Key Points - Control and Coordination

Living organisms respond and react to various stimuli like heat, light, cold, touch, pressure etc. Plants and animals both respond to stimuli but in different manner.
Example: withdrawl of hand on touching a hot object.

Control and Coordination in Animals
It is brought about in all animals with the help of two main systems 
a) Nervous System
b) Endocrine System

Nervous System:
Functions i) To receive the information from environment
 ii) To receive the information from various body parts. (Stimuli fi

Response) iii) To act accordingly through muscles and glands.
Stimulus: Any change in environment or within that bring about the reaction eg: touching a hot plate.
Response: The reaction of our body to these changes. eg. withdrawal of our hand

How do we detect that we are touching a hot object?
Receptors: Are specialised tips of some nerve cells that detect the information from the environment.
Receptors are
Sense Organs
Inner
Ear
Photo receptors
Eyes
Skin
Olfactory
Receptor (Nose)
Gustatory
Receptor (Tongue)
Hearing/
Balance of the body
Visual
Stimulus
Pain
Touch
Heat
Smell
Detection
Taste
Detection

- Neuron: Structural and functional unit of nervous system.
Neuron (3 main parts)
Dendrite
Cell body and Axon
Synapse

Information is acquired
Information travels as an electrical impulse
Part where electrical signal is converted into chemical message for onward transmission to next neuron by release of neurotransmitters
Nucleus
Nerve ending
Dendrite
Axon
Cellpody
Structure of neuron
Fig. 7.1 (a) P 115

Synapse: The point of contact between the terminal branches of axon of one neuron with the dendrite of another neuron is called synapse.

Reflex Action
A quick, sudden, immediate response of the body to the certain stimuli that involves Spinal cord. eg. (not brain) withdrawal of hand, knee jerk etc.

Reflex arc: The pathway through which impulses pass is called reflex arc.

- Stimulus - eg. Heat
Sensory Nerves
RECEPTOR
ORGAN (SKIN)
Spinal Cord
Response
 eg. Withdrawal of Hand

EFFECTOR
ORGAN (MUSCLE)
Motor Nerves
Refer to diagram Fig 7.2 Reflex arc
Response

Responses are of three main types
Voluntary: Controlled by fore brain eg. Talking, Writing
Involuntary: Controlled by mid and hind brain eg. Heart beat, vomiting, regulation of heartbeat
Reflex action: controlled by spinal cord eg. Withdrawl of hand on touching a hot object.

Human Nervous System
Central Nervous System
Peripheral Nervous System
Autonomic Nervous  System
 (CNS
 (PNS)
 (ANS)

Brain
Spinal
Cord.
Fore Brain
Mid Brain
Cranial
Nerves
Spinal
Nerves
Arise from the brain
Arise from
Spinal Card
Sympathetic
Nervous
System
Para
Sympathetic
Nervous
System
Hind Brain

6. Human Brain
Human brain has three major parts or regions a) Forebrain b) Mid Brain c) Hind Brain

FOREBRAIN
Most complex/specialized part of the brain is CEREBRUM

FUNCTIONS:

1. Thinking part of the brain

2. Control the voluntary actions.

3. Store information (Memory)

4. Centre associated with HUNGER

5. Receives sensory impulses from various body parts and integrates it

Mid Brain:
HYPOTHALAMUS: Chemical co-ordination
PITUITARY GLAND: Secretes hormones
Hind Brain:
CEREBELLUM i) Controls posture and balance ii) Control precision of voluntary actions
MEDULLA
Controls involuntary actions eg. blood pressure, salivation, vomiting
PONS
Involuntary action, regulation of respiration

- PROTECTION OF BRAIN AND SPINAL CORD
Brain:
Spinal Cord:
Brain is protected by a fluid filled balloon which acts as shock absorber and enclosed in cranium (Brain Box)
Spinal Cord is enclosed in Vertebral column.
Coordination between Nervous and Muscular Tissue
Information
[collected by
Nervous tissue] (Sensory Nerve)
Central
Nervous
System
[CNS]
Information
Processed by
[CNS]
Decesion made
[by CNS]
Action
Muscle shorten
Contraction
[Muscle cell]
 (Motor Nerves)
Message
Muscles
[Change in shape and arrangement of proteins]
Passed to muscles
Coordination in Plants
Movement in Plants
Movement dependent on growth
Movement independent of growth
[immediate response to stimulus] eg. dropping of leaves of Touch-me-not plant on touching it
Tropic movements
[directional movements in response to stimulus]
Phototropism
Geotropism
Chemotropism
Hydrotropism
Movement towards light
Movement towards gravity
Movement towards Chemicals/ growth of pollen tube towards avule
Movement towards / water

- Plant hormones:
Are chemical compounds which help to coordinate growth, development and responses to the environment.
Plant hormones: Main plant hormones are: a) Auxin: [Synthesized at shoot tip]
Function: -  Helps in growth
Phototropism: more growth of cells towards light. b) Gibberellin: Helps in the growth of the stem c) Cytokinins: Promotes cell division d) Abscisic acid: Inhibits growth, cause witting of leaves. (Stress hormone)
Hormones in Animals
Hormones: These are the chemical messengers secreted in very small amounts by specialised tissues called ductless glands. They act on target tissues/organs usually away from their source.
Endocrine System helps in control and coordination through chemical compounds called HORMONES

- S. No. - Hormone - Endocrine - Gland - Location - Functions

1. Thyroxine
Thyroid
Neck/
Throat region
Regulation of metabolism of carbohydrates, fats and proteins.

2. Growth hormone
Pituitary
Mid
Regulates growth and development.

3. Adrenaline
Adrenal
Above both kidneys
Regulation (increasing) of blood pressure, heart heat, carbohydrate metabolism (during emergency)
Testosterone in Males
Testes
Changes associated with puberty (Sexual maturity)
 estrogen
Ovaries
Genital/ lower abdomen area
Insulin
Pancreas
Below stomach
Reduces and regulates blood sugar level

4. SEX
Hormone

5. {
G
O
N
A
D
S

IODISED SALT IS NECESSARY BECAUSE:
Iodine mineral is essential part of thyronine hormone so it is important that we must consume iodised salt as in turn it is essential for thyroid gland as it controls carbohydrate, proteins and fat metabolism for best balance of growth deficiency of iodine might cause disease called goitre
Diabetes:
Cause: It is due to deficiency of Insulin hormone secreted by Pancreas that is responsible to lower/control the blood sugar levels.
Treatment: Patients have to internally administer injections of insulin hormone fi which helps in regulating blood-sugar level.
Feedback Mechanism fi makes sure that hormones should be secreted in precise quantities and at right time, which is regulated by feedback mechanism.

- SWITCH OFF
Feedback sent
Sugar level in the blood rises
Detected by cells of Pancreas
Synthesis insulin
Blood sugar level falls (like a float in watertank)
Stop secreting more insulin

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Question Bank
Very Short Answers (1 Mark)

1. Where is auxin synthesized in plants?

2. Which gland is known as Master gland?

3. Name the hormone that regulates blood sugar level.

4. What is synapse.

5. What are tropic movements? Give one examples

6. Define hormones

7. Which hormone has inhibiting effect on growth of plants

8. What is phototropism?

9. What are the components of central Nervous System.

10. What happens at synapse between two neurons.Short Answers (2 Marks)

1. Draw diagram of neuron and label cell body, dendrites and axon.

2. What is reflex arc? Explain with the help of a flow-chart.

3. Mention one function of each of the following i) Cerebellum  ii) Pons.

4. What is the cause of diabetes? How it can be controlled.

5. Why it is advisable to use iodised salt.

6. What are the different receptors present in our body? What are their functions.

7. What are plant hormones? Name a plant hormone that promotes growth in plants.

8. What are sensory and motor neurons? Write their functions.

Long Answers (5 Marks)

What are hormones (in animals) List four characteristics of hormones. Name the hormone required for the following. i)
Development of moustache and beard in human male
ii) Lowering of blood glucose.
Mention the functions of a)
Fore brain
b) Mid brain
c) Hind brain