Transcript Diapositiva 1

NERVOUS SYSTEM
Sensory organs (receptors) capture
information from the body and the
environment, and then transmits it to
the nervous system, which receives
and processes the information thus
generating responses. These
responses are transmitted by nervous
impulses to effectors, which execute
these responses.
Nervous system functions.
- Receives information perceived by the
sensory organs.
- Interprets the information.
- Produces appropriate responses.
- Transmits the necessary orders to the
effectors.
- Coordinates the operation of every
organ in our body.
- Makes intellectual and mental decisions.
- Is responsible for emotions and feelings.
Brain
Neuron
Fibres
Spinal Cord
NEURONS AND NERVE IMPULSES
Neurons have a unique ability: to generate and transmit
nerve impulses (currents). When a neuron is stimulated
it triggers electrical changes in the cell membrane
that are transmitted from dendrites to the axon. The
connection established between neurons is called
synapse. Synapses are points of control of the
transmission of nerve currents. They allow the nerve
impulses to pass from one neuron to the other through
certain areas.
There is a narrow space between neurons known as a
synaptic gap or cleft.
At the end of the axon there are very small vesicles
that contain substances called neurotransmitters.
-Axon is a long, thin fiber that
carries nerve impulses.
-
- Dentrites are thin extensions
of the cell body that carry nerve
impulses towards the cell body.
According to their function Neurons
can be:
- Sensitive. Transmit the information
from the receptors to the major nervous
centers.
- Motor. Transmit orders to the
effectors.
- Intercalary. Located between sensory
and motor neurons. They are located on
the higher nervous centers. They run
between and connect two other neurons.
The Cerebro-spinal nervous
system regulates and
coordinates the relations
between the organism and the
external environment. It is
made up of the Central
Nervous System (CNS) and
the Peripheral Nervous
System (PNS).
PERIPHERAL NERVOUS SYSTEM (PNS)
The peripheral nervous system
connects the sensory organs to the
central nervous system, and the
central nervous system to the
effectors. It is made up of nerves,
which are kinds of cords made up of
several associated axons.
CENTRAL NERVOUS SYSTEM (CNS)
The central nervous system consists of the spinal
cord and the brain, which are the centers that
receive, integrate, and process information.
The central nervous system is protected from
accidental external injury by:
- The skull and the vertebral column (spine or back bone)
- Three membranes called meninges. The cerebrospinal
fluid fills the space between the meninges.
In the central nervous system there are two
different areas:
- White matter
- Grey matter
THE BRAIN
The brain is the part of the central nervous system
housed inside the skull. The brain is divided up into four
parts:
- The medulla oblongata. Is an extension of the spinal
cord.
- The brain stem. Includes several parts of the brain,
located between the medulla and the brain.
- The cerebellum is located at the back of the brain.
- The cerebrum is the biggest and most important
organ of the nervous system.
The cerebrum consists of inner white matter, and outer
grey matter that is the cerebral cortex.
There are two types of folds on the cerebrum
surface:
• Gyri (circumvolutions). Are numerous and
shallow folds.
• Sulcus (fissures). Are rare and deep folds.
One of the sulcus divides the brain into two
hemispheres (right and left), which are
connected by the corpus callosum. The
remaining fissures and gyri define different
areas of the cerebral cortex, known as lobes.
The left hemisphere is logical and analytical.
The right is intuitive and creative.
THE FUNCTIONS OF THE
BRAIN.
- Receives information from all sensory
organs and produces the corresponding
sensations.
- It processes the information received
and prepares responses and orders for the
effectors.
- Coordinates and controls the operation
of all parts of the nervous system.
- hosts the intellectual faculties and
higher nervous system functions.
THE SPINAL CORD
The spinal cord is a nerve cord that
runs inside the channel formed by
the spine.
The functions of the spinal cord are:
- Carries out reflexes.
- Conducts sensory impulses to the
brain, and the motor commands from
the brain to the effectors.
Types of nerves as related to
their origin in the NCS:
-Cranial nerves. They come from
the brain.
- Spinal or spinal nerves. They
come from the spinal cord.
A few small lumps called ganglia
are observed In the trajectory
of certain nerves .
The axons are electrically isolated by the
myelin sheath. This prevents against the
passage of the nervous current between
different axons.
Types of nerves as related to the way
they transmit the nervous impulse:
- Sensory nerves. Transmit information from
the sensory organs.
- Motor nerves. Send commands to the
effectors.
- Mixed nerves. Contain both types of axons.
NERVOUS ACTS
-Reflex actions. They are fast
and automatic acts in which the
brain does not participate.
The three types of neurons
(sensory, motor and intercalary)
are involved in reflex actions.
- Voluntary actions, in which the
brain does participate.
AUTONOMIC NERVOUS SYSTEM (ANS)
The autonomic nervous system, also known as
visceral or involuntary, is responsible for the
proper regulation and coordination of internal
organs. There are two types of autonomic
nervous systems:
- Sympathetic. It induces the body organs to
work more intensively (activation).
- Parasympathetic. It’s action causes
relaxation and slower and less intense
performance of the organs (inactivation).
DEMENTIA
Dementia is an impairment in memory
and long-term problems associated
with abstract thinking and other
disorders of brain function and
personality changes. The disorder is
severe enough to significantly
hamper the ability to perform
routine activities.
ALZHEIMER
Alzheimer's Disease is a degenerative
brain disease for which there is no cure.
Slowly and inexorably, the disease attacks
nerve cells in all parts of the brain's
cortex, as well as some surrounding
structures, thereby impairing the person's
abilities to govern emotions, recognize
errors and patterns, coordinate movement,
and remember. In the end, the afflicted
person loses all memory and mental
functioning.
EPILEPSY
Epilepsy is a physical condition that
occurs when there is a sudden, brief
change in the brain. When brain cells
are not working well, consciousness,
movements or actions of one person
can be altered for a short period of
time. These physical changes are
called epileptic seizures.
PARKINSON’S DISEASE
It is a neurological disease that is associated with
muscle rigidity, difficulty walking, tremors and
impaired movement and coordination.
Parkinson's disease is a chronic neurological
process which causes progressive alteration in the
substantia nigra of the midbrain (areas that
control and coordinate movements), and the
decline of brain dopamine. Dopamine is a
neurotransmitter substance that transmits nerve
impulses to other cells.
DEPRESSION
People affected by this disorder
undergo anxiety, sense of failure
and loss of interest in most
things. Depression can be
developed by external
circumstances, such as
bereavement, or by internal
unknown causes .
HEALTHY HABITS
- Conduct an orderly life and regular schedules
with time for rest and recreation.
- Do not use drugs.
- Exercise by doing continuous intellectual and
mental activities to encourage proper
maintenance of nerve function.
- Make sure your diet contains sufficient
vitamins for an optimal functioning of the
nervous system.
- Avoid stress.
- Be critical aware of advertisements that are
not suitable for nervous and emotional stability.
CREDITS
-Patricia Rodríguez Torner
-Rocío Mendoza López
-Sara Sánchez Romero
-Tania Romero Caña