Topic 7: Run for your life Flashcards
what is antagonistic muscle action
muscles can only pull in one direction and so they act in antagonistic muscle pairs
a muscle pulls in one direction at a joint whilst the other pulls in the opposite direction
the flexor bends a joint when it contracts
the extensor straightens out a joint when it contracts
define tendon
non-elastic tissue connecting muscle to bone
define ligament
elastic tissue joining bones together, determines amount of movement possible at a joint
define joint
the site where 2 bones are attached for the purpose of allowing body parts to move, made of fibrous connective tissue and cartilage
outline the structure of a muscle
sarcomeres are made up of thick myosin and thin actin filaments
myofibrils are composed of repeated sarcomeres
a muscle fibre is made up of many myofibrils
muscles are made from muscle fibre bundles
outline the arrangement of muscle filaments during extension and contraction (sliding filament theory)
sarcomeres within myofibrils shorten bc Z discs are pulled closer together
the myofilaments, myosin and actin molecules remain the same length
Myosin and actin filaments slide over one another
explain the sliding filament theory of muscle contraction
- nerve impulse arrives at a neuromuscular junction
- Ca2+ are released from the sarcoplasmic reticulum into the sarcoplasm and bind to troponin
- troponin and the attached tropomyosin shift, exposing myosin binding sites on actin filaments
- ATP binds to myosin head and causes it to unbind from actin
- ATPase helps ATP split to release energy so that the myosin head can move and bind to actin
ATP binds again; etc. - the actin slides over the myosin which shortens the muscle fibre
- when a muscle relaxes, it isn’t being stimulated by nerve impulses and Ca2+ are actively pumped out of the muscle sarcoplasm using ATP. the troponin and tropomyosin move back, and again block the myosin binding site on the chain
what is actin
thin filament, made of 2 strands twisted around each other
what is myosin
thick filament, bulbous heads and rod shaped tail
what are troponin and tropomyosin
tropomyosin is wound around the actin, forming a fibrous strand
troponin is attached to the tropomyosin
define homeostasis
the maintenance of a steady internal environment
define negative feedback
when a deviation from the set level results in a change in the opposite direction, returning the change to the set level
define positive feedback
when a deviation from the set level results in the control centre moving the condition further away from the set level
define dynamic equilibrium
a state of balance between continuing processes
outline slow twitch skeletal muscles
- muscle fibres that contract slowly and so are good for endurance activities (maintaining good posture (high proportion in back) and long distance running)
- more effectively at aerobic respiration because more mitochondria and lots of capillaries for good O2 supply
- reddish in colour as theyre rich in myoglobin that can store oxygen and so probs won’t build up lactate
outline fast twitch skeletal muscles
- muscle fibres that contract very quickly and are so used for fast movement (eye movement and sprinting), so high proportion in eyes and legs
- get tired very quickly as energy is released quickly via anaerobic respiration using glycogen and there are few mitochondria/blood vessels
- whitish in colour bc they don’t have much myoglobin and so can’t store much oxygen
what is BMR and how is it measured
Basal Metabolic Rate is the minimum energy required to carry out basic metabolic processes required for life
BMR is dependent on age and gender due to impact of body fat % (as more body fat = more insulation = less heat loss = less energy needed to maintain bdy temp)
it is calculated during a fasting period in a temperature controlled room
what coenzymes are involved in respiration
NAD
FAD
coenzyme A
define respiration
a series of chemical reactions which bring about the release of energy which is used to make ATP
define aerobic respiration
respiration involving oxygen, where the substrate is oxidised completely into CO2 and H2O
define anaerobic respiration
respiration in the absence of oxygen, resulting in lactic acid formation in animals
what are the 4 stages of aerobic respiration and where do they occur
- glycolysis: cell cytoplasm
- link reaction: mitochondrial matrix
- kreb’s cycle: mitochondrial matrix
- oxidative phosphorylation: inner membrane of mitochondria
explain the 1st stage of aerobic respiration; glycolysis
occurs in cytoplasm (or sarcoplasm of muscle cells)
- phosphorylation of glucose:
2ATP hydrolysed –> 2ADP + 2Pi
glucose + 2Pi –> 2triose phosphate - oxidation of triose phosphate
enzyme oxidises triose phosphate, removing a H from each
NAD takes the H: 2NAD + 2H –> 2NADH
the Pi from each triose phosphate forms 2ATP; so 4ATP
this turns 2triose phosphate –> 2pyruvate
products: 2ATP, 2NADH, 2pyruvate
outline and explain the link reaction; the 2nd stage of aerobic respiration
if O2 available, pyruvate moves across mitochondria’s double membrane into matrix via active transport
- pyruvate is dehydrogenated and decarboxylated via pyruvate dehydrogenase to form acetate
removed carboxyl forms CO2
removed H accepted by NAD –> NADH
- acetate combines with Coenzyme A to form acetyl coenzyme A
products: CO2, NADH, acetyl CoA
this occurs 2x bc there are 2 pyruvate
outline and explain the Kreb’s cycle; 3rd stage of respiration
occurs twice per glucose, happens in mitochondrial matrix
- acteyl CoA (from Link reaction) –> CoA(reused in link) + actetate
2C acetate + 4C oxaloacetate –> 6C citrate - citrate is dehydrogenated and decarboxylated –> CO2 + 5C compound + NADH
- the 5C is decarboxylated and dehydrogenated –> 4Coxaloacetate + FADH2 + 2NADH + CO2 + ATP
ADP + Pi –> ATP (substrate level phosphorylation)
total products per cycle: 3NADH + FADH2 + 2CO2 + ATP
oxaloacetate is then reused!
outline and explain oxidative phosphorylation; the last stage of aerobic respiration
involves a combination of the electron transport chain (ETC) and chemiosmosis
1. NADH + FADH2 are oxidised to NAD + FAD, releasing H atoms
H –> e-+ H+
2. e- move down ETC and lose energy at each carrier in the chain
3. carriers use the energy to pump H+ from matrix to inter membrane space, forming an electrochemical gradient
4. chemiosmosis: H+ move down gradient back into matrix via ATP synthase, drives ADP + Pi —> ATP
5. in the matrix at the end of the ETC, H+, e- and O2(from blood) combine to H2O; O2 said to be final e- acceptor
3ATP made from each NADH
2ATP made from each FADH2
outline the process of anaerobic respiration
glucose —> lactic acid + energy
lactate fermentation:
NADH (from glycolysis) transfers H to pyruvate(from glycosisis)–> lactate + NAD
this oxidation needs extra oxygen (known as oxygen debt and is why u breathe hard and deep after excercise)
the NAD is then reused in glycolysis
how is lactic acid build up dealt with
- cells: lactic acid —> pyruvate, which can re-enter aerobic respiration at the krebs cycle
- liver cells: lactic acid —> glucose, which can be respired/stored
outline the experiment looking at respiration rate
method:
- set up the respirometer and run the experiment with both tubes for 30 minutes
- CO2 produced during respiration is absorbed by soda lime or KOH, reducing volume of gas
- This reduces the pressure in the capillary tube and manometer fluid will move towards the test tube containing the seeds
- Measure the distance moved by the liquid in a given time
- Use this measurement to calculate the change in gas volume within a given time, x cm3 min-1
- Allow air to re-enter the tubes via the screw cap and reset the manometer fluid using the syringe
- Repeat experiment several times and calculate the average volume of oxygen consumed
define myogenic
the ability to contract without any external stimulus because the impulse and depolarisation originates in the heart muscle
what is the SA node
a group cells in the wall of the right atrium aka pacemaker
outline electrical activity in the heart during the cardiac cycle
- SA node sends out a wave of excitation/change in depolarisation
- atria contract simultaneously
- a band of non-conducting collagen tissue prevents the waves of activity from being directly passed from the atria to the ventricles
- the wave of electrical activity is instead transferred from the SA to the AV node
- the AV node passes these waves of activity onto the bundle of His with a slight delay to ensure that the atria have emptied before the ventricles contract
- the purkyne fibres carry the waves of excitation into the muscular walls of each ventricle and cause simultaneous contraction from the bottom up
label and explain this healthy heart ECG
milivolts
P wave: atrial depolarisation (atrial systole)
QRS complex: ventricular depolarisation (ventricular systole); largest bc most muscle mass
T wave: ventricular repolarisation (diastole)
higher wave = higher electrical charge = stronger contraction
what condition is shown by this ECG
tachycardia; when an individual has a resting heart rate of over 100bpm
what condition is shown by this ECG
bradycardia: when the resting heart rate is below 60bpm
what condition is shown by this ECG
ectopic heartbeat: caused by an earlier contraction of the atria followed by a pause
can be found occasionally in a healthy person without problem
what condition is shown by this ECG
atrial fibrillation: irregular heartbeat disrupting the heart rhythm, the atria/ventricles stop contracting properly
in severe cases it can be fatal
label this spirometer trace
residual, vital, tidal, total
how many ATP formed from one glucose molecule in respiration
38
how do you calculate tidal volume
difference between peak and trough
how do you calculate oxygen consumption
give it as a rate
how much the peaks decrease by over a given time frame
