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Alayna Dixon Period 3 Anatomy and Physiology Endocrine - Coggle Diagram
Alayna Dixon
Period 3 Anatomy and Physiology
Endocrine
Major functions of the Endocrine system
The endocrine system works with the nervous system to maintain homeostasis
The endocrine system is made up of cells, tissues, and organs called endocrine
glands, that secrete hormones into body fluids
Hormones diffuse into the bloodstream to act on specific target cells some
distance away
Major Endocrine glands/organs and their functions (separate by region/body cavity)
Pancreas
Abdominalpelvic
Adrenal Gland
Adrenal cortex
Adrenal medulla
Pineal
Brain
Posterior Pituitary
Brain
Anterior pituitary
Brain
Hypothalamus
Brain
Thymus
thoracic cavity
Thyroid
Throat
Parathyroid
Throat
Gonads
pelvic
Major hormones produced and target organs
Posterior Pituitary
Neurons in the hypothalamus produce antidiuretic hormone
(ADH) and oxytocin (OT), which are stored in the posterior pituitary
Plays a role in childbirth by contracting muscles in the uterine
wall, and in milk-letdown by forcing milk into ducts from the milk glands
Causes the kidneys to conserve water, and reduces amount of
water excreted in the urine
Anterior pituitary
Growth Hormone (GH):
• Stimulates body cells to grow and reproduce
• Speeds the rate at which cells use carbohydrates and fats
• Growth hormone-releasing hormone (GHRH) from the hypothalamus
increases the amount of GH secreted, GH inhibiting hormone (GHIH,
somatostatin) inhibits its secretion
• Nutritional status also affects the release of GH; more is released
when glucose is low, or when certain amino acids increase
GH imbalances:
• Pituitary dwarfism: Due to GH deficiency during childhood
• Gigantism: Due to GH oversecretion during childhood
• Acromegaly: Due to GH oversecretion in adulthood
Anterior Pituitary Hormones 2
Prolactin (PRL):
• Promotes milk production following the birth of an infant
• Controlled by prolactin releasing factor (PRF) and prolactin inhibiting
hormone (PIH) from the hypothalamus
• There is no known normal physiological role in males
Thyroid-stimulating hormone (Thyrotropin or TSH):
• Controls the secretion of hormones from the thyroid gland
• Thyrotropin-releasing hormone (TRH) from the hypothalamus
stimulates the release of TSH
• As blood concentration of thyroid hormones increases, secretions of
TRH and TSH decrease
Adrenocorticotropic hormone (ACTH):
• Controls the secretion of certain hormones from the adrenal cortex
• Regulated by corticotropin-releasing hormone (CRH) from the
hypothalamus
• Stress can also increase release of CRH, which increases ACTH
secretion
Gonadotropins (FSH and LH):
• Follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
affect the male (testes) and female (ovaries) gonads
• In males, LH is also known as interstitial-cell stimulating hormone
(ICSH).
Pineal
Melatonin
Homeostatic mechanisms of hormone regulation (negative and positive feedback)
Negative feedback loops
Negative feedback control mechanisms:
• Release of hormones from the hypothalamus controls
secretions of the anterior pituitary, and anterior pituitary
hormones affect the activity of other endocrine glands
• The nervous system influences certain endocrine glands directly
• Other glands respond directly to changes in the internal fluid
composition
Commonly, negative feedback mechanisms control hormone release
In a negative feedback system, a gland is sensitive to the concentration
of the substance it regulates
As hormone level rises, the hormone exerts its effects, further secretion
is inhibited by negative feedback, and then hormone secretion
decreases
When the concentration of the hormone then drops below its normal
level, the inhibition is removed, and the gland begins secreting more
hormone again
By this mechanism, hormone levels remain fairly constant, fluctuating
within a normal average range
Compare and contrast steroid vs non-steroid hormones and list the hormones for each category
Steroid hormones:
Steroid hormones are able to penetrate the cell membranes giving it access to give a direct message to the receptors on the cells nucleus; derive from cholesterol
Non-steroid
Non-steroid hormones are not able to penetrate the cells membrane meaning it must attach itself to receptors on the membrane so the message is able to be passed to the nucleus ; derive from amino acids
Steroid hormones are lipid-soluble, so they can pass through cell
membranes
Carried in the bloodstream weakly bound to plasma proteins
Protein receptors for steroid hormones are located inside the
target cell
The hormone-receptor complex binds with the DNA and activates
specific genes that, in turn, direct the synthesis of specific proteins
The new protein may function as an enzyme, transport protein, or
hormone receptor; it carries out the effects of the steroid
hormone
Nonsteroid hormones combine with receptors in target cell membranes; the
receptors have a binding site and an activity site
The hormone is called the first messenger
The chemicals in the cell that respond to binding of the hormone, and cause
changes in the cell, are called second messengers
The cascade of biological activity through the cell membrane to the inside,
beginning with the binding of the hormone, is called signal transduction
Other proteins are activated and they carry out the effects of the hormone
Diseases associated with the endocrine system
Diabetes insipidus is a condition resulting from insufficient ADH
Hyperthyroidism:
• Overactivity of the thyroid gland
• Causes high metabolic rate, restlessness, overeating in adults
• May lead to eye protrusion (exophthalmia)
Hypothyroidism
• Underactivity of the thyroid gland
• Causes low metabolic rate, fatigue and weight gain in adults
• In infants, causes cretinism: poor growth and bone formation,
abnormal mental development, sluggishness
