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A Level Biology OCR > 13 - Neural Communication > Flashcards

13 - Neural Communication Flashcards

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1
Q

What is a stimulus?

A

A change in the internal or external environment of an organism

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2
Q

What is a sensory receptor?

A

Specialised nerve cell that is designed to respond to a specific sensory stimulus

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3
Q

What are the two main features of any sensory receptor?

A
  1. Acts as a transducer 2. Is specific to a single stimulus
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4
Q

What is a pacinian corpuscle?

A

They are nerve endings in the skin, responsible for sensitivity to deep pressure touch

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5
Q

What type of energy do sensory receptors convert stimuli into?

A

Electrical energy

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6
Q

What are the 3 main parts of a neurone?

A

Cell body, dendrons, axons

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7
Q

Why do Pacinian Corpuscles stop responding when pressure is constant?

A

They are only sensitive to changes in pressure

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8
Q

What is the structure of a Pacinian Corpuscle?

A

Oval shaped, with many concentric rings of connective tissue which are wrapped around a nerve ending

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9
Q

How do Pacinian Corpuscles work?

A

Pressure on the skin deforms the rings of connective tissue, which then press against the nerve ending

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10
Q

What 2 organelles are very prevalent within a neurone’s cell body and why?

A

Mitochondria and endoplasmic reticulum, in order to produce lots of neurotransmitters

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11
Q

What are dendrons responsible for?

A

Transmitting electrical impulses towards the cell body

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12
Q

What are axons responsible for?

A

Transmitting electrical impulses away from the cell body

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13
Q

How many axons and dendrons does a sensory neurone have?

A

One of each

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14
Q

How many axons and dendrons does a relay neurone have?

A

Many short ones of each

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15
Q

How many axons and dendrons does a motor neurone have?

A

One long axon and many short dendrons

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16
Q

What is a myelinated neurone?

A

One covered in a myelin sheath (many layers of cell membrane)

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17
Q

What is the function of a Schwann Cell?

A

Produce myelin sheaths by growing around the neurone many times

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18
Q

What is the resting potential of a neuron?

A

-70mV

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19
Q

How many times quicker can a myelinated neurone conduct a nerve impulse than an unmyelinated neurone?

A

Up to 100 times quicker

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20
Q

What is the purpose of a myelin sheath?

A

Electrically insulates the axon of a neuron and increases speed of nerve impulse conduction.

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21
Q

What is a node of Ranvier?

A

A small gap in the myelin sheath of a nerve, between adjacent Schwann cells.

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22
Q

Why is the transmission of electrical impulses so much faster in myelinated neurones?

A

The electrical impulse ‘jumps’ between the nodes of Ranvier, which is much quicker than being continuously transmitted along an unmyelinated neurone

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23
Q

What neurones are myelinated in mammals?

A

Around 1/3 of peripheral neurones

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24
Q

What neurones are not myelinated in mammals?

A

All of them in the CNS and approximately 2/3 of the peripheral nervous system

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25
Q

What are the 4 main types of sensory receptor in an animal?

A
  1. Mechanoreceptor 2. Photoreceptor 3. Chemoreceptor 4. Thermoreceptor
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26
Q

What special type of ion channel is found within Pacinian Corpuscles?

A

Stretch-mediated sodium channels

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27
Q

How is a generator potential created within a Pacinian Corpuscle?

A

The change in pressure causes stretch-mediated sodium channels to become permeable to sodium, causing an influx of positive sodium ions which depolarises the membrane

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28
Q

What is resting potential?

A

The difference in electric charge between the inside and outside of a neuron’s cell membrane when it is not transmitting an action potential

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29
Q

When at its resting potential, why is a membrane said to be polarised?

A

Because there is a potential difference across it (i.e. a different charge on each side)

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30
Q

Movement of what creates the resting potential?

A

Sodium and potassium ions across the membrane of the neurone

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31
Q

What distance do myelinated and unmyelinated neurones tend to transmit nerve impulses?

A

Myelinated tend to transmit further, hence the need for quicker transmission than the shorter, unmyelinated neurones

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32
Q

Why can’t sodium or potassium ions travel across the neuronal membrane via simple diffusion?

A

They cannot pass through the phospholipid bilayer

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33
Q

How does the sodium potassium pump work?

A

ATP causes the membrane to transport 3 sodium ions out of the neurone, and this causes 2 potassium ions to enter via the same pump

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34
Q

What does the action of the sodium potassium pump cause in terms of diffusion of sodium and potassium ions?

A

Potassium ions try to diffuse out of the neurone, sodium ions try to diffuse back in

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35
Q

How is resting potential maintained?

A

There are more gated potassium channels open in the neuronal membrane than gated sodium channels. This means that more potassium can diffuse out than sodium can diffuse back in, giving a relative negative charge within the neurone

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36
Q

At resting potential, is the inside of the neurone more negative or positive than the outside?

A

More negative

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37
Q

What happens to the charges on the sensory neurone’s membrane when a stimulus is detected?

A

They are temporarily reversed

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38
Q

What is the membrane’s charge during an action potential?

A

40mV

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39
Q

What is depolarization of a membrane?

A

The change of the membrane’s charge from negative to positive

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40
Q

What is repolarization of a membrane?

A

The return of the membrane’s charge from positive to negative, restoring the resting potential

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41
Q

What is hyperpolarisation?

A

Where, during the process of repolarisation, the membrane temporarily becomes more negatively charged than the resting potential

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42
Q

What causes an action potential?

A

The opening of voltage-gated sodium channels allows sodium ions to enter the neurone, which in turn changes the potential difference of the neurone and causes more voltage-gated sodium channels to open

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43
Q

What causes voltage-gated sodium channels to open, triggering an action potential?

A

The energy of the stimulus being, converted to electrical energy by the sensory receptor

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44
Q

What is the opening of more and more sodium ion channels during an action potential an example of?

A

Positive feedback

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45
Q

What occurs when the charge reaches +40mV due to depolarisation?

A

The voltage-gated sodium channels close and voltage-gated potassium channels open.

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46
Q

What causes repolarisation?

A

Opening of K+ channels allowing K+ out of the cell, whilst the closing of the Na+ channels means that no more can enter.

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47
Q

What causes hyperpolarisation?

A

So many potassium ions leave the cell that its charge is somewhat more negative than during resting potential

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48
Q

What occurs after hyperpolarisation?

A

The voltage-gated potassium channels close and the sodium-potassium pumps restore resting potential

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49
Q

What is a nerve impulse?

A

An action potential which starts at one end of the neurone and is propagated along it to the other end

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50
Q

How is a nerve impulse propagated along the neurone?

A

The local electrical currents created by the movement of Na+ ions during depolarisation of one end of the neurone causes the voltage-gated sodium channels a little further along the neurone to open, propagating the nerve impulse

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51
Q

What is the refractory period?

A

A short period of time after an action potential during which a neurone cannot be stimulated again, as the voltage-gated sodium channels remain closed

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52
Q

Why is the refractory period important in neurones?

A

Because it ensures that nerve impulses are not propagated back along the neurone as well as forwards, and also that the action potentials do not overlap, but rather exist as discrete impulses

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53
Q

What is saltatory conduction?

A

The propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials.

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54
Q

Why is saltatory conduction more energy efficient?

A

Because you are opening fewer channels at the nodes, and so less ATP is used in return

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55
Q

What 2 things other than myelination affect the speed of transmission of a nerve impulse?

A
  1. Axon diameter 2. Temperature
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56
Q

How does axon diameter affect speed of conduction?

A

The bigger the diameter of the axon, the quicker the transmission, as there is less resistance to the flow of ions

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57
Q

How does temperature affect speed of conduction in neurones?

A

Generally, the higher the temperature, the faster the impulse, as ions diffuse faster at higher temperatures. However, this isn’t the case above 40°C as the membrane proteins begin to denature

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58
Q

What type of response are action potentials said to be?

A

All-or-nothing responses

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59
Q

What is the threshold value for a neurone?

A

The level of stimulus needed to trigger a response

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60
Q

What is the all-or-nothing principle?

A

The idea that, if the threshold value is reached, this will always cause an action potential to occur, and that the action potential will always be the same size no matter the size of the stimulus

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61
Q

How does size of the stimulus affect the number of impulses generated in a given time?

A

Larger stimuli cause impulses to be generated more frequently

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62
Q

Why are axons generally narrow?

A

To create greater resistance, and thus a greater temperature, which increases transmission speed

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63
Q

Can unmyelinated neurones be wrapped in Schwann cells?

A

Yes, but generally only one Schwann cell wrapped loosely around a few neurones to make the action potential travel along them in a wave

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64
Q

What are 4 ways a Synapse can be disrupted?

A
  1. Agonists- mimic the neurotransmitter 2. Blocking- prevent neurotransmitters reaching receptors 3. Enzyme inhibitors 4. Neurotransmitter inhibitors- block Ca2+ channels in the presynaptic membrane
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65
Q

What type of synapse disruptor is nicotine?

A

An agonist, as it mimics acetylcholine

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66
Q

What type of synapse disruptor is curare?

A

A blocker, as it blocks acetylcholine

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67
Q

What type of synapse disruptors are organophosphates?

A

Enzyme inhibitors

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68
Q

What type of synapse disruptors are opiates?

A

Neurotransmitter inhibitor

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69
Q

What is a synapse?

A

The junction between two adjacent neurones

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70
Q

What chemicals are used to convey messages in synapses?

A

Neurotransmitters

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71
Q

What is the gap between two neurones at a synapse called?

A

Synaptic cleft

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72
Q

What is the presynaptic knob?

A

The bulbous end of the presynaptic neurone, where the neurotransmitters are released from

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73
Q

What two organelles does the presynaptic neurone and why?

A

Mitochondria and endoplasmic reticulum, in order to help it manufacture neurotransmitters

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74
Q

What are synaptic vesicles?

A

Vesicles containing neurotransmitters which fuse with the membrane of the presynaptic neurone

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75
Q

What are the two main types of neurotransmitter?

A

Excitatory and Inhibitory

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76
Q

What is an example of an excitatory neurotransmitter?

A

Acetylcholine

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77
Q

What do excitatory neurotransmitters do?

A

Depolarise the postsynaptic neurone, approaching or exceeding threshold

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78
Q

What do inhibitory neurotransmitters do?

A

Cause hyperpolarisation of the postsynaptic neurone, preventing further transmission of the action potential

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79
Q

What is an example of an inhibitory neurotransmitter?

A

GABA

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80
Q

What two places are cholinergic synapses common?

A
  1. The CNS of vertebrates 2. Neuromuscular junctions
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81
Q

What is the neuromuscular junction?

A

Meeting point of a motor neurone and a muscle cell

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82
Q

What neurotransmitter do cholinergic synapses use?

A

Acetylcholine

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83
Q

What enzyme breaks down acetylcholine?

A

Acetylcholinesterase

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84
Q

What does Acetylcholinesterase break acetylcholine down into?

A

Ethanoic Acid and Choline

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85
Q

What happens to the broken down products of acetylcholine?

A

They reenter the presynaptic bulb seperately by diffusion, and recombine to form acetylcholine

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86
Q

What are the 3 main functions of synapses?

A
  1. Ensures one-way transmission of nerve impulses 2. Interconnection of nerve pathways 3. Memory and learning
87
Q

What is the sequence of events at a synapse?

A
  1. Action potential causes voltage-gated calcium channels in the presynaptic bulb to open 2. Calcium ions cause acetylcholine vesicles to exocytose out of the pre-synaptic bulb 3. Acetylcholine diffuses across synaptic cleft 4. 2 acetylcholine molecules bind to each ligand-gated sodium ion channel on the post-synaptic neurone, causing them to open 5. This causes an action potential 6. Acetylcholinesterase recycles the acetylcholine
88
Q

Why is the ion used in the presynaptic bulb calcium and not sodium?

A

To prevent the neurone firing all the time as it would if they were sodium channels

89
Q

What is synaptic convergence?

A

When many neurones connect to one neurone information can be amplified (made stronger)

90
Q

What is synaptic divergence?

A

When one neurone connects to many neurones information can be dispersed to different parts of the body

91
Q

What do inhibitory neurones do?

A

Stop the action potentials of other neurones

92
Q

What is summation?

A

Where the neurotransmitter from one action potential is not enough to trigger an action potential in the postsynaptic neurone, so it needs to build up

93
Q

What does spatial summation prevent?

A

Overreaction to minor stimuli

94
Q

What is spatial summation?

A

Where several neurones connect to one postsynaptic neurone in order to release enough neurotransmitter to cause a response

95
Q

What does spatial summation allow?

A

Signals from multiple stimuli to be coordinated into a single response

96
Q

What is temporal summation?

A

Where the same presynaptic neurone transmits two or more action potentials in quick succession, increasing the chance that there will be enough neurotransmitter to cause an action potential in the postsynaptic neurone.

97
Q

What is the peripheral nervous system?

A

The sensory and motor neurons that connect the central nervous system to the rest of the body

98
Q

What is the central nervous system?

A

The brain and spinal cord

99
Q

What two functional categories is the nervous system organised into?

A

Somatic and Autonomic

100
Q

What is the somatic nervous system?

A

That which is under voluntary control

101
Q

Where does the somatic nervous system carry signals to?

A

Skeletal muscles

102
Q

Where does the autonomic nervous system carry signals to?

A

Smooth muscle, glands, cardiac muscle

103
Q

What is the autonomic nervous system?

A

This regulates events that are automatic, or involuntary. This is often referred to as the involuntary nervous system.

104
Q

What 2 categories is the autonomic nervous system divided into?

A

Sympathetic and parasympathetic

105
Q

What does the sympathetic nervous system do?

A

Increases bodily functions (in response to fight or flight)

106
Q

What does the parasympathetic nervous system do?

A

It creates a reverse response of the sympathetic nervous system to help slow the body down and reduce activity, known as rest and digest

107
Q

What two things physically protect the brain?

A

The skull and the meninges (protective membranes)

108
Q

What is an advantage of having the brain as a central control centre for the body?

A

Communication between the different neurones is much quicker than if the control centres were spread throughout the body

109
Q

What are the 5 main areas of the brain?

A
  1. Cerebrum 2. Cerebellum 3. Medulla oblongata 4. Hypothalamus 5. Pituitary gland
110
Q

What does the cerebrum and cerebral cortex control?

A

Voluntary actions such as learning

111
Q

What does the cerebellum control?

A

Unconscious functions such as balance and coordination

112
Q

What does the medulla oblongata control?

A

Autonomic control of things such as heart and breathing rate

113
Q

What does the hypothalamus control?

A

Temperature, autonomic nervous reflexes, glucose and hormone levels, and the visceral reflexes (digestion, sweating, hunger, thirst, and sleep).

114
Q

What does the pituitary gland do?

A

Stores and releases hormones that regulate many body functions

115
Q

How does the cerebrum coordinate responses?

A

It receives sensory information, interprets it with respect to prior experiences, then sends impulses along motor neurones to relevant effectors

116
Q

Why is the cerebrum highly folded?

A

To increase surface area, in order to increase its capacity for complex activity

117
Q

Where do the most sophisticated processes of the brain take place?

A

The frontal and prefrontal lobes of the cerebral cortex

118
Q

What two things is the cerebrum split into?

A

Two hemispheres, each controlling half of the body

119
Q

What are the hemispheres of the cerebrum split into?

A

Sensory areas, which receive information from receptor cells in sensory areas

120
Q

What is the size of each sensory area or motor area of the cerebrum in proportion to?

A

The relative number of receptor cells or motor endings present in the body part

121
Q

What are association areas?

A

A region of the cerebrum of the brain that connects sensory and motor areas, and that is thought to be concerned with higher mental activities.

122
Q

Where do association areas pass impulses onto?

A

The motor areas of the cerebrum

123
Q

What are the two centres of the hypothalamus for?

A

Controlling the sympathetic and parasympathetic nervous systems

124
Q

What are the two sections of the pituitary gland?

A

Anterior and posterior

125
Q

What does the anterior pituitary gland do?

A

Produces 6 hormones, including FSH

126
Q

What does the posterior pituitary do?

A

Stores and secretes hormones that are made in the hypothalamus

127
Q

What is a reflex arc?

A

A pathway of neurones that a nerve impulse follows to produce a reflex

128
Q

What is a spinal reflex?

A

Where the neural circuit only goes to the spinal cord, not the brain

129
Q

What is the stimulus for the knee jerk reflex?

A

The patellar tendon being stretched

130
Q

What does the body use the knee jerk reflex for?

A

To help maintain posture and balance

131
Q

What causes the leg to kick during the knee jerk reflex?

A

The extensor muscle is stimulated to contract by the reflex, while an inhibitory relay neurone inhibits the motor neurone of the flexor muscle, causing it to relax

132
Q

What is the stimulus for the blinking reflex?

A

When the cornea is stimulated, such as by being touched, a bright light appearing or a loud noise occurring

133
Q

What is a cranial reflex?

A

One which travels to the brain

134
Q

What type of reflex is the knee jerk reflex?

A

Spinal reflex

135
Q

What type of reflex is the blink reflex?

A

Cranial reflex

136
Q

What is the optical reflex?

A

Blinking as a result of bright light

137
Q

What is the corneal reflex?

A

Blinking in response to something touching the cornea

138
Q

How does the blink reflex work?

A

The touch causes a sensory neurone (5th cranial nerve) to send a signal to the lower brain stem, where it passes along a relay neurone and along a motor neurone (7th cranial nerve) to initiate a motor response to close the eyelids of both eyes

139
Q

Why are 4 reasons reflexes are important for survival?

A
  1. They are involuntary, so prevents the brain getting overloaded 2. They don’t have to be learnt 3. They have very short reflex arcs, and so are very fast 4. They control many everyday actions
140
Q

What are the 3 types of muscle cell?

A

Smooth, cardiac, skeletal

141
Q

What are skeletal muscles responsible for?

A

Voluntary movement

142
Q

What special property do cardiac muscles have?

A

They are myogenic (can contract without a nerve impulse telling them to)

143
Q

Are cardiac muscles only found in the heart?

A

Yes

144
Q

What parts of organs are smooth muscle cells usually found in?

A

The walls

145
Q

What are smooth muscles responsible for?

A

Involuntary movement

146
Q

What is actin?

A

A protein in skeletal muscle that is thin and light

147
Q

What is myosin?

A

Thick filament protein with a head and elongated tail, the heads form cross bridges with the thin filaments during muscle contraction

148
Q

What is myoglobin?

A

A red pigment which stores oxygen in muscle cells and enables rapid diffusion of oxygen from blood to muscle

149
Q

What is a myofibril?

A

Many of these units make up a single muscle fibre. These are made up of sarcomeres.

150
Q

What is a sarcomere?

A

The contractile unit of the muscle fibre. From z-line to z-line.

151
Q

What is the sarcolemma?

A

Plasma membrane of a muscle cell

152
Q

What is the sarcoplasm?

A

Cytoplasm of a muscle cell

153
Q

What is the sarcoplasmic reticulum?

A

The endoplasmic reticulum of a muscle cell

154
Q

What does the sarcoplasmic reticulum do?

A

Stores and releases calcium

155
Q

What type of muscle cell is not striated?

A

Smooth

156
Q

Is cardiac muscle voluntary or involuntary?

A

Involuntary

157
Q

How are skeletal muscles arranged?

A

Regularly, so that muscle contracts in one direction

158
Q

How rapidly does each type of muscle contract?

A

Skeletal contracts most rapidly, cardiac intermediate speed, smooth muscle slowly

159
Q

How long does each type of muscle contract for?

A

Skeletal contracts for a short time, cardiac intermediate length, smooth muscle can contract for a long time

160
Q

What is the structure of skeletal muscle?

A

Long, tubular, multinucleate cells; obvious striations

161
Q

What is the structure of cardiac muscle?

A

Faintly striated, short, branched, one or two nuclei per cell

162
Q

What is the structure of smooth muscle?

A

Long and slender, no striations, spindle shaped with a single central nucleus

163
Q

What are skeletal muscles composed of?

A

Bundles of skeletal muscle fibres plus connective tissues, nerves and blood vessels.

164
Q

How are skeletal muscle cells different from most cells?

A

They contain a number of nuclei and are much longer than normal cells

165
Q

Why are skeletal muscle cells multinucleate?

A

They are formed by the fusion of several embryonic muscle cells

166
Q

What is an advantage of muscle fibres being formed of joined-up cells?

A

It is stronger as there are no junctions between cells to act as points of weakness

167
Q

What part of the nervous system controls smooth muscle cells?

A

The autonomic nervous system

168
Q

How are smooth muscle cells arranged?

A

In sheets

169
Q

Why are cardiac muscles branched?

A

To ensure electrical stimulation occurs evenly across the walls of the heart

170
Q

Where specifically in the heart are cardiac muscle cells located?

A

The walls of the atria and ventricles

171
Q

What coordinates cardiac muscle cells?

A

The SAN

172
Q

What gives skeletal muscle its striated appearance?

A

The arrangement of actin and myosin fibres

173
Q

What things do ligaments connect?

A

Muscles to muscles

174
Q

What things do tendons connect?

A

Muscles to bones

175
Q

What are T-tubules?

A

Invaginations of the sarcolemma

176
Q

What is the purpose of T-tubules?

A

They conduct impulses to the deepest regions of the muscle cell and every sarcomere, in order to ensure that they all receive the signal to contract at the same time

177
Q

Why are myofibrils lined up in parallel?

A

To provide maximum contractile force

178
Q

What makes up thin filaments?

A

Two twisted actin filaments

179
Q

What two types of filaments make up myofibrils?

A

Thin (actin) and thick (myosin) filaments

180
Q

What makes up thick filaments?

A

Myosin

181
Q

Why are myofibrils striated?

A

Because of the alternating light and dark bands

182
Q

What are light bands also known as?

A

I-bands

183
Q

What are dark bands also known as?

A

A-bands

184
Q

Why do light bands appear light?

A

They are the areas where actin and myosin filaments do not overlap

185
Q

Why do the edges of dark bands look especially dark?

A

Because this is where actin and myosin filaments overlap

186
Q

What is a Z-line?

A

A band in the middle of the light zone which signals the start/end of sarcomeres

187
Q

What happens to the sarcomere and H-band when muscle contraction occurs?

A

They shorten

188
Q

What is a H-band?

A

A lighter part of the dark band where only myosin filaments are present

189
Q

What is wound round each thin filament?

A

A tropomyosin molecule

190
Q

What model is used to describe muscle contraction?

A

The sliding filament model

191
Q

What two binding sites are located on the myosin head?

A

ATP and actin

192
Q

What does tropomyosin do?

A

Blocks actin-myosin binding site at rest, attached to troponin

193
Q

What 3 things does troponin bind to?

A

Actin, tropomyosin and calcium

194
Q

What structure allows myosin to move?

A

Hinged heads

195
Q

What happens to the Z lines during muscle contraction?

A

They move closer together, shortening the sarcomere

196
Q

What bonds do myosin heads form during muscle contraction?

A

Actin-myosin cross bridges

197
Q

How do actin filaments move during contraction?

A

The myosin heads pull them over myosin molecules

198
Q

What triggers muscle contraction?

A

An action potential arriving at a neuromuscular junction

199
Q

Why are there many neuromuscular junctions along a muscle?

A

To ensure that the whole length of the muscle receives the signal to contract at the same time

200
Q

What is a motor unit?

A

A single motor neurone and all the muscle fibres it innervates

201
Q

What happens when an action potential reaches a neuromuscular junction?

A

Normal cholinergic synapse action occurs, and the sarcolemma is depolarised

202
Q

What happens when the sarcolemma is depolarised?

A

Because the T-tubules are in contact with the sarcoplasmic reticulum, they stimulate calcium ion channels to open, which causes the sarcoplasm to be flooded with calcium ions from the sarcoplasmic reticulum

203
Q

What do the calcium ions which are released from the sarcoplasmic reticulum do?

A

Bind to troponin, which changes shape and pulls the tropomyosin away from the actin-myosin binding site, unblocking it and allowing actin-myosin cross bridges to form

204
Q

What does the myosin head do once bound to the actin filament?

A

Flex, pulling the actin fibre over the myosin fibre

205
Q

What is released from the myosin head when it flexes?

A

An ADP molecule

206
Q

What does the release of an ADP molecule from the myosin head allow?

A

An ATP molecule to bind to the myosin head

207
Q

What does the ATP molecule binding to the myosin head cause?

A

The head to release from the actin-myosin binding site

208
Q

What activity of the myosin, apart from muscle contraction, does calcium stimulate?

A

ATPase action

209
Q

What does the ATPase activity of the myosin filament do?

A

Allows hydrolysis of ATP, which gives energy to return the myosin head to its original position

210
Q

What happens when the myosin head releases from the actin-myosin binding site?

A

It can attach further along the actin filament to continue the contraction

211
Q

What happens to calcium ions after muscle contraction?

A

They are rapidly pumped back into the sarcoplasmic reticulum, causing the muscle to relax

212
Q

What 3 things are used as sources of energy for muscle contraction?

A
  1. Aerobic respiration 2. Anaerobic respiration 3. Creatine phosphate
213
Q

What 2 things require energy in muscle contraction?

A
  1. Release of the myosin head 2. Active transport of calcium ions back into the sarcoplasmic reticulum
214
Q

How is creatine phosphate used to generate energy?

A

It is used as a reserve supply of phosphate to make ATP

A Level Biology OCR (23 decks)

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