Matric Notes Biology Class 10th Ch 12 Co-Ordination and Control Short Questions

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Q1: How does the reflex actions work in human beings?

Ans: Reflex actions:

The actions which are automatic, quick and immediately performed to an environmental stimulus are called reflex actions.

Examples:

• If something is coming towards our face, we move our head away.
• Blinking of the eyes when something comes close to the eyes.
• Jerking of the knee, when it is hit with the hard objects.
• Watering of the mouth when we see any delicious food or Pickles.

Mechanisms:

1. Reflex actions is involuntary response of the body.
2. Reflex actions is performed by the connection of three neurons making an arc called Reflex arc.
3. Reflex actions is performed by the spinal cord and generally brain is not involved.
4. The receptor feel the stimulus and sends the message through sensory neuron to the spinal cord.
5. The associate neuron gives impulses to the motor neuron.
6. The motor neuron sends the impulses to the effectors and the effectors obey the order accordingly.
7. In this way a reflex action is performed.

Pathway:

RECEPTOR→SENSORY NEURON →ASSOCIATIVE NEURON (SPINAL CORD) → MOTOR NEYRON → EFFECTOR (MUSCLES GLAND)

Q2: What are the causes of epilepsy and paralysis?

Ans: Epilepsy: This is a type of functional disorder of the neuron system in which suddenly excessive discharge of nerve impulses takes place from the brain.

Causes:

Epilepsy may be caused by the following

• Changes in the brain due to genetic reason.
• Severe head injuries. Stroke
• Brain infections Drug abuse.

Paralysis:

Paralysis is the vascular disease of the brain.

Causes:

• It occurs when a blood clot is stuck in the fine blood vessels of the brain.
• Due to high blood pressure the rupturing of the blood vessel of the brain occur and oozes out in the brain

Q3: What will happen If Islet of Langerhans secret insulin but not glycogen?

Ans: Reason: If Islet of Langerhans secret insulin but not glycogen then all glucose content of blood will be metabolized completely. The patient blood sugar level will drop due to which they will face severe deficiency of energy. Glycogen will not be converted into glucose due to the non-secretion of glycogen.

Q4: Why is pituitary glands known as master gland?

ANS: Shape: It is oval in shape.

Location: It is attached to the hypothalamus of the brain.

Size and weighs: It is about the size of a pea seed and weighs about 0.5gm in adults.

Lobes: It has two main lobes i.e. anterior and posterior Master gland: It is generally known as ‘the master gland’ of the body.

Reason:

There are the following reason.

1. Produces hormones: The pituitary gland produces hormones that control the other gland.
2. Body function: It control many body function including growth.

Q5: Differentiate between two types of coordination system.

Ans: Coordination: Coordination means to integrate among different parts of the body and to respond to stimuli in order to keep harmony with the environment. Characteristic/properties:

Coordination is the property of all living organisms

Types of coordination:

There are two types of coordination.

1. Nervous coordination (electrical coordination)
2. Chemical coordination (hormonal coordination)

1.Nervous coordination:

1. The coordination due to nervous system is known as nervous coordination.
2. Nervous system consists of central nervous system and peripheral nervous system.
3. The basic unit of nervous system is neuron.
4. Neuron transmit information in the form of electrical signals called “nerve impulse”.
5. The nervous coordination works at the speed of electricity, so we can say that nervous coordination is a type of electrical coordination.

2.Chemical coordination:

1. The coordination through hormone is known as chemical coordination.
2. The hormones are chemical which are secreted by endocrine glands.
3. The endocrine glands synthesize these hormones by taking material from our body.
4. These hormones reach the target site with the circulation of blood. That is why chemical coordination is slower than the nervous coordination.

Q6: What is the role of insulin and glycogen?

Ans: Insulin: Insulin decreases blood glucose level either by metabolizing it or by converting it into lipids and protein, if the body fails to produce insulin it leads to condition called diabetes mellitus.

Role of insulin:

Insulin is a hormone which plays a number of roles in the body metabolisms.

• Insulin regulate how the body uses and stores glucose and fat.
• Many of the body’s cells rely on insulin to take glucose from the blood for energy.

Glucagon:

• Glycogen works opposite to insulin and increases blood glucose level. It promotes the breakdown of glycogen to glucose in the lever and muscles.

Role of glycogen:

Glycogen works opposite to insulin and increases blood glucose levels. For this purpose it promotes the breakdown of glycogen to glucose in the liver and muscles. It also increases the release of glucose from the liver to the blood.

Q7: What characters are control by the ovarian hormones?

Ans: Hormones of the ovary:

Ovary: A female reproductive organ in which ova or eggs are product, present in the humans and other vertebrates. The ovaries maintain the health of the female reproductive system.

Secretion: They secrete two main hormones. They are the following.

Oestrogens: It bring about the development of secondary sexual characters in the female. These includes breast , regulation of menstrual cycle.

In male:

In male the estrogen helps in the maturation of the sperm and maintenance of a healthy libido.

Progesterone:

It prepares the female body for maintaining the state of pregnancy. It is involved in the menstrual cycle, pregnancy , and embryogenesis of humans.

Q8: State the hormones of the pituitary and thyroid glands and write their functions?

Ans: Pituitary gland:

Shape: It is oval in shape.

Location: It is attached to the hypothalamus of the brain.

Size and weighs: It is about the size of a pea seed and weighs about 0.5gm in adults.

Master gland: It is generally known as ‘the master gland’ of the body. Lobes:

It has two main lobes i.e. anterior and posterior.

Anterior lobe of pituitary gland: It secretes the following hormones.

1: Growth hormones:

This hormone increases the cell division of somatic cells and promotes the growth of the body. It is secreted more in childhood but in adults the secretion become normal. If it is secreted in excess during early life it results in a disorder called gigantism

Its under-secretion in early life causes dwarfism in which the body of the child does not grow.

2: Thyroid stimulating hormone (TSH):

This hormone controls the development and secretion of the thyroid hormone (thyroxin).

3: Adrenocorticotrophic hormone (ACTH):

It acts on the cortex part of the adrenal gland to release the adrenal hormone.

4: Luteinizing hormone (LH):

It is needed for the release of egg cells from the ovary (ovulation) in females. In males, it stimulate the testes to produce sex hormones.

Posterior lobe of pituitary gland: It secrete the following hormones:

i. Antidiuretic Hormone(ADH) or Vasopressin:

This hormones affects the renal tubules to reabsorb large quantities of water from the glomerular filtrate.

ii. Oxytocin:

Its main function is to contract the uterus muscles during childbirth. It also stimulates the flow of milk from the breasts during lactation.

2: Thyroid gland:

Location: The thyroid gland is situated above the larynx. It consists of two lobes, one on each side of the larynx. It secretes two hormones.

i. Thyroxin:

This hormone increase the metabolism of the body and produces heat in the body. It promotes growth, hence it is secreted more in young age. Thyroxin is an iodine containing compound.

Under-secretion:

If thyroxin is produced less than the required amount, cellular metabolism slow. It results in lethargy, weight gain, and heat rate and body temperature.

Over-secretion:

If thyroxin is produced more than required, cellular metabolism become faster than normal. It results in weight loss and high blood pressure, heart rate and body temperature.

ii. Calcitonin:

It stimulates the transfer of calcium ions from the blood to bone, where the calcium ions can be used to generate bone tissue. In this way, calcitonin maintain blood calcium level.