Chemical Coordination and Integration Class 11 Notes Biology Chapter 22

 Page 1


Points To Remember
Endocrine glands : These are ductless glands which secrete hormones 
directly into the blood stream.
Hormones : Non-nutrient chemicals synthesised in trace amount by  
Endocrine glands that act as intracellular messengers and are specific in their 
action which are transported by blood from site of production to site of action.
Hypothalamus :
? It is basal part of diencephalon.
? Has neurosecretory cells called nuclei which produce hormones to regulate
the synthesis and secretion of pituitary gland hormones.
? Two types of hormones released are :
 Releasing hormones : Simulate secretion of pituitary hormones, e.g.,
Gonadotrophin releasing hormone stimulates pituitary gland to synthesise
gonadotrophins.
Inhibiting hormones : Inhibit secretions of pituitary hormones, e.g.,
Somatostatin inhibits secretion of growth hormone.
Pituitary Gland :
? Located in bony cavity called as sella tursica.
? Attached to hypothalamus by a stalk.
? Divided anatomically into : Adenohypophysis (Anterior lobe) and
Neurohypophysis (Posterior lobe).
? Hormones released from hypothalamic neurons reach anterior pituitary
through portal system and through neurons in Posterior pitutary.
? Posterior pituitary is under neural control of hypothalamus.
Page 2


Points To Remember
Endocrine glands : These are ductless glands which secrete hormones 
directly into the blood stream.
Hormones : Non-nutrient chemicals synthesised in trace amount by  
Endocrine glands that act as intracellular messengers and are specific in their 
action which are transported by blood from site of production to site of action.
Hypothalamus :
? It is basal part of diencephalon.
? Has neurosecretory cells called nuclei which produce hormones to regulate
the synthesis and secretion of pituitary gland hormones.
? Two types of hormones released are :
 Releasing hormones : Simulate secretion of pituitary hormones, e.g.,
Gonadotrophin releasing hormone stimulates pituitary gland to synthesise
gonadotrophins.
Inhibiting hormones : Inhibit secretions of pituitary hormones, e.g.,
Somatostatin inhibits secretion of growth hormone.
Pituitary Gland :
? Located in bony cavity called as sella tursica.
? Attached to hypothalamus by a stalk.
? Divided anatomically into : Adenohypophysis (Anterior lobe) and
Neurohypophysis (Posterior lobe).
? Hormones released from hypothalamic neurons reach anterior pituitary
through portal system and through neurons in Posterior pitutary.
? Posterior pituitary is under neural control of hypothalamus.
1. Pituitary Gland
Pituitary Gland
  Adenohypophysis (Anterior lobe)               Neurohypophysis (Posterior lobe)
    (It stores hormones sureated by hypothalamus
    Pars distalis Pars intermedia
    Secretes MSH
GH       PRL      TSH      ACTH     LH     FSH
Adenohypophysis :
? Growth hormone (GH) : Oversecretion leads to gigantism and low secretion
causes dwarfism and Proper reaction leads to proper growth of body.
? Prolactin (PRL) : Growth of mammary gland and formation of milk in
them.
? Thyroid stimulating hormone (TSH) : Stimulates synthesis and secretion
of thyroid hormones from  thyroid gland.
? Adrenocorticotrophic hormone (ACTH) : Stimulates synthesis and
secretion of steroid hormones called glucocorticoids from adrenal cortex.
? Luteinizing hormone (LH) : Synthesis and secretion of hormones called
androgens in males, and helps in ovulation and maintenance of corpus luteum
in females.
? Follicle stimulating hormone (FSH) : Regulate spermatogenesis in males,
and growth and development of ovarian follicles in females.
? Oxytocin  helps in contraction of uterus during child birth and milk ejection
from mammary gland in females.
? Vasopressin : Acts on kidney and stimulates reabsorption of water and
electrolytes by distal tubules to reduce water loss through urine. It is also
called as Anti Diuretic Hormone (ADH).
? Acrommegaly : It  is a condition when the pituitary gland makes too much
growth hormone. It is due to a tumour in pituitary gland. Person suffering
from acromegaly (acro means tip and megaly means enlargement) may
gradually develop a long face with protruding lower law, enlarged nose and
wider spacing between teeth and enlarged hands and feet.
2. Pineal Gland :
? Located on dorsal side of forebrain.
            Pars nervosa
Oxytocin    Vasopressin
(ADH)
Page 3


Points To Remember
Endocrine glands : These are ductless glands which secrete hormones 
directly into the blood stream.
Hormones : Non-nutrient chemicals synthesised in trace amount by  
Endocrine glands that act as intracellular messengers and are specific in their 
action which are transported by blood from site of production to site of action.
Hypothalamus :
? It is basal part of diencephalon.
? Has neurosecretory cells called nuclei which produce hormones to regulate
the synthesis and secretion of pituitary gland hormones.
? Two types of hormones released are :
 Releasing hormones : Simulate secretion of pituitary hormones, e.g.,
Gonadotrophin releasing hormone stimulates pituitary gland to synthesise
gonadotrophins.
Inhibiting hormones : Inhibit secretions of pituitary hormones, e.g.,
Somatostatin inhibits secretion of growth hormone.
Pituitary Gland :
? Located in bony cavity called as sella tursica.
? Attached to hypothalamus by a stalk.
? Divided anatomically into : Adenohypophysis (Anterior lobe) and
Neurohypophysis (Posterior lobe).
? Hormones released from hypothalamic neurons reach anterior pituitary
through portal system and through neurons in Posterior pitutary.
? Posterior pituitary is under neural control of hypothalamus.
1. Pituitary Gland
Pituitary Gland
  Adenohypophysis (Anterior lobe)               Neurohypophysis (Posterior lobe)
    (It stores hormones sureated by hypothalamus
    Pars distalis Pars intermedia
    Secretes MSH
GH       PRL      TSH      ACTH     LH     FSH
Adenohypophysis :
? Growth hormone (GH) : Oversecretion leads to gigantism and low secretion
causes dwarfism and Proper reaction leads to proper growth of body.
? Prolactin (PRL) : Growth of mammary gland and formation of milk in
them.
? Thyroid stimulating hormone (TSH) : Stimulates synthesis and secretion
of thyroid hormones from  thyroid gland.
? Adrenocorticotrophic hormone (ACTH) : Stimulates synthesis and
secretion of steroid hormones called glucocorticoids from adrenal cortex.
? Luteinizing hormone (LH) : Synthesis and secretion of hormones called
androgens in males, and helps in ovulation and maintenance of corpus luteum
in females.
? Follicle stimulating hormone (FSH) : Regulate spermatogenesis in males,
and growth and development of ovarian follicles in females.
? Oxytocin  helps in contraction of uterus during child birth and milk ejection
from mammary gland in females.
? Vasopressin : Acts on kidney and stimulates reabsorption of water and
electrolytes by distal tubules to reduce water loss through urine. It is also
called as Anti Diuretic Hormone (ADH).
? Acrommegaly : It  is a condition when the pituitary gland makes too much
growth hormone. It is due to a tumour in pituitary gland. Person suffering
from acromegaly (acro means tip and megaly means enlargement) may
gradually develop a long face with protruding lower law, enlarged nose and
wider spacing between teeth and enlarged hands and feet.
2. Pineal Gland :
? Located on dorsal side of forebrain.
            Pars nervosa
Oxytocin    Vasopressin
(ADH)
? Secretes Melatonin to regulation 24-hours rhythm, sleep-wake cycle,
menstrual cycle, pigmentation etc.
3. Thyroid Gland :
? Has  two lobes on either side of trachea interconnected by isthmus (connective
tissue).
? Composed of follicles and stromal tissues.
? Follicular cells synthesis thyroxine (T
4
) and tri-iodothyronine (T
3
).
? Iodine is necessary for normal functioning in of thyroid.
? Goitre (Hypothyroidism) : Enlargement of thyroid gland; Hypothyroidism
may lead to mental retardation and stunted growth (cretinism) Deaf-mutism
in the baby if it occurs during pregnancy.
? Hyperthyroidism : Occurs due to cancer or due to development of nodules
in thyroid glands. Effects body physiology as abnormal high levels of thyroid
hormones is synthesised. Basic metabolic rate increase.
? Exophthalmic goitre : It is a form of hyperthyroidism, characterised by
enlargement of thyroid gland, protrusion of eye balls and increased BMR
? Thyroid hormone controls protein, carbohydrate metabolism.
? Also secretes a protein hormone called Thyrocalcitonin (TCT) which regulates 
blood calcium level.
4. Parathyroid Gland :
? Present on back side of thyroid gland. Each lobe of thyroid gland has its one
pair.
? Secrete peptide hormone called parathyroid hormone (PTH) which increases
calcium levels in blood so called hypercalcemic hormone.
? PTH stimulates bone resorption, and reabsorption of calcium from blood and
reabsorption of calcium by renal tubules, thus increasing blood Ca
++
 level.
5. Thymus Gland
? Located on dorsal side of heart and aorta.
? Secrete peptide hormones called Thymosins which play role in differentiation
of T-lymphocytes (help in cell mediated immunity.)
? Thymosins also produce antibodies and provide humoral immunity.
? Immunity of old people usually becomes weak as thymus gets degenerated
with age.
6. Adrenal Gland
? Located at anterior part of each kidney.
? Has centrally located adrenal medulla and at  periphery in adrenal cortex.
Page 4


Points To Remember
Endocrine glands : These are ductless glands which secrete hormones 
directly into the blood stream.
Hormones : Non-nutrient chemicals synthesised in trace amount by  
Endocrine glands that act as intracellular messengers and are specific in their 
action which are transported by blood from site of production to site of action.
Hypothalamus :
? It is basal part of diencephalon.
? Has neurosecretory cells called nuclei which produce hormones to regulate
the synthesis and secretion of pituitary gland hormones.
? Two types of hormones released are :
 Releasing hormones : Simulate secretion of pituitary hormones, e.g.,
Gonadotrophin releasing hormone stimulates pituitary gland to synthesise
gonadotrophins.
Inhibiting hormones : Inhibit secretions of pituitary hormones, e.g.,
Somatostatin inhibits secretion of growth hormone.
Pituitary Gland :
? Located in bony cavity called as sella tursica.
? Attached to hypothalamus by a stalk.
? Divided anatomically into : Adenohypophysis (Anterior lobe) and
Neurohypophysis (Posterior lobe).
? Hormones released from hypothalamic neurons reach anterior pituitary
through portal system and through neurons in Posterior pitutary.
? Posterior pituitary is under neural control of hypothalamus.
1. Pituitary Gland
Pituitary Gland
  Adenohypophysis (Anterior lobe)               Neurohypophysis (Posterior lobe)
    (It stores hormones sureated by hypothalamus
    Pars distalis Pars intermedia
    Secretes MSH
GH       PRL      TSH      ACTH     LH     FSH
Adenohypophysis :
? Growth hormone (GH) : Oversecretion leads to gigantism and low secretion
causes dwarfism and Proper reaction leads to proper growth of body.
? Prolactin (PRL) : Growth of mammary gland and formation of milk in
them.
? Thyroid stimulating hormone (TSH) : Stimulates synthesis and secretion
of thyroid hormones from  thyroid gland.
? Adrenocorticotrophic hormone (ACTH) : Stimulates synthesis and
secretion of steroid hormones called glucocorticoids from adrenal cortex.
? Luteinizing hormone (LH) : Synthesis and secretion of hormones called
androgens in males, and helps in ovulation and maintenance of corpus luteum
in females.
? Follicle stimulating hormone (FSH) : Regulate spermatogenesis in males,
and growth and development of ovarian follicles in females.
? Oxytocin  helps in contraction of uterus during child birth and milk ejection
from mammary gland in females.
? Vasopressin : Acts on kidney and stimulates reabsorption of water and
electrolytes by distal tubules to reduce water loss through urine. It is also
called as Anti Diuretic Hormone (ADH).
? Acrommegaly : It  is a condition when the pituitary gland makes too much
growth hormone. It is due to a tumour in pituitary gland. Person suffering
from acromegaly (acro means tip and megaly means enlargement) may
gradually develop a long face with protruding lower law, enlarged nose and
wider spacing between teeth and enlarged hands and feet.
2. Pineal Gland :
? Located on dorsal side of forebrain.
            Pars nervosa
Oxytocin    Vasopressin
(ADH)
? Secretes Melatonin to regulation 24-hours rhythm, sleep-wake cycle,
menstrual cycle, pigmentation etc.
3. Thyroid Gland :
? Has  two lobes on either side of trachea interconnected by isthmus (connective
tissue).
? Composed of follicles and stromal tissues.
? Follicular cells synthesis thyroxine (T
4
) and tri-iodothyronine (T
3
).
? Iodine is necessary for normal functioning in of thyroid.
? Goitre (Hypothyroidism) : Enlargement of thyroid gland; Hypothyroidism
may lead to mental retardation and stunted growth (cretinism) Deaf-mutism
in the baby if it occurs during pregnancy.
? Hyperthyroidism : Occurs due to cancer or due to development of nodules
in thyroid glands. Effects body physiology as abnormal high levels of thyroid
hormones is synthesised. Basic metabolic rate increase.
? Exophthalmic goitre : It is a form of hyperthyroidism, characterised by
enlargement of thyroid gland, protrusion of eye balls and increased BMR
? Thyroid hormone controls protein, carbohydrate metabolism.
? Also secretes a protein hormone called Thyrocalcitonin (TCT) which regulates 
blood calcium level.
4. Parathyroid Gland :
? Present on back side of thyroid gland. Each lobe of thyroid gland has its one
pair.
? Secrete peptide hormone called parathyroid hormone (PTH) which increases
calcium levels in blood so called hypercalcemic hormone.
? PTH stimulates bone resorption, and reabsorption of calcium from blood and
reabsorption of calcium by renal tubules, thus increasing blood Ca
++
 level.
5. Thymus Gland
? Located on dorsal side of heart and aorta.
? Secrete peptide hormones called Thymosins which play role in differentiation
of T-lymphocytes (help in cell mediated immunity.)
? Thymosins also produce antibodies and provide humoral immunity.
? Immunity of old people usually becomes weak as thymus gets degenerated
with age.
6. Adrenal Gland
? Located at anterior part of each kidney.
? Has centrally located adrenal medulla and at  periphery in adrenal cortex.
? Adrenal medulla secretes adrenaline (epinephrine) and nor adrenaline
(norepinephrine), commonly called as catecholamines or emergency
hormones or hormones of fight or flight.
? These hormones increase heart beat, rate of respiration, breakdown of
glycogen thus increase blood glucose level, breakdown of lipids and protein,
alertness, raising of hairs, sweating etc.
? Adrenal Cortex-(3 layers) : Zona reticularis (inner layer)
Zona fasciculata (middle layer)
Zona glomerulosa (outer layer)
? Adrenal cortex secretes :
1. Androgenic steroids :
? Secreted in small amounts.
? Play role in growth of axial pubic and facial hair during puberty.
2. Glucocorticoids :
? Involved in carbohydrate metabolism.
? Stimulates gluconeogenesis, lipolysis and proteolysis.
? e.g., Cortisol which is also involved in cardio-vascular and kidney functions.
? It also suppresses immune response and stimulates RBC production.
3. Mineralocorticoids :
? Regulate balance of water and electrolytes in body.
? e.g., Aldosterone which also helps in reabsorption of NA
+
 and water excretion
of K
+
 and phosphates ions from renal tubules.
? When adrenal cartex is damaged, it does not produce enough cortisols (which
regulate body’s reaction to stressful situations) and aldosterone.
? It result in Addison’s disease. Symptons of addison’s disease are weak
muscles, extreme fatigue, increased skin pigmentation, weight loss, sores
in mouth and depression.
Two major causes :
1. Primary adrenal insufficiency where our immunity system mistakes adrenal
for an antigen and tries to damage it.
2. Secondary adrenal insufficiency-when pituitary gland can’t produce ACTH
Page 5


Points To Remember
Endocrine glands : These are ductless glands which secrete hormones 
directly into the blood stream.
Hormones : Non-nutrient chemicals synthesised in trace amount by  
Endocrine glands that act as intracellular messengers and are specific in their 
action which are transported by blood from site of production to site of action.
Hypothalamus :
? It is basal part of diencephalon.
? Has neurosecretory cells called nuclei which produce hormones to regulate
the synthesis and secretion of pituitary gland hormones.
? Two types of hormones released are :
 Releasing hormones : Simulate secretion of pituitary hormones, e.g.,
Gonadotrophin releasing hormone stimulates pituitary gland to synthesise
gonadotrophins.
Inhibiting hormones : Inhibit secretions of pituitary hormones, e.g.,
Somatostatin inhibits secretion of growth hormone.
Pituitary Gland :
? Located in bony cavity called as sella tursica.
? Attached to hypothalamus by a stalk.
? Divided anatomically into : Adenohypophysis (Anterior lobe) and
Neurohypophysis (Posterior lobe).
? Hormones released from hypothalamic neurons reach anterior pituitary
through portal system and through neurons in Posterior pitutary.
? Posterior pituitary is under neural control of hypothalamus.
1. Pituitary Gland
Pituitary Gland
  Adenohypophysis (Anterior lobe)               Neurohypophysis (Posterior lobe)
    (It stores hormones sureated by hypothalamus
    Pars distalis Pars intermedia
    Secretes MSH
GH       PRL      TSH      ACTH     LH     FSH
Adenohypophysis :
? Growth hormone (GH) : Oversecretion leads to gigantism and low secretion
causes dwarfism and Proper reaction leads to proper growth of body.
? Prolactin (PRL) : Growth of mammary gland and formation of milk in
them.
? Thyroid stimulating hormone (TSH) : Stimulates synthesis and secretion
of thyroid hormones from  thyroid gland.
? Adrenocorticotrophic hormone (ACTH) : Stimulates synthesis and
secretion of steroid hormones called glucocorticoids from adrenal cortex.
? Luteinizing hormone (LH) : Synthesis and secretion of hormones called
androgens in males, and helps in ovulation and maintenance of corpus luteum
in females.
? Follicle stimulating hormone (FSH) : Regulate spermatogenesis in males,
and growth and development of ovarian follicles in females.
? Oxytocin  helps in contraction of uterus during child birth and milk ejection
from mammary gland in females.
? Vasopressin : Acts on kidney and stimulates reabsorption of water and
electrolytes by distal tubules to reduce water loss through urine. It is also
called as Anti Diuretic Hormone (ADH).
? Acrommegaly : It  is a condition when the pituitary gland makes too much
growth hormone. It is due to a tumour in pituitary gland. Person suffering
from acromegaly (acro means tip and megaly means enlargement) may
gradually develop a long face with protruding lower law, enlarged nose and
wider spacing between teeth and enlarged hands and feet.
2. Pineal Gland :
? Located on dorsal side of forebrain.
            Pars nervosa
Oxytocin    Vasopressin
(ADH)
? Secretes Melatonin to regulation 24-hours rhythm, sleep-wake cycle,
menstrual cycle, pigmentation etc.
3. Thyroid Gland :
? Has  two lobes on either side of trachea interconnected by isthmus (connective
tissue).
? Composed of follicles and stromal tissues.
? Follicular cells synthesis thyroxine (T
4
) and tri-iodothyronine (T
3
).
? Iodine is necessary for normal functioning in of thyroid.
? Goitre (Hypothyroidism) : Enlargement of thyroid gland; Hypothyroidism
may lead to mental retardation and stunted growth (cretinism) Deaf-mutism
in the baby if it occurs during pregnancy.
? Hyperthyroidism : Occurs due to cancer or due to development of nodules
in thyroid glands. Effects body physiology as abnormal high levels of thyroid
hormones is synthesised. Basic metabolic rate increase.
? Exophthalmic goitre : It is a form of hyperthyroidism, characterised by
enlargement of thyroid gland, protrusion of eye balls and increased BMR
? Thyroid hormone controls protein, carbohydrate metabolism.
? Also secretes a protein hormone called Thyrocalcitonin (TCT) which regulates 
blood calcium level.
4. Parathyroid Gland :
? Present on back side of thyroid gland. Each lobe of thyroid gland has its one
pair.
? Secrete peptide hormone called parathyroid hormone (PTH) which increases
calcium levels in blood so called hypercalcemic hormone.
? PTH stimulates bone resorption, and reabsorption of calcium from blood and
reabsorption of calcium by renal tubules, thus increasing blood Ca
++
 level.
5. Thymus Gland
? Located on dorsal side of heart and aorta.
? Secrete peptide hormones called Thymosins which play role in differentiation
of T-lymphocytes (help in cell mediated immunity.)
? Thymosins also produce antibodies and provide humoral immunity.
? Immunity of old people usually becomes weak as thymus gets degenerated
with age.
6. Adrenal Gland
? Located at anterior part of each kidney.
? Has centrally located adrenal medulla and at  periphery in adrenal cortex.
? Adrenal medulla secretes adrenaline (epinephrine) and nor adrenaline
(norepinephrine), commonly called as catecholamines or emergency
hormones or hormones of fight or flight.
? These hormones increase heart beat, rate of respiration, breakdown of
glycogen thus increase blood glucose level, breakdown of lipids and protein,
alertness, raising of hairs, sweating etc.
? Adrenal Cortex-(3 layers) : Zona reticularis (inner layer)
Zona fasciculata (middle layer)
Zona glomerulosa (outer layer)
? Adrenal cortex secretes :
1. Androgenic steroids :
? Secreted in small amounts.
? Play role in growth of axial pubic and facial hair during puberty.
2. Glucocorticoids :
? Involved in carbohydrate metabolism.
? Stimulates gluconeogenesis, lipolysis and proteolysis.
? e.g., Cortisol which is also involved in cardio-vascular and kidney functions.
? It also suppresses immune response and stimulates RBC production.
3. Mineralocorticoids :
? Regulate balance of water and electrolytes in body.
? e.g., Aldosterone which also helps in reabsorption of NA
+
 and water excretion
of K
+
 and phosphates ions from renal tubules.
? When adrenal cartex is damaged, it does not produce enough cortisols (which
regulate body’s reaction to stressful situations) and aldosterone.
? It result in Addison’s disease. Symptons of addison’s disease are weak
muscles, extreme fatigue, increased skin pigmentation, weight loss, sores
in mouth and depression.
Two major causes :
1. Primary adrenal insufficiency where our immunity system mistakes adrenal
for an antigen and tries to damage it.
2. Secondary adrenal insufficiency-when pituitary gland can’t produce ACTH
7. Pancreas : It is called composite/dual gland. As it acts as Exocrine and
endocrine gland i.e. has both exocrine and endocrine function.
? Contains about 1-2 million islets of Langerhans which has glucagon secreting
a-cells and insulin secreting ß-cell.
? Glucagon : Peptide hormone, stimulates glycogenolysis by acting on
liver cells. Also, stimulates gluconeogenesis. Hence called hyperglycemic
hormone.
? Insulin : Peptide hormone, acts on hepatocytes and adipocytes to enhance
cellular glucose uptake, stimulates conversion of glucose to glycogen
(glycogenesis), so decrease blood glucose level called hypoglycemic
hormone.
? Deficiency of insulin causes diabetes mellitus in which loss of glucose occurs
through urine. Excessive hunger and thirst (polydipsia) are other symptoms
of Diabetes.
? Insulin and glucagon are antagonistic hormones i.e. play apposite role.
 Glycogenolysis : Breaking of glycogen into glucose.
 Gluconeogenesis : Formation of glucose from substances other than glycogen.
 Glycogenesis : Conversion of glucose into glycogen.
8. Testis :
? A pair of testis composed of seminiferous tubules and interstilial cells is
present in the scrotal sac of males.
? Leydig cells (interstitial cells) produce androgens (mainly testosterone) which
regulate development and maturation of male accessory sex organs, formation
of secondary sex characters and play stimulatory role in spermatogenesis.
Male sexual behaviour (libido) is influenced by androgens.
 Ovary : A pair of ovaries which produce one ovum in each menstrual cycle are 
present in abdomen in females.
? Ovary composed of ovarian follicles and stromal tissue.
? Estrogen synthesised by growing ovarian follicles helps in stimulation of
growth of female secondary sex organs, female behaviour, mammary gland
development and female secondary sex characters.