2. Sensitivity
Ability to detect
STIMULI and react to
them
Useless to an organism
unless it can respond to
them in some useful way
RECEPTORS pick up
the stimuli
(pain
or
receptors)
chemical
EFFECTORS like
MUSCLES and
GLANDS
A COMMUNICATION/
COORDINATION
SYSTEM
3.
4. Receptors groups of specialised cells.
They can
*detect changes in the environment
(stimuli)
*turn them into electrical impulses.
Receptors are often located in the sense
organs such as the ear, eye and skin
Receptors often located in the
sense organs such as the ear, eye
and skin
Sense organs
Skin
Tongue
Nose
Eyes
Ears
Effectors parts of the body that
produce a response. Here are three
examples:
1.a muscle contracting to move an arm
2.a muscle squeezing saliva from the
salivary gland
3.a gland releasing a hormone into the
blood
Receptors
sensitive to
touch, pressure,
pain and
temperature
chemicals in food
chemicals in the air
light
sound and position
of the head
5. Most animals have 2 methods of sending
messages from RECEPTORS to EFFECTORS
Nervous System
Endocrine System
Receptors, nerves
and neurons
Secretory cells
ELECTRICAL
impulses along the
nerves
faster
Effect of the
message only lasts a
very short while
Chemicals called
HORMONES transported
by the bloodstream to target
organs
Slower
Effect of the
message lasts longer
6. NERVOUS
SYSTEM
a system of organs working together to detect
and respond to stimuli.
made up of two systems, the Central Nervous
System (C.N.S) and the Peripheral Nervous
System (P.N.S)
connects the central nervous system to the
other parts of the body
Central Nervous System
(CNS)
the processing center for the nervous
system. It receives information from
and sends information to the
peripheral nervous system. The two
main organs of the CNS are the brain
and spinal cord. The brain processes
and interprets sensory information
sent from the spinal cord
7. Components of the Nervous System
Central
Nervous System
Social
– Brain and Spinal Cord
life
Peripheral Nervous
System – Cranial and
Spinal nerves
Autonomic Nervous
Vegetative
System –
life
parasympathetic and
sympathetic
8.
9. The human nervous system.
The brain and spinal
cord form together the
CENTRAL
NERVOUS
SYSTEM.
Nerves carry electrical impulses, from the central nervous system to all
parts of the body EFFECTORS (muscles and glands) go into action
when they receive nerve impulses MOTOR IMPULSES
Nerves carry electrical impulses BACKto the CNS from RECEPTORS in
the sense organs the nerve impulses SENSORY IMPULSES
10. Nerve impulses from
the sense organs
(skin, eye, ears) to
the central nervous
system are called
SENSORY
IMPULSES. This is
the way by which
information from
the peripheral
receptors travel to
the central nervous
system.
From the central
nervous system, this
impulses are carried to
the
EFFECTORS, resulting
in action. These are
called MOTOR
IMPULSES.
11.
12. There are millions of neurons, which form
the electrical connections that let us think.
Dendrite Fine hair-like extensions on the end of a neuron.
Function: receive incoming stimuli.
Cell Body or Soma The center of the neuron, containing
the nucleus and the organelles
Function: Directs impulses from the dendrites to
the axon.
Nucleus Control center
Axon Pathway for the nerve impulse (electrical message) from the
soma to the opposite end of the neuron. Some of them can reach a
length of up to a metre in humans
Myelin Sheath An insulating layer around an axon (composed
mainly of fat) letting the signal travel about 100 times faster
than in an unmyelinated axon It is made up of Schwann cells..
Nodes of Ranvier Gaps between schwann cells.
Function: Saltatory Conduction (Situation where speed of
an impulse is greatly increased by the message ‘jumping’
the gaps in an axon).
14. NEURONES.
The central nervous system, and the peripheral
nerves are made up of neurones.
MOTOR NEURONE
Carry impulses from
the central nervous
system to the muscles.
MULTI POLAR
NEURONES
Are neither sensory
nor motor but make
connections to other
neurones inside the
central nervous
system.
SENSORY NEURONES
Carry impulses from
the sense organs to the
central nervous
system.
15. Automatic response to a stimulus
REFLEX
Pupillary reflex
The brain is informed but you don’t waste time thinking
about what to do
Plantar reflex
Achiles reflex
Knee jerk
Reflexes can be divided
into:
-innate/primitive
-acquired
16. Passes the
message on
to the brain
The brain is informed but you don’t
waste time thinking about what to do
We need to inform the CNS
to allow a variety of
behaviours under different
circumstances
20. It is necessary for impulses to pass from one
Synapse
neurone to another. The regions where impulses
are able to cross from one neurone to the next are
called SYNAPSES.
At a synapse a branch at the end of one fibre is in close contact with a
dendrite of another neurone. When an impulse arrives at the
synapse, it releases a tiny amount of a chemical substance called a
NEUROTRANSMITTER SUBSTANCE, which sets off an impulse
in the next neurone. (relay neurone)
SYNAPSES ensure that nervous impulses only travel
in
22. The NERVE IMPULSE
The impulse is a series of electrical
pulses, which travel down the fibre. All
the impulses are similar.
The difference is that each impulse is sent
to different parts of the brain.
For example, the nerves from the eye go to the part
of the brain concerned with sight. Then the brain
recognizes that the impulses comes from the eye
and we SEE something.
23. *receives sensory impulses
*sends motor impulses to glands and muscles
*correlates the stimuli and the memory
*stores information so as to modify behaviour
*co ordinates the mechanisms and chemical reactions the body
works efficiently
24. The Triune Brain
Neocortex - Thought (including
planning, language, logic &
will, awareness)
Limbic System - Emotion
(feelings, relationship/nurturing,
images and dreams, play)
Reptilian Brain - Instinct
(survival, breathing/swallowing/h
eartbeat, startle response)
Three Brains in One
25. Sensory information such as
vision, smell and hearing
processed here. Higher
cognitive functions.
cerebral cortex
hypothalamus
Homeostasis:
control of body
temperature and
osmoregulation.
Secretes hormones
pituitary gland
Produces hormones that
control growth, sexual
development and
metabolism
midbrain
Involved in control of visual
and auditory systems. Also
controls body movement
corpus collosum
Connects the left and
right hemispheres to
coordinate
information
cerebellum
Fine motor
control,
posture and
balance
pons
Links the
medulla with the
thalamus
medulla oblongata
Controls breathing, heart rate
and blood pressure; reflex
actions such as vomiting and
sneezing
27. The Cerebrum
The largest portion of the brain
is the cerebrum. It consists of
two hemispheres that are
connected together at the
corpus callosum.
The cerebrum is often divided
into five lobes that are
responsible for different brain
functions.
Corpus callosum
29. Lobes of the Cerebrum
Limbic Lobe
Frontal Lobe
Parietal Lobe
Occipital Lobe
Temporal Lobe
30. Frontal Lobe
The frontal lobe is the area of
the brain responsible for
higher cognitive functions.
These include:
•
•
•
•
•
•
•
•
Problem solving
Spontaneity
Memory
Language
Motivation
Judgment
Impulse control
Social and sexual behavior.
31. Temporal Lobe
The temporal lobe plays a
role in emotions, and is
also responsible for
smelling, tasting, percepti
on, memory, understandi
ng
music, aggressiveness, a
nd sexual behavior.
The temporal lobe also
contains the language
area of the brain.
32. Parietal Lobe
The parietal lobe plays a
role in our sensations of
touch, smell, and taste. It
also processes sensory
and spatial awareness,
and is a key component
in eye-hand co-ordination
and arm movement.
The parietal lobe also
contains a specialized
area called Wernicke’s
area that is responsible
for matching written
words with the sound of
spoken speech.
34. Limbic Lobe
The limbic lobe is
located deep in the
brain, and makes up
the limbic system.
area of the brain that
regulates emotion and
memory. It directly
connects the lower and
higher brain functions.
A. Cingulate gyrus
B. Fornix
C. Anterior thalamic
nuclei
D. Hypothalamus
E. Amygdaloid nucleus
F. Hippocampus
35. The cerebellum is connected to the brainstem, and it is
the center for body movement and balance.
It receives sensory impulses from – muscles
- semicircular canals
- utriculus
Cerebellum
36. Thalamus
Thalamus means ―inner room‖ in
Greek, as it sits deep in the brain at the
top of the brainstem.
The thalamus is called the gateway to
the cerebral cortex, as nearly all
sensory inputs pass through it to the
higher levels of the brain.
37. Hypothalamus
The hypothalamus sits under the thalamus at
the top of the brainstem. Although the
hypothalamus is small, it controls many critical
bodily functions:
• Controls autonomic nervous system
• Center for emotional response and behavior
• Regulates body temperature
• Regulates food intake
• Regulates water balance and thirst
• Controls sleep-wake cycles
• Controls endocrine system
The hypothalamus is
shaded blue. The pituitary
gland extends from the
hypothalamus.
38. The Brainstem
The brainstem is the most
primitive part of the brain and
controls the basic functions of
life: breathing, heart
rate, swallowing, reflexes to
sight or sound, sweating, blood
pressure, sleep, and balance.
The brainstem can be divided
into three major sections.
39. The divisions of the brain are seen
here in a Frontal (Coronal) Slice of
the brain.
1- Cerebrum
2- Thalamus
3- Mesencephalon - Midbrain
4- Pons
5- Medulla oblongata
6- Medulla spinalis - Spinal
cord
40. The Medulla Oblongata (=BULBO RAQUIDEO)
The medulla oblongata merges
seamlessly with the spinal cord and
creates the base of the brainstem.
The medulla is primarily a control
center for vital involuntary reflexes
such as
swallowing, vomiting, sneezing, co
ughing, and regulation of
cardiovascular and respiratory
activity.
The medulla is also the origin of many
cranial nerves.
41. The Pons (=PROTUBERANCIA)
The pons is the rounded
brainstem region between the
midbrain and the medulla
oblongata. In fact, pons means
―bridge‖ in Latin.
The main function of the pons is
to connect the cerebellum to
the rest of the brain and to
modify the respiratory output of
the medulla.
The pons is the origin of several
cranial nerves.
42. The Ventricles
The ventricles are a complex
series of spaces and tunnels
through the center of the brain.
The ventricles secrete
cerebrospinal fluid, which
suspends the brain in the skull.
The ventricles also provide a
route for chemical messengers
that are widely distributed through
the central nervous system.
Click image to play or pause video
43. The Meninges
•The meninges are layers
of tissue that separate
the skull and the brain.
*Cerebrospinal fluid is a
colorless liquid formed
within the ventricles of
the brain that circulates
throughout the central
nervous system.
*Cerebrospinal fluid fills
the ventricles and
meninges allowing the
brain to ―float‖ within the
skull.
Skull
Dura mater
Arachnoid Layer
Pia Mater
Brain
44. GREY MATTER: bodies
of neurons + dendrites
concentrated
WHITE MATTER:
consists of all the axons
PONS
MEDULLAOBLONGATA
SPINAL CORD
grey matter inside,
surrounded by white
matter
CEREBELLUM
CEREBRUM white matter
inside, surrounded by grey
matter
