Transcript Endocrine System

Endocrine System
What is it?
• Consists of a group of ductless (without tubes) glands
that secrete substances directly into the bloodstream
• These substances are called HORMONES
• Hormones are chemical substances produced and
secreted by endocrine glands, frequently called
“chemical messengers”
• Hormones are transported throughout the body by
the bloodstream and perform many functions--stimulate exocrine glands to produce secretions,
stimulate other endocrine glands, G&D, regulate
metabolism, maintain fluid and chemical balance,
control sex processes
Endocrine system consists of:
• 1. Pituitary
gland
– Called the master gland of the body because it
produces many hormones that affect other glands
– Located at the base of the brain in a small, bony
depression of the sphenoid bone called the sella
turcica
– Divided into two sections- anterior lobe and
posterior lobe; Each lobe secretes certain
hormones (Look at handout)
Diseases affecting the pituitary gland
• 1. Acromegaly
– Oversecretion of somatotropin (GH) in an adult
– Cause: usually caused by a benign tumor of
pituitary gland called an adenoma
– Sx: Bones of the hands, feet, and face enlarge; skin
and tongue thicken R/I slurred speech
– Tx: surgical removal and/or radiation of the tumor
– *Tumor frequently returns ; Eventually causes
cardiovascular and respiratory dz which shortens
life
• 2. Giantism
– Oversecretion of somatotropin (GH) before
puberty
– Excessive growth of long bones, extreme tallness,
decreased sexual development, retarded mental
development at times
– Tx: if tumor of pituitary is the cause- removal or
radiation
• 3. Diabetes insipidus
– Decreased secretion of vasopressin or ADH
hormone (antidiuretic hormone)
– Low level of ADH R/I water not being reabsorbed
in the kidneys
– Sx: polyuria, polydipsia, dehydration, weakness,
constipation, dry skin
– Tx: ADH (replace missing hormone)
• 4. Dwarfism
– Undersecretion of somatotropin (GH), can be
caused by a tumor, infection, genetic factors, or
injury
– Small body size, short extremeties, lack of sexual
development, mental development is usually
normal
– If diagnosed early, can be treated with injections
of somatotropin (GH) hormone for 5 years or
more until long bone growth is complete
Endocrine system consists of :
• 2. Thyroid
gland
– Synthesizes hormones that regulate the body’s
metabolism and control the level of calcium in the
blood
– Located in front of upper part of trachea in the
neck
– Has two lobes, one on either side of the larynx
– To produce its hormones, Iodine is required,
which is obtained from certain foods and iodized
salt
Diseases affecting the thyroid gland
• 1. Goiter
– Enlargement of the thyroid gland
– Cause may be a hyperactive thyroid, iodine
deficiency, oversecretion of TSH on the part of the
pituitary gland, or a tumor
– Sx: thyroid enlargement, dysphagia, cough,
choking sensation
– Tx: eliminate the cause, Ex: surgery if needed to
remove the goiter, give iodine
• 2.Hyperthyroidism
– Overactivity of the thyroid gland, which causes an
increased production of thyroid hormones
– Sx: extreme nervousness, tremors, irritability,
rapid pulse, diarrhea, diaphoresis, polydipsia,
*excessive appetite with extreme weight loss*
– Tx: radiation to destroy part of the thyroid,
thyroidectomy
– If thyroid is removed, thyroid hormones are given
for the individual’s lifetime
• 3.Grave’s disease
– A severe form of hyperthyroidism- more common
in women than men
– Sx: strained and tenses facial expression,
Exophthalmia, goiter, nervous, irritable, emotional
instability, tachycardia, diarrhea, huge appetite
with weight loss
– Tx: medications, radioactive iodine to destroy
thyroid tissue, and/or thyroidectomy
• 4. Hypothyroidism
– Underactivity of thyroid gland and deficiency of
thyroid hormones
– 2 main forms:
• Cretinism- develops in infancy or early childhood
– Results in a lack of mental and physical growth leading to mental
retardation and abnormal dwarf stature
– If diagnosed early- oral thyroid hormone can be given to minimize
mental and physical damage
Myxedema
occurs later in childhood or adulthood
Sx: coarse, dry skin, slow mental function, fatigue, weakness,
intolerance for cold weight gain, slow pulse
Tx: oral thyroid hormone
Endocrine system consists of:
• 3. Parathyroid glands
– Four small glands located behind and attached to the thyroid gland
– It’s hormone, parathormone, regulates the amount of calcium in the blood
• A. stimulates bone cells to break down bone tissue and release
calcium and phosphates into the blood
• B. Causes the kidneys to conserve and reabsorb calcium
• C. Activates intestinal cells to absorb calcium from digested
foods
• D. Most of the body’ s calcium is in bone
• E. Calcium circulating in the blood is very important for blod
clotting, the tone of hart muscle, and muscle contraction
• F. Constant exchange of calcium and phosphate between bone
and blood
• G. Parathyroid hormone plays and important function in
maintaining proper level of circulating calcium
Diseases affecting the parathyroid
gland
• 1.Hyperparathyroidism
– Overactivity of the parathyroid gland R/I and overproduction of
parathormone
– R/I hypercalcium (increased calcium in the blood), which leads
to renal calculi, lethargy, GI disturbances, and calcium deposits
– Because calcium is drawn from bones, bones become weak,
deformed, and easy to fracture
– Cause: often by an adenoma (glandular tumor)
– Removal of the tumor usually R/I normal parathyroid function
– Other tx: surgical removal of the parathyroids; will then need
parathormone, diuretics to increase the excretion of H2O and
calcium, low calcium diet
• 2. Hypoparathyroidism
– Underactivity of the parathyroid gland R/I low level of
calcium in the blood
– Causes- if you had surgical removal or injury of
parathyroid and/or thyroid glands
– Sx: tetany (sustained muscular contraction),
irritability of nervous system, convulsive twitching,
death if larynx and respiratory muscles are involved
– Tx: calcium, Vit. D (helps to increase calcium
absorption), parathormone
Endocrine system consists of:
• 4. Adrenal glands
– Located above each kidney (suprarenal)
– Each gland has 2 parts
• *Outer portion (cortex)- secretes many steroid
hormones
• Steroid hormones are classified into 3 groupsmineralocorticoids, glucocorticoids, and
gonadocorticoids
• *Inner portion (medulla)- secretes two main hormones
epinephrine and norepinephrine (these hormones
mimic fight or flight response)
Diseases affecting adrenal glands
• 1. Addison’s disease
– Cause- decreased secretion of aldosterone from the
adrenal cortex (outer) which interferes with the absorption
of sodium & H20 causes an increased level of potassium in
the blood.
– Sx: dehydration, diarrhea, fatigue, hypotension, mental
lethargy, weight loss, muscle weakness, excessive
pigmentation which leads to a “bronzing” of the skin,
hypoglycemia, edema
– Tx: give corticosteroid hormones, control sodium intake,
fluid regulation for dehydration
• 2. Cushing’s syndrome
– Oversecretion of glucocortoids on the part of the
adrenal cortex
– Cause: tumor of the adrenal cortex, excess production
of ACTH on the part of the pituitary gland
– Sx: hyperglycemia, hypertension, muscle weakness,
fatigue, hirsutism, poor wound healing, bruises easily,
“moon face”, obesity
– Tx: remove tumor, give hormones to replace missing
ones
– ** Cushing’s syndrome can occur in patients who
receive long term steroid therapy**
Endocrine system consists of
• 5. Pancreas
– Located behind the stomach
– Pancreas is a exocrine and endocrine gland
– Exocrine– secretes pancreatic juices, which are carried
to the small intestine by pancreatic duct to aid in
digestion of food
-Beta cells located throughout the pancreas in patches
of tissue called Islets of Langerhans that produce the
hormone insulin---- Insulin regulates????
- Alpha cells produce hormone glucagon (increases
glucose level in blood)
Disease affecting pancreas
• 1. Diabetes mellitus
– Chronic disease caused by decreased secretion of
insulin
– 2 types of diabetes mellitus
• 1. Insulin dependent diabetes mellitus (IDDM) or Type 1
– Usually occurs early in life
– Requires insulin
2. Non-insulin dependent diabetes mellitus (NIDDM) or Type 2
-mature onset form of diabetes
-usually controlled with diet and/or oral meds
• Sx of DM- hyperglycemia, polyuria, polydipsia,
glycosuria, polyphagia fatigue, slow healing of
skin infections, vision changes
• If not treated- diabetic coma and death may
occur
• Tx: regulate diet to control blood sugar,
regular exercise, oral meds, insulin injections,
insulin pumps
• Diabetes can cause atherosclerosis, MI, CVA,
peripheral vascular disease that leads to poor
wound healing and gangrene in the legs and
feet, diabetic retinopathy causes blindness,
kidney disease/failure
• *** Prevention is key** control weight and
exercise
Endocrine system consists of
• 6. Ovaries
– Sex glands of the female
– Located in the pelvic cavity, one on each side of
the uterus
– Hormones– secrete to regulate menstruation
• Estrogen- for G&D of sex organs in females
• Progesterone- maintains lining of uterus
Endocrine system consists of
• 7. Testes
– Gonads of the male
– Located in the scrotal sac and are outside of the
body
– Hormone
• Testosterone- G&D of sex organs in males, stimulates
maturation of sperm
Endocrine system consists of
• 8. Thymus
– Mass of tissue located in upper part of chest and
under sternum
– Functioned early in life with immune system but
atrophies during puberty
– Becomes a small mass of connective tissue and fat
– Hormone
• Thymosin– production of antibodies early in life
Endocrine system consists of
• 9. Pineal body
– Small structure located in the brain (attached to
roof of 3rd ventricle)
– Hormones
• Melatonin- may help regulate sleep/wake cycles, may
delay puberty by inhibiting sex hormones
• Adrenoglomerulotropin- may stimulate adrenal cortex
to secrete aldosterone
• Serotonin- may prevent vasoconstriction of blood
vessels in the brain
Endocrine system consists of
• 10. Placenta
– Temporary endocrine gland produced during
pregnancy
– Link between mother and baby
– Provides nutrition for the developing baby
– Promotes lactation (production of breast milk)
– After birth of baby, it is expelled– called afterbirth
– Hormones– see handout