Homeostasis - Homeostasis Process whereby internal...

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Homeostasis Process whereby internal conditions are maintained within acceptable ranges Despite changes in the external environment What conditions do we have to maintain? What organs/tissues/systems are involved? Body temperature Glands Skin Blood (circulatory system) Brain Sodium levels Thyroid Kidney Balance of water Linked to blood pressure Blood glucose Liver Pancreas pH levels Hormones and the Endocrine system Hormone- A molecules that is secreted into the extra cellular fluid, circulates in the bloodstream or hemolymph , and communicates regulatory messages throughout the body. Eg. Hormones regulate the timing of metamorphosis in the caterpillar and ensure the parts of the body develops in unison Only target cells have the receptors to respond to the hormones Endocrine system - System in charge of chemical signalling of body by hormones - One of the two main basic systems for communication and regulation throughout the body *LABELLED PICTURE* Hypothalamus in the brain tells the pituitary what to do, which then tells the body what to do
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In charge of: Reproduction Development Energy metabolism Growth Behavior Nervous system Neurons – Network of specialized cells that transmit signals along dedicated pathways Often overlaps function of endocrine system Endocrine glands – Ductless organs where some of the endocrine cells are grouped. They excrete hormones directly into the hemolymph. Crine means separate, reflecting the moving away of the hormones from the secreting cell Local regulators Paracrine signalling (para means to one side of) – target cells lie near the secreting cell. Secreted molecules diffuse locally and trigger a response in neighbouring cell Paracrine signalling Autocrine signaling Autocrine signalling (auto means self) – secreted molecule acts on the secreting cell itself Neurotransmitters and neurohormones – Neurons communicate with target cells such as other neuron and muscle cells at specialized junctions known as synapses. Molecules called neurontransmitters
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Homeostasis - Homeostasis Process whereby internal...

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