January 22 Lecture - January 22, 2009 The Endocrine System...

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January 22, 2009 The Endocrine System Pineal Gland - Also known as the epiphysis - Very close proximity to the central nervous system, but is not innervated directly to it, instead innervated to the autonomic nervous system by peripheral neurons - Unsure number of hormones produced by pineal gland - Melatonin is produced by the pineal gland o Inhibits gonads (endocrine and production of germ cells) o Suppressive effect on reproductive functions o Inhibitory effect on ACTH levels of the body (decreases the levels) o Involved in synchronizing a number of “rhythms” in the body Peaks of body temperature display the body’s circadian rhythms 24 hour rhythm o If pineal gland is removed, circadian rhythms will no longer be observed Gland synchronizes daily body temperature with corresponding environmental cues Ex. photoperiod (the amount of light we are exposed to relative to the nocturnal period) Humans are not good subjects of this because we manipulate the environmental factors to suit ourselves, and tend to stay up during the night, etc. - Melatonin are produced at much greater rates or concentrations during darkness o While sleeping, pineal gland is secreting small amounts of melatonin - Melatonin is frequently used to cure insomnia or other sleep disorders - Melatonin alters body temperature, when melatonin levels are higher the body temperature is higher The Gonads and Placenta will be discussed at a later date
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The Cardiovascular System The Blood - Blood is a type of connective tissue - Connective tissues usually contain o Cells o Fibres o Ground substance - Blood is a specialized connective tissue o Cells o Ground Substance (plasma) o No fibres are present in blood - Blood makes up a significant portion of the biomass o About 8% of your total body weight is blood - Specific gravity of blood is 1.05-1.06 (approximately the same as water) - Viscosity of blood is much higher than that of water (about 5 times) - pH of blood varies from 7.3-7.5 - Blood carries out a number of function o Involved in transportation of oxygen (by the cells) and carbon dioxide (the plasma) throughout the body o Involved in the transport of nutrient materials Carries nutrient materials to the cells and brings the metabolic wastes to
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January 22 Lecture - January 22, 2009 The Endocrine System...

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