Download Hormones

Memmler’s
The Human Body in Health and Disease
11th edition
Chapter 12
The Endocrine System: Glands
and Hormones
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The Endocrine System
•Consists of a group of glands that produce hormones
•Works with nervous system to control and coordinate all
other body systems
•Affects body systems by chemical stimuli
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Hormones
•Chemical messengers with regulatory effects on cells or organs
•Hormones from endocrine glands are released directly into tissue
fluids; not through ducts
•Some affect many tissues
–
Growth hormone
–
Thyroid hormone
–
Insulin
•Some affect a specific tissue (target tissue). Receptors on the cells of
the target tissue interpret the hormone message.
–
Thyroid-stimulating hormone (TSH) - acts on Thyroid gland
–
Adrenocorticotropic hormone (ACTH) - acts on Adrenal glands
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Hormone Chemistry
•Amino acid compounds
– Proteins or related compounds
– All hormones except steroids
•Lipids
– Made of fatty acids
– Most are steroids, derived from the steroid cholesterol
– Produced in adrenal cortex and sex glands
– Prostaglandins are also lipids
– Steroid hormones can be recognized by the suffix -one.
Testosterone and progesterone
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Checkpoint 12-1: What are hormones and what are some
effects of hormones?
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Question:
Hormones from the sex glands are made
up of:
a. amino acid compounds
b. lipids
c. proteins
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Answer:
b. lipids
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Hormone Regulation
•Negative feedback (most common)
– Endocrine gland over secretes hormone
– Tissue becomes too active
– Tissue negatively affects gland to decrease secretion
•Positive feedback
– Hormone response produces more hormone
•Rhythmic pattern
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Checkpoint 12-2: Hormone levels are normally kept
within a specific range. What is the most common method
used to regulate secretion of hormones?
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The Endocrine Glands and
Their Hormones
Tissues other than endocrine glands also secrete hormones
•Brain
•Digestive organs
•Kidney
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The endocrine
glands.
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The Pituitary
Pituitary (hypophysis) gland
•Master gland
•Size of a cherry
•Releases hormones that affect working of other glands
•Controlled by hypothalamus
•Consists of 2 lobes - Anterior Pituitary Lobe and the
Posterior Pituitary Lobe
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The hypothalamus,
pituitary gland, and
target tissues.
Arrows indicate the
hormones’ target
issues and feedback
pathways.
ZOOMING IN
• What two structures
does the infundibulum
connect?
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Control of the Pituitary
Hypothalamus
•Sends releasing hormones (RH) and inhibiting hormones
(IH)
– Hormones stimulate (RH) and suppress (IH) anterior
pituitary secretions
– Nerve impulses stimulate secretions
– RH and IH are sent from the Hypothalamus to the
Anterior Pituitary lobe.
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Checkpoint 12-3: What part of the brain controls the
pituitary?
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Hormones of the Anterior Lobe
•Growth hormone (GH) or somatotropin - promotes growth
of all body tissue
•Thyroid-stimulating hormone (TSH) or thyrotropin promotes thyroid hormone production
•Adrenocorticotropic hormone (ACTH) - promotes adrenal
cortex hormone production
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Hormones of the Anterior Lobe
•Prolactin (PRL) - promotes lactation
•Gonadotropins - acts on male and female reproductive
systems.
– Follicle-stimulating hormone (FSH) - promotes the
development of egg (ovaries) and sperm (testes)
– Luteinizing hormone (LH) - promotes ovulation and
sex hormone secretion in males and females
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Hormones of the Posterior Lobe
•Hormones are produced by the Hypothalamus
•They are stored in the Posterior Pituitary lobe
•Antidiuretic hormone (ADH) - promotes water
reabsorption in the kidneys therefore preventing water loss
– Too much ADH will raise blood pressure
– Not enough ADH will cause excessive water loss
•Diabetes insipidus
•Oxytocin - promotes uterine contractions and lactation
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Checkpoint 12-4: What are the hormones from the
anterior pituitary?
Checkpoint 12-5: What hormones are released from the
posterior pituitary?
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Tumors of the Pituitary
•Excessive number of tumor growth hormone (GH) cells in
childhood
– Gigantism
•Overactive GH-producing tumor cells in adulthood
– Acromegaly
•Tumors that destroy secreting tissues
– Underactivity
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The Thyroid Gland
•Largest endocrine gland
•Lateral lobes on either side of larynx
•Connecting band (isthmus) - center
•Enclosed by connective tissue capsule
•Functions with iodine
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Hormones of the Thyroid Gland
•Thyroxine (T4)
– Principle hormone
– Increases energy and protein metabolism rate
•Triiodothyronine (T3)
– Increases energy and protein metabolism rate
•Calcitonin
– Regulates calcium metabolism
– Lowers the amount of calcium in blood ,depositing it in bone
tissue
– Works with parathyroid hormone and vitamin D
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Disorders of the Thyroid Gland
•Goiter is enlargement of thyroid gland
– Simple goiter
– Adenomatous or nodular goiter - tumor formation
•Hypothyroidism - underactive thyroid
–
Infantile hypothyroidism (cretinism) - failure of thyroid to form in utero, lack
of physical and mental development
– Myxedema - thyroid atrophy - can be treated
•Hyperthyroidism - overactive thyroid
–
–
Graves disease - goiter, bulging eyes, intense nervousness, rapid pules
Thyroid storm - develops quickly and will likely cause death
•Thyroiditis - thyroid inflammation
– Hashimoto disease - autoimmune disorder
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Checkpoint 12-6: What is the effect of thyroid hormones
on cells?
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The Parathyroid Glands
•Four glands in posterior capsule of thyroid
•Secrete parathyroid hormone (PTH)
– Works with calcitonin to regulate calcium metabolism
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Calcium Metabolism
Calcium balance requires
•Calcitriol (dihydroxycholecalciferol)
– AKA - Vitamin D
– Produced by modifying vitamin D in liver and then in
kidney
•Parathyroid hormone
•Calcitonin
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Disorders of the Parathyroid Glands
•Tetany - muscle spasms
– Inadequate production of parathyroid hormone (PTH)
•Fragile bones and kidney stones
– Excess production of parathyroid hormone (PTH)
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Question:
Which gland secretes
triiodothyronine to help increase
the metabolic rate in cells?
a. parathyroid
b. thyroid
c. adrenal
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Answer
b. thyroid
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Checkpoint 12-7: What mineral is regulated by calcitonin
and parathyroid hormone (PTH)?
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The Adrenal Glands
•Two small glands on top of kidneys
•Each gland has two parts that act as separate glands
– Medulla - inner area
– Cortex - outer portion
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Hormones from the Adrenal Medulla
Fight-or-flight hormones
•Epinephrine (adrenaline)
•Norepinephrine (noradrenalin)
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Checkpoint 12-8: The main hormone from the adrenal
medulla also functions as a neurotransmitter in the
sympathetic nervous system. What is the name of this
hormone?
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Hormones from the Adrenal Cortex
•Glucocorticoids - maintains the body’s carbohydrate
reserve.
– Cortisol or hydrocortisone - released in times of
stress, increases carbohydrates in blood
•Mineralocorticoids - regulates electrolyte balance
– Aldosterone - controls sodium and potassium levels
by influencing water volume
•Sex hormones
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Disorders of the Adrenal Cortex
•Addison disease
–
Hypofunction of adrenal cortex
–
Muscle atrophy, weakness, and inadequate water and salt
balance.
•Cushing syndrome
–
Hypersecretion of cortisol
–
Obesity, round (moon) face, thin skin, easily bruised, bone loss,
and elevated blood sugar
•Aldosteronism
–
Hyperfunction of adrenal cortex resulting in excess secretion of
aldosterone
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Checkpoint 12-9: What three categories of hormones are
released by the adrenal cortex?
Checkpoint 12-10: What effect does cortisol have on
glucose levels in the blood?
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The Pancreas and Its Hormones
Islets of Langerhans are specialized pancreas cells that
secrete hormones and are part of the Endocrine system
•Insulin
– Lowers blood sugar level
– Stimulates manufacture of amino acids into protein
– Produced by beta cells of the Pancreas
•Glucagon
– Increases blood sugar
– Produced by alpha cells of the Pancreas
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Checkpoint 12-11: What two hormones produced by the
islets of the pancreas act to regulate glucose levels in the
blood?
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Diabetes Mellitus
•Insulin-dependent diabetes mellitus (IDDM)
–
Type 1 diabetes
–
Less common but more severe
–
Results in the destruction of Pancreatic beta cells - not enough
insulin
•Non—insulin-dependent diabetes (NIDDM)
–
Type 2 diabetes
–
Body cells cannot respond to insulin - Obesity
•Gestational diabetes
–
Usually disappears after childbirth
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Metabolic Syndrome
•Also called syndrome X or insulin-resistance syndrome
•Related to type 2 diabetes
•High state of hyperglycemia and obesity
•Caused by insulin resistance in combination with high
plasma glyceride levels, low HDL levels, and hypertension
•Treated with weight loss, diet, exercise; drugs to lower
blood pressure and cholesterol; drugs to lower insulin
resistance
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Checkpoint 12-12: What hormone is low or ineffective in
cases of diabetes mellitus?
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The Sex Glands
Ovaries and testes produce hormones to
•Develop sexual characteristics - secondary sex
characteristics
•Maintain reproductive organs
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Hormones of the Sex Glands
•Male sex hormone
– Testosterone
•Female sex hormones
– Estrogen - stimulates ovulation, menstruation
– Progesterone - maintains pregnancy
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Checkpoint 12-13: In addition to controlling reproduction,
sex hormones confer certain features associated with male
and female gender. What are these features called as a
group?
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Question:
What is the name for the male sex
glands?
a. gonads
b. pituitaries
c. testes
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Answer:
c. testes
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The Thymus Gland
•Mass of lymphoid tissue in upper chest superior to heart
•Important in development of immunity
•Produces thymosin
– Assists in maturity of T lymphocytes
– T lymphocytes circulate in the lymph
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The Pineal Gland
•Cone-shaped structure posterior to midbrain
•Produces melatonin
– Influences sleep–wake cycles
– Stimulated by light intensity
– Appears to delay onset of puberty
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Other Hormone-Producing Tissues
Substances that regulate body actions are also produced
by
•Stomach
•Small intestine
•Kidneys
•Brain
•Atria of heart
•Placenta
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Question:
Which endocrine gland is also called
the hypophysis and is known as the
“master gland”?
a. the pituitary gland
b. the thyroid
c. the pancreas
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Answer:
a. the pituitary gland
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Prostaglandins
Group of hormones made by most body tissues
•Produced, act, and rapidly inactivated in or close to origin
•Constrict structures - blood vessels, bronchi, and
intestines
•Dilate structures - blood vessels, bronchi, and intestines
•Promote inflammation
– Anti inflammatory drugs block prostaglandin
production.
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Checkpoint 12-14: What are some organs other than the
endocrine glands that produce hormones?
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Hormones and Treatment
Hormones are extracted from animal tissue, manufactured in the
lab, or genetically engineered
•Growth hormone
•Insulin
•Adrenal steroids
•Epinephrine (adrenaline)
•Thyroid hormones
•Oxytocin
•Androgens
•Estrogen and progesterone
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Question:
Which hormone is used medically to
treat a severe allergic reaction
(anaphylactic shock)?
a. oxytocin
b. insulin
c. epinephrine
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Answer:
c. epinephrine
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Hormones and Stress
Stress response involves both nervous and endocrine
system
•Hormones released during stress help body cope - ACTH,
Insulin, Sex hormones, and Thyroid hormones
•Unchecked levels of hormones can harm body
– High blood pressure
– Heart disease
– Headaches
– Insomnia
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Checkpoint 12-15: What are some hormones released in
time of stress?
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Aging and the Endocrine System
•Pancreas
– Adult-onset diabetes mellitus - Type 2
•Thyroid
– Decreased hormone secretion
•Pituitary
– Decreased bone mass
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End of Presentation
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