CONTROL & COORDINATION

NEURON

GROUP ACTIVITY

Group ADefine Neuron

Group BCompare gustatory receptors and olfactory receptors

Group CIdentify the transmission of energy taking place in

nerve impulse conduction.

REFLEX ACTION

• When the stimulation of a receptor results in a spontaneous, involuntary reaction, it is called reflex action or simply reflex.

SPINAL REFLEX ACTION• The reflexes of this type which involve only the

spinal cord are called spinal reflexes. • Please note that when we lift a hot plate, then

along with heat, the pain produced by heat also acts as a 'stimulus'.

• Most of the reflex actions involve only the spinal cord. They are called spinal reflexes.

BRAIN REFLEX ACTION• Reflex actions which involve brain are called

cerebral reflexes. • Cerebral reflexes occur in the organs present in the

head because these organs are directly connected to the brain.

• Example. Our eyes are present in the head. In dim light, the pupil (a hole in the front of eye) is large so that more light can enter into the eye and make us see properly even in dim light.

Reflex arc

• Rather than think about the sensation of heat if the nerves detect heat were to be connected to the nerves that move muscles in a simpler way, the process of detecting the signal or the input and responding to it by an output action might be completed quickly. Such connections commonly called as reflex arc.

Group activity• Group A• Define reflex action.

• Group B• Components of reflex action.

• Group C• Discuss the process of reflex action.

Part I:

Lobes, the Cerebral Cortex, and Cortical Regions of the Brain

Cerebrum -The largest division of the brain. It is divided into two hemispheres, each of which is divided into four lobes.

Cerebrum Cerebrum

Cerebellum

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Cerebral Cortex

Cerebral Cortex

Cerebral Cortex - The outermost layer of gray matter making up the superficial aspect of the cerebrum.

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Lobes of the Brain (4)

• Frontal• Parietal• Occipital• Temporal

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Lobes of the Brain - Frontal• The Frontal Lobe of the brain is located deep to the

Frontal Bone of the skull.

• It plays an integral role in the following functions/actions:

- Memory Formation- Emotions

- Decision Making/Reasoning - Personality

Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg

Lobes of the Brain - Parietal Lobe

• The Parietal Lobe of the brain is located deep to the Parietal Bone of the skull.

• It plays a major role in the following functions/actions:

- Senses and integrates sensation(s)

- Spatial awareness and perception(Proprioception - Awareness of body/ body parts in space and in relation to each other)

Lobes of the Brain – Temporal Lobe

• The Temporal Lobes are located on the sides of the brain, deep to the Temporal Bones of the skull.

• They play an integral role in the following functions:

- Hearing- Organization/Comprehension of

language

- Information Retrieval (Memory and Memory Formation)

Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg

Lobes and Structures of the Brain

B. A.

C.

D. E.

F.

G.

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Group activity

• Group A• What do you mean by CNS? • Group B• Give the components of peripheral nervous

system.• Group C• Distinguish between voluntary and involuntary

action.

Brain has 3 regions• Fore- Brain - cerebrum, thalamus, and

hypothalamus (part of the limbic system).

• Mid-brain - The midbrain consists of the tectum and tegmentum.

• Hind-brain - cerebellum, pons and medulla. Often the midbrain, pons, and medulla are referred to together as the brainstem.

Fore- brain• The forebrain is divided into 2 halves – the right and

left cerebral hemispheres. • The cerebral hemispheres control your movement,

thinking, memory, emotions, senses and speech.• As the nerve fibres leave the brain, they cross over

from one side to the other.• This means that the nerves that come from the

right side of your brain control the left side of your body.

• Each hemisphere is divided into 4 areas called the

• Frontal lobe• Temporal lobe• Parietal lobe• Occipital lobe

• The frontal lobe contains areas that control your personality, thought, memory and behaviour.

• Towards the back of the frontal lobe are areas that control movement and feeling.

• The temporal lobe helps to control behaviour, memory, hearing, sight and your emotions.

• The parietal lobe is mainly to do with language. It is responsible for your speech, reading, writing or understanding of words.

• The occipital lobe is the visual centre of the brain.

Functions • Cerebellum - This structure is associated with

regulation and coordination of movement, posture, and balance.

• Brain Stem: This structure is responsible for basic vital life functions such as breathing, heartbeat, and blood pressure.

How brain tissues are protected?• The brain is protected by a series of bone, membrane,

and fluid. • The outermost protection is the cranium, or skull, which

protects the brain from blows that could easily damage it.

• Then there are three membranes called meninges. • Then brain is protected by a clear liquid called

cerebrospinal fluid. This forms a cushion between the soft brain tissue and the hard cranial bones. This same fluid also fills spaces inside the brain.

• Tissues inside the spaces produce cerebrospinal fluid, which flow through the spaces between the membranes.

Coordination in plants• Chhui mui or touch- me -not plant or sensitive plant• Mimosa family

Two different types of movement in plants

• 1. Growth dependent movement• 2. Growth independent movement

Immediate response to stimulus

• Immediate response ……• No nervous tissues/ muscle tissues involved in plant

body.• Plants undergo cell to cell communication system

different from nervous system and muscular system in animals.

• They use chemical signals followed by cells swelling due to uptake of more water and shrinking of cells due to loss of water from plant cells. So the cell shapes change due to response.

• Movement due to growth• Tendrils are plants that climb up on other plants or

fences.

• When tendrils come in contact with any support, the part of

• Tendril which is in contact with object does not grow as rapidly as away from the object or support. THIS MAKES TENDRILS TO CLING OR COIL AROUND SUPPORT.

• Environmental triggers such as light, or gravity will change in the directions that plant parts grow in.

Hydrotropism in plants

Plant hormones

• 1 . AUXIN - cell growth in shoot / root tip. • 2. GIBBERELLINS - cell growth in stems.• 3. CYTOKININS - cell division (dividing cells)• 4. ABSCISIC ACID - inhibits (stops) growth, wilt

leaves.

Phototropism with auxin hormone

The endocrine systemHormones :A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required. It is a chemical messenger that transports a signal from one cell to another.Hormones –secreted by ductless glands. Directly secreted into blood and lymph.

Endocrine system

Hormones are produced and secreted by

glands in the endocrine system.

It consists of various endocrine glands.

These glands do not have ducts (tubes)

for transporting chemical signals from

one part of the body to another. So, they

are referred as DUCTLESS GLANDS.

Target organs: The organs responds to

hormones.

Hormone producing glands and their secretions

Gland Location Secretion Function

Thyroid Neck Thyroxin Controls metabolic rate

Adrenal Above kidneys

Adrenalin Prepares body for emergency.

Pancreas Abdomen Insulin, glucagon

Regulates sugar level in blood.

Testes Lower abdomen (male)

Testosterone Controls sexual development.

Ovaries Lower abdomen (female)

Oestrogen Controls sexual development.

Pituitary Brain Growth hormone stimulating hormones

Speeds up growth, activates other glands.