Kerboodle 13

Question 1

a cell which converts stimulus energy into an electrical impulse

Answer 1

(sensory) receptor

Question 2

b junction between two nerve cells

Answer 2

Synapse

Question 3

c a fast automatic response to a stimulus

Answer 3

Reflex

Question 4

d a source of ATP in muscle that does not involve respiration

Answer 4

Creatine phosphate

Question 5

e part of the nervous system controlling glands and involuntary muscles

Answer 5

Autonomic

Question 6

2 Describe the differences between the structure of:

a the peripheral and central nervous system

Answer 6

Central consists of brain and spinal cord but peripheral consists of nerves running , from sense organs/to muscles/to glands Central consists of relay neurones but peripheral consists of sensory and motor, neurones

Question 7

2 Describe the differences between the structure of:b voluntary and involuntary muscle

Answer 7

Two from: Voluntary is striated/has bands of actin & myosin, but involuntary is unstriated Voluntary has cylindrical fibres but involuntary has spindle-shaped fibres Voluntary is multinucleate but involuntary has cells with one nucleus

Question 8

2 Describe the differences between the structure of:b voluntary and involuntary muscle

Answer 8

Sarcomere is made of actin and myosin but sarcolemma is made of phospholipids and (globular) proteins Sarcomere is a structural unit of a myofibril but sarcolemma is the muscle fibre cell surface membrane

Question 9

b Describe how the potential difference across a neurone membrane is returned to resting potential after the peak of an action potential.

Answer 9

Sodium ion channels close/sodium ion influx stops Potassium ion channels open/K+ ions leave Hyperpolarisation due to loss of positive ions resting potential re-established by sodium-potassium (ion) pump removing 3 Na+ for every 2 K+ entering Diffusion of K+ ions back out 20 times greater than diffusion of Na+ back in (these two factors lead to) build-up of positive ions outside membrane Inside of axon membrane becomes relatively more negative

Question 10

iii state the effect of Na+ entering the postsynaptic neurone

Answer 10

Depolarisation (of postsynaptic membrane)/action potential

Question 11

iv explain the role of acetylcholinesterase in the synapse.

Answer 11

Hydrolyses ACh Into acetate and choline Stops continuous depolarisation of postsynaptic membrane/AW Choline recycled (into presynaptic neurone)

Question 12

b Some synapses in the brain use the neurotransmitter dopamine. After the postsynaptic membrane has been depolarised, dopamine leaves the receptor proteins and moves back into the presynaptic neurone through specific transporter proteins. Schizophrenia is a condition in which there is a higher than usual concentration of dopamine in certain areas of the brain. The drug phenothiazine has a similar shape to dopamine and is used to treat schizophrenia. Suggest and explain what occurs at the synapse when phenothiazine is used in the treatment of schizophrenia.

Answer 12

Binds to/blocks, dopamine receptors (on postsynaptic membrane) Prevents depolarization (of postsynaptic membrane) reduces effect of dopamine

Question 13

b Movement disorders are conditions in which people lose the ability to control their body movements. Scientists have discovered that inserting electrodes to stimulate parts of the brain can help to cure some movement disorders. This discovery has resulted from experimental work with monkeys, which has made the research controversial. Suggest why monkeys rather than other laboratory animals, such as rats, were used for this work and comment on whether their use in this way is justified or not.

Answer 13

Monkeys rather than rats – two from: Idea that (humans & monkeys) closely related/share more genes/share a common ancestor (humans & monkeys) both primates idea that brain/body, structure/physiology/behaviour, similar (to humans) Monkey brain bigger (than rat)