[biology] the endocrine system.pptx
DESCRIPTION
IGCSE BiologyTopic: the endocrine systemQuick notes for students that are about to give their IGCSE examinationsTRANSCRIPT
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Biology
The Endocrine system
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The endocrine system
• Have ductless glands, endocrine glands, which secrete hormones into the bloodstream
• The certain organs that the hormones reach are called as target organs.
• Responses of body to hormones are slow• Excess of hormone production illness
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The endocrine glands
• Thyroid• Adrenal• Pancreas• Reproductive • organs• Pituitary gland
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• situated in front of neck – in front of windpipe• produces thyroxine (made from iodine and amino acid)
• Effects metabolic rate• Controls level of activity• Promotes normal skeleton growth• Essential for normal development
of the brain
Thyroid gland
The endocrine glands
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The endocrine glands
• attached to back of abdominal cavity, above kidneys• outer layer adrenal cortex• inner zone adrenal medulla• produces hormones:
Adrenaline - Adrenaline on the body causes a rise in body glucose and it increases heart rate. It also constricts the blood vessels, dilates air passages and also participates in the fight-or-flight response of the sympathetic nervous system of the body. Epinephrine is another name for adrenaline.
Corticosteroids - are a class of chemicals that includes steroid hormones naturally produced in the adrenal cortex. Control metabolism of carbohydrates, fats, proteins, salts and water
Adrenal glands
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The endocrine glands
• also a digestive gland• the hormone producing cells are arranged in islets• hormones produced:
• Glucagon - comes into the scene when sugar level in blood becomes low
• Insulin – comes into the scene when sugar level in blood becomes high
Pancreas
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The endocrine glands
•IN FEMALES:• Oestrogen• Progesterone
•IN MALES:• Testosterone
Reproductive organs
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The pituitary gland is an endocrine gland – hence it produces hormones.Hormones it produces: Antidiuretic hormone (ADH) -
acts on kidneys; regulates water reabsorption in kidney tubules
Growth hormone – affects growth rate of whole body
Follicle-stimulating hormone (FSH) – reaches ovaries and makes one of the follicles start to mature and to produce oestrogen
Luteinizing hormone (LH) – together with FSH, induces ovulation
Thyroid-stimulating hormone (TSH) - acts on thyroid gland; makes it produce thyroxine
Pituitary Gland
The endocrine glands
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Fate of hormones
hormones
bloodstream
Spent hormones
Liver
Spent hormones are converted to inactive substances by the liver
Excretedbykidneys
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brain
pituitary gland
follicle-stimulating hormone (FSH)
ovary
oestrogen
oestrogen
uterus
Homeostasis and negative feedback
A follicle is a group of cells enclosing an ovum (egg cell). The follicle enlarges, and protrudes from the surface of the ovary before bursting and releasing its ovum