Warm Up 2/14/11 Announcements:

Warm Up 2/14/11 Announcements:
Pick up a new warm up sheet from the counter Warm ups due THIS Friday End of six weeks THIS Friday Make up testing TODAY after school Warm Up: What is homeostasis? What is the chemical messenger released by neurons which act on a target cell? What is anabolism? Differentiate between exocrine and endocrine glands.

Endocrine System Chapter 16

Overview Overall goal of endocrine system: maintain a stable internal environment (homeostasis) Endocrine glands are “ductless glands” Endocrine glands secrete hormones which travel through the blood to a target cell Receptor must be present on target cell Glands of the endocrine system are present throughout the body Most cells are regulated by the endocrine system

Endocrine vs Nervous System
Both systems function to maintain homeostasis Main differences: Feature Endocrine System Nervous System Effector cells Target cells throughout the body Postsynaptic cells in muscle and glandular tissue only Chemical messenger Hormone Neurotransmitter Distance traveled by messenger Long – in blood Short – across synaptic cleft Regulatory effects Slow to appear; long-lasting Appear rapidly; short

Endocrine vs Nervous System

Major Endocrine Glands

Classification of Hormones
Classified by Function Tropic hormones: target other endocrine glands and stimulate their growth & secretion Sex hormones: target reproductive tissues Anabolic hormones: stimulate anabolism in their target cell

Classification of Hormones
Classified by Chemical Structure Steroid Hormones Derived from cholesterol Lipid soluble; can pass through phospholipid bilayer Nonsteriod Hormones Synthesized from amino acids Proteins, Glycoproteins, peptides, amino acid derivatives (Fig 16-3)

Chemical Classifications of Hormones

Make up testing today after school (room 2212) Extra credit due this Friday Warm Up: What is the overall goal of the endocrine system? What is the chemical messenger released by the endocrine system? Describe the regulatory effects of the endocrine system? What are the two ways hormones can be classified? What is the main difference between steroids and nonsteroids? True/False: Cells can be targets for multiple hormones.

How Hormones Work Hormones bind to receptors on target cells
Lock & key Hormone-receptor interactions produce regulatory changes within the target cell Ex: initiating protein synthesis; activation/inactivation of enzymes; opening/closing of ion channels Endocrine glands produce more hormone molecules than necessary to hit the target cells Excess hormones are excreted in urine or broken down by metabolic processes

How Hormones Work Synergism: combinations of hormones have a greater effect on the target cell compared to a single hormone acting alone Permissiveness: a small amount of one hormone allows a second hormone to exhibit its full effect on the target cell Antagonism: two hormones produce opposite effects

Mechanisms of Steroid Hormone Action
Steroids are lipids  not soluble in blood plasma (mostly H2O) In blood steroids attach to plasma proteins Steroid reaches a target cell  dissociates from plasma protein  diffuses into target cell In the nucleus a hormone-receptor complex is formed Hormone-receptor complexes in the nucleus trigger protein synthesis (transcription & translation) Increase steroid = increase response (protein synthesis) Regulatory effects of hormones are slow to appear

Mechanisms of Steroid Hormone Action

Mechanisms of Nonsteriod Hormone Action
Nonsteroid hormones operate according to the second messenger hypothesis Nonsteroid hormone is the “1st messenger” and binds to a receptor on the plasma membrane of the target cell The “message” is relayed inside the cell to a “2nd messenger” which triggers the appropriate cellular response

Second Messenger Mechanism
Nonsteroid hormone (1st messenger) binds with receptor on plasma membrane Hormone-receptor complex activates a membrane protein called the G protein G protein activates guanosine triphosphate (GTP) which also activates another membrane protein (adenyl cyclase)

Adenyl cyclase removes 2 phosphate groups from ATP creating cyclic adenosine monophosphate (cAMP) (second mesenger) cAMP activates or inactivates protein kinases Protein kinases activate specific intracellular enzymes

Enzymes influence specific cellular reactions (target cell’s response to hormone)

Summary: Hormone or 1st messenger binds to plasma membrane receptor Triggers formation of intracellular 2nd messenger 2nd messenger activates cascade of chemical reactions Target cell’s response to the hormone is produced

Another Second Messenger
Some hormones produce effects in target cells by triggering opening of calcium channels Hormone binds to receptor on plasma membrane Ca2+ channels open Ca2+ binds with calmodulin Ca2+/Calmodulin complex acts as 2nd messenger Enzymes are activated/inactivated Target cell’s response is produced

Calcium-Calmodulin as 2nd Messenger

Regulation of Hormone Secretion
Hormone secretion is controlled by a negative feedback loop Ex: parathyroid hormone (PTH) and blood calcium levels (fig 16-10) Ex: insulin and blood glucose levels

Endocrine Feedback Loop

Hyper vs Hyposecretion
Tumors or abnormalities of the endocrine glands cause secretion of too much or too little hormone Hypersecretion: production of too much hormone Hyposecretion: production of too little hormone Results in lack of target cell response Also caused by target cell insensitivity

Regulation of Target Cell Sensitivity
Sensitivity of target cell depends on number of receptors it has for a specific hormone Receptors are constantly begin broken down and re-synthesized by the cell Up-regulation: synthesis of new receptors > degeneration of old receptors Increase target cell sensitivity to that particular hormone Down-regulation: synthesis of new receptors < degeneration of old receptors Decrease target cell sensitivity

Prostaglandins Group of lipid molecules that play an important role in the body but to not classify as hormones Structure: 20-carbon unsaturated fatty acid with a 5 carbon ring

Prostaglandins Secreted into the bloodstream
Metabolize quickly; circulating levels remain low Prostaglandins are produced in certain tissues and travel to other cells within the same tissue Tissues that secrete prostaglandins: Kidneys, lungs, brain, thymus, seminal vesicles

Warm Up 2/16-2/17/11 Announcements End of the six weeks is FRIDAY
Gradebook is updated except for last warm up and extra credit Extra credit due FRIDAY Warm Up: Differentiate between synergism, permissiveness and antagonism. What is the main difference between the mechanisms of steroid action and nonsteroid action on a target cell. What two molecule can act as 2nd messengers? By what mechanism is hormone secretion controlled? Differentiate between up-regulation and down-regulation. What do each result in?

Pituitary Gland Also called hypophysis
Located on ventral surface of brain, inferior to the hypothalamus “Master gland” because functions are crucial to life Composed of two parts: Anterior Pituitary and Posterior Pituitary

Anterior Pituitary Hormones secreted from Anterior Pituitary:
Growth Hormone Prolactin Trophic hormones Thyroid-stimulating hormone (TSH) Adrenocorticotropic hormone (ACTH) Gonadotropic hormones Follicle-stimulating hormone (FSH) Luteinizing hormone (LH)

Growth Hormone Growth Hormone (GH) – promotes growth by stimulating protein anabolism Increased protein anabolism allows increased growth rate Target cells: Promotes growth of bone and muscle GH has a hyperglycemic effect; antagonist of insulin Hyperglycemic effect because GH stimulates fat metabolism Interaction vital to maintaining homeostasis of blood glucose levels GH stimulates fat metabolism Shift cells away from glucose catabolism towards lipid catabolism for an energy source Less glucose is used by cells; causes hyperglycemia

Growth Hormone Abnormalities
Hypersecretion Prior to ossification of the epiphyseal plates hypersections of GH results in rapid skeletal growth  Gigantism After closure of epiphyseal plates hypersecretion causes cartilage to continue to form new bone  Acromegaly Distorted appearance; enlarged hands, feet, face, jaw; thickened skin

Growth Hormone Abnormalities
Hyposecretion Results in stunted body growth  pituitary dwarfism Treated with genetically engineered growth hormone

Prolactin (PRL) Also called lactogenic hormone
Initiates milk secretion (lactation) Target cells: Mammary glands During pregnancy PRL promotes development of breasts At birth PRL stimulates milk production

Prolactin Abnormalities
Hypersecretion: Lactation in non-nursing women Disruption of menstrual cycle Impotence in men Hyposecretion: Insignificant unless mother wishes to breastfeed

Trophic Hormones Review: a trophic hormone stimulate effects of other endocrine glands Trophic hormones released from anterior pituitary gland: Thyroid-stimulating hormone (TSH) Adrenocorticotropic hormone (ACTH) Gonadotrophic hormones Follicle-stimulating hormone (FSH) Luteinizing hormone (LH)

Thyroid-stimulating hormone (TSH)
Promotes and maintains growth and development of thyroid gland Required for thyroid gland to secrete its hormones

Adrenocorticotropic hormone (ACTH)
Promotes and maintains normal growth and development of the cortex (outer portion) of the adrenal gland Required for adrenal cortex to secrete its hormone

Gonadotrophic hormones
Target cells: gonads (testes & ovaries) Follicle-stimulating hormone (FSH) Females: Stimulates growth & development of an ovum that is released each month during ovulation Stimulate estrogen release from the ovaries Males Stimulates development of seminiferous tubules and maintains sperm production in the testes

Gonadotrophic hormones
Luteinizing hormone (LH) Females: Triggers ovulation Promotes development of corpus luteum which secretes progesterone and estrogen; these hormones help maintain pregnancy Males: Stimulates cells of the testes to synthesize and secrete testosterone

Control of Anterior Pituitary Secretion
The hypothalamus releases chemical called releasing hormones which influence hormone secretion from the anterior pituitary gland This regulatory mechanism is a negative feedback loop

Posterior Pituitary Hormones secreted from Posterior Pituitary:
Antidiuretic Hormone (ADH) Oxytocin (OH)

Antidiuretic Hormone (ADH)
Target cells: kidney Prevents formation of large volumes of dilute urine Antidiuresis Helps conserve water balance Example: Blood is hypertonic  change detected by osmoreceptors  ADH is released  water reabsorbed in kidneys and returned to blood

ADH Abnormalities Hyposecretion Hypersecretion Diabetes insipidus
Increased urine output of dilute urine “high and dry” Na+ levels are increased; ICF dehydrated Hypersecretion Syndrome of inappropriate antidiuretic hormone (SIADH) Decreased urine output Fluid overload; low Na+ levels

Oxytocin (OT) Target cells: mammary glands & uterine smooth muscle
Operates on a positive feedback loop Stimulates uterine smooth muscle contractions During childbirth stretching of receptors causes continued release of oxytocin until after delivery of the placenta Ejection of milk into ducts of the breast of lactating women When breastfeeding the suckling action of the baby causes secretion of additional oxytocin increasing milk production Breastfeeding also helps the uterus continue to contract back to normal size during the postpartum period

Turn in extra credit to the tray – please keep or recycle the article Check grades online Warm Ups: What is a trophic hormone? What are the six hormones release from the anterior pituitary? What is the action of antidiuretic hormone? What are the functions/actions of oxytocin? Differentiate between gigantism and acromegaly.

Project Reminders Make sure your illustrations shows both the anterior and posterior pituitary. Show ovaries and testes (only testes) Remember that trophic hormones will be a double pathway Plan ahead – we have not learned about all of the hormones yet so make sure you leave room for future information You will be adding additional organs to represent target cells Questions??

Warm Up 2/21/11 Announcements: 5th six weeks starts TODAY
Tentative test date for chapter 16 – Friday March 4th Project due Friday March 4th Please ROLL project at the end of class Warm Up: What causes diabetes insipidus? Describe the fluid and electrolyte balance of a patient with this diagnosis. True/False: Prostaglandins are classified as hormones. True/False: Hyposecretion of prolactin can be life-threatening. Defend your answer.

Pineal Body Regulates the body’s biological clock Secretes melatonin
Patterns of eating Sleeping Female reproductive cycle Behavior Secretes melatonin Induces sleep Secretion is inhibited by sunlight Target cell in humans is unknown

Melatonin & Seasonal Affective Disorder
Also know as “winter depression” During shorter days, melatonin secretion increases causes a depressed feeling in affected patients Treatment Exposure to high-intensity lights to inhibit melatonin secretion

Thyroid Gland The thyroid gland is composed of two lateral lobes connected by an isthmus Located on the anterior and lateral surfaces of the trachea, below the larynx

Thyroid Hormones Tetraiodothyronine or thyroxine (T4)
Most abundant thyroid hormone Contains 4 iodine atoms May have effect on target cells, but mostly serve as precursor to T3 Triodothyronine (T3) “principal thyroid hormone” Contains 3 iodine atoms

Thyroid Hormones Both hormone bind to plasma proteins once secreted into the bloodstream Function: Regulate metabolic rate of all cells Regulate cell growth Regulate tissue differentiation Target cells: “general” because thyroid hormones can potentially interact with all cells of the body

Hypersection Graves Disease
Autoimmune condition (thyroid stimulating antibodies causes abnormal secretion) Weight loss Increases basal metabolic rate Increased heart and respiratory rate exophthalmos

Exophthalmos

Hyposecretion of Thyroid Hormone
Cretinism – develops during the growth years due to hypothyroidism Low metabolic rate Retarded growth and sexual development Mental retardation (possibly) Hypothyroidism later in life Decreased metabolic rate Loss of mental & physical vigor Weight gain Loss of hair Yellow discoloration of the skin myxedema

Goiter Caused by lack of iodine in the diet
Iodine is needed to synthesize thyroid hormone Lack of iodine causes drop in thyroid hormone production/secretion Negative feedback loop informs hypothalamus and anterior pituitary to release releasing hormones and TSH Lack of iodine causes enlargement of thyroid gland

Calcitonin The 3rd hormone secreted from the thyroid gland
Target cells – bone Function – regulates calcium levels in the blood by decreasing blood calcium levels Increases action of osteoblasts (build bone) and inhibits action of osteoclasts (breakdown bone) Antagonist to parathyroid hormone

Quiz on block day – will cover notes up through today Test and Project due next Friday (3/4) Bring your book on block day to help with project Warm Up: How/why does melatonin cause “winter depression”? Name the two thyroid hormones. Which is considered the “principle thyroid hormone”? Why? What is/are the target(s) of the thyroid hormones? What is needed to synthesize thyroid hormones? Calcitonin serves as an antagonist to which other hormone?

Parathyroid Glands Parathyroid glands are embedded in the posterior aspect of the thyroid glands Usually 4 or 5 parathyroid glands

Parathyroid Hormone Secreted from Parathyroid glands
Target cells: bone and kidney Action: maintains calcium homeostasis Increases osteoclast activity; decrease osteoblast activity Calcium absorbed in kidneys and returned to the bloodstream Activates vitamin D in the kidneys which increases intestinal absorption of calcium Parathyroid hormone is an antagonist to calcitonin

Adrenal Glands Located on top of both of the kidneys
Composed of two parts: Outer portion  adrenal cortex Inner portion  adrenal medulla Both parts of the adrenal glands are structurally and functionally different; often treated as two different glands

Adrenal Cortex Composed of three distinct layers or zones
Outer zone  secrete mineralocorticoids Middle zone  secrete glucocorticoids Inner zone  secrete glucocorticoids and gonadocorticoids

Mineralocorticoids Mineralocorticoids – regulate electrolytes in the body In humans the most important mineralcorticoid is aldosterone Target cell – kidneys Function – maintaining sodium homeostasis in the blood In the kidneys, sodium ions are reabsorbed from the urine back to the blood Sodium ions are exchanged for potassium or hydrogen ions Aldoesterone also promotes water retention because re-absorption of sodium ions also causes water to be reabsorbed

Regulation of Aldosterone Secretion
Aldosterone secretion is controlled by the renin-angiotensin mechanism This mechanism is a negative feedback loop that helps maintain homeostasis of blood pressure Blood pressure drops in the kidneys  renin (an enzyme) is secreted Renin converts angiotensinogen to angiotensin I Angiotensin I travels to the lungs where enzymes split the molecule forming angiotensin II Angiotensin II travels to the kidneys where it simulates the secretion of aldosterone Aldosterone causes reabsorption of sodium ions  followed by water reabsorption  increase in blood pressure

Glucocorticoids Main glucocorticoid secreted from the adrenal cortex is cortisol (also hydrocortisone) Target cells – general; affect every cell in the body

Cortisol - Functions Accelerate protein breakdown into amino acids
Amino acids travel to liver and are converted to glucose (gluconeogenesis) Increased glucocorticoids (cortisol)  increased breakdown of proteins in tissue (tissue wasting)  hyperglycemia Shift cells from carbohydrate catabolism to lipid catabolism for energy sources Further causes hyperglycemia

Cortisol – Functions cont…
Help maintain blood pressure Permissiveness relationship with epinephrine and norepinephrine Epi and NE cause vasoconstriction of blood vessels Suppression of immune system responses

Gonadocorticoids The adrenal cortex secretes small amounts of male hormones (androgens) Secretes in males and females Causes appearance of pubic and axillary hair in males and females

Glucocorticoid Hypersecretion
Cushing Syndrome Too much cortisol is being secreted Causes: Could be caused by hypersecretion of ACTH from anterior pituitary (tumor) Cirrhosis of liver or liver failure  can’t breakdown hormones Signs/Symptoms: Abnormal hair growth buffalo hump muscle wasting skin breakdown (thin skin) striae across abdomen and thighs truncal obesity Susceptible to infection

Adrenal Insufficiency
Hyposecretion of mineralcorticoids & glucocorticoids  Addison Disease Signs/Symptoms: Drop in blood sodium Hypoglycemia Increase in blood potassium Dehydration Weight loss

Adrenal Medulla Secretes two nonsteroids in the catecholamine class
Epinephrine and norepinephrine Bind to sympathetic effectors and enhance the effects of the “fight or flight” response of the autonomic nervous system

Warm Up Announcements: Project due next Friday (3/4)
Chapter 16 test next Friday (3/4) TAKS next week – different schedule Warm Up – Matching (write it out – it helps you learn  ) Aldosterone A. Hypersecretion of ADH Cortisol B. Mineralcorticoid Addison Disease C. Adrenal Insufficiency Cushing Syndrome D. Glucocorticoid SIADH E. Hypersecretion of cortisol

Pancreas Located in the LUQ
Contains both endocrine and exocrine tissue Endocrine portion is made up of tiny islands of cells called pancreatic islets (also islets of Langerhans) Alpha cells secrete glucagon Beta cells secrete insulin

Pancreatic Hormones Glucagon Insulin
Increases blood glucose levels Converts glycogen to glucose in liver cells Stimulates gluconeogenesis Target cells  liver Insulin Decreases blood glucose levels Promotes movement of glucose, amino acids, fatty acids into cells Promotes metabolism of these molecules once by cells Target cells  general (all cells) Glucagon and Insulin produce antagonistic effects (fig 16-27, page 512)

Diabetes Results from either
1) inadequate or absence of insulin production 2) Insulin resistance – decreased insulin receptors results in decreased effectiveness of glucose uptake

Diabetes – Signs & Symptoms
Hyperglycemia – elevated amounts of glucose in the blood Results glucose not entering the cells properly Glycosuria – glucose present in the urine Elevated glucose levels in the blood exceeds kidney’s abilities to reabsorb glucose; glucose “spills over” into the urine Polyuria – increased urine production Water follows glucose lost in urine

Diabetes – Signs & Symptoms
Polydipsia – excessive thirst Polyuria causes dehydration Polyphagia – excessive and continuous hunger Although blood sugar is high cells are “starving” because cells cannot uptake glucose **3 P’s = polyuria, polydipsia, polyphagia**

Diabetic Ketoacidosis
Diabetics are unable to utilize glucose for energy – cells must use protein and fat Large quantities of fat metabolism results in build up of acidic metabolites called ketone bodies Signs/Symptoms Acidosis Abdominal pain Nausea/vomiting Fruity breath Decreased LOC Coma death

Type 1 Diabetes Absolute deficiency of insulin production
Cause of beta cell destruction is unknown Requires insulin injections or an insulin pump

Type 2 Diabetes Previously called non-insulin-dependent diabetes (NIDDM) or adult onset diabetes Beta cell produce reduced amounts of insulin Loss of insulin receptors on target cells leads to insulin resistance Treated with insulin injections, oral diabetic medication and lifestyle modifications

Complications of Diabetes
Untreated or poorly controlled diabetes can lead to many complications that affect almost every system in the body: Atherosclerosis – build up of fatty materials in the blood vessls Lead to heart attack, stroke, reduced circulation Diabetic retinopathy – can lead to blindless

Complications of Diabetes
Neuropathy – nerve damage Amputations Kidney disease May require dialysis

Warm Up 2/28/11 Announcements: Project due this Friday
Test – Chapter 16 – This Friday Warm Ups due this Friday Please make up quiz ASAP (today after School) Corrections in notes (highlighted in red – online) Warm Up: Explain the relationship between diabetes and “the 3 P’s”.

Gonads – Testes & Ovaries
Composed mainly of coils of seminiferous tubules & interstitial cells Interstitial cells secrete testosterone Target cells – general Function: Growth & maintenance of male sexual characteristics Sperm production Testosterone secretion is regulated by the gonadotropin  leutinizing hormone (LH)

Estrogen Secreted by cells of the ovarian follicles Target cells: general Functions: Promote development & maintenance of female sexual characteristics Breast development Regulation of menstrual cycle

Progesterone (“pregnancy-promoting hormone”) Secreted by corpus luteum Target cells: general Functions (with estrogen): Maintains the lining of the uterus to maintain a pregnancy Remember Estrogen & Progresterone secretion is regulated by FSH and LH (gonadotropic hormones)

Placenta Tissue that forms along the lining of the uterus
Serves as the connection between the circulatory systems of the mother and developing fetus Secretes human chorionic gonadotropin (hCG) Target cells: ovaries

Placenta Function: hCG is high during the 1st trimester
Stimulates hormone (estrogen & progesterone) secretion from the ovaries High levels of estrogen & progesterone help maintain uterine lining for pregnancy hCG is high during the 1st trimester A high hCG level is used to confirm a pregnancy

Warm Up 2/14/11 Announcements:

Similar presentations

Presentation on theme: "Warm Up 2/14/11 Announcements:"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Warm Up 2/14/11 Announcements:

Similar presentations

Presentation on theme: "Warm Up 2/14/11 Announcements:"— Presentation transcript:

Similar presentations

About project

Feedback