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Endocrine system in detail
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21/10/14
Challenge the future Delft University of Technology
Anatomy & Physiology Endocrine System
BM1107
2 Endocrine System
Today…
• First hour: Lecture: Hormonal control Case 1: Thyroid gland
• Second hour:
Lecture: Other glands and hormones Case 2: Pancreas
3 Endocrine System
Hormones?
4 Endocrine System
Diseases
5 Endocrine System
Hormones
• Hormone = to excite
• Chemical messengers secreted by cells into the extracellular fluids
• Binds to receptor → effect
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Endocrine glands
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Body processes
• Growth and development • Maintenance of electrolyte, water, and nutrient balance of blood
• Regulation of cellular metabolism and energy balance • Mobilization of body defenses • Reproduction
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Difference between Nervous and Endocrine system
Nervous system
Endocrine system
9 Endocrine System
Difference between Nervous and Endocrine system
Nervous system • Electrochemical pulses delivered
by neurons
• Immediate response (ms)
• Short effect
Endocrine system • Hormones produced in glands
that travel through blood
• Delay of seconds/days
• Short or long-lasting effect
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Two chemical classes
• Amino acid-based hormones -Most hormones -Size varies widely
• Steroids -Synthesized from cholesterol -Hormones from adrenals and testis/ovary
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Hormone release – Action – Cell Response
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Hormone release – Action – Cell Response
1) Membrane receptors Second-messenger system
Water-soluble hormones:
Can not go through cell membrane.
2) Intracellular receptors Direct gene activation
Lipid soluble hormones: go through cell membrane
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1) Membrane receptor Second-messenger system
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2) Intracellular receptors Direct gene activation
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Hormone release – Action – Cell Response
• Depends on target cells!
Example: Epinephrine (Adrenaline)
@smooth muscle cells → contraction @liver cells → produce glucose
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Back to anatomy…
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Pituitary gland and hypothalamus Pituitary-hypothalamic relationships
hypothalamus
posterior lobe pituitary
anterior lobe pituitary
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Posterior pituitary
• Oxytocin • Strong stimulant of uterine contraction
• Released during childbirth
• Hormonal trigger for milk ejection
• Antidiuretic hormone (ADH) • Prevents urine formation
• Regulates water balance
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Anterior pituitary
• Growth hormone (GH) Metabolic and growth-promoting actions
• Thyroid-stimulating hormone (TSH) Affects secretory activity of thyroid
• Adrenocorticotropic hormone (ACTH) Helps resist stressors
• Gonadotropins (FSH & LH) Regulate functions of gonads
• Prolactin Simulate milk production
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Growth Hormone Gigantism, acromegaly and dwarfism
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Possible cause
MRI Normal Pituitary tumor
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Thyroid
• Thyroid hormone (T4 & T3) -Increases metabolic rate and heat
production
-Regulation of tissue growth and development
-Maintenance of blood pressure
• Calcitonin Reduces blood Ca2+ levels
23 Endocrine System
Thyroid Hormones & Iodine
• Iodine is necessary to produce T4/T3 • Dietary intake: seafood, iodized salt, dairy products • Iodine deficiency big problem
• Finally: low level T4/T3
• ‘Goiter’ – swelling of thyroid
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Thyroid
• Basal Metabolic Rate/temperature regulation
• Metabolism
• Nervous system
• Cardiovascular system
• Muscular system • Skeletal system
• Gastrointestinal system
• Reproductive system
• Skin
Targets of thyroid hormone in the body
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Feedback loop TRH
Draw a simplified feedback model with + and -
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Thyroid
T4
Pituitary gland
TSH
Hypothalamus
TRH
+
+
-
-
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Patient comes in…
What is the problem? Where is it located? 1. TSH low, T4 high?
2. TSH high, T4 low?
3. TSH high, T4 high?
4. TSH normal, T4 normal?
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Patient comes in…
What is the problem? Where is it located? 1. TSH low, T4 high?
Hyperthyroidism
2. TSH high, T4 low? Hypothyroidism
3. TSH high, T4 high? 4. TSH normal, T4 normal?
→ Thyroid → Thyroid → Pituitary gland → Normal J
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Summary • Introduction hormones and glands
• Second messenger system / Direct gene activation
• Humeral / Neural /Hormonal stimuli
• Pituitary gland & Thyroid
• Balance of TSH and T4 levels
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Next hour…
Lecture: Other glands and hormones Case 2: Pancreas
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32 Endocrine System
Other glands…
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• Thyroid hormone (T4 & T3)
• Calcitonin: Reduces blood Ca2+ levels by:
§ Inhibiting release of Ca2+ from bone
matrix.
§ Stimulating Ca2+ uptake and
incorporation into bone matrix
Thyroid
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Parathyroid glands • Embedded in thyroid • 4 tiny glands • Parathyroid hormone (PTH)
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Parathyroid hormone (PTH) and
Ca2+ control
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Adrenal glands
ad = to, toward, at ren = kidney
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Adrenal glands
Epinephrine & Norepinephrine
Corticosteroids - Aldosterone - Cortisol - Androgens (sex
hormones)
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Aldosterone
• Complex system • Maintaining blood pressure
through kidneys
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Cortisol
‘Stresshormone’ – long term stress Main functions: • formation of glucose • anti-inflammatory
• aids metabolism of fat, protein and carbohydrates
• reduces bone formation
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1. What happened here? Cushing’s syndrome 2. Causes? - Tumor (various places) - Drugs
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Androgens
• Adrenal sex hormones • Can convert into testosterone or estrogen • The amount is insignificant compared to what the testes/
ovaries produce during puberty and adulthood.
• Functions: - contribute to secondary sex characteristics - sex drive
42 Endocrine System
Epinephrine (Adrenaline)
• Hormone, but also neurotransmitter • Neural stimulus • ‘Fight or flight hormone’ –short term stress
Organ Effects Cardiovascular Increases heart rate and cardiac output
Vasoconstriction Respiratory Increases respiratory rate Metabolic Stimulates release of glucose Systemic Triggers breakdown of fat
Muscle contraction
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Other glands and hormones
Ovaries
Pineal gland
Testes
melatonine
estrogens and progesterone
testosterone
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Case 2: Pancreas
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Anatomy
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Case 2: Blood glucose levels
Glucagon Increases blood glucose level by releasing stored glucose from liver cells & synthesize glucose out of other molecules Insulin Lowers blood glucose level by storing free glucose in bodycells (liver, fat and muscle tissue)
Directly after a meal: Blood glucose levels: go up / go down Pancreas excretes: glucagon / insulin
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Case 2: Blood glucose levels
During a period of fasting: Blood glucose levels: go up / go down Pancreas excretes: glucagon / insulin
Glucagon Increases blood glucose level by releasing stored glucose from liver cells & synthesize glucose out of other molecules Insulin Lowers blood glucose level by storing free glucose in bodycells (liver, fat and muscle tissue)
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Insulin and Glucagon
49 Endocrine System
Case 2: Blood glucose levels
Draw a feedback scheme of how blood glucose levels are regulated by insulin and glucagon!
Glucagon Increases blood glucose level by releasing stored glucose from liver cells & synthesize glucose out of other molecules Insulin Lowers blood glucose level by storing free glucose in bodycells (liver, fat and muscle tissue)
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Diabetes Mellitus
• What does the name actually mean?
• diabetes = to go through • mellitus = honeysweet • Two different types: - Type 1: Lack of insulin - Type 2: Ineffective use of insulin https://www.youtube.com/watch?v=QeT1V8RmIbU
54 Endocrine System
Diabetes Mellitus
• >340 million people suffering worldwide • 90% of all cases is type 2 diabetes. • Mainly due to overweight and low-activity lifestyle.
• Treatment?
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Diabetes Mellitus
• Treatment options?
• Type 1: - Inject insulin
• Type 2: - Change lifestyle! - Insulin or other medications
+
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Long term effects
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Summary
• Other glands and hormones:
- Parathyroid glands and Ca2+ control - Adrenal glands - Pancreas and blood glucose levels
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Next time
• Exam on November 3rd Digital, open question, closed book
• DON’T FORGET TO REGISTER IN OSIRIS!
• Studymaterial (all lectures so far) is on Blackboard
• Good luck!
• Next lecture is on November 11th about the Immune System.
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OUDE SLIDES
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Working range
Biological Control Different stadia of a disease
Hyper condition Chronic
Manifest Latent Normal
condition
Hypo condition Chronic
Time (Months)
Leve
l of
sign
al
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Role of Negative Feedback Loops
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Biological Control (Simple) model control system
-
Controlled process
Controlling process
K1
K2
S (set point)
+
Comparator Error signale
Control variable y
sensor
C
64 Endocrine System
Endocrine System
Hypothalamus and the Anterior Pituitary Gland
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Endocrine System Negative Feedback Control of Thyroxine Secretion
=T4
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Secretion of Cortisol (stress hormone)
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[Ca]control in blood Parathyroid
Thyroid
Bone
[PT
H]
[Cal
cit.]
[Ca++]
[Ca++]
[PTH]
[Calcitonine] [C
a++]
[Ca++
]
Cooperation of
2 systems
Most important: PTH
Extra: Calcitonine
Advantage:
Increase and decrease actively
controlled
