezed into the arteries through the semi-lunar valves. VENTRICULAR SYSTOLE
What is the area of the brain that controls the heart rate
Medulla oblongata
1st part- A centre linked to sinoatrial node that INCREASES heart rate via the SYMpathetic nervous system.
2nd part - A centre linked to the sinoatrial node that DECREASES heart rate via PARAsympathetic nervous system.
Pressure changes in blood are controlled how
- Pressure receptors in the wall of aorta and carotid artery
- If BP is LOW receptors send a message via SYMpathetic NS
- If BP is HIGH receptors send a message via PARAsympathetic NS
Chemical changes in blood are controlled how
- Detected by chemoreceptors in wall of aorta and carotid artery.
- Low O2 means increased CO2 & lactate and low pH.
- If pH is low (acid blood): heart rate and breathing rate increases via SNS to remove CO2 from blood.
- If pH is high (alkaline blood): heart rate and breathing rate decreases via PSNS to increase CO2 in blood.
What neurotransmitter decreases heart rate
Acetylcholine, used in PSNS slows the rate of depolarisation
What neurotransmitter increases heart rate
Noradrenaline, used in SNS stimulates the adrenal gland to secrete adrenaline
What happens during glycolysis (in CYTOPLASM)
- NO OXYGEN REQUIRED
1. Glucose turns into 2 molecules of TP (3C) using 2 ATP molecules.
2ATP –> 2ADP
2. The 2 GP molecules (3C) get dehydrogenised into 2 Pyruvate molecules (3C) using 4 ADP and 2 NAD.
4ADP –> 4ATP & 2NAD –> 2NADH
3. OVERALL net 2 ATP produced and 2 NADH
What happens during link reaction (in MATRIX)
- Link reaction happens TWICE, once for each pyruvate molecule.
1. Pyruvate (3C) turns into Acetate (2C) by decarboxylation, producing 1 CO2 and using 1 NAD.
NAD –> NADH
2. Acetate (2C) then reacts with Coenzyme A making Acetyl coenzyme A (2C).
3. OVERALL 2 CO2 and 2 NADH are made
What happens during krebs cycle (in MATRIX)
- Krebs cycle happens TWICE, once for each acetyl coenzyme A molecule.
1. Acetyl coenzyme A (2C) binds with Oxaloacetate (4C) to make Citrate (6C).
2. Citrate (6C) then turns into a 5C compound by decarboxylation producing 1 CO2 and using 1 NAD.
3. The 5C compound then turns into a 4C compound by carboxylation producing 1 CO2 and using 1 NAD.
4. The 4C compound turns back into Oxaloacetate (4C) using 1 ATP, 1 FAD and 1 NAD.
5. OVERALL 4 CO2, 6 NADH, 2 ATP and 2 FADH are made.
What happens during oxidative phosphorylation (in MATRIX MEMBRANE)
- Hydrogen atoms released from NADH and FADH as they are oxidised.
- Hydrogen atoms split into protons and 2 electrons.
- Electrons move along the electron transport chain, losing energy at each carrier.
- Energy is used to pump protons into inter-membrane space forming an electrochemical gradient.
- Protons move down electrochemical gradient back to matrix via ATP synthase.
- Movement of protons drives synthesis of ATP from ADP and inorganic phosphate.
- Protons, electrons and oxygen combine to form water, the final electron acceptor.
2e- + 2H+ + 1/2 O2 –> H2O - OVERALL 1 NAD, 1 FAD, 1 H2O and lots of ATP are made.
What happens during anaerobic respiration in ANIMALS
- ONLY GLYCOLYSIS can happen
- Glucose is turned into pyruvate
- Producing 2 NADH and 2 ATP
- Pyruvate then turns into lactate using 2 NADH
- Lactate becomes lactic acid which decreases blood pH causing muscle fatigue
- Only 4 ATP molecules are created for energy
- When O2 is available again lactic acid is taken to the liver and converted to glucose and stored as glycogen.
What happens during anaerobic respiration in PLANTS
- Alcohol fermentation
- Pyruvate accepts a hydrogen from NADH using ADP.
- And loses a carbon to make CO2
- The pyruvate turns into ethanol
pyruvate + NADH –> ethanol + CO2 + NAD
What happens if cyanide is present in blood
- Cyanide will bind to the oxygen used to make water in the final electron acceptor in the ETC.
- Stoping the production of water.
- No cells can make water and will therefore die.
Equation for cardiac output
cardiac output (dm3 min-1) = heart rate (min-1) x stroke volume (dm3)
