NCERT Class 11 Biology Chapter 22 Notes Chemical Coordination And Integration- Download PDF Notes

Chemical coordination and integration is a very important chapter of the NCERT from an exam point of view. The NCERT Class 11 Biology Chapter 22 notes give you a basic idea of the chapter chemical coordination and integration. The main topics covered in NCERT Class 11 Biology notes are definition, endocrine glands and hormones, human endocrine system, hormones of heart, kidney and gastrointestinal tract, and mechanism of hormone action. Download the CBSE Notes for Class 11 Biology, Chapter 22, PDF to use offline anywhere. Students must go through each topic in Chemical coordination and integration in Class 11 Notes Biology in the easiest and most effective way possible with the help of NCERT Notes for Class 11.

Class 11 Biology chapter 22 notes also cover all the important concepts related to this chapter discusses the endocrine system of humans in detail, which are useful in various competitive exams. Chemical coordination and integration NCERT Notes for Class 11 Biology help you revise these major concepts given in the NCERT Book in no time during CBSE Board exam preparation. CBSE Class 11 Biology Chapter 22 notes will help you with quick revision. The Chemical Coordination and Integration chapter covers all headings of NCERT. CBSE Class 11 Biology chapter 22 notes also contain important examples that have been frequently asked in the various exams. Having revision notes and NCERT Solutions for Class 11 Biology Chapter 22 handy is beneficial to save you time.The NCERT Class 11 notes pdf can be downloaded through the link given below.

Also, students can refer to:

• NCERT Solutions for Class 11 Biology Chapter 22 Chemical Coordination and Integration
• NCERT Exemplar for Class 11 Biology Chapter 22 Chemical Coordination and Integration

NCERT Class 11 Chapter 22 Class Notes

Chemical Coordination and Integration

• To maintain homeostasis and to regulate various functions of the body, the nervous system, as well as the endocrine system, plays a very important role.
• Both the systems control and coordinate at different parts of the body, however, there are some basic differences.
• The nervous system acts rapidly in a fraction of a second but its response in a muscle lasts for only a few milliseconds.
• On the other hand, the hormones released from the endocrine system take much more time.

Endocrine Glands And Hormones

• Endocrine glands are called ductless glands since they do not have ducts.
• The secretions of these ductless glands are known as hormones.
• These hormones are produced only in small amounts in the human body to facilitate many functions like transport between cells.
• They function as intracellular messengers.

Human Endocrine System

The endocrine glands constitute the endocrine system.

Fig.1.1 Location of Endocrine Glands

The Hypothalamus:

• It forms the basal part of the diencephalon, forebrain.

• The hypothalamus has nuclei. It contains neurosecretory cells called nuclei which produce hormones. The function of nuclei is the regulation of secretions of pituitary hormones.

• Hormones of the hypothalamus are:

1. Releasing hormones: It stimulates secretions of pituitary hormones.

2. Inhibiting hormones: It inhibits the secretions of pituitary hormones.

The Pituitary Gland:

• It is present in sella tursica ( bony cavity ) and is attached to the hypothalamus by a stalk (Figure 1.2).

Fig.1.2. Representation of Pituitary and Hypothalamus

• It is classified into adenohypophysis and neurohypophysis.

• Adenohypophysis has two portions, pars distalis, and pars intermedia.

1. The pars distalis region produces several hormones like growth hormone (GH), prolactin (PRL), thyroid-stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH).

2. Melanocyte stimulating hormone ( MSH ) is produced by Pars intermedia.

• Oxytocin and vasopressin are stored and released by neurohypophysis .

• Hyper-secretion of GH causes gigantism(abnormal growth of the body) and lower secretion of GH results in pituitary dwarfism(stunted growth).

• Oxytocin causes vigorous contraction of the uterus at the time of childbirth. It also causes milk ejection from the mammary gland.

• Vasopressin( antidiuretic hormone) acts in the kidney. It helps in the reabsorption of water and electrolytes by the distal tubules and hence reduces the loss of water through urine (diuresis).

• A disorder affecting the synthesis or release of ADH causes water loss and dehydration. It is called Diabetes Insipidus.

The Pineal Gland:

• It is present on the dorsal side of the forebrain and secretes melatonin which helps in the regulation of a 24-hour (diurnal) rhythm of our body.

The Thyroid Gland:

• The thyroid gland consists of two lobes that are present on either side of the trachea (Figure 1.3).

• Isthmus is the point of interconnection between two lobes (a thin flap of connective tissue).

• The thyroid gland synthesizes two hormones, tetraiodothyronine or thyroxine (T4 ) and triiodothyronine (T3 ).

• Iodine deficiency results in hypothyroidism and enlargement of the thyroid gland commonly called goitre.

• Hypothyroidism causes stunted growth (cretinism) and mental retardation.

Fig.1.3 Diagrammatic View of Position of Thyroid Gland

Parathyroid Gland:

• Parathyroid glands are four in number.

• They are present on the backside of the thyroid gland.

• The parathyroid glands secrete parathyroid hormone (PTH) which is a peptide hormone.

• Its secretion is controlled by the circulating levels of calcium ions.

• PTH stimulates the process of bone dissolution/ demineralisation.

Fig.1.4. Diagrammatic View of Position of Parathyroid Gland

Thymus:

• It is a lobular structure present between the lungs behind the sternum

• It helps in the development of the immune system and secretes the peptide hormones called thymosins which helps in the differentiation of T-lymphocytes.

Adrenal Gland:

• There is a pair of adrenal glands at the anterior part of each kidney (Figure 1.5 a).

• The gland consists of two types of tissues. The centrally located tissue is called the adrenal medulla, and the outside adrenal cortex is present. (Figure 1.5 b).

• The deficiency of hormones causes acute weakness and fatigue leading to a disease called Addison’s disease.

Figure 1.5 Diagrammatic Representation of (a) Adrenal Gland Above Kidney (b) Section Showing Two Parts of The Adrenal Gland

• The adrenal medulla synthesizes two hormones adrenaline/epinephrine and noradrenaline/ norepinephrine. These are commonly called catecholamines.

• Adrenaline and noradrenaline are called emergency hormones or hormones of Fight or Flight because they are secreted in response to stress emergencies.

Pancreas:

• The pancreas is a mixed gland (Figure 1.1) that acts as both exocrine and endocrine glands.

• The endocrine part is called ‘Islets of Langerhans’.

• α-cells and β-cells are types of cells in the Islet of Langerhans The α-cells produce glucagon, while the β-cells secrete insulin.

Testis:

• One pair of the testis is present in the scrotal sac in males.

• It acts as a primary sex organ and an endocrine gland.

• It contains seminiferous tubules and stromal or interstitial tissue.

• Leydig cells or interstitial cells are present in the intertubular spaces that produce androgens, mainly testosterone.

• Androgens maintain the functions of the male accessory sex organs like epididymis, vas deferens, seminal vesicles, etc., and promote muscular growth, growth of axillary and facial hair, low pitch of voice, etc.

Ovary:

• A pair of ovaries are located in the abdomen in females (Figure 1.1).

• It is the primary female sex organ.

• It produces two groups of steroid hormones called estrogen and progesterone.

• Estrogens regulate female sexual behaviour and progesterone supports a pregnancy.

Hormones of Heart, Kidney, and Gastrointestinal Tract

• The heart contains an atrial wall that produces a hormone called atrial natriuretic factor (ANF). ANF causes dilation of the blood vessels, which decreases blood pressure.

• Erythropoiesis is stimulated by erythropoietin which is the juxtaglomerular cells of the kidney.

• Gastrin, secretin, cholecystokinin (CCK), and gastric inhibitory peptide(GIP) are the four major types of peptide hormones secreted by endocrine cells of the GI tract.

• Many other non-endocrine tissues secrete hormones called growth factors which are important for the normal growth of tissues and their repairing/regeneration.

Mechanism of Hormone Action:

• When a hormone binds to its receptor it forms a hormone-receptor complex (Figure 1.6 a, b).
• Hormone-Receptor complex formation leads to the development of certain biochemical changes in the target tissue.
• Hormones can be classified into different groups based on their chemical nature:

(i) Peptide, polypeptide, protein hormones - insulin, glucagon, pituitary hormones, hypothalamic hormones, etc.

(ii) Steroids - cortisol, testosterone, estradiol, and progesterone

(iii) Iodothyronines- thyroid hormones

(iv) Amino-acid derivatives - epinephrine.

Figure 1.6 Representation of The Mechanism of Hormone Action

Significance of NCERT Class 11 Biology Chapter 22 Chemical Coordination and Integration Notes

Class 11th notes on Chemical Coordination and Integration will be helpful in revising the chapter and getting a sense of the main themes discussed. By covering the fundamental topics of the CBSE Biology Syllabus in Class 11, these NCERT Class 11 Biology chapter 22 notes can also be used to study for the competitive exams such as VITEEE, BITSAT, JEE MAIN, NEET, and others. When you are not connected to the internet, you can use the Class 11 Biology chapter 22 notes PDF download to study.

Chapter-Wise NCERT Class 11 Notes Biology

Subject Wise NCERT Exemplar Solutions

• NCERT Exemplar Class 11 Solutions
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• NCERT Exemplar Class 11 Physics
• NCERT Exemplar Class 11 Chemistry
• NCERT Exemplar Class 11 Biology

Subject Wise NCERT Solutions

• NCERT Solutions for Class 11 Mathematics
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• NCERT Solutions for Class 11 Physics

• NCERT Solutions for Class 11 Biology