Endocrine system ch 16

11. Describe the structures of thyroid, adrenal gland and pancreas.

-thyroid glands In neck below larynx (Adam's apple) - Two Cell types: > FOLLICULAR CELLS- secrete TRIIODOTHYRONINE(T3) and THYROXINE(T4) > PARAFOLLICULAR CELLS- secrete CALCITONIN adrenal glands= either of a pair of complex endocrine glands situated near the kidney Pancreas=a large elongated exocrine gland located behind the stomach

name all 9 endocrine organs including the last one kidneys

1Pineal gland 2Hypothalamus 3Pituitary gland 4Thyroid gland 5Parathyroid glands (on dorsal aspect of thyroid gland) 6Thymus 7Adrenal glands 8Pancreas Ovary (female) 9Gonads< Testis (male) 110Kidneys

ACTH

ACTH ( adrenonocotropic hormone - this is controlled by CRH. This hormone affects the release of cortisol from adrenal gland.

ADH

ADH- antidiuretic hormone is produced by hypothalamus, it prevents dehydration by conserving fluids. This is regulated by osmoreceptors in hypothalamus. If the concentration of the blood is too thick, ADH is released to increase the fluid content of the blood. Alcohol suppresses ADH release. So, that is the reason why you have to visit the bathroom often after drinking beer. So does that mean you get dehydrated? The hangover after alcohol is due to the dehydration.

Negative feedback mechanism of the control of hormone release?

Most of the hormones are regulated by negative feedback mechanism E.S. is fine tuned by nervous system so it is not mechanical like a thermostat. Sometimes, at the time of stress, the glucose levels may go higher than 90-110 mg/100 ml of blood because the body requires more glucose. Or we may feel cold if we move from Florida to Colorado at the same temperatures so the arteries may constrict and provoke shivering to generate heat

Neural control

Neural control - nerve fibers stimulate hormone release Preganglionic sympathetic nervous system (SNS) fibers stimulate the adrenal medulla to secrete epinephrine. At times of stress, sympathetic nervous system helps release of epinephrine and norepinephrine from the adrenal glands. Epinephrine along with glucagon can magnify the release of glucose from the liver reserves.

Norepinephrine influences

Norepinephrine influences peripheral vasoconstriction and blood pressure

Adipose tissue Leptin is involved in appetite control, and stimulates increased energy expenditure

Other Hormone-Producing Structures

Kidneys Erythropoietin signals production of red blood cells Renin initiates the renin-angiotensin mechanism

Other Hormone-Producing Structures

Skin Cholecalciferol, the precursor of vitamin D

Other Hormone-Producing Structures

posterior pitutary step 3

Oxytocin and ADH are stored in axon terminals in the posterior pituitary.

posterior pitutary step 2

Oxytocin and ADH are transported along the hypothalamic-hypophyseal tract to the posterior pituitary.

posterior pitutary step 4

Oxytocin and ADH are released into the blood when hypothalamic neurons fire.

PRL

PRL (prolactin ) is stimulsted by drcrese of PIH released enhansed by estrogen, birth control pills brest feeding and by blocking drugs

what harmone does the parathyroid contain

PTH—( Parathyroid hormone)most important hormone in Ca2+ homeostasis

Adrenal (Suprarenal) Glands shape and located

Paired, pyramid-shaped organs atop the kidneys

Pancreatic islets contain

Pancreatic islets (islets of Langerhans) contain endocrine cells Alpha () cells produce glucagon (a hyperglycemic hormone) Beta () cells produce insulin (a hypoglycemic hormone)

Major endocrine organ

Pituitary gland.

Pineal Gland

Small gland hanging from the roof of the third ventricle Pinealocytes secrete melatonin, derived from serotonin Melatonin may affect Timing of sexual maturation and puberty Day/night cycles Physiological processes that show rhythmic variations (body temperature, sleep, appetite)

antagonism (Nervous System Modulation)

Some hormones act in antagonism, they have opposite reactions: glucagon helps release glucose from glycogen reserves, insulin helps uptake of glucose by cells thereby reducing the blood glucose level concentrations.

synergism (Nervous System Modulation)

Some hormones act in synergism i.e. more than one hormone amplifies the effect caused by each one. Glucagon helps to convert glycogen to glucose when glucose levels in blood are falling down (like in between meals), at the time of stress, epinephrine amplifies this reaction because body requires more glucose to burn.

what are the functions of the paratyhroid glands

Stimulates osteoclasts to digest bone matrix Enhances reabsorption of Ca2+ and secretion of phosphate by the kidneys Promotes activation of vitamin D (by the kidneys); increases absorption of Ca2+ by intestinal mucosa

Adrenal (Suprarenal) Glands Structurally and functionally

Structurally and functionally, they are two glands in one Adrenal medulla—nervous tissue; part of the sympathetic nervous system Adrenal cortex—three layers of glandular tissue that synthesize and secrete corticosteroids pg 612

neurohypophysis

The posterior part is strictly a nervous tissue and it stores ADH and oxytocin (hormones) which is produced by hypothalamus. It is called neurohypophysis

hormones are

They are chemical messengers as opposed to electrical impulses of nervous system.

Oxytocin

This hormone is released by positive feedback mechanism. As the uterine contractions intensify, the hormone is released increasingly which increase the contractions which in turn increase the release of oxytocin..... This goes on till the baby is born and there is no more stimulus left

what are the three layers & the corticosteroids produce inthe Adrenal Cortex

Three layers and the corticosteroids produced Zona glomerulosa—mineralocorticoids to regulate SALT) like aldesterone Zona fasciculata—glucocorticoids to regulate SUGARS) like Cortisol. Zona reticularis—sex hormones, or gonadocorticoids( to regulate SEXual characteristics). Pg 612

in the pinel gland Melatonin may affect

Timing of sexual maturation and puberty Day/night cycles Physiological processes that show rhythmic variations (body temperature, sleep, appetite)

Pancreas

Triangular gland behind the stomach (retroperitoneal) Has both exocrine and endocrine cells Acinar cells (exocrine) produce an enzyme-rich juice for digestion Pancreatic islets (islets of Langerhans) contain endocrine cells Alpha () cells produce glucagon (a hyperglycemic hormone) Beta () cells produce insulin (a hypoglycemic hormone)

anterior pitutary step 1

When appropriately stimulated, hypothalamic neurons secrete releasing and inhibiting hormones into the primary capillary plexus.

Goiter

abnormally enlarged thyroid gland lack of iodine

posterior pitutary

action potentials travals down the axon of the hypothalamus neurons causeing hormones relese fm thier exon terminals in the posterior pitutary.

Renin-angiotensin mechanism

decreased blood pressure stimulates kidneys to release renin, triggers formation of angiotensin II, a potent stimulator of aldosterone release.

What is the affect of alcohol on ADH release?

drinking alcoholic beverages inhibits secretion and causes urine output dry mounth intense trist & "hangover"

Ovaries: produce

estrogen & progesterone

What is acromegaly? How can it be cured or treated?

excessive GH is secreted after the epihyseal have closed after puberty, "enlarged extremityes. the ususal treatment is surgical removal of the tumour but does not reverse anatomical changes that have already occured

What is the difference between endocrine and exocrine gland?

exocrine gland (have ducts) are located all over body. There are lots in the palms, feet, forehead. They produce sweat for evaporative cooling. Excrete mostly water, some salts, wastes, some antimicrobial chemicals. Endocrine glands do not have ducts. They secrete their products, hormones, directly into the blood rather than through a duct. (pituitary gland, pancreas, ovaries, testes, thyroid gland, and adrenal gland)

the endocrine system influences metabolic activity by means of

hormones (hormone) = to excite

What are the three types of control over hormonal release?

humoral stimuli = w/ it detect a decline fm normal values they secret PTH ( Parathriod Harmoe) Neural Stimuli = stimulates the medulla to release norepinephrine & epinephrine Hormornal stimuli = stimulii harmones fm hypothalmus

addison disease

hypofunctioning of the adrenal cortex

anterior pitutary

hypothalamus hormones released intospecail body vessals the (hypophyseal portal system ) control the realse of the anterior pituary hormones.

Thyroxin helps in?

in metabolism

Thyroid gland is located

in the anterior part of the neck

In a case of hyperthyroidism what diease is casued

it results if Graves' disease which causes eyes to bulge ou due to the formation of extra tissue behind the eyeball

Epinephrine stimulates

metabolic activities, bronchial dilation, and blood flow to skeletal muscles and the heart its use clinically as a heart stimulant & dilate the bronchioles.

Hypothalamus has endocrine as well as neural functions so it is called

neuroendocrine gland

Diabetes insipidus

occurs when ADH is secreted in less quantities. The person with this problem has to urinate often and gets dehydrated. In diabetes mellitus there is insufficient insulin.

Permissiveness (Nervous System Modulation)

one hormone cannot exert its effects without another hormone being present. Even if growth hormone is produced , its effect will not seen unless Thyroxin is produced.

Which hormone is on positive feedback mechanism?

oxytocin Suckling sends a message to the hypothalamus via the nervous system to release oxytocin, which further stimulates the milk glands

Hormonal control

release of hormones in response to hormones produced by other endocrine organs The hypothalamic hormones stimulate the anterior pituitary In turn, pituitary hormones stimulate targets to secrete still more hormones

ACTH: causes small increases of aldosterone during?

stress

what is the meaning of endocrinology

the scientific study of hormones & the endocrine or gans is called endocrinology

Thyroid gland produces two hormones

thyroxin and calcitonin.

Acinar cells (exocrine) produce

Acinar cells (exocrine) produce an enzyme-rich juice for digestion

Calcitonin

Antagonist to parathyroid hormone (PTH) Inhibits osteoclast activity and release of Ca2+ from bone matrix Stimulates Ca2+ uptake and incorporation into bone matrix

anterior pitutary step 3

Anterior pituitary hormones are secreted into the secondary capillary plexus.

(ANP):

Atrial natriuretic peptide

The Posterior Pituitary hormones

Contains axons of hypothalamic neurons Stores antidiuretic hormone (ADH) and oxytocin ADH and oxytocin are released in response to nerve impulses

Cretinism

Cretinism= severe hypothyroidism resulting in physical and mental stunting

Humoral control

Humoral control- The release of hormone is controlled by presence or absence of some other chemical substance in the blood, lymph or any of the transcellular fluids. e.g. Concentration of Ca++ triggers release of thyroxin or PTH. Another example would be high glucose levels trigger insulin release from pancreas.

Grave's Disease

Hyperthyroidism, 2-3 times size, and 5-15 times hormone production, causes by IgG bound to TSH receptor. Symptoms: Exophthalmos, anxiety, irritability, Difficulty sleeping, fatigue, rapid or irregular heartbeat, tremor of hands or fingers, increase perspiration, sensitivity to heat, weight loss, brittle hair, goiter, change in menstrual cycle, frequent bowel movement.

posterior pitutary step 1

Hypothalamic neurons synthesize oxytocin and ADH.

anterior pitutary step 2

Hypothalamic hormones travel through the portal veins to the anterior pituitary where they stimulate or inhibit release of hormones from the anterior pituitary.

neuroendocrine gland

Hypothalamus has endocrine as well as neural functions so it is called

How do the osmoregulators help in production of ADH and oxytocin?

In ADH osmoregulators transmit excitory implusesto the hypothalamus for the hypothatamus to release ADH for examle water balance. The osmorereglators cause contraction and streches out the uterus and cervix as child birth strarts.

Thyroid Gland/Follicular/Parafollicular

In neck below larynx Two cell types: -______________ cells secrete triiodothyronine (T₃) and thyroxine (T₄) -______________ cells secrete calcitonin

thyroid glands

In neck below larynx (Adam's apple) - Two Cell types: > FOLLICULAR CELLS- secrete TRIIODOTHYRONINE(T3) and THYROXINE(T4) > PARAFOLLICULAR CELLS- secrete CALCITONIN

LH

LH (LUTEINIZING HORMONES)this is regulated by gonadotropin releasing hormone GNRH also produced by hypothalamus. These are also called gonadotropin hormones because they affect the gonads.

Effects of insulin

Lowers blood glucose levels Enhances membrane transport of glucose into fat and muscle cells Participates in neuronal development and learning and memory Inhibits glycogenolysis and gluconeogenesis

Glucagon

Major target is the liver, where it promotes Glycogenolysis—breakdown of glycogen to glucose Gluconeogenesis—synthesis of glucose from lactic acid and noncarbohydrates Release of glucose to the blood

12. What is cretinism? Goiter? Graves' disease? Addison's disease?

Cretinism= severe hypothyroidism resulting in physical and mental stunting Graves disease= , Hyperthyroidism, 2-3 times size, and 5-15 times hormone production, causes by IgG bound to TSH receptor. Symptoms: Exophthalmos, anxiety, irritability, Difficulty sleeping, fatigue, rapid or irregular heartbeat, tremor of hands or fingers, increase perspiration, sensitivity to heat, weight loss, brittle hair, goiter, change in menstrual cycle, frequent bowel movement. Goiter = abnormally enlarged thyroid gland lack of iodine addison disease=hypofunctioning of the adrenal cortex

9. What is the difference between diabetes mellitus and diabetes insipidus?

Diabetes Mellitus (Mel) = honey ,is mainly caused by deficiency of insulin due to either destruction of Istet of Langerhans present in the pancreas or any autoimmune cause. Here there is increased blood sugar level and sugar starts to appear to come with urine. It even becomes fatal when sugar level increases very much) Diabetes insipidus (diabetes) = overflow & (inspidus) = tteasteless is caused by defect in secretion of vasopressin (Antidiuretic Harmone) which is secreted from pituitary gland present in hypothalamus. Its function is to reabsorb water from distal tubules in the kidney and due to this it contol the concentration of urine. But its deficiency causes increased water excretion through urine even in low intake of water.

endocrine glands

Ductless glands secreting hormones into blood stream or lymph systems. Includes thyroid, parathyroid, adrenal, pituitary, pancreas, thymus, and pineal glands, plus gonads( acts as messenger throughout the body , controll alot of what is happening in the body.)

Adrenal Medulla

Epinephrine stimulates metabolic activities, bronchial dilation, and blood flow to skeletal muscles and the heart Norepinephrine influences peripheral vasoconstriction and blood pressure

FSH

FSH (FOLLICLE STIMULATING HORMONE) this is regulated by gonadotropin releasing hormone GNRH also produced by hypothalamus. These are also called gonadotropin hormones because they affect the gonads.

how many tiny gland does the Parathyroid Glands have

Four to eight tiny glands embedded in the posterior aspect of the thyroid they are oval like shape

GH

GH ( growth hormoe ): It is controlled by GHRH & GHIH produced by hypothalamus.I t affects various organs , especially the epiphyseal plate of growing bones. The hypersecretion causes acromegaly in adults when there is no more epiphyseal plate left . See the chart : it is only for showing how many organs are effected by the growth hormone. You don't have to memorize the chart.

What is the role of hypothalamus in the regulation of GH, PRL ,TSH, ACTH, FSH and LH.

GH = growth hormome, GH = growth hormone Promotes growth, controls metabolism,It is controlled by GHRH & GHIH PRL= prolactin, It is found only in lactating females . It is controlled by PRH (prolactin releasing hormone) and PIH( prolactin inhibiting hormone). PIH is the hormone produced normally and PRH is produced only in lactating females. TSH = Thyroid stimulating hormone, is controlled by TSHRH or TRH released by hypothalamus. This causes release of thyroxine by the thyroid gland regulates growth hormones & deveolpement. ACTH = Adrenocotropic hormone- this is controlled by CRH. This hormone affects the release of cortisol from adrenal gland FSH & LH= follicle stimulating hormone & Luteinzing hormone this is regulated by gonadotropin releasing hormone GNRH . These are also called gonadotropin hormones because they affect the gonads.

Gastrointestinal tract enteroendocrine cells produce

Gastrin stimulates release of HCl Secretin stimulates liver and pancreas Cholecystokinin stimulates pancreas, gallbladder, and hepatopancreatic sphincter

Gluconeogenesis

Gluconeogenesis—synthesis of glucose from lactic acid and noncarbohydrates

Glycogenolysis

Glycogenolysis—breakdown of glycogen to glucose

Graves disease

Graves disease= , Hyperthyroidism, 2-3 times size, and 5-15 times hormone production, causes by IgG bound to TSH receptor. Symptoms: Exophthalmos, anxiety, irritability, Difficulty sleeping, fatigue, rapid or irregular heartbeat, tremor of hands or fingers, increase perspiration, sensitivity to heat, weight loss, brittle hair, goiter, change in menstrual cycle, frequent bowel movement

Anterior Pituitary Hormones

Growth hormone (GH) Thyroid-stimulating hormone (TSH) or thyrotropin Adrenocorticotropic hormone (ACTH) Follicle-stimulating hormone (FSH) Luteinizing hormone (LH) Prolactin (PRL)

pancreas has what two cells?

Has both exocrine and endocrine cells

Heart produces

Heart produces Atrial natriuretic peptide (ANP) reduces blood pressure, blood volume, and blood Na+ concentration

What is the relationship of hypothalamus and pituitary gland?

Structurally, they are connected by the Median eminence in the brain. Hormones are made in nerve cell bodies positioned in the hypothalamus, and these hormones are then transported down the nerve cell's axons to the posterior pituitary. This gives rise to the Tuberoinfundibular pathway. Dopamine released from the hypothalamus travels via this pathway to activate the secretion of prolactin from the anterior pituitary. Many hormones released by both affect the release of hormones of the other. For example, the release of some hypothalamic hormones affect the synthesis and release of ACTH, TSH, prolactin, growth hormone, endorphins, FSH, and LH from the pituitary gland. The hypothalmus also produces vasopresin (ADH) and oxytocin, which both affect hormone secretion from the pituitary. Here are some more: Corticotropin-releasing hormone and vasopresin from the hypothalamus stimulates anterior pituitary to secrete ACTH. Gonadotropin-releasing hormone from the hypothalamus stimulates the anterior pituitary to secrete LH and FSH. Growth hormone-releasing hormone stimulates anterior pituitary to secrete growth hormone. Somatostatin inhibits secretion of growth hormone from the anterior pituitary. Thyrotropin-releasing hormone stimulates the anterior pituitary to secrete TSH. The subsequent hormones released from the pituitary usually serve multiple functions, one being to create a negative feedback message to the hypothalamus to tell it to stop sending hormones to the pituitary so that these hormones do not get produced in excess. Therefore, each regulates the other in order to maintain homeostasis

TSH

TSH ( thyrois stimulateing hormone) is controlled by TSHRH or TRH released by hypothalamus. This causes release of thyroxine by the thyroid gland.

Testes produce

Testes produce testosterone

What is adenohyphysis? neurohypophysis?

The anterior part is made up of glandular tissue and is called adenohypophysis responsible for producing six hormones. The posterior part is strictly a nervous tissue and it stores ADH and oxytocin (hormones) which is produced by hypothalamus. It is called neurohypophysis

Interaction of hormones on target cells

The chemicals in both systems act by binding to specific receptors. Neurotransmitters have to travel a short distance across the synaptic cleft whereas the: hormones have to travel in the blood before finding the appropriate receptor. Some hormones have very specific target organs because their receptors are found only in certain organs such as calcitonin has receptors only on bone cells to take up the extra calcium circulating in the blood as compared to thyroxine which has receptors in all cells to increase the metabolism.

Endocrine organs are were in the body

The endocrine organs are scattered all around the body

The major endocrine organs include

The major endocrine organs include pituitary gland, thyroid, parathyroid, adrenal, pineal and thymus.