Download Unit2-KA3a-NervousSystem

N5- Unit 2 –Key area 3- Control and communication- Nerve and hormones
1-Why is internal communication
For survival of multicellular organisms because cells in
needed?
multicellular organisms do not work independently.
Nervous control
2- What is the nervous system
The central nervous system (CNS, made of the brain
made of?
and the spinal cord.) and the nerves.
3- Identify the parts of the brain
1- Cerebrum: the largest part, divided into two halves.
and their function
Different regions are responsible for memory, conscious
thought, reasoning, intelligence, personality.
2- Cerebellum: controls balance and co-ordination.
3- Medulla: controls automatic functions of the body:
breathing, heart beat, etc…
4- What is a stimulus? Other name
for it?
5- Job of the sensory neuron and
effect?
6- Job of the motor neuron?
7- What is a relay/intermediate
neuron?
8- In what form is the message
carried along a neuron?
9- What is the name of the gap
found between 2 neurons?
10- How is the message passed
from on neuron to the next?
11- What is a reflex action?
12- Function of a reflex action and
example
13- Describe how a reflex action
works, using the
simple model of a reflex arc.
A change in conditions that is detected by a receptor.
Other name: sensory input.
To pass the message to the CNS.
The CNS processes the information from our senses
which needs a response
Motor neurons enable a response brought about by the
CNS to occur. It can be a rapid action from a muscle or
a slower response from a gland.
A nerve cell which is found between a sensory and a
motor neuron. The relay neuron is part of the CNS (i.e.
brain and spinal cord).
Electrical impulses carry messages along neurons.
A synapse.
Chemicals transfer these messages across synapses.
It is a fast automatic responses which require no input
from the brain.
- protect the body from damage (e.g. removing hand
from heat, pupil of the eye becoming smaller in bright
light to protect the sensitive cells at the back of the
eye from damage, sneeze)
- help the body’s normal functioning (e.g. swallowing).
It is the passage of an impulse from a sensory neuron,
across a relay neuron to a motor neuron.
Receptors (1) are stimulated (e.g. pain) and send a nerve
impulse though the sensory neuron (2).
From the sensory neuron, the message has to pass
through a synapse (junction, 3) before it reaches the
intermediate neuron or relay neuron (4) in the spinal
cord.
From the intermediate/relay neuron, it crosses another
synapse (5) and travels down a motor neuron (6) which
stimulates a muscle to contract (7) (e.g. jerking
movement of the hand).
Hormonal control
14-Features of hormones
15- What releases hormones
directly into the blood stream and
why?
16- How are hormones perceived by
the target tissue?
17- Why are hormones ignored by
non-target tissues?
18- Which organ detects changes in
blood glucose level?
19- How and where is glucose stored
in the body?
20- Explain the role of insulin in the
control of blood glucose levels.
21- Explain the role of glucagon in
the control of blood glucose levels.
22- What can happen if blood
glucose levels are not controlled? (2
answers)
23- What is diabetes?
24- Consequences of diabetes
25- Treatment of diabetes
26- Give two reasons for the recent
increase in the number of people
with diabetes in Scotland
- Chemical messengers
- Made of protein
- Carried in the blood
Endocrine glands release hormones in the blood stream
so that they can travel to target tissues.
Cells have receptors on their surface.
Because non-target tissues don’t have receptors for
them.
The pancreas.
As glycogen (many glucose molecules chemically bound)
in the liver.
When blood glucose level increases, the pancreas
releases more insulin, which travels to the liver where
it activates enzymes in the liver cells to convert
glucose into glycogen.
When the blood glucose level decreases, the pancreas
releases more glucagon, which travels to the liver
where it activates enzymes in the liver cells to convert
glycogen into glucose.
- it is important to control blood glucose levels since, if
they are high, they can cause damage to blood vessels
and affect the functioning of the eyes and kidneys in
particular.
- uncontrolled blood glucose levels can cause problems
with osmosis in cells.
A communication pathway that has failed due to a fault
in release or a failure to respond to insulin
High blood glucose levels (see above n.22)
Injections of insulin to help the uptake of glucose
from the blood to the cells.
- Poor diet
- Lack of exercise