Endocrine System

Biology 12

Jokes of the day:

Homeostasis

Endocrine System and the nervous system often work together to bring about homeostasis

The division between the nervous and endocrine systems occurs in the hypothalamus. o The hypothalamus regulates the pituitary gland

through nerve stimulation. o The pituitary gland regulates the endocrine glands

through secretion of chemicals which can also affect the nerve activity of the hypothalamus.

Endocrine System

is the system of glands, each of which secretes different types of hormones directly into the bloodstream to regulate the body.

Endocrine Glands

Endocrine glands o Ductless organs that secrete their molecules directly

into the bloodstream All endocrine cells are located within highly

vascularised areas to ensure that their products enter the bloodstream immediately

Note: Exocrine glands discharge their secretions into ducts that carry them where they are used (ex. glands of the digestive system).

THE GLANDS

1. Pituitary gland

this is the “master Gland” which controls other endocrine glands associated with hormones

Anterior lobeo TSH: thyroid stimulating hormone, regulates cell metabolismo FSH: follicle stimulating hormone, stimulates follicle and sperm developmento LH: luteinizing hormone, stimulates ovulation and production of testosteroneo GH: growth hormone (somatotrophin STH), promotes growtho ACTH: adrenocortictropic hormone, stimulates release of hormones involved

in stress response.o PRL: prolactin, stimulates milk production in lactating females.

Posterior lobeo oxytocin: stimulates contraction of muscles in the uterus, triggers milk releaseo ADH: antidiruretic hormone ( increases reabsorption of water)o vasopressin: helps maintain the body’s water balance/blood pressure.

2. Hypothalamus gland

controls the release of hormones from the pituitary and is a major link between nervous and endocrine systems.

TSH is associated with this gland.

3. Pineal Gland

affects sexual development and biorhythms

4. Thyroid Gland

influences the metabolic rate it is associated with the hormone thyroxine

5. Parathyroid Glands

controls the blood calcium in the neck area

7. Thymus Gland

aids in immunity, it is the organ in which the lymphocytes mature (T cells)

8. Pancreas

production of hormones that regulate the level of sugar in the blood. o If blood sugar is high it produces Insulin to reduce sugar

level. o When blood sugar is low glucagon is produced.

9. Adrenal Gland

located on top of the kidneys.o adrenalin – helps to cope with stress, converts glycogen

to glucose.o cortisone – prevents inflammation and increases the

level of sugar in the blood.

10. Testis

production of male sex hormone (testosterone) causes secondary sex characteristics, stimulates sperm

production

11. Ovaries

production of female sex hormones o estrogen: development of secondary sex characteristics,

prepares uterus for pregnancy.o progesterone: maintains the uterus during pregnancy

To do :

Read Chapter 8Page 377 #1, 2Page 383 #1Page 387 #1 – 4, 6Page 392 # 1, 2