Response: the reaction of an organism to an internal or external
stimulus.
NEURONS:
Dendrites
Gap between the nerve ending of one neuron and dendrite of the
other neuron.
Electrical signal to Chemical signals
Neuromuscular junction (NMJ):
a synaptic connection between the
terminal end of a motor nerve and a muscle.
Nerve ending
Voluntary Actions Involuntary
Actions Reflex Actions
Aspect
Monitored through the spinal cord.
the pathway taken by nerve impulses in a reflex action is called
reflex arc.
Human brain:
Protection of nervous system
Brain in cranium (bone
box, part of skull).
Covered by 3 membrane
layers (meninges).
Fluid protects brain from
injuries.
Spinal cord wrapped
in meninges.
Protected by
vertebral column
(backbone).
Vertebral column
made of 33 bones
(vertebrae).
Spinal cord: cylindrical
extension of brain, starts
from medulla.
Surrounded by meninges.
31 pairs of nerves arise.
Handles spinal reflexes.
Conducts nerve impulses
to/from brain.
TROPIC
Control & Coordination
Coordination: working together of the various organs of an
organism to adjust various activities of life.
Stimuli: change in the environment that can cause a physical or
behavioral change in a living organism.
Receptors: Cells or groups
of cells in sense organs
that detect stimuli and
convert them into impulses.
Effectors: Parts of the body that
respond to impulses sent by the nervous
system, converting them into actions. e.g.
muscles and glands.
COORDINATION IN ANIMALS:
Nervous system
Endocrine system
Hormones
Central Spinal cord
Fore - Brain
Mid - Brain
Hind- Brain
Cranial nerves
Arise from the brain Arise from
spinal cord
Spinal nerve
Cell body
Acquired information
travels as an electrical impulse
Longest fibre on the cell body. It
transmits electrical impulse from
cell body to dendrite of next neuron.
Axon
Acquires information Nerve ending
Synapse
Dendrites Cell body Axon Synapse
Types of Neuron:
Sensory Neurons Transmit impulses from sense organs to brain
Motor Neurons Transmit impulses from Brain and spinal cord to body
Relay Neurons Allow sensory and motor neuron to communicate
Definition
Control
Actions under
conscious control
Actions occurring
without conscious
control
Sudden, automatic
responses to
stimuli
Involves the brain’s
thinking and decision-
making
Controlled by
the autonomic
nervous system
or lower brain
centers
Controlled by
the spinal cord
via reflex arc
Examples Walking, writing,
speaking
Heartbeat,
digestion,
breathing
Pulling hand away
from a hot
object, blinking
Reflex action: spontaneous automatic and involuntary response.
Brain is the main coordinating centre of the body.
Controls involuntary actions
such as:
Changing pupil size.
reflex movement of head,
neck and trunk
Most complex or specialized part of brain (largest also).
Consists of cerebrum, Thalamus, Hypothalamus.
Functions: Thinking part of the brain Control the voluntary
actions. Store information. Receives sensory impulse
Centre associated with hunger.
Control involuntary actions,
regulation of respiration
controls posture and balance.
Precision of voluntary act.
controls voluntary
act. Eg: blood
pressure,
salivation, vomiting.
Spinal cord
Brain
more about Spinal cord
CHEMICAL COORDINATION IN PLANTS :
NASTIC
Thigmonasty
Non-directional
movement in response to
touch (e.g., Mimosa
pudica).
Photonasty
Non-directional
movement in response
to light (e.g., dandelion,
moonflower)
Phototropism: Growth towards
or away from light.
Hydrotropism: Growth in
response to water.
Geotropism: Growth in
response to gravity.
Chemotrpism: Growth towards or
away from chemicals.
Thigmotropism : Growth in
response to touch.
Brain Peripheral
PRASHANT KIRAD
Photo
Phono
Thermo
Olfactory
Gustatory
