www.soran.edu.iq physiology behrouz mahmoudi endocrine system 1
TRANSCRIPT
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• What are the Properties of the Endocrine System?– Controls longer term metabolic processes– Shares some functions with nervous system– Releases hormones from endocrine cells
• Hormones are chemicals• Hormones change metabolism of many cells• Release controlled by negative feedback• Hormones act on target cells
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Overview of the Endocrine System
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•An Overview of the Endocrine System
Overview of the Endocrine System
Figure 10-1
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• What is the Structure of Hormones?– Three chemical families
• Amino acid derivatives• Peptides and proteins
– Chains of amino acids• Lipid derivatives
– Steroids (e.g., testosterone)
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• Target Cells Peripheral cells that can respond to a particular hormone
• Hormone receptor A protein in the cell membrane, or within the cytoplasm or nucleus, to which a hormone specifically binds to trigger its actions on a target cell.
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• The Role of Target Cell Receptors in Hormonal Action
Figure 10-2
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•Key Note•Hormones control cells on a sustained basis. They circulate in the blood and bind to specific receptors on or in target cells. They change membrane permeability, activate or inactivate key enzymes, or change genetic activity.
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•What is the Hypothalamus and Endocrine Control?
– Three steps of action• Hypothalamus releases hormones as an
endocrine organ• Hypothalamus releases regulatory hormones to
control pituitary gland endocrine cells• Autonomic centers cause direct neural control of
adrenal medullae
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•Three Mechanisms of Hypothalamic Control over Endocrine Organs
Figure 10-4
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The Pituitary Gland• What is the Pituitary Gland?
– Also called the hypophysis– Releases nine important hormones
• All are peptide hormones
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The Pituitary Gland
Figure 10-5
• The Location and Anatomy of the Pituitary Gland
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The Pituitary Gland
• What are the Anterior Pituitary Hormones?– Thyroid-Stimulating Hormone (TSH)
• Triggers thyroid hormone release
– Adrenocorticotropic Hormone (ACTH)• Stimulates glucocorticoid release from adrenal gland
– Follicle-Stimulating Hormone (FSH)• Stimulates estrogen secretion, egg production
(females), sperm production (males)
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The Pituitary Gland• What are the Anterior Pituitary Hormones?
(continued)– Luteinizing Hormone (LH)
• Triggers ovulation, progestin production (females), androgen production (males)
– Prolactin (PRL)• Stimulates mammary gland development and milk
secretion– Growth hormone (hGH)
• Stimulates cell growth • Melanocyte Stimulating Hormone (MSH)
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The Pituitary Gland
• What is the Posterior Pituitary Gland?– Antidiuretic Hormone (ADH)
• Reduces water loss in the urine• Increases thirst
– Oxytocin• Stimulates uterine contraction, milk delivery• Stimulates prostate gland smooth muscle
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The Pituitary Gland• Pituitary Hormones and Their Targets
Figure 10-8
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The Pituitary Gland•Key Note
•Hypothalamic regulatory factors control the anterior pituitary (source of seven hormones). Most of these control other glands (thyroid, adrenal, gonads). It also produces growth hormone. The posterior pituitary releases two hormones produced in the hypothalamus, ADH (restricts water loss) and oxytocin (stimulates contractions in the mammary glands and uterus, and the prostate gland).
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The Thyroid Gland • What is the Anatomy of the Thyroid
Gland?– Lies near thyroid cartilage of larynx– Has a rich blood supply– Contains numerous thyroid follicles
• Produce, store, release thyroid hormones
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The Thyroid Gland• What are the Thyroid Follicles and Thyroid
Hormones?– Production requires adequate iodine in the diet
– Occurs in two forms, thyroxine (T4) and triiodothyronine (T3)
– Increases metabolism and heat production (calorigenic effect)
– Required for normal development
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The Thyroid Gland
• What is the function of the C Cells of the Thyroid Gland?– Secrete calcitonin
• Lowers blood Ca2+ levels• Increases urinary calcium loss
– Caused by high blood Ca2+ level
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The Parathyroid Glands
• What are the Parathyroid Glands?• Chief cells produce parathyroid hormone• Low blood Ca2+ triggers secretion• PTH raises blood Ca2+
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Thyroid glandproducescalcitonin
Increased excretionof calciumin kidneys
Calcium deposition inbone (inhibitionof osteoclasts)
Uncertain significancein a healthy
nonpregnant adult
Blood calciumlevels decline
HOMEOSTASISDISTURBED
Rising calciumlevels in blood
HOMEOSTASISRESTORED
HOMEOSTASIS
Normal calciumlevels
(8.5-11 mg/dl)HOMEOSTASIS
RESTORED
HOMEOSTASISDISTURBED
Falling calciumlevels in blood
Release of storedcalcium from bone
(stimulation ofosteoclasts, inhibition
of osteoblasts)
Enhancedreabsorption
of calcium in kidneys
Stimulation ofcalcitriol production
at kidneys;enhanced Ca2+, PO4
3-
absorption bydigestive tract
Parathyroidglands secrete
parathyroidhormone (PTH)
Blood calciumlevels
increase
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The Parathyroid Glands
Figure 10-11
•The Parathyroid Glands
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The Parathyroid Glands•Key Note
•The thyroid gland produces (1) hormones that adjust tissue metabolic rates, and (2) a hormone that usually plays a minor role in calcium ion homeostasis by opposing the action of parathyroid hormone.
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The Adrenal Glands• What is the Adrenal Gland
Anatomy?– Lie along superior border of each
kidney– Made of two parts
• Adrenal cortex (outer)• Adrenal medulla (inner)
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The Adrenal Glands
• What is the Adrenal Cortex?– Makes steroid hormones (corticosteroids)
• Glucocorticoids (e.g., cortisol)• Mineralocorticoids (e.g., aldosterone)• Androgens (male hormone)
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The Adrenal Glands
• What is the Adrenal Medulla?– Produces two related hormones
• Epinephrine (adrenaline)• Norepinephrine (noradrenaline)
– Increases heart rate and force, releases glucose, fatty acids into blood, opens airways
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The Adrenal Glands
•Key Note•The adrenal glands produce hormones that adjust metabolic activities at specific sites, affecting either the pattern of nutrient utilization, mineral ion balance, or the rate of energy consumption by active tissues.
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The Pineal Gland
• What is the Pineal Gland?– Produces melatonin
• Stops reproductive function• Allows daily wake-sleep cycle
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The Pancreas
• What is the Overview of the Pancreas?– Lies behind stomach and beneath liver– Endocrine cells organized into islets of
Langerhans– Islet cells secrete insulin and glucagon
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The Pancreas
• What are the Actions of Insulin and Glucagon?– Insulin
• Lowers blood glucose concentration– Glucagon
• Raises blood glucose concentration
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Beta cellssecreteinsulin
Increased rate ofglucose transport
into target cell
Increased rate ofglucose utilization
and ATP generation
Blood glucoseconcentration
declines
HOMEOSTASISDISTURBED
Rising bloodglucose levels HOMEOSTASIS
RESTOREDHOMEOSTASIS
Normal glucoselevels
(70-110 mg/dl) HOMEOSTASISRESTORED
HOMEOSTASISDISTURBED
Declining bloodglucose levels
Increased breakdownof glycogen to glucose(liver, skeletal muscle)
Increased breakdownof fats to fatty acids
(adipose tissue)
Increased synthesisand release ofglucose (liver)
Alpha cellssecrete
glucagon
Blood glucoseconcentration
rises
Increased conversionof glucose to glycogen(liver, skeletal muscle)
Increased amino acidabsorption and
protein synthesis
Increased fatsynthesis
(adipose tissue)
www.soran.edu.iq 37Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Beta cellssecreteinsulin
Increased rate ofglucose transport
into target cell
Increased rate ofglucose utilization
and ATP generation
Blood glucoseconcentration
declines
HOMEOSTASISDISTURBED
Rising bloodglucose levels HOMEOSTASIS
RESTOREDHOMEOSTASISNormal glucose
levels(70-110 mg/dl)
Increased conversionof glucose to glycogen(liver, skeletal muscle)
Increased amino acidabsorption and
protein synthesis
Increased fatsynthesis
(adipose tissue)
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Figure 10-1415 of 16
HOMEOSTASISNormal glucose
levels(70-110 mg/dl)
HOMEOSTASISRESTORED
HOMEOSTASISDISTURBED
Declining bloodglucose levels
Increased breakdownof glycogen to glucose(liver, skeletal muscle)
Increased breakdownof fats to fatty acids
(adipose tissue)
Increased synthesisand release ofglucose (liver)
Alpha cellssecrete
glucagon
Blood glucoseconcentration
rises
www.soran.edu.iq 39Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Beta cellssecreteinsulin
Increased rate ofglucose transport
into target cell
Increased rate ofglucose utilization
and ATP generation
Blood glucoseconcentration
declines
HOMEOSTASISDISTURBED
Rising bloodglucose levels HOMEOSTASIS
RESTOREDHOMEOSTASIS
Normal glucoselevels
(70-110 mg/dl) HOMEOSTASISRESTORED
HOMEOSTASISDISTURBED
Declining bloodglucose levels
Increased breakdownof glycogen to glucose(liver, skeletal muscle)
Increased breakdownof fats to fatty acids
(adipose tissue)
Increased synthesisand release ofglucose (liver)
Alpha cellssecrete
glucagon
Blood glucoseconcentration
rises
Increased conversionof glucose to glycogen(liver, skeletal muscle)
Increased amino acidabsorption and
protein synthesis
Increased fatsynthesis
(adipose tissue)
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Patterns of Hormonal Interaction
• What Hormones are Needed for Normal Growth?– Growth Hormone– Thyroid Hormones– Insulin– Parathyroid Hormone– Calcitriol– Reproductive Hormones
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Patterns of Hormonal Interaction
• What are Hormones and Behavior?– Sex hormones
• Testosterone causes aggressiveness• Estrogen causes sexual receptivity
– Thyroid hormones• Excess leads to nervousness, restlessness• Deficiency leads to sluggishness
– Antidiuretic hormone• Leads to feeling of thirst, water intake
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings