Download Endocrine System

Endocrine and Lymphatic/
Immune Systems
Endocrine System – works with
the Nervous System to coordinate and integrate
the activity of body cells
Endocrinology
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Endo = inside or within
Crine = Secrete
Ology = study of
Hormon – to excite
Definition = Study of hormones and how they
work in the body
• Hormone – a mediator molecule that gets
released in one part of the body but regulates
the activity of cells in other parts of the body
Functions
• Work with Nervous System to coordinate
body functions
• Maintain homeostasis within the body
Hormone Facts
• Two types of glands in the body
– Exocrine
• Secretes products to outside of body
– Endocrine
• Ductless glands and make hormones
• Secrete products inside the body
• Organs
– Hypothalamus, thymus, pancreas, ovaries,
testes, kidneys, stomach, liver, small intestine,
skin, heart, adipose tissue, placenta
Hormone Travels
• Circulating Hormones – True Hormones
– Affect specific target cells
– Stay in the blood stream
• Local Hormones - Pseudohormones
– Act on neighboring cells
– Do not enter the blood stream
• Paracrine – act locally, but affect cell types other than those
releasing them
– Somatostatin – secreted by the pancreas – stops the release of
insulin
• Autocrine – chemicals that exert their effects on the same cells
that secrete them
– Prostaglandins - released by smooth muscle cells to make the
smooth muscles contract
Hormone Interactions
• Permissiveness - When one hormone cannot exert its full
effects without another hormone being present
• Reproductive hormones develop the reproductive system (estrogen,
testosterone, LH, FSH), but those do not start working unless the
Thyroid hormone is released
• Synergism - More than one hormone produces the same
effects at the target cell and their combined effects are
amplified
• Glucagon and epinephrine cause the liver to release glucose in the
blood – when they act simultaneously, they release about 150% more
than what they would by themselves
• Antagonism - When one hormone opposes the action of
another hormone
• Ex Insulin lowers blood glucose levels; it is antagonized by glucagon
which raises blood glucose levels
Chemical Classes of Hormones
• Lipid-soluble hormones
– Dissolve in fats
• Water-soluble hormones
– Dissolve in water
Lipid-Soluble Hormones
• Steroids
– Derived from cholesterol
– Cortisol, Estrogen, Testosterone, Aldosterone,
Androgens, Calcitriol, Progesterone
• Thyroid Hormones
– T3 and T4
• Nitric Oxide
– Hormone and neurotransmitter
Water-Soluble Hormones
• Amines – made by modifying amino acids
– Epinephrine and norepinephrine, melatonin, histamine,
serotonin
• Peptide Hormones – chains of amino acids
– Antidiuretic hormone, oxytocin, HGH, Thyroid-stimulating
hormone, adrenocorticotropic hormone, FSH, LH,
Prolactin, melanocyte-stimulating hormone, insulin,
glucagon, somatostatin, parathyroid hormone, calcitonin,
gastrin, secretin, cholecystokinin, erythropoietin, leptin
• Protein Hormones – more complex chains of amino
acids – subtype of peptide hormones
• Eicosanoid – derived from a 20-carbon fatty acid
– Prostaglandins
– Leukotriens
How Hormones work
• Lipid-Soluble – diffuse through the lipid
bilayer of the plasma membrane and bind
to receptors within target cells
• Water-Soluble – cannot diffuse through
the membrane
– Bind to Integral Proteins on the membrane
surface
Control of Hormone Secretion
• Hormones are secreted in short bursts
• Regulated by
– Signals from NS
• Hypothalamus signals the Pituitary Gland to make
and realease hormones
• Hypothalamus secretes 9 hormones
• Pituitary Gland secretes 71q
– Chemical changes in the blood
– Other hormones
Hypothalamus and Pituitary Gland
• Hypothalamus is the “Master” of the Pituitary
Gland
– Major link between the NS and ES
– Secretes 9 hormones
• Pituitary Gland
– Secretes 7 hormones
– Two Lobes: Anterior and Posterior
– Rests in the Sella Turcica
• Hypothalamus and Pituitary Gland are
connected by the INFUNDIBULUM
Anterior Pituitary Gland
• Releases tropic hormones which
influences other endocrine glands
• Regulated by Releasing and Inhibiting
Hormones
Anterior Pituitary Hormones
• Human Growth Hormone (HGH)
– Most plentiful Ant. Pituitary Hormone
• Gigantism – too much HGH – typically reach 8ft
• Pituitary Dwarfism – too little HGH – 4ft. or under, body is
properly proportioned
• Thyroid-Stimulating Hormone
– Stimulates Thyroid gland to make and secrete
Thyroid Hormone which has 2 forms: T3 and T4 m
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– Released in response from TRH hormone of the
Hypothalamus
Thyroid Problems
• Hypothyroidism
– Underactive thyroid gland
• Adults - Myxedema – low metabolism, cold, constipation,
thick/ dry skin, puffy eyes, edema, lethargy and mental
sluggishness
– If myxedema is from a lack of Iodine, the thyroid gland can
enlarge and protrude and become an endemic goiter
– Why salt is now IODIZED; Goiter Belt
• Infants – Cretinism – mental retardation, disproportionate
body size, thick tongue and neck – might be a genetic
defect of fetal thyroid or a lack of iodine in mother’s diet
– Can be prevented by hormone replacement therapy if diagnosed
early enough
» Most states test newborns to check for hypothyroidism at
birth
Thyroid Problems
• Hyperthyroidism – overactive thyroid
– Grave’s Disease – believed to be
autoimmune because people who have this
disease have abnormal antibodies that mimic
TSH and will stimulate the release of TH
• Increased metabolism, sweating, irregular/ rapid
heart beat, nervousness, weight loss
• Signs – enlarged thyroid (goiter), exophthalmos
• Treatment – Thyroidectomy or treatment with
Radioactive Iodine which will destroy most of the
active thyroid cells
Parathyroid Hormone
• Controls calcium balance within the blood
• Hyperparathyroidism
– rare, usually happens because of a tumor –
Ca gets leached from the bones – bones will
soften and deform as their mineral salts are
replaced by fibrous CT – high blood Ca can
suppress the nervous system and cause
kidney stoes
Parathyroid Hormone
• Hypoparathyroidism
– Usually after some type of parathyroid trauma
or removal during thyroid surgery, extended
lack of dietary Mg
• Hypocalcemia – tetany (loss of sensation, muscle
twitches, convulsions)
• Untreated – symptoms progress to respiratory
paralysis and death
• Was how the Parathyroid gland was discovered
Anterior Pituitary Hormones
• Follicle-Stimulating Hormone
– Hypothalamus – Anterior Pituitary – Testes,
Ovaries
– Stimulates production of sperm and maturing of
follicles (eggs)
• Luteinizing Hormone
– Controlled by the hypothalamus
– Stimulates secretion of estrogen and
progesterone and ovulation in females; in males it
stimulates the release of testosterone
Anterior Pituitary Hormones
• Adrenocorticotropic Hormone (ACTH)
– Influences glucose metabolism
• Prolactin
– Hypothalamus secretes Releasing and
Inhibiting Hormones to control Prolactin
– Makes the body recognize a pregnancy
– Stimulate milk production in women
Posterior Pituitary Gland
• Does not make hormones
– Stores and releases them
Posterior Pituitary Hormones
• Oxytocin
– Enhances muscle contraction during childbirth
– After childbirth – stimulates milk production
and delivery of the placenta
– Pitocin to induce labor – synthetic verson
• Antidiuretic Hormone or Vasopressin
– Diabetes Insipidus – excessive urine and
intense thirst – results in fluid retention,
headache, disorientation
Cushing’s Syndrome
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Excessive Cortisol in the blood stream
Persistent hyperglycemia
Loss in muscle and bone protein
Water and salt retention
Swollen “moon” face
Redistribution of fat – buffalo hump
Ease in bruising
Hypoglycemia – low blood glucose
• Stimulates the hypothalamus to release GHRH (growthhormone-relasing-hormone) and GHRH goes to the Anterior
Pituitary
• Anterior Pituitary is then stimulated to release HGH into the
blood stream
• HGH – stimulates the release of insulin-like growth factors
that speed up the breakdown of liver glycogen into glucose
• As a result, blood glucose rises to the normal level
(90mg/100mL of blood plasma)
• An increase in blood glucose above the normal level inhibits
(stops) the release of GHRH
NEGATIVE FEEDBACK
Hyperglycemia – abnormally high
blood glucose
• Stimulates the hypothalamus to secrete GHIH (Growthhormone-inhibiting-hormone) while inhibiting the release of
GHRH
• GHIH travels to the Anterior Pituitary and prevents it from
releasing Growth Hormone
• Low levels of GH in the blood stream and IGFs slows down
the breakdown of glycogen in the liver and glucose is
released into the bloodstream more SLOWLY
• Blood glucose falls to its normal level
• A decrease in the blood glucose below the normal level
inhibits the release of GHIH
NEGATIVE FEEDBACK
Congenital Adrenal Hyperplasia
• Genetic disorder in which a person lacks the
enzymes needed to make Cortisol
• If there is low or no cortisol, another hormone
(ACTH) stimulates enlargement of the adrenal
glands
• Causes Virilism
– Females – masculinization – growth of a beard,
deep voice, body hair similar to male, growth of
clitoris to resemble a penis, loss of breasts
– Males – same as females – over-masculinization
Addison’s Disease
• Cause – ACTH is blocked from it’s receptors
• Symptoms – lethargy, anorexia, nausea,
vomiting, weight loss, hypoglycemia,
weakness, bronzed appearance to skin
• Treatment – hormone replacement and
increasing sodium in diet
• JFK had this
Diabetes
• Diabetes Mellitus (mell = honey sweetened)
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Inability to produce insulin
4th leading cause of death in the US
Causes glucosuria (excessive glucose in the urine)
Key defining symptoms
• Polyuria – excessive urine production due to an inability of the
kidneys to resabsorb water
• Polydipsia – excessive thirst
• Polyphagia – excessive eating
– Genetic and Environmental components
– 2 types – Type I and Type II
Type I Diabetes – Insulin-dependent
Diabetes Mellitus
• Insulin level is low because the person’s
immune system destroys the pancreatic beta
cells that make the insulin
• People with this must have daily doses of
insulin to prevent death
• Develops in people younger than age 20
• If not treated properly can lead to blindness
and kidney disease
Type II Diabetes – Non-insulin-dependent
Diabetes Mellitus
• Most common, 90% of all cases of diabetes
• Typically found in obese people over age 35
• Can be controlled through diet, exercise and
weight loss
– Can be temporary
• No shortage of insulin, rather the target cells
become less sensitive to it
Gestational Diabetes
• Occurs in pregnant women who may or may
not have had diabetes before the pregnancy
• Pregnancy hormones block mom’s insulin
receptors from being able to absorb insulin
• Glucose can’t get absorbed properly so it is
transferred to the baby
– Baby grows more than it should – can lead to
marcosomia (fat baby)
– Concerns for during and after birth
• Goes away immediately after giving birth