The Endocrine System Flashcards
Definition of an endocrine gland
A ductless gland that produces hormones which are directly released into the blood stream
Definition of a hormone
A chemical messenger produced by an endocrine gland and carried by the bloodstream to another part of the body where it has a specific effect
Exocrine glands definition
Have ducts to carry secretions e.g salivary glands
The significance of the Pancreas
Is both an exocrine and endocrine gland
Exocrine Function of the Pancreas
Produces enzymes such as amylase. These flow to the duodenum through ducts
Endocrine function of the pancreas
Contains Islets of Langerhans which produce the hormone insulin which is carried away by the bloodstream
Compare the Endocrine and Nervous System
Endocrine system Cells involved - Glands Message - Chemical hormones Carried by - Bloodstream Message sent to - Cells throughout the body Received by - Target organ Transmission - Usually slow Effects - Can be widespread Response - Slower - eg growth Long lasting duration
The nervous system
Cells involved - sense receptors
Message - electrical (impulse)
Carried by - nerve cell
Message sent to a specific cell or tissue
Received by - effector - muscle or gland
Speed of transmission - rapid
Effects - localised usually
Speed of response - fast acting - eg catching a ball
Duration of response - brief
Pituitary gland
Location , hormone, function
Below the brain
Growth hormone
Causes bone elongation
Pituitary second hormone produced
Thyroid Stimulating Hormone (TSH)
Stimulates the thyroid to produce thyroxine
Pituitary third hormone produced
FSH & LH
Follicle stimulating hormone
Stimulates the production of eggs , surrounded by Graafian follicles
Luteinising hormone
Causes ovulation
Causes the remains of Graafian follicle to develop into corpus luteum
Hypothalamus
Base of brain, above pituitary
ADH - made in the hypothalamus and stored in the pituitary gland and released from there when needed
Stimulates water reabsorption in the kidneys
Pineal
Within the brain, near hypothalamus
Melatonin
Controls body rhythms such as sleeping pattern
Thyroid
In the neck on the trachea
Thyroxine
Controls the metabolic rate of body cells
Parathyroid
Behind the thyroid
Parathormone
Controls calcium levels in the blood
