endocrine and lymphatic/ immune systems. endocrine system – works with the nervous system to...
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Endocrine and Lymphatic/ Immune Systems
Endocrine System – works with the Nervous System to coordinate and integrate
the activity of body cells
Endocrinology• 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• Invtrsdrd nsdsl mrysnoliv tsyr snf nofy hrsy ptofuvyion
– 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
• 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 (growth-hormone-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 (Growth-hormone-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)
– 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