Download Chapter 6 Chapter Review Questions Q2. This would be a

Chapter 6 Chapter Review Questions
Q2. This would be a disadvantage for the person as they would not be able to sense if they are in
danger. For example if you accidentally touch your hand on a hot frying pan, you move it away
because keeping it there would cause severe damage, however, someone who has an autoimmune
disorder which prevents them from feeling pain would not be able to feel that the hot frying pan is
damaging their hand. Similarly people who cannot feel pain would not know when they have broken
ones, this can be serious as broken bones can often cause internal bleeding and if this goes
undetected, it could result in the person's death.
Q3. A dart or arrowhead with curare would have lead to the death of a person as they would lose all
muscle control. Curare prevents acetylcholine (ACh), which is a neurotransmitter, from binding to
the receptor sites on muscle fibres. This means that muscle cells are not stimulated to contract and
the person is paralysed. Breathing and other bodily functions which rely on skeletal muscle
contraction are unable to occur.
Q4.
a) Somatic
b) Parasympathetic
c) Parasympathetic for eating food and Somatic for watching a movie
d) Somatic
Q5. When a hungry person salivates, the parasympathetic effector neurons are active. This is
because a person cannot consciously control salivation. A full stomach might inhibit these neurons
by feeding back to the parasympathetic system that saliva is not needed any more.
Q6. The nerves do not appear to have the same speed of conduction.This is probably because:

there are more nerves involved in sending the pain message and so it takes longer.

to reduce tissue damage, it would be more important for the heat message to reach the
brain first.
It may also be the case, that the tissue damage does not begin immediately and so pain would be
perceived after temperature.
Q7.
a) Because the colour and texture of the chameleon changes rapidly, it indicates that this is under
the control of the nervous. If it were under the control of the endocrine (hormonal) system the
chameleon would not be able to change as rapidly as hormones are slower to act than neurons.
b) As darker colours tend to absorb more heat, the chameleon can change in order to absorb more
or less heat depending on the temperature and the time of the day. As the chameleon is a reptile, it
is an ectoderm meaning that its internal functioning is under the control of its external environment
and hence being able to control the amount of heat available to it proves as an advantage.
Q8.
a)
1- is a sensory receptor (sensory cell)
2- is the cell body of an afferent neuron (sensory neuron, affector neuron)
3- is the cell body of a connecting neuron (an interneuron)
4- is the cell body of an efferent neuron (motor neuron, effector neuron)
5- is an effector cell/muscle
b) You would expect to find structure 3 in the central nervous system, the spinal cord in particular.
c) You would expect to find structure 4 in the spinal cord. This is the cell body of a peripheral
efferent (motor) neuron.
Q9.
a) Distinctive grey and white areas visible in the section cut across the spinal cord are due to areas of
myelinated axons running up and down the spinal cord (white areas) and areas of cell bodies where
synapsing occurs that are not myelinated (grey areas).
b) The central canal in the spinal cord is important because cerebrospinal fluid flows down the
central canal. Cerebrospinal fluid helps to protect the spinal cord from trauma.
c) The man would no longer be able to feel heat and hence cannot respond to heat.
d) The man would be able to feel the heat, however he would not be able to respond to it.