Human Endocrine System. The endocrine system consists of ductless glands that produce hormones...
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Transcript of Human Endocrine System. The endocrine system consists of ductless glands that produce hormones...
Human Endocrine System
Human Endocrine System
The endocrine system consists of ductless glands that produce hormones Hypothalamus, pituitary, pineal, thyroid,
parathyroid, thymus, adrenal, pancreas, ovary, testes
Hormones are chemical messengers that travel through the blood stream and affect activities throughout the body. Steroid hormones Nonsteroid hormones
Hormones Hormones are chemical messengers that
bind to target cells and affect cell activities Nonsteroid hormones are made from amino
acids and generally cannot pass through the cell membrane. These hormones bind to a receptor site on the outside of a cell in order to initiate chemical reactions inside the cell.
Steroid hormones are produced from the lipid, cholesterol and are able to pass through cell membranes and bind to receptor proteins.
Steroid hormones – can go through cell membrane to reach receptors inside the cell
Nonsteroid hormones – cannot go through cell membrane, must activate proteins in the cell membrane
Hormones have specific shapes that fit receptors or the surface of the target organ or structure they are going to influence
Bind with cell receptors
If incorrect receptor the particular hormone has no effect
Pons
Pituitary gland
Hypothalamus
Cerebrum
Medulla oblongata Spinal cord
Cerebellum
Pineal gland
Thalamus
Section 35-3
The BrainPituitary gland biology AnimationEndocrine Glands biology Animation
HypothalamusThe hypothalamus makes hormones that control the pituitary gland. In addition, it makes hormones that are stored in the pituitary gland.
Pituitary glandThe pituitary gland produces hormones that regulate many of the other endocrine glands.Parathyroid glandsThese four glands release parathyroid hormone, which regulate the level of calcium in the blood.ThymusDuring childhood, the thymus releases thymosin, which stimulates Tcell development.Adrenal glandsThe adrenal glands release epinephrine and nonepinephrine, which help the body deal with stress.
Pineal glandThe pineal gland releases melatonin, which is involved in rhythmic activities, such as daily sleep-wake cycles.
ThyroidThe thyroid produces thyroxine, which regulates metabolism.
PancreasThe pancreas produces insulin and glucagon, which regulate the level of glucose in the blood.OvaryThe ovaries produce estrogen and progesterone. Estrogen is required for the development of secondary sex characteristics and for the development of eggs. Progesterone prepares the uterus for a fertilized egg.
Testis The testes produce testosterone, which is responsible for sperm production and the development of male secondary sex characteristics
Section 39-1 The Endocrine Glands
Glands I
Hypothalamus – coordinates activities of the nervous and endocrine systems and produces hormones to regulate the pituitary gland
Pituitary – produces hormones that direct the activities of other endocrine glands
Pineal – releases melatonin which is involved in rhythmic or cyclic activities
Thyroid – produces hormones that regulate metabolism and development
Parathyroid – helps maintain appropriate calcium levels
Glands II Thymus – involved with immune development during childhood Adrenal – regulates the body’s stress response (epinephrine,
norepinephrine, cortisol, aldosterone) Pancreas – controls glucose levels in the blood (insulin,
glucagon)
Ovary – secretes estrogen and progesterone to regulate reproduction
Testes – produces testosterone to control formation of sperm and sexual behavior
Negative Feedback
The level of one hormone in the blood inhibits or stimulates the production of another hormone or substance
Homeostasis biology Animation
CONTROL OF THE ENDOCRINE SYSTEMCONTROL OF THE ENDOCRINE SYSTEM
REGULATED BY FEEDBACK MECHANISMSFEEDBACK MECHANISMS EX: HEATING SYSTEMS
ROOM COOLS DOWN
ROOM WARMS
UP
FURNACE KICKS
OFF
FURNACE KICKS
ON
Negative Feedback
The release of hormones is controlled through a negative feedback system
Negative feedback systems are control mechanisms that operate by inhibiting a process or activity that originally led to starting the process or activity For example, as glucose levels in the body
increase, sensors in the pancreas signal the release of the hormone insulin
Insulin promotes the entry of glucose into cells, lowering glucose levels
As the glucose levels in the blood decrease, the pancreas stops secreting insulin.
Beta cells release insulin into the blood
Body cells absorb glucose
Blood glucose level decreases
Homeostasis: Normal blood glucose level
Blood glucose level decreases
Alpha cells release glucagon into blood
Liver converts glycogen to glucose
Blood glucose level increases
Blood glucose level increases
Liver converts glycogen to glucose
Actions of Insulin and GlucagonSection 39-2
Disorders Goiter
Enlargement of the thyroid gland due to the inability to manufacture thyroxin (hypothyroidism)
Grave’s Disease Hyperthyroidism- over secretion of thyroxin
Diabetes Insulin deficiency which results in elevated
blood sugar level
Symptoms of Diabetes Excessive thirst Frequent urination Extreme hunger Unexplained weight loss Glucose in urine Fatigue Vision problems Numbness tingling in extremities High infection rate
regulates
Concept MapSection 39-2
by meansof the
by meansof the
by meansof the
by meansof the
by meansof the
by meansof the
GrowthWater
balanceReproduction Metabolism
Calciumand glucose
levels
Responseto stress
The Endocrine System
Pituitary
Ovaries
Testes Thyroid Pancreas Adrenals
Parathyroids