The Endocrine System Flashcards
What is the endocrine system?
A regulatory system that uses organ glands to regulate the metabolism, growth and development, tissue function, sexual function. reproduction, sleep and mood. It worked the with nervous system, which is another regulatory system.
Define the DUCTLESS GLAND
A ductless gland is a gland that secretes hormones directly into the bloodstream. All endocrine glands are ductless.
What responses do the endocrine and nervous system give?
The endocrine system produces long term effects
The nervous system gives quick, immediate responses
What are the key glands in the endocrine system?
The hypothalamus/pituitary The thyroid The parathyroid The adrenal gland The pancreas
Describe the hypothalamus/pituitary gland
The hypothalamus is a portion of the brain that directly controls the pituitary gland. The pituitary gland is termed the ‘master gland’ as it is important for the development and control of the endocrine system.
It is the main link between the endocrine and nervous systems. Produces ADH, FSH and LH.
Describe the thyroid gland
A major gland that wraps around the trachea in a C shape, made up of two joined lobes. The hormone produced (thyroxine, targets the whole body) has particular effect of the heart, respiration, digestions and growth. It influences the enzyme concentration and activity.
Define CALCITONIN
Calcitonin is the hormone produced in the C-cells of the thyroid, and released when excessive levels of calcium are detected within bone.
Describe the parathyroid gland
Either side of the thyroid. Important for the balance of calcium/phosphorous. Produces parathromone, which is released if there is not enough calcium detected.
Either on the surface of the thyroid or partially embedded in it.
Describe the adrenal gland
Located slightly above the kidneys on either side. Plays a role in the reproductive system and often surround by fat. Consists of:
- the medulla
- the cortex
Produces adrenaline which increases blood flow to muscles and blood sugar levels.
Describe the pancreas
A secondary endocrine gland that has endocrine and exocrine functions. Produces digestive enzymes and allows glucose to move into cells while ensuring there is not too much. Produces insulin (controls blood sugar levels - glucose intake up), glucagon (controls blood sugar levels - glucose intake down).
What are the secondary endocrine glands?
The testes, the ovaries, the placenta, the small intestine, liver, thymus and nephron in the kidney
Define HORMONES
Hormones are organic compounds that target specific organs by acting as chemical messengers. Each target cell has receptor sites specific to certain hormones. They do not make cells do anything new, they just affect the rate at which functions are performed.
Some are secreted fairly constantly, and others in cycles, and some respond to certain stimuli.
What does the response of the cell depend on when targeted by a hormone?
The concentration of the hormone
The number of receptors
The bond between the receptor and the hormone
How are hormones transported around the body?
- they are free in blood transport or bound to plasma
- if the base is lipid soluble, it readily diffuses through capillary walls
- if the base is water soluble it can pass through pores in capillary walls
What is negative feedback?
A system of keeping things within a normal range. It is necessary to keep hormones regulated, as they are not always secreted at the same rate.
