Honors Anatomy Endocrine System

Free response question: What are the different types of stimuli?

Hormonal- stimulated by other hormones

Humoral- stimulated by changing blood levels of different ions

Neural- Stimulated by nerve impulses

What is the endocrine system?

A system that uses chemical messengers (hormones) that are released in the body.

What processes do hormones use?

1. Reproduction
2. Regulation of metabolism
3. Growth and Development
4. Maintenance of homeostasis
5. Mobilization of body defenses

Effects caused by hormones

1. Changes in plasma membrane permeability
2. Activation or inactivation of enzymes
3. Synthesis of proteins, such as enzymes
4. Stimulation of mitosis
5. Promotion of secretory activity

Direct gene activation (steroid hormone action)

A. Diffuse through plasma membrane of target cells

B. Enter the nucleus

C. Bind to a specific protein within the nucleus

D. Bind to specific sites on the cell’s DNA

E. Activate genes that result in synthesis by making mRNA

Control of hormone release

Hormone levels in the blood are maintained by negative feedback.

Pineal gland

Releases melatonin “the sleep trigger”

Hypothalamus

Releases “releasing and inhibiting hormones” that regulate anterior pituitary gland and produces oxytocin and antidiuretic hormones

Anterior pituitary lobe

releases growth hormone, FSH (stimulates egg and sperm production), LH (triggers ovulation and testosterone production)

Posterior pituitary

Stores hormones made by the hypothalamus (oxytocic, simulates uterine contractions; antidiuretic, water retention by decreasing urine production)

What is antidiuretic (ADH) called?

Vasopressin

What does the thymus gland produce

Thymosin, and is essential for the development of T cells (Three T’s)

Thyroid gland

Produces thyroxine (T4) and (T3) hormones which control *body metabolism* (iodine is an essential nutrient for these)

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Produces calcitonin- decreases calcium volume

Parathyroid gland

Produces PTH, or parathyroid hormone

* This hormone raises calcium, if not enough is present, muscle spasms will occur

Adrenal Cortex

Mineralocorticoids mainly **aldosterone**- absorbs sodium and secretes salt

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Glucocorticoids-helps by body resist stress by increasing blood glucose promote normal cell metabolism

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Sex Hormones

Adrenal Medulla

Releases epinephrine (adrenaline and norepinephrine)

Pancreas

Insulin-released when blood glucose is high, produced by the beta cells of the pancreas, lowers overall blood sugar

Acromegaly

Hyposecretion of growth hormone in adults after bones stop growing, eyebrow ridge, jaws, hands and feel increase in size

Diabetes insipidus

Hyposecretion of ADH (antidiuretic hormone), causes excessive urine output, causes one to be very thirsty

Goiter

Enlarging of the thyroid gland due to iodine deficiency, thyroid keeps getting stimulated but it cannot make T3 or T4

Addison’s disease

Hyposecretion of all adrenal cortex hormones, causes bronzing of the skin alone with a weak immune system+ (electrolyte balance, an inability to cope with stress, hypoglycemia

Cretinism

Hyposecretion of thyroxine in childhood, thyroid dwarfism, may also result in mental retardation in untreated

Diabetes mellitus

Body cannot use glucose because no insulin is produces, the starved cells start to breakdown fats and proteins (results in weight loss, ketosis, and depressed immune system

3 signs of diabetes

Polyuria- urinating alot

Polydipsia- increased thirst

Polyphagia- increased hunger

Cushing’s

excessive output of glucocorticoids, moon face, hump in back, increased blood pressure, depression of immune system

Ovaries

released hormones in a cyclic way by gonadotropic hormones of the anterior pituitary.

What do ovaries release

estrogen and progesterone

Testes

testoserone

Placenta

takes control of the female hormones, it is large enough estrogen, progesterone, and HCG (pregnancy hormone)

Glucocorticoids

cell metabolism, helps the body resist long term stresses

Mineralocorticoids

Mainly aldosterone which regulates mineral and salt content, absorbs salt and secretes potassium

Sex hormones

androgen and estrogen

Thyroxine

controls body metabolism (thyroid)

Calcitonin

decreases blood calcium levels (thyroid)

PTH (parathyroid gland)

raises calcium levels, not enough pth causes muscle spasms