Endocrine system secretes chemical messengers, called hormones act on receptors to cause change at target organs

endocrine glands. ductless, synthesises and secretes hormones

Endocrine system is long lasting and slow. whilst the nervous system short term and fast

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Hormones

peptide.

Amino- acid derived

lipid derived

Steroids

Eicosanoids

Derived from cholesterol

androgens, oestrogens and progesterone, corticosteroids, calcitriol

arachidonic acid, a phospholipid found in cell membranes

prostaglandins, clotting factors, leukotrienes

Short-chain polypeptides (ADH and OXT)

Small water-soluble hormones
that can cross cell membranes

Structurally related to amino
acids (tyrosine & tryptophan)

thyroid hormone, serotonin and
melatonin

chains of amino acids, glycoproteins and short polypeptides and small proteins

cannot pass through cell membranes due to size and water solubility

most abundant type. TSH, LH, FSH and insulin

Glands

Intracellular communication

Direct communication

Autocrine communication

Chemicals involved are autocrine

prostaglandins secreted by smooth muscle cells cause the same cells to contract

Exchange of ions and molecules between adjacent cells across gap junctions

occurs across two cells of the same type

Highly specialised and rare

Endocrine communication

Paracrine communication

Chemical information transfers information from cell to cell within a single tissue.

Hormones are produced by the cell to then act locally on that cell

Endocrine release chemicals (hormones) that are transported in the blood stream

Alters metabolic activities of many organs

Synaptic communication

Across synapses and uses neurotransmitters

Effects limited to specific areas

Target cell must have appropriate receptors

Target cells must have receptors to bind and read hormonal messages

Change types, quantities or activities of enzymes and structural proteins in target cells

Can alter metabolic activities of multiple tissues and organs at the same time

Hormones

Can alter metabolic activities of multiple tissues and organs at the same time

endocrine_system (1)

Hypothalamus, pituitary gland, pineal gland, thyroid and parathyroid glands, adrenal gland, pancreas and reproductive glands.

Screenshot brain

Anti- diuretic hormone, Corticotropin-releasing hormone, Thyrotropin-releasing hormone (TRH), Gonadotropin-releasing hormone (GnRH), Growth hormone–releasing hormone. Prolactin-releasing hormone (PRH) ( Dopamine) Oxytocin

Hypothalamus

Reproduction and stress responses, Regulates metabolism and energy balance. coordinates function between cells, produces hormones, controls release. Maintains homeostasis. Regulates water and electrolyte levels. Biological clock and aids immune system

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Function

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