Chemical Coordination and Integration
Class 11 · Biology
5 ideas in Class 11 Biology, explained in plain words, with games and quizzes to practise.
Endocrine Basics and Hypothalamus-Pituitary
Part of: Glands and Major Hormones
Ductless glands drip trace messengers into fluid for distant targets; hypothalamic releasers and blockers steer pituitary synthesis through portal vessels while neural wires run the rear lobe. Six-three trophic, one intermediate and two stored hormones separate growth, milk, thyroid, adrenal, gonad and water duties.
Why it matters. Wire-plus-portal logic explains pituitary control. Hormone counts decode the gland.
Key words
- Endocrine glands
- : Ductless glands dripping trace messengers into circulating fluid.
- GnRH
- : Hypothalamic signal releasing pituitary hormones.
- Somatostatin
- : Hypothalamic signal blocking pituitary release.
- Portal vessels
- : Vessels linking hypothalamus to anterior pituitary.
- ADH
- : Stored rear-lobe hormone saving water in tubules.
- Oxytocin
- : Stored rear-lobe hormone starting labour and milk flow.
- Trophic hormones
- : Pituitary overseers steering distant glands.
Try it in two minutes
- Order hypothalamus to pituitary.
- Count six plus one plus two.
- Match each hormone with its duty.
Try at home. Chart pituitary hormones and targets.
Thyroid, Parathyroid and Pineal
Part of: Glands and Major Hormones
Follicle twins T4 and T3 need iodine; lack swells goitres and stunts babies while excess speeds Graves. Thyrocalcitonin and parathyroid hormone seesaw calcium from gut, tubules and bone; pineal melatonin clocks sleep and temperature.
Why it matters. Iodine links diet with thyroid. Calcium seesaw explains two glands.
Key words
- T3 and T4
- : Iodine-needing follicle twins setting the body pace.
- Goitre
- : Iodine-lack swelling of the thyroid gland.
- Cretinism
- : Birth-time thyroid lack stunting growth and mind.
- Graves disease
- : Excess thyroid working with bulging eyes.
- Thyrocalcitonin
- : Thyroid signal lowering circulating calcium.
- Parathyroid hormone
- : Gland brew raising calcium from bone, tubules, gut.
- Melatonin
- : Pineal brew clocking sleep and temperature.
Try it in two minutes
- Link iodine with goitre.
- Seesaw TCT with PTH.
- Clock melatonin rhythms.
Try at home. Check salt labels for iodine.
Adrenal, Pancreas and Thymus
Part of: Stress, Fuel and Immunity
Medulla catecholamines fight-or-flight while three-layer cortex splits fuel glucocorticoids from salt aldosterone, failing into Addison. Islet alpha-beta cells seesaw glucagon with insulin around glucose, failing into sugary ketone diabetes; thymosins train T-lymphocytes before fading with age.
Why it matters. Zone maps decode adrenal steroids. Opposing pairs explain glucose and calcium.
Key words
- Catecholamines
- : Adrenal medulla pair driving fight-or-flight responses.
- Glucocorticoids
- : Cortex group tuning fuel use under stress.
- Mineralocorticoids
- : Cortex group balancing salt and water.
- Addison disease
- : Cortex failure causing bronze skin and salt loss.
- Glucagon
- : Alpha-cell hormone that raises circulating sugar.
- Insulin
- : Beta-cell hormone that lowers circulating sugar.
- Thymosins
- : Thymus peptides training T-cells for defence.
Try it in two minutes
- Split medulla from cortex.
- Seesaw glucagon with insulin.
- Train T cells young.
Try at home. List stress symptoms and match hormones.
Gonads and Other Hormone Sources
Part of: Gonads, Gut and Action
Leydig gaps brew testosterone for male tracts and voices while follicles brew estrogen and yellow bodies brew progesterone for pregnancy; heart ANF dilates high pressure, kidneys boost red cells, gut quartets digest, and growth factors repair.
Why it matters. Gonad products explain puberty and pregnancy. Tissue hormones extend the endocrine map.
Key words
- Testosterone
- : Leydig-cell brew building the male tract and voice.
- Estrogen
- : Follicle brew driving female growth and cycles.
- Progesterone
- : Yellow-body brew holding pregnancy in place.
- ANF
- : Heart signal that widens vessels under high pressure.
- Erythropoietin
- : Kidney signal that boosts red-cell production.
- Gastrin and CCK
- : Gut quartet triggering acid, bile and enzymes.
Try it in two minutes
- Brew male versus female steroids.
- Dilate with ANF.
- Order four gut hormones.
Try at home. List puberty changes per hormone.
Hormone Action
Part of: Gonads, Gut and Action
Exclusive receptors sit on membranes or inside cells; surface binders spawn cAMP-IP3-calcium relays while insider complexes steer genes. Peptides, steroids, thyroid and amine chemistries sort all hormones.
Why it matters. Location predicts mechanism. Chemistry sorts every hormone.
Formulas
- Surface receptors act through second messengers, inner receptors steer genes
Key words
- Receptor specificity
- : Lock-and-key match between one hormone and its target.
- Membrane receptors
- : Outside-cell docks spawning relay molecules inside.
- Intracellular receptors
- : Inside-cell docks steering gene activity directly.
- Second messengers
- : Relay molecules such as cAMP, IP3 and calcium.
- Steroid hormones
- : Gene-steering hormones built from cholesterol.
- Peptide hormones
- : Relay-using hormones built from amino-acid chains.
Try it in two minutes
- Place each receptor.
- Relay with messengers.
- Sort four chemistries.
Try at home. Sort ten hormones by chemistry.
What your child will practise
- Adrenal, Pancreas and Thymus: Space Quick Fire (Quick Fire)
- Endocrine Basics and Hypothalamus-Pituitary: Ocean Puzzle (Clue Puzzle)
- Gonads and Other Hormone Sources: Ocean Quest (Flip and Match)
- Hormone Action: Candy Quick Fire (Quick Fire)
- Thyroid, Parathyroid and Pineal: Desert Puzzle (Clue Puzzle)
- Quiz: Adrenal, Pancreas and Thymus (8 questions)
- Quiz: Endocrine Basics and Hypothalamus-Pituitary (8 questions)
- Quiz: Gonads and Other Hormone Sources (8 questions)
- Quiz: Hormone Action (8 questions)