Title: Endocrine Glands
1Endocrine Glands
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3Endocrine Glands
- Islets of Langerhans
- Gonads
- Ovaries
- Testes
- Pineal gland
- Thymus
- others
- Hypothalamus
- Pituitary
- Anterior lobe
- Posterior lobe
- Thyroid gland
- Parathyroid glands
- Adrenal Glands
- Cortex
- Medulla
Hormonal Communication
4Hypothalamus
- Part of brain
- Regulates ANS, emotions, feeding/satiety, thirst,
body temperature, etc. - Hormones related to these functions
- Releasing hormones
- Axonal transport to posterior lobe
5Anterior Pituitary
- Releasing hormones regulate AP aka
- adeno hypo physis glands under
growth - All proteins
- TSH (thryoid stimulating hormone/thyrotropin)
- ACTH (adrenocorticotropic hormone)
- FSH (gonadotropin)
- LH (gonadotropin)
- Tropins/tropic hormones
- GH (growth hormone)
- Prolactin-releasing H
Hypothalamic Pituitary Axis Animation IP Web
6Anterior Pituitary
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8Anterior P. Homeostatic Imbalances
- Growth hormone (GH or hGH)
- Promotes mitosis, cell division
- Elongation of long bones, etc.
- Healing of wounds Lack of hGH retards growth
- Hypersecretion in youth produces giantism
- Hyposecretion in childhood produces pituitary
dwarfism - Hypersecretion in adult produces acromegaly
9Posterior Pituitary
- Axonal transport to Posterior Pituitary aka
- neuro hypo physis
- nerve under growth
- Hypothalamic cell bodies synthesize
- oxytocin
- ADH
10PituitaryPosterior lobe
- Oxytocin
- Stimulates smooth muscle contraction of uterus
mammary glands. - Antidiuretic H.
- Stimulates water reabsorption in collecting
ducts. - Stimulates vasoconstriction (vasopressin)
- Lack ? diabetes insipidus
11Posterior Pituitary Homeostatic Imbalances
- ADH
- Hyposecretion produces diabetes insipidus
tasteless - Excessive thirst and urination
- central or neurogenic DI
- gestagenic or gestational DI
- nephrogenic DI
- dipsogenic DI
Diabetes Insipidus Foundation, Inc.
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13Thyroid Gland
- Location in neck
- Inferior to larynx
- Anterior lateral to trachea
- Composed of follicles
- Follicle cells produce thyroglobulin
- Thyroxin (T4)
- Triiodothyronine (T3)
- Both thyroid hormone, bodys major metabolic
hormone - Parafollicular/ C cells
- Calcitonin
- Decreases blood Ca2 by depositing it in bones
14Homeostatic imbalances
- Hypothyroidism results
- Myxedema (in adults)
- Goiterlow levels of iodine
- Cretinism (in children)
- Hyperthyroidism results
- Graves disease
15Parathyroid Glands
- Four small glands embedded in posterior of
thyroid - Parathyroid hormone (PTH)
- Stimulates osteoclasts to free Ca2 from bone
- Stimulates Ca2 uptake from intestine kindey
Hormonal Regulation of Calcium
16Parathyroid Homeostatic Imbalances
- Severe hyperparathyroidism causes massive bone
destruction - If blood Ca2 fall too low, neurons become
overactive, resulting in tetany
17- Feedback Loop
- Negative feedback in calcium homeostasis. A rise
in blood Ca2 causes release of calcitonin from
the thyroid gland, promoting Ca2 deposition in
bone and reducing reabsorption in kidneys. - A drop in blood Ca2 causes the parathyroid gland
to produce parathyroid hormone (PTH), stimulating
the release of Ca2 from bone. - PTH also promotes reabsorption of Ca2 in kidneys
and uptake of Ca2 in intestines.
18Adrenal Glands
- One on top of each kidney
- Cortex
- Corticosteroid
- glandular
- Medulla
- Catecholamines
- neurohormonal
- Epinephrine
- Norepinephrine
19Adrenal Cortex
- Cortex
- Activity stimulated by ACTH
- Controls prolonged responses by secreting
corticosteroids. - Mineralcorticoids
- Aldosterone? regulate salt and water balance
- Glucocorticoids
- Cortisol? regulate glucose metabolism and the
immune system. - Gonadocorticoids
- Androgens
- Estrogens
20Adrenal Cortex Imbalances
- Hypersecretion leads to Cushings disease
- ACTH-releasing tumors or side effects of
corticoid drugs. - Hyposecretion leads to Addisons Disease
- Deficits in glucocorticoids and mineralcorticoids
21Adrenal Medulla
- Medulla
- The adrenal medulla mediates shortterm responses
by secreting catecholamine hormones. - Cells are modified neurons (lack axons)
- Epinephrine (adrenaline)
- Norepinephrine (noreadrenaline)
- enable a rapid ( fight-or-flight ) responses to
stress by increasing blood glucose and blood
pressure and directing blood to the heart, brain,
and skeletal muscles.
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23Pancreas
- Consists of two major types of secretory tissues
which reflects its dual function - Exocrine gland
- secretes digestive juice
- localized in the acinar cells
- Endocrine gland
- releases hormones
- localized in the islet cells (islets of
Langerhans)
24Pancreatic Islets
- About a million embedded in pancreas
- Control centers for blood glucose
- Insulin from beta cells
- Glucagon from alpha cells
25Insulin Glucagon
26Islets of Langerhans
- Insulin stimulates glucose uptake, glycogenesis
- Glucagon stimulates glycogenolysis, glucose
release from liver (vs gluconeogenesis)
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28- Feedback Loop
- A rise in blood glucose causes release of insulin
from beta cells the pancreas, promoting glucose
uptake in cells and storage as glycogen in the
liver. - A fall in blood glucose stimulates alpha cells in
the pancreas to secrete glucagon, which causes
the liver to break down glycogen and release
glucose.
29Pancreas Homeostatic ImbalancesDiabetes siphon
mellitus mel honey
- Symptoms
- Polyuria
- Polydipsia
- Polyphagia
Blood Level Regulation in Diabetics
30Gonads
- Ovaries
- Estrogens
- Progesterone
- Testes
- Testosterone
- Reproductive functions when we study reproductive
system.
31Pineal gland
- Melatonin
- ? Inhibits early puberty
- ? Day/night cycles
- Timing of sleep, body temperature, appetite
- Secretes melatonin during darkness
- Participates in setting the bodys clock
- Melatonin is a potent antioxidant
- Melatonin is high when young and is reduced as we
age
32Thymus
- Thymus gland
- Thymopoietins, thymic factor, thymosins
- Influence development of T lymphocytes
33Non-Endocrine Gland Hormones
- Stomach (gastrin)
- Small intestine (duodenum?intesetinal gastrin,
secretin, cholecystokinin) - Heart (atrial natriuretic peptide)
- Kidneys (erythropoietin, active vitamin D3)
- Adipose tissue (leptid, resistin)
- Skin
- Placenta (human chorionic gonadotropin, human
placental lactogen, relaxin)
34Functions regulated by the Endocrine System
- Growth
- Healing
- Water balance Blood Pressure
- Calcium Metabolism
- Energy Metabolism
- Stress
- Regulation of other Endocrine Organs
35Growth
- Growth hormone-releasing hormone
- Human growth hormone (hGH)
- Thyrotropin (TSH)
- Thyroxine triiodothyronine
- Calcitonin
- Somatostatin (GHIH)
36Healing
- Growth hormone-releasing hormone
- Human growth hormone (hGH)
- Thyrotropin (TSH)
- Thyroxine triiodothyronine
- Calcitonin
- Glucagon, Insulin
- Erythropoietin
37Water balance Blood pressure
- ADH
- Aldosterone
- Angiotensin II
- Atrial natriuretic H.
- Epinephrine
38Calcium Metabolism
- Calcitonin
- Parathyroid H. (PTH)
- Estrogens/androgens
- Growth hormone
39Energy Metabolism
- Thyroxine triiodothyronine
- Thyroid-stimulating H. (thyrotropin, TSH)
- Epinephrine norepinephrine
- Insulin
- Glucagon
- Adrenocorticotropic H. (ACTH)
- Cortisol
40Stress
- Epinephrine norepinephrine
- T4 T3 ??
- ACTH
- Cortisol