The Endocrine System Flashcards
(26 cards)
Two types of cell to cell communication
Gap junctions found in cardiac and smooth muscle cells. Use of chemical messengers- paracrines, neurotransmitters, neurohormones and hormones
The endocrine system provides the means to
Interpret the electrical system from the brain as biochemical signals, maintain homeostasis
Paracrines hormones
Specific substances secreted by one cell or cell type which act upon neighbouring cells
Neurotransmitters
Short range chemical messengers, released by neurones in response to an action potential which act on adjacent cells, another neuone, a muscle cell or a gland
Neurohormones
Hormones secreted by the body into the blood by the secretory neurones. Inhibit or stimulate the pituitary gland produced by the hypothalamus
Hormones
Lipid soluble and water soluble. Secret into the body by the endocrine glands in response to a specific signal.
Water soluble hormones
Combine with specific receptors at the cell surface. secondary messengers
Lipid soluble hormone
Pass through the plasma membrane and bind with receptors within the cystol or nucleus
Functions of hormones
Regulate composition and volume or interstitial fluid, metabolism and energy balance, contraction of smooth and cardiac muscle, glandular secretion and the immune system
Major endocrine glands
Pituitary gland, thyroid gland, adrenal gland, testies, pineal gland, thymus, pancreas as ovary
Control of hormone secretion
Regulates by signals from the nervous system, fluctuations in the chemical composition of the blood, other hormones. This is through the feedback system (usually negative)
Adrenal cortex produced
Glucocorticoid, mineralocorticoids and adrenogenital corticoids
Adrenal medulla (part of the adrenal gland)
Secretes adrenaline and noradrenaline also increases HR, cardiac contraction and BP
Pineal gland
Consists if secretory pinealocytes that produce melatonin
Hypothalamus
Connected to the pituitary via the pituitary stalk.
Pituitary gland
Works with the hypothalamus form the primary interface between the electrical activity or the brain and biochemical activity of other organs
2 distinct parts of the pituitary gland
Anterior lobe and the posterior love
Disorders of the pituitary gland
Hyperpituitarism (over secretion) hypopituitarism (deficiency)
Antidiuretic hormone
Fascillitates the re absorption of water
Thyroid gland
Secretes calcitonin, T3 and T4. Increase the metabolic rate of all body tissues and the plasma level is controlled by a feedback loop
Primary hypothyroidism
To do with the pituitary
Secondary hypothyroidism
Due to lack of TSH. Can lead to myxodema
Myxodema
Accumulation or interstitial fluid causes facial tissues to swell. Slows HR, low body temp
Parathyroid glands
Contained within the posterior surface of the lateral loves of the thyroid glands contains two types of epithelial cells. Chief cells and oxy phill cells
