Matric Notes Biology Class 10th Ch 12 Co-Ordination and Control Extra Short and Long Questions
Q1: Define the following terms: Coordination, control, stimulus, response, receptors and effectors.
Ans: Coordination: In multicellular organisms the cells, organs and systems work in close cooperation and combination with one another. This cooperative working of cell, organs and systems with one another to perform proper function is called coordination.
Importance: Coordination provides better chance for adjustment and survival of organisms in the environment.
Control: The keeping of changes in the external environment with in the survival range is known as control.
Stimulus: A change in the internal or external environment to which the organisms show reaction (response) is known as stimulus. Its plural is stimuli.
Response: The reaction of organisms after feeling a change in the environment is known as response e.g.: when we see any delicious food or pickle, then our mouth waters. The seeing of pickle food is stimulus and the watering of mouth is response.
Receptors: Receptors are the organs which first feel the stimulus in the environment the most common example of receptors is our sense organs i.e. ear, eye, nose, tongue and skin.
Effectors: Effectors are the organs of our body which show response.
Example:
The most common effectors are:
ii. Glands
Q2: Describe the mechanisms (process) of coordination with example?
Ans: Coordination:
Definition: Coordination means to integrate among different parts of the body and to respond to stimuli in order to keep harmony with the environment.
Mechanisms of coordination:
Phase 1: receiving stimulus: When some change occurs in our external or internal environment, specific parts of the body feel that change. Any change in the environment which can initiate the response in the body is called stimulus.
Example: Touch, light and sound. The parts of the body which receive or feel the stimulus are called receptors. Special organs, tissues or even cells of the body may act as a receptors .e.g, our sense organs (eye, ear, skin, tongue and nose) are the main receptors of the body.
Phase 2 message to coordinator: The receptors send the information of stimulus to a coordinator. It analysis the information and makes a decision. In nervous coordination the brain and the spinal cord are the coordinator. They receive and send messages through neurons in the form of electrical signal (nerve impulse).In chemical coordination the endocrine glands are the coordinators. They receive information in the form of chemicals and send messages by secreting hormone in the blood.
Phase 3 producing response: The coordination sense a message to special parts of the body for proper actions (response).These parts are called effectors. In nervous coordination, muscles and glands are the effectors. While in chemical coordination, different tissues of the body act as effectors. On receiving the coordinator’s message, the effectors carry out actions (response) according to their specialization.
Example: When the door of our house is knocked, the sound produced by knocking is a stimulus. Our ears (receptors) receives the stimulus and send a message to our brain (coordinator).The brain analysis the information and send a message to the muscles (effectors) of our legs to move and take us to the door. Then signals are communicated to the hands to move and open the door.
Q3: How nervous system helps us to play a piano and writing something?
Ans: The nervous system helps to coordinate complex and intricate movements of the hand to play a piano or write an alphabets. The intention begins in the special area of the brain. The neuron of this area compile a set of information required for an action such as typing or speaking. The information is then transmitted to another area of the brain. It integrates information and ensures that all the muscles work together to produce well coordinative movements.
Q4: Make a table showing difference between the nervous and chemical coordination.
| --- | Nervous coordination | Chemical coordination |
|---|---|---|
| Mode of coordination | Electrical | Hormonal |
| Receptors | Sense organs(eyes, ears, nose ,tongue, skin | Many body parts (e.g. kidney, liver, etc.) |
| Coordinator | Brain and spinal cord | Endocrine glands |
| Effectors | Muscles and glands | Many body parts (e.g. kidney, liver, stomach etc.) |
| Nature of message | Electrical(nerve impulse) | Chemicals(e.g. hormones) |
| Carrier of message | Neurons | Blood |
| Nature of response | 1 .Contraction of muscles 2 .Secretion from glands |
1. Various types(e.g. growth, reabsorption of water by kidneys) |
Q5: Define neuron. Also describe its structure.
Ans: Neuron:
2. Neuron are therefore, called as nerve cells.
3. The nervous system is composed of billions of neurons of different sizes and shapes performing different function.
Structure of a typical neuron:
A typical neuron has a three main parts.
ii. Axon
iii. Dendron
i. Cell body:
A cell body consist of a cell membrane encircling cytoplasm, nucleus and other cell organelles like Golgi complex, mitochondria, ribosomes , endoplasmic reticulum etc.
ii. Dendron
One or more short structure called Dendron (plural dendrites) arises from the cell body.
Function: Their function is to bring the impulses towards the cell body.
i. Axon
ii. It takes nerve impulses away from the cell body. iii. Axons of large neurons are generally covered by a white sheath called myelin sheath. iv. This sheath is made up of fatty material and it insulate the axon. v. The sheath is broken at different intervals called nodes. vi. Distance between two nodes is termed as Schwan cells.
Q6: Describe types of neuron?
Ans: On the basis of function the neuron may be classified into three groups. i. Sensory neurons ii. Motor neurons iii. Associative neurons
1.Sensory neurons
ii. In these neurons cell body is at one side, the axon is short whereas the Dendron (or dendrites) is long.
2.Motor neurons
ii. The cell body is in the length of the neuron
3.Associative neurons:
ii. They are found in the CNS and make brain and spinal cord.
iii. They have short dendrites and axon.
Q7: What do you know about nerve? Describe its types.
Ans: Nerve: A nerve is a collection of axon that are enveloped by a covering.
Location: Nerve arise from the brain and spinal cord and make the peripheral nervous system.
Types: There are three types of nerve, on the basis of axons present in them.
Sensory nerve: It contains the axon of sensory neuron only.
Motor nerve: It contains the axon of the motor neuron only.
Mixed nerve: It contains the axon of sensory and motor neurons.
Q8: Write a note on central nervous system.
Ans: Central nervous system:
2. The brain is present in the skull (cranium) and whole spinal cord is present in the vertebral column.
3. The skull and vertebral column provides protection to the brain and spinal cord.
4. The brain and spinal cord are also covered and protected by a tough membrane called “meninges” which is made up of three layers.
5. Between the three layers of meninges, a fluid is present which is called cerebro spinal fluid(C.S.F)
6. The brain has many cavities called ventricles while the spinal cord has hollow central canal and these cavities are also filled by cerebro-spinal fluid.
Q9: What is spinal cord? Explain its function.
Ans: Spinal cord:
2. It starts from the narrow end of medulla oblongata.
3. It is thread like, oval shaped, hollow cylindrical structure.
4. Spinal cord lies in the neural canal of vertebral column.
5. It is about 18 inches long and half inch broad.
6. The spinal cord has two parts.
7. The inner butterfly shaped structure made from gray matter.
8. The outer part which is made of white matter.
Function:
2. It carries messages (impulses) from the trunk and limbs towards brain for final response.
3. It carries orders from brain towards trunk and limbs.
Spinal nerves:
There are 31 pairs of spinal nerves that arises from the spinal cord. All the spinal nerves are mixed nerves because each contain axon of both sensory and motor neurons. Each spinal nerve arises by two roots. Both roots unite and form the mixed spinal nerves.
Dorsal root:
The dorsal root contains sensory axons and a ganglion where cell bodies are located.
Ventral root:
The ventral root contains axon of the motor neurons.
Q10: Explain the mechanism of hormonal secretion (negative feedback mechanisms).
Ans: Mechanisms of hormonal secretion:
The process of controlling and regulating hormones in an automatic manner is known as mechanisms of hormonal secretion.
The most common mechanisms is negative feedback mechanisms which is discussed below.
Negative feedback mechanisms:
2. Let’s take the example of insulin secreted by islets of Langerhans.
3. When we take the meal, the carbohydrates are digested and converted into glucose.
4. Glucose is absorbed into the blood from small intestine. This increases the glucose level in the blood.
5. When this blood passes through pancreases, the islets of Langerhans at one sense this increases. They start secreting insulin in the blood.
6. Insulin causes a reduction in the blood glucose by promoting their uptake into muscles, liver, adipose tissue etc.
7. These actions reduce the blood glucose level and this low glucose blood when passes through islets of Langerhans, they feel this decreases and stop releasing insulin.
8. This process is called as the negative feedback mechanisms of the hormone action.
Q11: How the thermostat of air condition work upon the negative feedback mechanism.
ANS: The thermostat of air conditioner controls the functioning of the air conditioner by using negative feedback. We set the thermostat of the conditioner at a certain temperature (20 degree centigrade).The thermostat detect the room temperature. When it finds it’s about 20C, it turns on the air conditioning to cool the room. Once the room temperature reaches its thermostat setting (20C), the thermostat turns off the air condition to stop further cooling.
Q12: Define the following term?
• Cranial nerves
• Spinal nerves
Peripheral nervous system: This is composed of nerves which arise from the CNS.
Cranial nerves: The nerves which arise from the brain is called cranial nerves.
Spinal nerves: The nerves which arise from the spinal cord is called spinal nerves.
Q13: How many pathways the cranial nerves and spinal nerves make?
Ans: Pathways make by spinal and cranial nerves:
The cranial and spinal nerves make two pathways i.e. sensory pathways (conducting impulses from receptors to CNS) and motor pathway (conducting impulses from CNS to effectors).Motor pathway makes two systems.
i. Somatic nervous system: It controls conscious and voluntary actions. It includes all of the motor neurons that are connected to skeleton muscles.
ii. Autonomic nervous system: It consists of motor neurons that are connected to cardiac muscles, smooth muscle and gland. It is without conscious control. Autonomic nervous system consist of sympathetic and parasympathetic system.
a. Sympathetic nervous system:
It prepare the body to deal with the emergency situation. This is often called the “fight or flight” situation. This system dilate pupils, speeds up heartbeat, increase breathing rate and inhibit digestion.
b. Parasympathetic nervous system:
When there is little or no stress, the parasympathetic nervous system normalizes the overall activity of the body. It is called the “rest and digest” response of the body. It causes pupil to contract, , it promote digestion, and it bring the heartbeat to normal.
Q14: Digestive system is involuntary? Justify this statement.
ANS: The digestive system is an involuntary system as it works on its own such as blinking of the eyes. Digestion starts from the mouth by the secretion of saliva. As soon as our eyes see delicious food it sends a message to the glands present in the mouth to release saliva, so that the food can be chewed and broken into small pieces. When we look at food item, the digestive system gets activated, enzymes are released in the mouth cavity in the form of saliva and hence our mouth starts watering.
Q15: Describe the contribution of Ibn-Haitham in the field of Biology?
Ans: CONTRIBUTION OF IBN-UL-HAITHAM:
2. In west he is renowned by Alhacen or Alhazen.
3. He was born in Basra in 965 A.D.
4. Ibn Al-Haitham is regarded as the “father of modern optics” for his influential book Kitab-ul-Manazir (book of optics).
5. He performed experiments in differents fields of optics, including lenses, mirrors, refraction, reflection, and dispersion of light into its constituents’ colors.
6. He studied binocular vision and the Moon illusion.
7. He postulated that light is made of particles, travelling straight lines.
8. One of his most important works was the description of the functional anatomy of eye as an optical system or optical instruments.
9. He was the first person concept of sight that rays come out of eye to see the objects.
10. He proved that it is light rays which reflect from objects and enter the eye to make image.
11. He also made the first camera, “the pinhole camera”.
12. He worked in many other fields of science as well like physics, astronomy, engineering, anatomy, medicine, mathematics, ophthalmology, philosophy, and psychology.
Q16: Describe the contribution of Ali bin Isa in the field of biology?
Ans: CONTRIBUTION OF ALI BIN ISA:
2. He was born in Baghdad in 940 and died in 1010 A.D.
3. He is considered one of the most famous physicians of tenth century.
4. He wrote the monumental book Tashkirat-ul-Kahhalin (note book of oculist).
5. This book contains information on treatment and classification of over one hundred different eye diseases.
6. This book was translated in Latin in 1497.
7. Afterward it was also translated in German and English.
8. The notebook of the oculists was widely used by European physicians for hundreds of years.
Q17: Describe the function of the ears.
Ans: Ear: The organ of hearing and balance in human and other vertebrates.
Sonoreceptor: The human ears are also known as sonoreceptor or audio receptor.
Function of the Ears:
The human ear performs the two functions.
2. Balance of the body.
1.Hearing:
ii. The vibrating ear drum strikes to the first bone, malleus, which starts vibrating.
iii. Then it transmits its vibration to next bone incus and then shape which also start vibrating.
v. This liquid converts the energy into electrical signals which are transmitted to brain through auditory nerve.
vi. The human ear can generally hear sounds with frequencies between 20Hz and 20,000Hz.
2. Balance of the body:
Ear is not only an organ of hearing but also the balancing organ of the body. The sense of balance and position works through internal ear.
Internal ear consists of three semi-circular canals which are filled with the liquid and contain a sensory epithelium that is studded with sensory hair cells.
The microscopic hair of these cells project out into the fluid.
Q18: What do you know about exocrine gland?
Ans: Exocrine gland: Many glands in our body have ducts for releasing their secretion e.g
2. Skin glands etc
Such glands are called exocrine glands.
Q19: What do you know about goiter? Write its causes and treatment.
Ans: Goiter: A swelling of the neck region resulting from enlargement of the thyroid gland.
Causes: When there is deficiency of iodine in the body, the thyroid gland is not able to produce thyroxine. When the gland tries to produce the hormone it swells up and the condition is called Goiter.
Endemic: This disease become endemic among the people living at high altitudes because they do not have sufficient iodine in there water.
Treatment: There are the following treatment for the cure of goiter.
✓ Radioactive iodine: In some cases, radioactive iodine is used to treat an overactive thyroid gland. The radioactive iodine is taken orally and reaches our thyroid gland through our bloodstream, destroying thyroid cells.
✓ Iodized salt: Iodized salt is recommended to overcome the deficiency of iodine and avoid goiter.
✓ Surgery: Goiter surgery to reduce the size of swelling is reserved for cases where the goiter is causing troublesome symptoms, such as difficulty breathing or swelling.
Q20: What do you about BGC test? And draw table for their test.
Ans: The amount of glucose in blood is measured by its test. It is used to diagnose diabetes. Blood glucose may be measured on a fasting basis (collected after an 8 to 10 hour fast), randomly (anytime) and after a meal. The result of some BGC test are given below:
| Blood glucose after 8-10 hours fast |
--- |
|---|---|
| BGC | Diagnosis |
| From 70 to 99 mg/ 100 ml | Normal |
| From 100 to 125 mg/ 100 ml | Pre-diabetes |
| 126 mg/100ml and above | Diabetes |
| Blood glucose 2 hours after a 75 gram glucose intake |
--- |
| BGC | Diagnosis |
| Less than 140 mg/ 100ml | Normal |
| From 140 to 200 mg/ml | Pre-diabetes |
| Over 200 mg/100ml | Diabetes |
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