The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses...
-
Upload
margaret-leonard -
Category
Documents
-
view
214 -
download
0
Transcript of The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses...
![Page 1: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/1.jpg)
The Endocrine System
![Page 2: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/2.jpg)
A. Overview• Second messenger system of the body (first is
nervous)• Uses chemical messages (hormones) that are
released into blood• Hormones control several major processes–Reproduction–Growth and development–Mobilization of body defenses against stress–Maintenance of much of homeostasis–Regulation of metabolism
![Page 3: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/3.jpg)
B. Hormones• Produced by specialized
cells in glands• Cells secrete hormones
into extracellular fluids• Blood transfers hormones to target sites or
effectors• Hormones regulate activity of other cells in
effector
![Page 4: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/4.jpg)
• Three chemical classifications of hormones–Amino acid-based hormones•Proteins•Peptides•Amines
–Steroids – made from cholesterol–Prostaglandins – made from highly
active lipids
![Page 5: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/5.jpg)
C. Hormones in Action• Affect only target tissues/organs via receptors– (that’s why heart muscle won’t produce
sperm – no receptors for that action)• Once hormone binds to receptor, alters
cellular activity – Increases or decreases normal metabolic
process
![Page 6: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/6.jpg)
• Binding of receptor causes up to four changes–Changes in plasma membrane permeability
or electrical state (chemicals in/out)– Synthesis of proteins, such as enzymes
(digestion)–Activation or inactivation of enzymes– Stimulation of mitosis (growth)
![Page 7: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/7.jpg)
• If steroid hormone:–Hormones diffuse through the plasma
membrane of target cells (steroids are lipid-based)– Enters the nucleus–Bind to a specific protein within the nucleus–Hormone-protein complex binds to specific
sites on the cell’s DNA–Activate genes that result in transcription &
translation to synthesize new proteins
![Page 8: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/8.jpg)
Steroid Hormone Action
Figure 9.1a
![Page 9: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/9.jpg)
• If non-steroid hormone (amino-acid or prostaglandins) …– Hormone binds to a membrane receptor (can’t
pass through membrane itself)– Hormone does not enter the cell– Sets off a series of reactions that activates an
enzyme– Catalyzes a reaction that produces a second
messenger molecule (either cAMP, Ca2+, or protein)– Messenger molecule oversees additional
intracellular changes to promote a specific response
![Page 10: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/10.jpg)
Non-steroid Hormone Action
Figure 9.1b
![Page 11: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/11.jpg)
D. Control of Hormone Release• Hormone levels in blood are maintained by negative
feedback• External or internal stimulus or low hormone levels
in blood triggers release of more hormone– Stimuli types: • Hormonal – hormones trigger endocrine glands• Humoral (blood chemistry) – levels of ions &
nutrients• Neural – nerve fibers trigger release (“flight or
fight”)• Hormone release stops once appropriate level in
blood is reached
![Page 12: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/12.jpg)
• Endocrine glands are activated by other hormones
Figure 9.2a
Hormonal Stimuli
![Page 13: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/13.jpg)
Humoral Stimuli• Changing blood levels
of certain ions stimulate hormone release
Figure 9.2b
![Page 14: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/14.jpg)
Neural Stimuli• Nerve impulses
stimulate hormone release
• Most are under control of the sympathetic nervous system – “flight or fight”
Figure 9.2c
![Page 15: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/15.jpg)
E. Major Endocrine Organs
Figure 9.3
![Page 16: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/16.jpg)
1.1. Pituitary GlandPituitary Gland• Size of a grape• Hangs by a stalk from the
hypothalamus• Protected by the sphenoid bone area called
“Turk’s saddle”• Has two functional lobes– Anterior pituitary – glandular tissue– Posterior pituitary – nervous tissue
![Page 17: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/17.jpg)
• Six anterior pituitary hormones– Two affect non-endocrine targets• Growth hormone (GH) – overall growth (synthesizing
protein), breaks down fats• Prolactin – stimulates breast milk production (lactation)
– Four stimulate other endocrine glands (tropic hormones)• Thyroid stimulating hormone (TSH)- thyroid gland• Adrenocorticotropic hormone (ACTH) - cortex of adrenal
gland• Follicle stimulating hormone (FSH) – follicles in ovaries
and sperm in testes• (women) Luteinizing hormone (LH) – ovulation of egg• (men) Interstitial cell-stimulating hormone (ICSH) –
testosterone production in testes
![Page 18: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/18.jpg)
• Characteristics of all anterior pituitary hormones– Proteins (or peptides)– Act through second-messenger systems– Regulated by hormonal stimuli, mostly negative
feedback
![Page 19: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/19.jpg)
• Posterior pituitary is not strictly an endocrine gland so it doesn’t MAKE hormones
• Posterior pituitary releases two hormones made by hypothalamus:– Oxytocin• Stimulates contractions of uterus during labor• Causes milk ejection triggered by suckling
– Antidiuretic hormone (ADH)• inhibits urine production• In large amounts, causes vasoconstriction leading
to increased blood pressure (as a result sometimes called vasopressin)
![Page 20: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/20.jpg)
Hormones of the Posterior Pituitary
Figure 9.5
![Page 21: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/21.jpg)
• produces the two hormones that are transported to neurosecretory cells of the posterior pituitary (ADH & oxytocin)
2.2. HypothalamusHypothalamus
![Page 22: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/22.jpg)
3.3. Thyroid GlandThyroid Gland• Found at base of throat• Consists of two lobes and a
connecting isthmus• Produces two hormones:
– Thyroid hormone (TH) - two active iodine-containing hormones • Thyroxine (T4) – secreted by
thyroid follicles• Triiodothyronine (T3) –
conversion of T4 at target tissues
– Calcitonin - Decreases blood calcium levels by causing it to be deposited on bone
![Page 23: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/23.jpg)
4.4. Parathyroid GlandsParathyroid Glands• Tiny masses on posterior
of thyroid• Secrete parathyroid
hormone (PTH)– Stimulate osteoclasts to
remove calcium from bone when levels in blood are too low
– Stimulate kidneys & intestine to absorb more calcium– Raise calcium levels in the blood (opposite calcitonin)
![Page 24: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/24.jpg)
Calcitonin vs PTH
Figure 9.9
![Page 25: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/25.jpg)
5.5. Adrenal GlandsAdrenal Glands• Two glands that sit on top of
kidneys• Divided into two areas:–Cortex – outer glandular
region in three layers–Medulla – inner neural tissue
region• Cortex produces three major groups of steroid
hormones collectively called corticosteroids
![Page 26: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/26.jpg)
• CORTICOSTEROIDS:– Mineralocorticoids (mainly aldosterone)• Produced in outer adrenal cortex• Regulate mineral content in blood, water, and electrolyte
balance (target organ is kidney)• Production stimulated by renin and aldosterone• Production inhibited by atrial natriuretic peptide
– Glucocorticoids (including cortisone and cortisol)• Produced in middle layer of adrenal cortex• Promote normal cell metabolism• Help resist long-term stressors (work, family, health stress)• Released in response to increased blood levels of ACTH
– Sex hormones• Produced in inner layer of adrenal cortex• Androgens (male) and some estrogen (female)
![Page 27: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/27.jpg)
Hormones of the Adrenal Cortex
Figure 9.10
![Page 28: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/28.jpg)
• Two hormones produced by medulla called catecholamines which are triggered by sympathetic nervous system– Epinephrine (adrenaline)– Norepinephrine (noradrenaline)
• prepare the body to deal with short-term stress as in fight-or-flight scenarios
![Page 29: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/29.jpg)
Figure 9.12
Adrenal Glands in Stress Response
![Page 30: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/30.jpg)
6.6. Pancreas (Pancreatic Islets)Pancreas (Pancreatic Islets)• pancreas is a mixed gland• islets of pancreas produce hormones– Insulin – allows glucose to cross plasma
membranes into cells from beta cells• Blood glucose delivered to cells for energy
– Glucagon – allows glucose to enter blood from alpha cells• Converts stored glucose (glycogen) back into glucose
– these hormones are antagonists that maintain blood sugar homeostasis
![Page 31: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/31.jpg)
Pancreatic Islets
Figure 9.13
![Page 32: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/32.jpg)
Blood Sugar Hormones
Figure 9.14
![Page 33: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/33.jpg)
Glucose ($)
Glycogen (€)
blood
liver
glycogenesis
Fats/protein (£)
gluconeogenesis
![Page 34: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/34.jpg)
7.7. Pineal GlandPineal Gland• Found on third
ventricle of brain• Secretes melatonin– Helps establish body’s
wake/sleep cycles– May have other as-
yet-unsubstantiated functions
![Page 35: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/35.jpg)
8.8. ThymusThymus• Located posterior to
sternum• Largest in infants and
children• Produces thymosin– Matures some types of
white blood cells– Important in developing the
immune system
![Page 36: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/36.jpg)
9.9. OvariesOvaries• Produce estrogens– Produced by Graafian follicles
in ovaries or placenta– Stimulates development of
secondary female characteristics (
– Matures female reproductive organs
– Helps prepare uterus to receive a fertilized egg
– Helps maintain pregnancy– Prepares breasts to produce
milk
![Page 37: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/37.jpg)
• Also produce progesterone– Produced by corpus luteum– Acts with estrogen to bring about menstrual cycle– Helps in implantation of an embryo in uterus
![Page 38: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/38.jpg)
10.10.TestesTestes• Interstitial cells of testes are
hormone-producing• Produce several androgens• Testosterone is the most
important androgen– Responsible for adult male
secondary sex characteristics– Promotes growth and
maturation of male reproductive system
– Required for sperm cell production
![Page 39: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/39.jpg)
11.11.PlacentaPlacenta• Produces hormones that
maintain pregnancy• Some hormones play a
part in baby delivery • Produces human chorionic
gonadotropin (hCG) in addition to estrogen, progesterone, and other hormones
• Home pregnancy tests check for presence of hCG
![Page 40: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/40.jpg)
12.12.OthersOthers• Duodenum (first part) of small intestine– Gastrin – delivered to stomach to inhibit HCl– Secretin – stimulates pancreas to release high pH
juice; stimulates release of bile from liver– Cholecystokinin (CCK) – stimulates pancreas to
release enzymes; gallbladder to release stored bile
• Stomach– Gastrin – stimulates stomach glands to release HCl
• Adipose tissue– Leptin – stimulates brain to suppress appetite &
increase energy usage
![Page 41: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/41.jpg)
Hormone Producing Agent
Function
Growth h. (GH) Ant. Pituitary Overall growth; synthesize proteins; breakdown fats
Prolactin Ant. Pituitary Stimulates lactation
Thyroid stimulating h. (TSH) Ant. Pituitary
Adrenocorticotropic h. (ACTH) Ant. Pituitary
Follicle stimulating h. (FSH) Ant. Pituitary
Luteinizing h. (LH) Ant. Pituitary
Interstitial cell-stimulating h. (ICSH) Ant. Pituitary
Oxytocin (released by post. pituitary) Hypothalamus
Antidiuretic h. (ADH) (released by post. pituitary) Hypothalamus
![Page 42: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/42.jpg)
F. Diseases/Disorders • Long-term imbalance of particular
hormones leads to diseases or disorders of endocrine system–Acromegaly (gigantism)–Goiter–Addison’s disease–Diabetes mellitus (Type I & Type II)–Sterility (male & female)
![Page 43: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/43.jpg)
Acromegaly• Hypersecretion (excess) of
pituitary growth hormone (GH) even after long bones have grown results in acromegaly or gigantism.– Facial bones, hands and feet
enlarge tremendously– Height can reach between 8 – 9
feet!– Results from tumor on pituitary
gland that secretes GH too.
Sandy Allen7’7 ¼”
![Page 44: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/44.jpg)
Goiter• Enlargement of thyroid gland as a result of
deficiency of iodine– Iodine is needed to make thyroxine– When TSH stimulates thyroxine production, it’s
produced, but it’s disfunctional– TSH continues to stimulate thryoid, so in turn, it
grows to meet demands (although demands are never met)
• Iodine only found naturally in seafood, so USA added iodine to salt– Other land-locked areas continue to produce
goiters
![Page 45: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/45.jpg)
![Page 46: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/46.jpg)
Addison’s Disease• Hyposecretion (deficiency) of all
adrenal hormones results in Addison’s disease, and a bronzing of skin is the effect (melanocyte-stimulating hormone overactive).– Low aldosterone leads to water &
electrolyte loss– Low glucocorticoids leads to
hypoglycemia (too little glucose in blood), and suppression of immune system• No glucocorticoids would mean
death
![Page 47: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/47.jpg)
Diabetes Mellitus• Hyperglycemia or excess glucose (sugar) in
blood– Literally from Latin “something sweet is being
siphoned from body”
• Normal blood glucose 80 – 120 mg/100 mL blood– Diabetes is higher than 126 mg (121-125 is
borderline)– Pancreas does not produce insulin (Type I) or cells’
receptors don’t recognize it (Type II)
![Page 48: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/48.jpg)
• No glucose means no fast energy– Body must then break down proteins or fats for
energy, blood becomes acidic• Acidosis or ketosis results which can lead to coma or
death
• Three main signs of diabetes:– Polyuria = excessive urination to rid body of
glucose/ketones– Polydipsia = excess thirst from lack of water– Polyphagia = hunger since cells don’t receive
glucose energy
![Page 49: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/49.jpg)
![Page 50: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/50.jpg)
![Page 51: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/51.jpg)
“Juvenile Diabetes”No insulin produced
“Adult-Onset Diabetes”Insulin produced, receptors weaker
![Page 52: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/52.jpg)
• Long-term effects of uncontrolled diabetes (I or II):– Cardiovascular disease• Excess glucose in blood causes heart to beat faster
(hypertension/high blood pressure), circulate slower leading to tissue damage (possible gangrene), eventually heart attack
– Chronic renal (kidney) failure• Kidneys have to filter so much glucose, eventually shut
down from overwork
– Blindness (retinal damage)• Blood vessels in retina get damaged & retina can’t
process image
![Page 53: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/53.jpg)
Sterility• Hormonal imbalances (too much or too little)
leads to sterility in both males and females– Males• Less FSH – little/no sperm production• Less LH – less testosterone• Less testosterone – little/no sperm production
– Females• Excess prolactin – no ovulation• Less FSH and/or LH – no ovulation• Less estrogen – less FSH/LH – no ovulation• Less progesterone - miscarriage
![Page 54: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/54.jpg)
G. Development• In utero– Up to 11 weeks pregnant, both males &
female fetuses have same genital makeup– At 12 weeks, Y chromosome triggers
testosterone to form male genitals; absence of Y chromosome triggers estrogen to form female genitals
– If hormone levels are off, can result in intersex (formerly hermaphrodite) individual• Chromosomes show male or female
but genitalia something in between
Embryo at 11 weeks
![Page 55: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/55.jpg)
• 46 XY Intersex– Male chromosomes, external
genitals incomplete or female-like
• 46 XX Intersex– Female chromosomes, ovaries,
male-like external genitalia
• Gonadal Intersex– Both ovarian and testicular tissue– May be either XY or XX
• Complex/Undetermined Intersex– XO, XXX, XXY, XYY
![Page 56: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/56.jpg)
• Puberty– Increase in hormone production by ovaries or
testes to initiate secondary sex characteristics and be able to reproduce
– Girls: begins at 10-11 and complete by 15-17– Boys: begins at 12-13 and complete by 16-18
![Page 57: The Endocrine System. A.Overview Second messenger system of the body (first is nervous) Uses chemical messages (hormones) that are released into blood.](https://reader037.fdocuments.us/reader037/viewer/2022110100/56649dd05503460f94ac597b/html5/thumbnails/57.jpg)
• Adulthood– Most endocrine organs operate smoothly until old
age
• Late Adulthood– Menopause in women is brought about by lack of
efficiency of the ovaries• Problems associated with reduced estrogen are
common (hot flashes, insomnia, moodiness)– Growth hormone production declines with age– Many endocrine glands decrease output with age
including testes