Run For Your Life Flashcards
(147 cards)
1
Q
What is a tendon?
A
Joins muscle to bones
- collagen fibres
2
Q
What are ligaments?
A
- hold bones to bones in correct alignment while allow movement
3
Q
What is cartilage
A
Tissue at the end of bones.
- collagen + chondrocytes
- hard flexible tissue
- protects bones from eroding
- good shock absorber
4
Q
How is movement brought about in muscles?
A
Arranged in antagonistic pairs of muscles that work in opposite directions:
- Flexor (bending muscles)
- Extensor (straightening muscles)
5
Q
What are synovial joints?
A
- Joints that have synovial fluid and surrounding synovial capsule
- bones are separated by fluid allowing free movement
6
Q
What are the two other types of joints other than synovial joints?
A
- fibrous
- cartilaginous joints
7
Q
What are fibrous joints?
A
- fixed non-moving
- bones connected by fibrous connective tissue
8
Q
What are cartilaginous joints?
A
- between vertebrae
- bones connected by cartilage
9
Q
What are the two types of muscle
A
- smooth muscle
- striated muscle
10
Q
What is smooth muscle?
A
- non striated, spindle shaped, uninuclear fibres
- in walls of internal organs
- involuntary
11
Q
What are the two types of striated muscle?
A
- cardiac muscle
- skeletal muscle
12
Q
What is cardiac muscle?
A
- striated, branched, uninuclear fibres
- walls of heart
- involuntary
13
Q
What is skeletal muscle?
A
- striated, tubular, multi nuclear fibres
- attached to skeleton
- voluntary
14
Q
What are muscle cells also known us?
A
- my oysters
15
Q
Why are muscle cells multi-nucleotes?
A
- have several nuclei
16
Q
Describe the cytoplasm of muscle cells
A
- mostly made up of contractile structures called myofibrils
17
Q
What is the cytoplasm of a muscle cell called
A
Sacroplasm
18
Q
What is the cell membrane of a muscle cell called
A
Sarcolemma
19
Q
What is the ER of muscle cells called?
A
- sacroplasmic reticulum
20
Q
What are the mitochondria in muscle cells called?
A
- sarcosomes
21
Q
What are myofibrils?
A
- bundle of myofilaments
22
Q
What are myofilaments
A
- long repeated chains of contractile units called sarcomere
- made of actin and myosin filaments
23
Q
Label this myofibril
A
24
Q
What is a sarcomere?
A
- basic building unit of a muscle cell
25
How is muscle contraction activated?
- nerve impulse reaches axon terminal at neuromuscular junction
- neurotransmitter is realeased and binds to receptors on muscle cell
- Ca2+ is released from sacroplasmic reticulum
26
Give an overview of how muscles contract (sliding filament theory)
- the actin filaments move between myosin filaments, shortening the length of the sarcomere
27
Describe muscle contraction
- In the absence of Ca2+, tropomyosin blocks myosin-binding site on actin filaments
1. Nerve impulses causes Ca2+ release from sarcoplastic reticulum. Ca2+ binding to troponin pulls tropomyosin away from myosin binding site on actin filament
2. Myosin head (bound to ADP+ Pi) attaches to actin filament forming a cross bridge
3. Pi is released, initiating the power stroke. Myosin head pivots and bends as it pulls on actin filaments
4. ADP is released, myosin remains attached to actin.
5. ATP binds to myosin head. Myosin-actin cross bridge detaches
6. Myosin ATPase hydrolyses ATP to ADP + Pi, myosin is now in high energy state ready to bind to actin
28
What are the two types of muscle fibres
1. Slow twitch
2. Fast twitch
29
What is a twitch?
- a single muscle contraction that occurs in response to a single nerve impulse
- ‘all or nothing’ response in muscle cell if stimulus above threshold
30
What is summation?
- if second nerve impulse occurs before relaxation is complete, the contraction of muscle fibres is added, increasing overall contraction strength
31
What is tetanus?
- if a muscle is repeatedly stimulated by nerve impulses before relaxation takes place, the muscle remains in a state of contraction.
- cannot be sustained as muscles fatigue
32
Describe the contraction speed in slow twitch muscle fibres
- slow
- sustained
- can remain in tetanus for long times
33
Describe the contraction speed of fast twitch fibres
- fast
34
What is the type of movement controlled by slow twitch fibres?
- maintaining posture and steady movement
35
What is the type of movement controlled by fast twitch fibres
- quick and sudden
36
What is innervation?
- number of fibres stimulated by motor neurons
37
Describe innervation in slow twitch fibres
- each motor neuron innervation only a few fibres so precise control is possible
38
Describe innervation in fast twitch fibres
- each motor neuron innervation many fibres so precise control is not possible
39
Describe blood supply in slow twitch fibres
- many capillary networks provide oxygen for aerobic respiration and removes heat generated
40
Describe blood supply in fast twitch fibres
- few capillaries: no oxygen needed, heat absorbed by the muscles themselves
41
What is myoglobin?
- O2 store in muscles
42
Describe myoglobin in fast and slow twitch muscles
Slow: lots of myoglobin
Fast: little or no myoglobin
43
Describe numbers of mitochondria and respiratory enzymes in slow twitch muscles
- lots to carry out reactions of aerobic respiration
44
Describe numbers of mitochondria and respiratory enzymes in fast twitch muscles
- few
45
Describe the colour of slow twitch muscles
Darker
- rich blood supply and high myoglobin levels
46
Desribe the colour of fast twitch muscles
- paler due to poor blood supply and low myoglobin levels
47
Describe glycogen content in slow twitch muscles
Low: aerobic respiration is relatively efficient and glycogen is used up slowly
48
Describe glycogen content in fast twitch muscles
High
- provides a plentiful store of glucose for glycolysis which is an inefficient way of generating ATP
49
Describe phosphocreatine stores in slow twitch muscles
Few
- atp is not needed quickly in large quantities
50
Describe phosphocreatine stores in fast twitch muscles
Lots
- atp is needed quickly in large quantities
51
Describe the sarcoplasmic reticulum within slow twitch muscles
Little:
- there is time for Ca2+ to diffuse to the fibres
52
Describe thesarcoplasmic reticulum in fast twitch muscles
- exstensive so that Ca2+ ions reach all the fibres quickly
53
Describe lactate and fatigue within slow twitch muscles
Low: most respiration is aerobic
54
Describe lactate and fatigue in fast twitch muscles
- high: lactate builds up quickly because it is produced by anareobic respiration, so fibres fatigue easily
55
What is myoglobin?
- present in muscle cells
- acts as an O2 store
- similar to haemoglobin but only has one polypeptide chain
- higher affinity for oxygen
56
How can we change our muscle fibre composition
Number of muscle fibres doesn’t change:
- exercise can alter type and size of fibres
- genetic component can change proportion of slow/fast twitch muscle fibres
57
What is phosphorylation
- adding a phosphate to a molecule
58
What is redox?
- reactions that involve oxidation and reduction
59
What is hydrolysis?
- splitting of a molecule using water
60
What is a metabolic pathway
- a series of small reactions
61
What is active transport?
- a process that requires ATP
62
What is respiration?
- process that creates ATP
63
What does eukaryotic mean?
- has a true nucleus
64
What is a catabolic reaction?
- breaking large molecules into smaller ones
65
What is adenine?
- a type of base
66
What is cristae
The folds in mitochondria
67
What is photolysis?
- splitting of a molecule using light
68
What is an anabolic reaction?
- combining smaller molecules to make bigger ones
69
What is the overall equation for respiration
C6H12O6 + O2 -> CO2 + H2O + ATP
70
Why do we need respiration
- muscle contraction
- active transport
- anabolism
- warmth
71
What are the four stages of respiration?
1. Glycolysis
2. Link reaction
3. Kerbs cycle
4. Electron transport chain
72
What is glycolysis?
- splitting of sugar (glucose)
- in cytoplasm
73
Describe the steps of glycolysis
1. Phosphorylation of glucose
- uses two molecules of ATP to provide two phosphate
- produces 2x triosphosphate and 2x ADP
2. Oxidation of triose phosphate
- triose phosphate loses 2 H+ ions to form 2x pyruvate
- 2x NAD is reduced to form 2x NADH
- 4x ATP produced
Equation: Glucose + 2ADP + 2Pi + 2NAD+ -> 2 Pyruvate + 2ATP + 2NADH + 2H+
74
Describe when pyruvate enters the mitochondrial matrix
- when oxygen is available
- active transport
75
Describe the link reaction
- Pyruvate is oxidised to form acetate
- pyruvate is decarboxylated to form CO2
- NAD is reduced to form NADH
- acetate combines with CoA to form acetyl CoA
Occurs twice for each molecule of glucose (as glycolysis produces 2 pyruvate)
Equation: 2 pyruvate + 2 NAD+ -> 2 Acetyl CoA + 2NADH + 2H+ + 2CO2
76
Describe the krebs cycle
- 2 Acetyl CoA enters the circular pathway and oxoaloacetate + 2C acetyl fragment to form citrate
- citrate is the converted back to oxoaloacetate through redox reactions:
- decarboxylation of citrate: releases 2CO2
- oxidation of citrate (H+ goes to 3NAD and 1 FAD -> 3 NADH + H+ + FADH2)
- substrate-linked phosphorylation (ADP+Pi)
Two cycles per glucose molecule so overall
- 2 ATP
- 6 NADH
- 2 FADH2
- 4 CO2
-
77
What is NAD+ / NADH + H+
- coenzyme
- reducing agent carrying hydrogen
- NAD+ (oxidised form)
- NADH (reduced form)
78
What is FAD/ FADH2
- coenzyme
- reducing agent carrying hydrogen
79
Describe the location of the electron transfer chain
Inener membrane of mitochondria
80
What does electron transfer chain involve?
- electron transport + chemiosis
81
What is chemiosmosis?
- movement of H+ across a selectively permeable membrane during respiration, down the electrochemical gradient
82
What is oxidative phosphorylation?
- production of ATP in a process where energy is released in the electron transport chain
- energy is used to establish the K+ which powers atp synthesise
83
Describe the electron transfer chain
1. Respiratory enzyme complexes transport electron and pump H+ out of the matrix
- final electron acceptor is O2 forming H2O
2. The resulting electrochemical H+ gradient is used by ATP synthase (through which H+ flows back into the matrix) to make ATP
84
Why is the maximum yield of atp not achieved?
- leaky membranes
- energy cost for transporting pyruvate and ADP into mitochondria
85
Where does the rest of energy from glucose go if not stored in atp?
- heat energy
86
Why is heat energy useful?
- to maintain body temperature and keep the rate of reactions high
87
How do we use fat as fuel?
- break down fatty acids into acetyl groups that attach to coenzyme a and are metabolised in the Krebs cycle
88
Which factors affect the rate of respiration
- ph
- temperature
- enzyme concentration
- substrate concentration
89
What are the advantages of respiration being enzyme controlled
- controlled release of energy
- prevents cell from overheating
90
What is a respirometer?
- used to measure the rate of respiration by measuring the rate of energy consumption
91
Carbohydrates, fats and proteins can all be broken down in the…
Krebs cycle
92
Carbohydrates, fats and proteins are…
Respiratory substrates
- they are a source of protons and electrons
93
How can you estimate the dominant respiratory substrate
Using the respiratory quotient
CO2 produced/O2 consumed
94
What is the respiratory quotient for carbohydrates?
1
95
What is the respiratory quotient for fat and alcohol?
0.7
96
What is the respiratory quotient for protein?
0.8
97
What is the equation for anaerobic respiration?
C6H12O6 -> 2C3H6O2 + 2ATP
98
What are the two stages of anaerobic respiration?
1. Glycolysis
2. Lactic fermentation
99
Describe lactic fermentation
- after glycolysis, pyruvate is reduced to lactic acid by oxidising NADH + H+
- this takes place in the cytoplasm
100
What are the downsides of anaerobic respiration?
- low energy yield
- build up of lactic acid
101
What is the problem with lactic acid?
- low PH in cells
- affects enzyme activity
102
Describe the amount of atp made in aerobic in comparison to anaerobic
15x less atp is made in anaerobic
103
How do cells get rid of lactic acid?
Resynthesised to pyruvate and then goes through kerb cycle
104
What is epoc?
Excessive post-exercise oxygen consumption:
- oxygen debt
- oxygen uptake greater than normal in recovery period in order to break down lactic acid
105
What is oxygen needed for during period of recovery?
- breakdown of lactic acid via krebs
- glucogenesis
- re oxygenation of myoglobin
- increased metabolism due to raised temperature
- energy to allow increased breathing + heart rate (intercostal + cardiac muscle)
106
What is gluconeogenesis
Transport of lactic acid to liver and resynthesised into glucose
107
Where does the energy at the beginning of excercise come from?
- only a small amount of energy is stored as atp
- as atp is used it is immediately regenerated from phosphocreatine stored in muscles (gives pi to ADP)
108
How long does phosphocreatine last?
- can generate atp for 6-10 seconds
109
How are pc levels restored?
- creatine gets pi from atp when we are at rest
110
What does the ability to do prolonged strenuous exercise depend on?
- genetics
- gender
- fitness
- ratio of fast + slow twitch muscle fibres
111
What is aerobic capacity
- ability to consume (=take in, transport and use) oxygen
112
What factors affect aerobic capacity?
- breathing efficiency (rate + depth of breathing)
- cardiac output (volume of blood pumped from a ventricle per minute)
- efficiency of oxygen use in muscle
113
What is VO2
- aerobic capacity (volume O2 consumption per minute)
114
What is VO2 max?
- maximal aerobic capacity during intense exercise
115
Why is VO2 max measured during submaximal activity?
- needs to be aerobic exercise, so below anaerobic threshold (65% max heart rate)
116
What is the effect of excericse and training on aerobic capacity
- increased vital capacity and increased capillarisation of lung
- increased heart stroke volume and cardiac output
- increased red blood cell production
- increased capillarisation of muscles, lower fat-to-muscle atio
- increased number and size of mitochondria
117
What is cardiac output?
The volume of blood pumped out by the heart in one stroke
- stroke volume x heart rate
- increases 4-5x during excercise
118
What is stroke volume?
- volume of blood pumped out of the left ventricle per contraction
- increases by x2 during excercise
119
What is the effect of exercise on stroke volume
- heart muscle is stretched more so contracts with greater force
- larger venous return
120
What is venous return
- the volume of blood returning to the heart in the vena cava
- increased during exercise due to effect of contracting skeletal muscle exerting pressure on veins
121
What is heart rate
- the number of left ventricle contractions per minute
122
What causes different resting heart rates?
- differences in heart size, due to differences in body size or genetic factors
- larger heart -> lower resting heart rate
123
Describe cardiac muscle contractions
- myogenic
- dont require nervous stimulation
- can be changed by nervous or hormonal influences
124
Describe heart electrical activity
1. SAN initiates depolarisation of atria leading to atrial systole
2. Delay at the av node allows atria to contract and all blood to reach the ventricles
3. Wave of depolarisation travels to heart apex down the bundle of his and back up the purkyne fibres initating ventricular systole
4. Ventricular systole pumps blood from ventricles into the arteries - ventricular repolarisation starts
5. Repolarisation of ventricles results in ventricular diastole
6. San and whole conduction system at rest, no electrical activity, diastole
125
Where is the cardiovascular control centre located
Medulla
126
What is the deceleration nerve also known as?
- sympathetic nerve
(Vagus nerve)
127
What type of nerve is the accelerator nerve?
- parasympathetic nerve
128
Where does the cardiovascular control centre receive impulses from?
- CO2 chemoreceptors
- baroreceptors (movement receptors) in vena cava
- aorta
- carotid artery
- stretch receptors in muscles signaling increased pressure
129
What is the effect of adrenaline?
- Activates SAN directly
- dilates arterioles to skeletal muscles
- constricts arterioles to digestive system
130
What is minute volume?
- volume of air taken into lungs in one minute
- tidal volume x breathing rate
131
What is a spirometer
- equipment for measuring the volume of air inspired and expired
132
Describe the spirometer
- revolving drum with kymograph
- airtight chamber filled with oxygen, lid moves up/down during breathing
- soda lime container
133
Why does the spirometer contain soda lime?
- so person does not inhale too much CO2
134
Describe changes during inhalation
- diaphragm flattens as it contracts
- external intercostal muscles contract
- chest volume increases
- pressure in chest decrease
- lungs expand
- atmospheric pressure forces air into lungs
135
Describe changes during exhalation
- diaphragm relaxes and moves up
- external intercostal muscles relax
- chest volume decreases
- pressure in chest increases
- air is forced out of lungs until air pressure inside + outside chest is equal
136
Normal inhalation is an ………. Process
Active
137
What sends impulses to the ventilation centre in medulla?
- control chemoreceptors in medulla (CO2 +, pH -)
- peripheral chemoreceptors in aorta + carotid bodies
138
How do chemoreceptors measure CO2 concentration?
- dissolved CO2 lowers blood pH
- [H+] measured by chemoreceptors in medulla, aorta and carotid bodies
139
What type of process is normal exhalation?
Passive
140
What sends impulses to ventilation centre in medulla during normal exhalation?-
Stretch receptors
141
Describe the type of process during excercise
Active process
142
What sends impulses to the ventilation centre in the medulla during exercise?
- motor cortex, temp, receptors
- central chemo receptors
- peripheral chemoreceptors
- stretch receptors in lungs
- movement receptors in muscles + joints
143
What is homeostasis?
- maintenance of a stable, internal environment despite varying conditions in the external environment
- a dynamic equilibrium where the variable oscillates around a set point
144
What is the general mechanism of homeostasis
Stimulus, receptor, integrator, effector, response, negative feedback
145
What is negative feedback?
- return to the set point triggers a mechanism to counteract further change beyond a set-point
146
What is positive feedback
- original stimulus produces a response that causes the variable deviate even more from set point
147
Describe homeostasis in metabolic rate
- fall in metabolic rate
- hypothalamus detects fall
- pituitary releases more thyroid SH
- thyroid gland releases more thyroxine
- metabolic rate of cells increases
