Nervous System controls the Endocrine System

• The endocrine system, along with the nervous system, functions in the regulation of body activities. (Maintaining Homeostasis)

• The nervous system acts through electrical impulses and neurotransmitters to cause muscle contraction and glandular secretion.

Nervous VS Endocrine

• The nervous system coordinates rapid and precise responses to stimuli using action potentials.

• The endocrine system maintains long-term control using chemical signals. – The endocrine system works in parallel with

the nervous system to control growth and maturation along with homeostasis

Endocrine system

• The endocrine system acts through chemical messengers called hormones that influence growth, development, and metabolic activities.

• The action of the endocrine system is measured in minutes, hours, or weeks and is more generalized than the action of the nervous system.

Endocrine System

Pituitary Gland• The pituitary gland is the

master gland because hormones released from the pituitary gland control other endocrine glands in the body.

• It is located at the base of the brain.

The Thyroid Gland

• The thyroid gland is located in the neck.

• Thyroid stimulating hormone (TSH) from the anterior pituitary causes thyroid hormones be be released. Almost all body cells are targets of thyroid hormones.

• Thyroid hormone– increases the overall

metabolic rate– regulates growth and

development as well as the onset of sexual maturity

The Pancreas• The pancreas is made up of

exocrine and endocrine

– Endocrine glands secrete the hormones insulin and glucagon, which regulate blood glucose levels.

Thymus Gland • The Thymus is an

endocrine gland and is located in the upper chest near the heart

• As a young child the thymus helps in the processing of lymphocytes

• The thymus secretes thymosin throughout childhood

• The thymus appears to have little or no function in adults

The Pineal Gland • The pineal gland is a pea shaped endocrine gland that is

attached to the base of the brain• It secretes melatonin which is thought to help control the

human sleep cycles. – Low levels of melatonin during the day and higher levels at night

Gonads

• Sex glands – Ovaries in female – produce eggs and female sex

hormones estrogen and progesterone– Testes in male – produce sperm and male sex

hormone testosterone• Both of these stimulate the development

secondary sex characteristics when they are stimulated (puberty)– In females this causes the broadening of the hips and

development of breasts – In males this cause the deepening of the voice, facial

hair, body hair, and broader shoulders

Improper Functioning of Glands

• Hypersecretion – When a gland secretes more hormone then normal

• Hyposecretion – When a gland secretes less hormone then normal

Negative feedback Loop

• Hypothalamus receptors monitor blood levels of thyroid hormones.

• Low levels of thyroxin cause the Hypothalamus stimulates the anterior pituitary

• Hypothalamus stimulates the release of TSH-releasing hormone from the anterior pituitary.

• TSH travels to the thyroid where it promotes production of thyroid hormones, which in turn regulate metabolic rates and body temperatures.

• The increased levels of thyroid hormone in the blood stops the release of TSH form the hypothalamus and anterior pituitary gland stopping the thyroid from releasing too much thyroid hormone.