Unit 4. B: Endocrine System

Index

1. Introduction2. How Parathormone Works3. Main Hormones 4.Regulation of the Hormones’ Production5. How Pancreas Works6. Differences between Nervous System and Endocrine System7. Ilnesses related to the Endocrine System

1. IntroductionThe endocrine system is a coordination system, that is, it regulates the functioningof the organism, allowing to keep the internal equilibrium (homeostasis)

Endocrine systemEndocrine glands

releaseHormones

•Thyroid gland•Parathyroid gland•Adrenal glands

•Pancreas•Testes•Ovaries

•Thyroxine and calcitonine•Parathyroid hormone•Cortisol, adrenaline and noradrenaline•Insulin and glucagon•Testosterone•Estrogens and progesterone

contains

Hormones are chemical messengers which act on specific cells in our body.These cells are called target cells. Endocrine glands release hormones into the blood. The target cells recognise the hormone because they have specific receptors for their regulating hormones.

Video: EndocrineSytemGeneral

2. How Parathormone Works

The function of the parathormone is to control the amount of calcium in the blood.It is released by the parathyroid gland.

The target organs of the parathormone are:

•Intestine

•Kidneys

•Bones

When the target organs detect the arrival of the parathormone, they begin to release calcium to the blood.

3. Main HormonesMain human hormones

Gland Hormone Function

Neurohypophysis (posterior pituitary)

OxitocineUterine contraction and lactation

Antidiuretic hormoneIt reduces the production of urine

Adenohypophysis (anterior pituitary)

Growth hormone It stimulates growth

ProlactinIt stimulates production of milk

Tropic hormones They regulate other glands

Thyroid

ThyroxineIt activates the cellular metabolism

CacitoninIt avoids the calcium loss in bones

Parathyroid ParathormoneIt increases the level of calcium in the blood

Main human hormones

Gland Hormone Function

Suprarrenal glandsAdrenaline and noradrenaline

They prepare the organism for physical effort

PancreasInsulin

It decreases the level of glucose in the blood, favouring its entry into the cells

GlucagonIt increases the level of glucose in the blood

Main human hormones

Gland Hormone Function

Testicles TestosteroneDevelopment of masculine sexual characteristics

OvariesEstrogens

Development of female sexual characteristics and control of the ovulation cycles

ProgesteroneUterus’ preparation for the pregnancy

3. Regulation of the hormones’ production

The hypothalamus relates the two coordination systems (endocrine and nervous)

The hypothalamus releases hormones, which control the adenohypophysis. And the adenohypophysis releases tropic hormones which control other glands

An endocrine gland begins to secrete its hormone when it receives a stimulus.Once the stimulus desappears the production of the hormone stops:

when the amount of hormone in the blood is high (FEED BACK)

Feed back

when the stimulus stops Video: Pituitary Gland Regulation

Activity 2 and 3 page 105

4. How Pancreas Works

Pancreas releases insulin and glucagon

Insulin It decreases the level of glucose in the blood, favouring its entry into the cells

Glucagon It increases the level of glucose in the blood

The combination of these hormones keeps the glucose levels in the blood

5. Differences between Nervous System and Endocrine System

Nervous Endocrine

Type of cells Neurons Glands

Type of messengers

Electrical impulses

Chemical messengers (hormones)

Way of transporting

Nerves Blood

Type of answers Fast and short Slow and maintained

Diabetes

It can be caused:

by a lack of insulin Type 1 Diabetes

because the cells do not recognise the insulin Type 2 DiabetesThe result is an increase in the level of glucose in the blood. This is called hyperglycemia

7. Ilnesses related to the Endocrine System

Video: Diabetes1