Download Port Said International Schools Unit 1: Revision1

Port Said International Schools
Better Education for Future Generations
Science Department
Revision: unit 5
Grade: 11
Sensitivity : it is the suitable response of the living organism to the internal and external stimuli to
maintain its life.
Sensitivity in plants
1) Response to touch and darkness:
2) Tropism:
It is the curvature of stem or root of plant, when their sides are subjected to factors (stimuli) as
light, humidity and gravity in an unequal form.
Types of tropism:
A. phototropism:
it is the response of the plant parts to the external stimuli (light) causing the curvature of the plant parts
towards or away from light.
B. Geotropism:
Geotropism is the response of plant parts to the external stimuli (gravity) where they move away or
towards the stimulus.
C. Hydrotropism:
it is the response of the plant parts to the external stimuli (humidity) causing the curvature of the plant
parts towards or away from water.
Auxins:
Chemical compound secreted from the coleoptiles’ tip of plants and affected by the external factors.
The main type of auxin is indole-acetic acid (IAA).
The nervous system in man :
Nerve cell(neuron)
It is the unit structure of the nervous system.
The nerve impulse:
The nerve impulse is the message transmitted through the nerves from
sense oragns (receptors) to the central nervous system, and from the
latter to the effectors (responding) organs. It is an electrical
phenomenon with a chemical nature (electro-chemical phenomenon).
1. The nerve cell at rest:
At rest, there is a difference in distribution and concentration of some
ions outside and inside the nerve cell, as follows:
a. The concentration of positive Sodium ions (Na+) outside the cell is
10 up to 15 times higher than inside.
b. The concentration of positive Potassium ions (K+) inside the cell is
30 times higher than outside.
c. The concentration of negative ions as Chloride (Cl-) and protein ions are higher inside the cell.
This unequal distribution of ions results in the presence of an electrical potential difference between outside and
inside the cell surface that equals – 70 millivolt (mV). The membrane of the nerve cell during this resting
condition is said to be polarized.
This state of polarization is a result of:
2. Changes in the nerve cell on stimulation:
The nerve cell is stimulated only when the stimulus is sufficient (strong enough). There are changes in
permeability of the membrane in which:
a. The inflow of the positively charged Sodium ions exceeds the outflow of the positively charged Potassium
ions through special channels in the membrane leading to accumulation of excess positive charges inside the
membrane, i.e. reverse of the original polarity and the membrane potential becomes +40 mV. This new state is
called depolarization.
The synapse:
The synapse is site between the terminal branches (arborizations) of the axon of one neuron and the dendrites of
the next neuron.
Mechanism of transmitting a nerve impulse across a synapse:
Acetylcholine (chemical transmitter) is destroyed (after performing its function) under the effect of an enzyme
called cholinesterase to terminate its action. Then, the postsynaptic membrane (dendrite) returns to the resting
state again.
The Nervous System (C.N.S)
1- Centerla N.S (brain – spinal cord)
2- Peripheral N.S (cranil nerves – spinal nerves)
3- Autonomic N.S (controls the involuntary muscles and glands)
The Central Nervous System (C.N.S)
The brain:
The brain occupies a bony space called the brain case or the cranium (a part of the skull).
The brain is surrounded by three membranes called the meningies ,which are responsible for the
protection and nutrition of the brain cells. These
membranes are:
A) The dura mater: The membrane which lines the skull.
B) The pia mater: The membrane which is in direct contact
and adheres to the brain.
C) The arachnoid: The membrane which is in between the
other two membranes and contains a transparent fluid to
protect the brain from mechanical trauma.
The main components of the brain
Forebrain
Brain cortex
Thalamus
Midbrain
Hypothalamus
Cerebellum
Hindbrain
Pons Varolii
Medulla Oblongata
Spinal cord:
Autonomic nervous system:
Regulate the different involuntary activities.
1- Sympathetic N.S
It is important as an emergency system, enable the body to confront the emergency situations.
2- Parasympathetic N.S
The following table summarizes the effects of the sympathetic and parasympathetic system on
some parts of the body:
The organ
Effect of
Sympathetic system
Effect of
Parasympathetic system
Heart
Increases heart beat rate and force of
contraction.
Vaso constriction of blood vessels of
skin, viscera, salivary glands, brain,
external genetalia and lungs.
Relaxation of the wall of stomach,
intestine and colon.
Dilatation (relaxation) of bronchioles
and decreases secretions.
Relaxation of the wall.
Dilatation of the eye pupils.
Stimulates small quantity of secretion.
Inhibits secretion.
Decreases heart beat rate and force of
contraction.
Vaso relaxation of salivary glands and
external genetalia.
Blood vessels
Alimentary
canal
Respiratory
system
Urinary bladder
Eyes
1. Salivary
2. Gastric
(of the stomach)
3. Liver
4. Pancreas
5. Adrenal
medulla
Break down of Glycogen and increases
Glucose level in blood.
Inhibits secretion of enzymes.
Stimulates the secretion of the
adrenaline hormone (epinephrine)
which increases blood pressure,
increases the heartbeat rate, and
increases the Glucose level in the blood.
Contraction of the wall of stomach,
intestine and colon.
Constriction (contraction) of bronchioles
and increases secretions.
Contraction of the wall.
Constriction of the eye pupils.
Stimulates large quantity of secretion.
Stimulates secretion.
No Parasympathetic fibers.
Stimulates secretion of enzymes.
No Parasympathetic fibers.
Revision VII
ٍٍٍSensitivity in Livings.
1. Give the scientific term that represents each of the following:
a. Two main functions for sensitivity in livings. (----------------------------------------)
b. Two types of stimuli to which sensitivity systems can pick up and respond to. (----------------------------------)
c. The movement in which the leaflets of Mimosa hang downwards and fold their upper surfaces at night.(------)
d. One of the main Auxins present in plants. (--------------------------------)
e. The response of plant parts to the external stimulus of gravity. (-----------------------)
f. The response of plant parts to the external stimulus of light. (-----------------------)
g. The response of plant parts to the external stimulus of humidity. (---------------------)
h. The two systems that organize the functions of different body organs and control the relation between Man
and his environment. (----------------------------------------)
i. The link between the nervous system and the endocrine glands system. (--------------)
j. The structures that receive information in the form of external and internal stimuli. (------------------------------)
k. The unit of structure of the nervous system. (-------------------------------------)
2- Compare between:
1- Sympathetic and parasympathetic nervous system.
2- White matter and grey matter of the spinal cord regarding their function.
3- Geotropism and phototropism.
Write the scientific term :
1234-
A material prevents the blood clot inside the blood vessels.
The inner region of the kidney.
An enzyme hydrolyzes the protein into a polypeptide in an acid medium.
A compound which is produced from breaking down of glucose, protein, fats, and enters the Kreb’s
cycle reactions.
5- The process occurs when the blood exposed to the air or firiction of blood with rough surface.
6- A coiled tube that reaches the skin surface through a pore in the human’s skin.
7- A tissue formed by Meristematic cells which causes thicking of the stem.
8- The process by which energy is extracted from bonds in the food molecules.
9- A biological process made by the living organism to get rid of wastes of metabolism.
10- Microscopic vessels which connect the arterioles with the venules.
What happens in the following:
12345-
Liver failure.
If there is no HCl in the stomach.
Absence of convolutions from the lining layer of large intestine.
Kidney failure
Absence of red blood cells from the blood.
Study the opposite figure then answer:
The opposite figure shows the anatomical structures responsible for heart beating
1- Which structure is considered as the pace maker of the heart?
2- Doctors can distinguish between 2 different heart sounds. Explain