Coordination and response

Coordination &

Response:

The Nervous System

Sensitivity

• One major characteristics of all living

organisms.

• The ability to detect/sense stimuli in the internal

or external environment and to react to them.

Stimuli

• Singular: stimulus

• A change in the environment that can be detected

by organisms.

• Could be anything from:

Environmental conditions

Levels of bodily substances

Social cues

Learning

Coordination

• Making sure that the actions of

different parts of the body
work together.

Response

• The reaction to a specific stimulus with the

help of the nervous system.

• Goal of response: survival

We jerk our hand away
immediately after
touching a hot object

Seeds will grow when water
becomes available in the soil

Coordination

• In animals is through:

Nervous System

●Rapid response

Endocrine System

●Slow, long-lasting response

Nervous System

• 2 Regions:

1. Central Nervous System (CNS)

1. Peripheral Nervous System (PNS)

Video: Introduction to
Nervous System

Nervous System

Video: Brain 101

Multiple Choice

Which of the following is a function of the central nervous system (CNS)?

a) Regulation of body temperature

b) Control of voluntary movements

c) Secretion of hormones

d) Filtering of blood

• a) Regulation of body temperature

• b) Control of voluntary movements

• c) Secretion of hormones

• d) Filtering of blood

Flow of Information

•Arrow:

Stimuli info.
Response info.

Receptor
Sensory
neurone
CNS

Motor neurone

Affector

Stimulus

Response

Processing…

Multiple Choice

Which part of a neuron carries messages away from the cell body?

• Dendrites

• Axon

• Synapse

• Nucleus

Neurone (Nerve) Structure

1.

2.
3.

4.

5.

6.

7.
Dendrites

Cell body
Nucleus

Axon

Myelin Sheath w/

Schwann Cell

Nodes of
Ranvier

Nerve endings

Impulse

• It is the information travelling across

the nerves as electrical signals.

Multiple Choice

What is the name of the specialized cells that detect changes in the environment and send signals to the nervous system?

A) Effectors

B) Receptors

C) Neurons

D) Neurotransmitters

• a

• b

• c

• d

Multiple Choice

What is the name of the chemical substance released at the synapse that transmits the nerve impulse from one neuron to the next?

A) Axon

B) Dendrite

C) Neurotransmitter

D) Receptor

• a

• b

• c

• d

Neurone (Nerve) Structure

Dendrites

Dendrites
Pick up electrical signals (nerve impulses) from
other neurones lying nearby or from receptor
organ.

Multiple Choice

What is the name of the specialized cells that bring about a response to a stimulus?

A) Effectors

B) Receptors

C) Neurons

D) Neurotransmitters

• a

• b

• c

• d

Multiple Choice

What is the name of the rapid, involuntary response to a stimulus?

A) Homeostasis

B) Coordination

C) Effector response

D) Reflex action

• A

• B

• C

• D

Neurone (Nerve) Structure

Axon

Axon
The extended fibre which delivers nerve
impulses to the nerve endings

Neurone (Nerve) Structure

Myelin sheath

Myelin sheath
Insulates the axons to speed up impulse
transmission

Multiple Choice

What is the main function of the myelin sheath?

A. To produce neurotransmitters

B. To speed up nerve impulse conduction

C. To connect neurons to muscles

D. To process sensory information

• A

• B

• C

• D

Neurone (Nerve) Structure

Nerve endings

Nerve endings
Deliver nerve impulse to the dendrites of
another neurone or to the affector organ

Neurone (Nerve) Structure

Types of
Neurone

Nerve Impulse

• Due to Electrical impulse
• also: Action Potential

Multiple Choice

What is the name of the junction between two nerve cells?

A) Neurotransmitter

B) Synapse

C) Receptor

D) Effector

• a

• b

• c

• d

Nerve Impulse

– What is the part in between neurones?

Synapse

Synapse

– Tiny gap between the nerve ending of

one neurone and the dendrite of another

Dendrite

Nerve ending

Neurotransmitter

– Chemicals that transmit nerve impulses

across the synapse

Dendrite

Nerve ending

Examples:
- Acetylcholine
- Norepinephrine

They travel through the
gap and attach to
dendrite, impulse starts
on next neurone

impulse

Neurotransmitters

• Acetylcholine

- in neuromuscular junctions
- released by motor neurons to activate

muscles

Neurotransmitters

• norepinephrine

- the neurotransmitter for alertness
- work together with adrenaline for

“fight or flight response”

Nervous System Actions

•
How the NS reacts to
stimuli.

•
Occurs in 2 ways:
1. Voluntary Actions

2. Involuntary Actions

1. Voluntary Actions

Nervous System Actions

•
Actions that involves conscious
thought.

•
There is decision-making involved in the process.

Multiple Choice

Which of the following is an example of a voluntary action?

a) Blinking

b) Breathing

c) Digestion

d) Writing

• a

• b

• c

• d

Multiple Choice

Which part of the eye controls the amount of light entering the eye?

a) Cornea

b) Pupil

c) Lens

d) Retina

• a

• b

• c

• d

2. Involuntary Actions

Nervous System Actions

•
Actions that does not involve
conscious thought.

•
They are automatic. Our body does them thoughtlessly.

Involuntary Actions

Purposes:

1. To maintain function of the most
important body processes

•
We would die in just minutes if our heart stops beating.

Involuntary Actions

Purposes:

2. As a survival reaction to
immediate danger.

•
Shouting when suddenly scared makes one feel more
powerful.

Reflex Arc

THE REFLEX ARC

•
Immediate, involuntary reactions
that does not involve brain
processing.

•
These automatic reaction is controlled only by the
spinal cord.

Watch video: reflex medical test

Multiple Choice

Which of the following is NOT a component of a reflex arc?

a) Sensory neuron

b) Motor neuron

c) Relay neuron

d) Brain

• A

• B

• C

• D

Multiple Choice

What is the correct order of events in a reflex arc?

a) Receptor, sensory neuron, motor neuron, relay neuron, effector

b) Receptor, sensory neuron, relay neuron, motor neuron, effector

c) Effector, motor neuron, relay neuron, sensory neuron, receptor

d) Effector, sensory neuron, relay neuron, motor neuron, receptor

• a

• b

• c

• d

Structures involved:

THE REFLEX ARC

Receptor

Sensory
neurones

Relay

neurones

Motor

neurones
Effector

Inside the spinal cord

Neurone (Nerve) Structure

Types of
Neurone

Multiple Choice

What is the difference between a reflex action and a voluntary action?

a) Reflex actions are involuntary, while voluntary actions are conscious

b) Reflex actions are slow, while voluntary actions are fast

c) Reflex actions involve the brain, while voluntary actions do not

d) Reflex actions are learned, while voluntary actions are innate

• a

• b

• c

• d

Neurone (Nerve) Structure

Types of
Neurone

Transmits electrical impulses from a

receptor to the central nervous system

(CNS).

Neurone (Nerve) Structure

Types of
Neurone

Transmits electrical impulses within the

CNS (brain and spinal cord).

Neurone (Nerve) Structure

Types of
Neurone

Transmits electrical impulses from the

CNS to an effector (Example: skin,

muscle).

Reflex Arc

THE REFLEX ARC

•
Example: jerking hand away
from hot/sharp object

•
These automatic actions is controlled only by the
spinal cord.

Reflex Arc

THE REFLEX ARC

•
Arm jerk reflex

(Effector)

Multiple Choice

In a reflex arc, the sensory neuron carries information:

a) From the effector to the brain

b) From the brain to the effector

c) From the receptor to the brain

d) From the brain to the receptor

• a

• b

• c

• d

●Sensation signals are relayed to the brain
for learning purposes.

sensory
neurone

Motor

neurone

relay

neurone

Bicep muscle
(effector)

What is a “Receptor”?

• Part of Nervous

system adapted to
receive stimuli.

• Stimuli – change in

environment

• Sensitivity – ability to

respond to stimuli

Multiple Choice

What is the function of the sensory receptors in the skin?

a) To detect changes in the environment

b) To transmit nerve impulses

c) To control muscle movement

d) To regulate body temperature

• a

• b

• c

• d

Types of Receptors

Receptor Type

For which stimuli?

Example

1. Photoreceptor

light

Cells in retina

of the eye

Receptor Type

For which stimuli?

Example

Types of Receptors

2. Chemoreceptor

chemicals

Taste buds

Receptor Type

For which stimuli?

Example

Types of Receptors

3. Thermoreceptor

Temperature

changes

Cells in skin

Multiple Choice

Which type of receptor detects changes in temperature?

A. Photoreceptor

B. Thermoreceptor

C. Mechanoreceptor

D. Chemoreceptor

• A

• B

• C

• D

Receptor Type

For which stimuli?

Example

Types of Receptors

4. Mechanoreceptor

Mechanical changes
Ex. Change in length

Hair cells in ear
(hearing and
balance)

Receptors are “Transducers”

Transducer
•it converts one form of
energy into another that can
be dealt by the N.S.

•converts any energy to
electrical impulse.

Ex. Light energy through eyes
converted to electrical impulse.

Grouping of Receptor Cells

• Receptor cells

are often
grouped
together with
other tissues to
form a sense
organ.

Location of Sense Organs
• Why do you

think most of
the sense
organs
located on
the head?

A Sense of Position

• Muscle Tissues
- send info to the brain about how
stretched they are.

Result: we know where
each part of the body is
in relation to other parts.

• Ex: touching your

nose with your eyes
shut

Eye Tissues

Cornea
• Focuses the

entry of light by
refraction

Eye Tissues

Pupil & Iris
• Control light
intensity entering
The retina

Eye Tissues

Lens & ciliary
body
• Control light

focusing on the
retina

Multiple Choice

What is the function of the iris in the eye?

a) To focus light onto the retina

b) To detect color

c) To regulate the amount of light entering the eye

d) To transmit visual information to the brain

• a

• b

• c

• d

Eye Tissues

retina
• Convert light

energy to electrical
impulse

Structure & Function

■ SCLERA

❑ whites of the eye

❑ supports eyeball

❑ provides attachment for

muscles

■ LENS

❑ converging lens

❑ allows us to see objects

near and far

Structure & Function

■ CORNEA

❑
transparent bulge over pupil

❑
focuses light (refracts) onto
retina

■ RETINA

❑
internal membrane

❑
contain light-receptive cells
(rods & cones)

❑
converts light to electrical signal

Multiple Choice

Which of the following structures in the eye is responsible for color vision?

a) Cornea

b) Pupil

c) Lens

d) Retina

• a

• b

• c

• d

Structure & Function

OPTIC NERVE

■ Transmits electrical

impulses from retina to
the brain

■ Brain takes inverted

image and flips it so we
can see

Inside the Retina

■
RODS

❑
120 million cells

❑
detect brightness
(black & white)

❑
for night vision

■
CONES

❑
6 million cells

❑
detect colour (RGB)

❑
GANGLION CELLS

❑
Detect movement and patterns

Rod cell
Cone cell

Multiple Choice

What is the primary function of the rods in the retina?

A. Detecting color

B. Detecting light intensity and movement in dim light

C. Focusing light

D. Controlling the size of the pupil

• A

• B

• C

• D

Photoreceptors: Rods and
Cones

■ This is a false color

image, rods and
cones are not
actually different
colors

rod

cone

The
Pupil
Reflex
■ This is how

our eyes
adjust to
varying light
intensities.

Structure of the Eye: Cornea and
Lens

Cornea

Eyelen
s

Retina

■
There are two lenses in your eye, the cornea and the eyelens.

■
Cornea - does most of the focusing in your eye

■
Eyelens - provides adjustable fine-tuning of the focus

Accommodation

less bulgy, longer
f

professor is in focus

thumb is out of focus

more bulgy, shorter
f

thumb is in focus

professor is out of focus

How the Eye Works during
Accommodation
Focusing on a distant
object

●The suspensory ligaments
contract (pulled tight)

●The eye lens is pulled thin

●The ciliary muscles relax

●The eye lens bends the
light rays lightly

Suspensory

ligament

contracted

Ciliary muscles

relaxed

Multiple Choice

Which part of the eye focuses light onto the retina?

a) Cornea

b) Iris

c) Lens

d) Optic nerve

• a

• b

• c

• d

How the Eye Works during
Accommodation
Focusing on a nearby
object

●The suspensory ligaments
relax (expand)

●The eye lens bulges

●The ciliary muscles contract

●The eye lens bends the
light rays greatly

Suspensory

ligament relaxed

Ciliary muscles

contracted

Suspensory

ligament

contracted

Ciliary muscles

relaxed

Focusing on Distant Object

Suspensory ligament

contracted

Ciliary muscles

relaxed

Focusing on Nearby Object

Suspensory ligament

relaxes

Ciliary muscles

contracts

Focusing Problems

Farsighted

Nearsighted

Far-Sighted Correction lens

With

convex

lens

Without

lens

Near-Sighted Correction lens

With

concave

lens

Without

lens

Diseases of the Eye

ASTIGMATISM

■
Eye cannot focus an object’s
image on a single point on
retina

■
Causes blurred vision

■
Some types can be corrected
with lenses

Diseases of the Eye

CATARACTS

■ Clouding forms in lens due

to denaturing of lens protein

■ Obstructs passage of light

■ Caused by age, chronic

exposure to UV, or due to
trauma

■ Removed by surgery

Diseases of the Eye

Macular degeneration
■ Age-related disease

causing blurred or loss of
vision in the center of the
visual field

■ The an area of the retina

(macula) containing rod
cells are destroyed

■ No cure but progression

may be slowed

Vision Correction
LASIK

■
“Laser Assisted In Situ
Keratomileusis”

■
Refractive surgery using
laser

■
Corrects near and far-
sightedness and
astigmatisms

Watch video: Lasik Treatment

Do plants have nervous
systems?
• Although plants react

to stimuli as any
other organism, their
coordination and
response system are
not brought upon by
a Nervous System.
Watch: how plants sees the world

How do plants react to
stimuli?
• Usually much

slower than
animals.
• In general, by

changing their rate
or direction of
growth.

How do plants react to
stimuli?
• In rare species,

immediate/fast
reaction to a
stimulus is possible

How do plants react to
stimuli?
• Positive

response -
growing towards
the stimulus
• Negative

response -
growing away
from the
stimulus

Respose to Gravity

TROPISMS

• The directional

growth of a plant in
response to an
external stimulus
• Allows plants to

respond to:

light

gravity

Types of Tropism

1. Phototropism

• A response where

a plant or its part
moves or grows
towards or away
from a light source

Types of Tropism
Phototropism

•

Plant shoots tend to
grow towards the light.

Light source

Plant bends
towards the hole
after a few days

Multiple Choice

Which of the following is a part of the plant response to light?

a) Phototropism

b) Geotropism

c) Hydrotropism

d) Thigmotropism

• a

• b

• c

• d

Types of TropismPhototropism

•

Purpose:

•

1. Photosynthesis -
so that the leaves are
held out into the
sunlight
[photosynthesis]

Types of Tropism
Phototropism

•

Purpose:

•

2. Reproduction - So
that flowers are held
exposed to pollinators.

Types of Tropism
Phototropism

•

Negative response:

•

Some plants have
roots that purposely
avoid sunlight

•

Ex: desert plants

Types of Tropism

2. Gravitropism

• A response where

a plant or its part
moves or grows
towards or away
from gravity

Source of gravity

Types of Tropism
Gravitropism

• Roots normally

grow towards the
pull of gravity

• Purpose:
• 1. To anchor the

plant in the soil.

Multiple Choice

Which of the following is an example of a tropism in plants?

a) Growth of roots towards gravity

b) Sweating to cool down the body

c) Rapid blinking in response to bright light

d) Shivering to generate heat

• a

• b

• c

• d

Types of TropismGravitropism

• Purpose:
• 2. To get to deeper

parts of soil which
is richer in water
and minerals

Multiple Choice

Which plant part is responsible for detecting gravity?

a) Leaves

b) Roots

c) Stem

d) Flowers

• a

• b

• c

• d

Types of Tropism
Gravitropism

• Negative

response:

• Shoots normally

grow against the
pull of gravity

Multiple Choice

Which of the following is a plant hormone responsible for regulating growth and response to light?

a) Insulin

b) Auxin

c) Melatonin

d) Thyroxine

• a

• b

• c

• d

Plant Responses

•

Plants takes a much
longer time to respond
to stimuli.

•

Their tropism
responses can be
tested easily using
either seeds, seedlings,
or grown plants.

Plant Hormones

•

Plants grow and or
extend/bend their
bodies with the help of
auxin.

Auxin

• Promotes

elongation of
the cells in
the shaded
side of a
shoot.

Auxin

• Promotes

elongation of
the cells in
the shaded
side of a
shoot.

Watch video: how auxin works

Multiple Choice

The hormone responsible for the fight-or-flight response in humans is:

a) Insulin

b) Adrenaline

c) Estrogen

d) Testosterone

• a

• b

• c

• d