E NDOCRINE S YSTEM

T HE F UNCTIONS OF THE E NDOCRINE S YSTEM  Endocrine System  Controls daily activities  Controls growth and development  Controls mood and emotions  Helps maintain blood sugar levels  Secretes enzymes to help in food digestion

 The endocrine system is made up of glands  Glands are organs that produce and secrete chemicals Hormones Secrete chemicals into blood Enzymes into the digestive system

H ORMONES  Chemical product of an endocrine gland  Chemical messenger  Can affect organs and tissues far away from the gland  Hormones have many jobs  Turn off activities of organs and tissues  Speed up activities of organs and tissues  Slow down activities of organs and tissues

H ORMONE P RODUCTION  A stimulus occurs  A nerve impulse is sent to the brain  The brain sends an impulse back to an endocrine gland  Endocrine gland produced a hormone and releases it into the blood  Hormone travels to target tissue and causes a response

H ORMONE A CTION  Nerve impulse has a quick, short lasting effect  Hormones have a slower, longer lasting effect  The effect lasts until the hormone is out of the blood

T ARGET C ELLS  Cells that the hormone effects  Each endocrine glands produces one kind of hormone  Each hormone effects a certain kind of cell  Key in a lock  Hormones will not effect cells that don’t fit

T HE H YPOTHALAMUS  Nervous and endocrine systems work together  The hypothalamus is the master gland in the brain that communicates between these two systems  Nerve messages controlling sleep, hunger, thirst and other conditions come from the hypothalamus

 The hypothalamus plays a major role in maintaining homeostasis

T HE P ITUITARY  Also located in the brain  Communicates with the hypothalamus to control many body activities  The hypothalamus sends its nerve impulses to the pituitary  The pituitary sends the signal to other endocrine glands in the body  Thyroid releasing hormone  Growth hormone

T HE P ITUITARY

E NDOCRINE G LANDS

H ORMONE P ATHWAYS

F EEDBACK  Many systems in the body maintain homeostasis using feedback loops  Negative feedback  Positive Feedback

N EGATIVE F EEDBACK  System where the product tells the body when to stop making it  Once a hormone reaches a certain level, a message is sent to the endocrine gland telling it to stop production

N EGATIVE F EEDBACK

P OSITIVE F EEDBACK  When a reaction causes more of the same effect  A stimulus causes an effect  That effect creates more stimulus

P OSITIVE F EEDBACK

B ODY SYSTEMS THAT WORK WITH THE ENDOCRINE SYSTEM ;  The reproductive system works with the respiratory, circulatory, and endocrine systems.

W HERE ARE THE G LANDS ?

P ITUITARY Pituitary The pituitary gland produces a growth hormone which controls growth and homeostasis.

P ARATHYROID Parathyroid The parathyroid gland produces parathormone which controls calcium levels in the body.

A DRENALS Adrenals The adrenal glands produce adrenaline in response to physical and emotional stress. Fight or Flight

T HYROID Thyroid The thyroid gland produces thyroxin to regulate metabolism.

P ANCREAS Pancreas The pancreas produces insulin which controls sugar levels in the blood.

T ESTES ( IN MALES ) Testes The testes produce testosterone used in sperm production and the development of male traits.

O VARIES ( IN F EMALES ) Ovaries The ovaries produce estrogen used in egg production and the development of female traits.