2. Two main control systems
1. The nervous system
2. The endocrine system
Slow control system
Rapid control system
3. Endocrine glands
Exocrine glands
ductless
Have ducts
Secrete their products
(hormones) into the
blood
Secrete their products to
the outer surface or the
lumen of GIT
Can reach distant tissue Can not
7. Classification of hormones
1. According to their chemical nature
1. Protein and polypeptide H.
Hypothalamic, pituitary, pancreatic &
parathyroid H.
2. Steroid H.
Adrenocortical and gonadal H.
3. Hormones derived from a.a.
Thyroid h. & adrenal medullary h.
9. 2. According to their origin
Hypophysiotropic hormones
1. Releasing H.
GHRH
Thyrotropin (TSH) RH (TRH)
Hypothalamus Corticotropin RH
Gonadotropin RH
2. Inhibiting H.
Somatostatin (SS)
Prolactin inhibiting H.
10. GHRH GHIH (SS)
Hypothalamus
PIH
TRH
CRH
Anti-diuretic H.
(ADH)
GnRH
Anterior
pituitary
Growth H.
prolactin H.
Thyrotropin
TSH
Corticotropin
ACTH
posterior
pituitary
FSH & LH
(gonadotropins)
gonads
T3&T4
Thyroid G.
Oxytocin
steroids
Sex H.
11. Mechanisms of hormone action
What is meant by a target cell?
What are the target cells
of GHRH?
a. cells of the Hypothalamus
b. Anterior pituitary cells
c. Posterior pituitary cells
d. Bone cells
GH
12. I. Mechanism of action of protein &
polypeptide hormones:
The hormone (1ry messenger) binds to a cell
membrane receptor of target cell
formation of a 2nd messenger inside the cell
- cAMP
- Calcium-calmodulin
- DAG & IP3
changing the activity of certain enzymes
16. II. Mechanism of action of Steroid H.
Receptor
Increase or a decrease in the synthesis
of a certain protein
17. III. Mechanism of action of Thyroid H.
T
T
T
T
T
T
Receptor
Increase in the synthesis of certain proteins in almost all cells
18. Protein or
polypeptide H.
Hypothalamic,
pituitary,
parathyroid,
pancreatic
Cell membrane
R.
2ry messenger
- cAMP
-Ca-calmodulin
-DAG & IP3
Change the
activity of
already present
enzymes
Steroid H.
H. derived from
a.a.
Adrenocortical
& Gonadal h.
Thyroid &
adrenal
medullary h.
Cytoplasmic R.
Nuclear R.
_
_
Synthesis of
new proteins
Synthesis of
new proteins
19. Regulation of hormone secretion
Hypothalamus
Ant. Pituitary G.
Hormone
-hormone
feedback
Target gland
Substratehormone
feedback
Target gland hormone
Substrate
Mineral
Mineralhormone
feedback
23. Hypothalamus
Anterior pituitary gland hormones
Anterior pituitary gland hormones
The anterior pituitary produces & secretes
its own hormones
Anti-diuretic H
Its Hormones are given the extension; (ADH)
tropic, tropin or trophic
posterior
Anterior
pituitary
It is the master pituitary
for the majority of the
Oxytocin
endocrine glands
Growth H.
prolactin H.
Thyrotropin
TSH
Corticotropin
ACTH
FSH & LH
(gonadotropins)
gonads
T3&T4
Thyroid G.
steroids
Sex H.
24. Which of these is not produced by
the anterior pituitary?
► ACTH
► follicle-stimulating
► Somatostatin
(ss)
► Somatotropic H.
hormone (FSH)
26. 2. On protein metabolism
It is an anabolic hormone
mRNA
1. Rate of DNA
transcription
2. a.a. transport into the
cell
a.a.
a.a
.
27. 3. On carbohydrate metabolism
It increases blood glucose level (diabetogenic
action)
Glycogen
glucose
1
Insulin R. X
Glycogen
synthase
Glucose 6-PO4
2
Glucose
transporter
phosphorylase
Glycolysis
pyruvate
28. 4. On lipid metabolism
GH
Lipolysis
Fat (T.G.)
FA
Glycerol
FFA
29. Factors affecting GH secretion
GH secretion is
increased by
GHRH
Low blood glucose
and FFA
Protein meal
Emotional stress
Deep sleep
GH secretion is
Decreased by
somatostatin
High blood glucose
and FFA
treatment with
corticosteroids
30. Disorders of GH secretion
A. Growth hormone deficiency (dwarfism)
Decrease in
the size of the
trunk &
extremities
Normal
mental &
sexual
development
32. B. Growth hormone Excess
Before closure of epiphyses
Gigantism
taller than normal
After closure of epiphysis
Acromegaly
33. Main features
of acromegaly
No linear growth
of bones
1. Bones of hands
and feet
2. Bones of the face
3. Mandible
4. The spine
5. Diabetes
34. Hormone
Actions
Deficiency
Pituitary
On bone
dwarfism:
linear
growth (via Only failure
somatomedin) of physical
develop.
Growth On protein
H.
Anabolic
(Ant.
Pituitary
On CHO
Pituitary(
infantilism:
Diabetogenic
Failure of
On lipid
physical &
lipolysis
sexual
develop.
Excess
Gigantism:
Before
closure of
epiphysis
Acromegaly
After
closure of
epiphysis
35. Growth hormone
A. directly stimulates growth of cartilage
and bone.
B. enhances protein breakdown in nonvital
muscles.
C. levels are subnormal in Gigantism.
D. promotes lipolysis in adipose tissue.
42. Regulation of ADH secretion
H2 o
+
ADH- secretion is
increased by
Hypovolaemia
osmotic pressure of ECF
Baroreceptors
& low pressure volume (e.g. Hge)
blood R
Stress
Drugs (e.g. morphine &
nicotine)
Na+
osmoreceptors
43. Disorders of ADH secretion
ADH deficiency
1. Polyuria
2. Polydipsia
3. Loss of water
soluble vitamins
Diabetes insipidus
44. Oxytocin
It is a protein hormone
Formed in paraventricular n. of the
hypothalamus and secreted from the
posterior pituitary
Actions of Oxytocin
1. Uterine contraction during delivery
2. Milk ejection action during suckling
3. Mild antidiuretic action
47. Hormones secreted from the thyroid gland
From thyroid follicle cells
From parafollicular
cells
Thyroid Hormones
T3 (tri-iodothyronine)
T4 (tetra-iodothyronine,
thyroxine)
Thyrocalcitonin
(calcitonin)
It affects body metabolism
It affects Ca
homeostasis
48. Actions of Thyroid hormones
T
T
T
T
T
T
Receptor
Synthesis of
new protein
49. mRNA
Physical
mental
Proteins for
growth &
maturation
Sexual
5 Respiration
6 CVS
7 CNS
O2
Enzymes &
transport
ptns
O2 consumption
No of
mitochondria
Metabolic rate 2
substrate
3 GIT
4 Metabolism
blood glucose
blood FFA (lipolysis)
1
Calorigenic
effect
50. Hypothalamus
Cold &
+
emotional
stress
Regulation of thyroid hormones
++
Thyroid h. secretion is Ant.
regulated by :
-1. TRH
pituitary
--
2. TSH
3. Feedback
Mechanism
++
4. Cold
5. Stress
Iodine
deficiency
Thyroid
51. Disorders of thyroid hormone
secretion
A. Hypothyroidism
In adults
Myxoedema
1. BMR & calorigenesis
2. Generalized decrease in activity of all body
systems
3. Myxoedematous tissue
CVS: Heart rate & Cardiac output
GIT: intestinal motility (constipation)
CNS: slow mentation & sluggish reactions, S
52. Since birth
Cretinism
Delayed physically: Dwarf, teeth erupt later
than normal
Delayed mentally
Delayed sexually
Special features:
Depressed nasal bridge
Wide nostrils
Protruding tongue
Protuberant abdomen
54. Characters of hyperthyroidism
1. BMR & calorigenesis
2. Generalized increase in activity of all body
systems
3. Loss of weight in spite of increased food
intake
CVS: Heart rate & Cardiac output
GIT: intestinal motility (diarrhea)
CNS: tremors, irritability, insomnia
55. Calcium homeostasis
The adult human body contains 1 Kg of calcium
Functions of calcium:
1. Mineralization of bones & teeth
2. Blood clotting
3. Neuromuscular excitability
4. Muscle contraction & relaxation
5. Release of neurotransmitters
6. Hormonal secretion & act as a 2ry messenger
57. Plasma calcium:
Its concentration is about 10mg/dl
1. Ionized 50%
2. Bound to protein 40%
3. Complex & diffusible form 10%
Solubility product:
[Ca2+] x [PO43-] = constant
58. Bone
Bone tissue is formed of:
1. Organic matrix (formed mainly of collagen)
2. Crystalline salts (mainly hydroxyapatite
crystals & calcium phosphate)
3. Bone cells
A. Osteoblast
Ca
hydroxide
Ca
phosphate
B. Osteocyte
C. Osteoclasts
hydroxyapatite
59. Secrete
Bone matrix
proteins
Alkaline
phosphatase
Phosphate
ester
phosphate
Secrete
Bone
forming
cells
Ca
phosphate
H+ that
dissolve
Bone
hydroxyapatite eating
Acid protease cells
that dissolve
collagen
61. Hormonal control of plasma Ca level
Ca++
3 hormones play a role in the control of plasma Ca
Ca++
level
1. Parathormone hormone (PTH)
Source: Parathyroid gland
Hydroxyapatite
Actions:
crystals
Ca++
1. On bones
A.Rapid phase
2. On kidney
B.Slow Phase
3. On GIT
Ca++
Ca++
Ca++
PTH
67. Tetany
It is a state of increased neuromuscular excitability
due to decreased ionized calcium
Causes
Hypoparathyroidism
Vitamin D deficiency
Renal disease
Akalemia
Types:
Latent tetany: when the total plasma Ca is
between 9 and 7 mg/dl. Its manifestations do
not appear during rest
Manifest tetany: when the total plasma Ca
drops below 7mg%. The patient is presented
by spasmodic contractions
68. The adrenal glands
Each adrenal gland consists of two
endocrine organs
1. Adrenal cortex
Secretes steroid hormones
2. Adrenal medulla
Secretes catecholamines
cortex
71. Actions of cortisol depends on its plasma
level:
1. Permissive Actions
its presence even at small amounts
permits certain processes to occur
2. Physiological Actions
Effects of the normally present hormone
levels in plasma
3. Pharmacological Actions
Effects of the high levels of hormone in
plasma
72. 1. Permissive Actions
It means that cortisol does not initiate the
changes, but its presence even at small
amounts permits certain processes
Glycogenolysis
Glucagon &
catecholamines
Arteriolar V.C.
response &
bronchodilatation
Catecholamines
73. 2. physiological Actions
I. Effect on metabolism
1
Gluconeogenesis
a.a.
Glucose
glycogen
Blood
glucose
Blood
FFA
Glycogen
protein
glucose
2
Glycogen
phosphorylase
Lipolysis
synthase
Glucose 6-PO4
Fat (T.G.)
3 Glycolysis
FA Glycerol
pyruvate
74. I. Effect on metabolism
II. Effect on CNS
Required for normal EEG pattern
III. Weak mineralocorticoid effect
IV. Anti-stress effect
Permissive action
catecholamines
V.C.
Blood glucose
Plasma a.a.
Plasma FFA
79. Disorders of adrenocortical hormones
1.cause:
Cushing’s syndrome
Hypersecretion of cortisol + excess androgen
2. Features
I. Excess cortisol
1. CHO metabolism (DM)
2. Excess protein catabolism
3. Disturbed fat deposition
II. Mineralocorticoid effect
III. Excess Androgens
Moon face
Buffalo hump
Purple striae
80.
81. Addison’s syndrome
1.cause:
Hyposecretion of adrenocortical hormones
2. Features
I. Mineralocorticoid deficiency
1. Hypotension
2. Polyuria & polydipsia
3. Hyperkalemia
Aldosterone H2O
actions
Na+
B. K
Actions
Mineraloco
:
rticoids
ECFV
+
82. II. Glucocorticoid deficiency
1. Metabolism
Depression of many metabolic
functions
- CHO
metabolism
2. Appetite
3. During
stress
4. ACTH
hypoglycemia
Loss of appetite
weight loss
Decreased resistance to stress
ACTH
skin pigmentation
87. Actions of insulin
I. On CHO metabolism:
In skeletal m., cardiac m. & adipose tissue
Glycogen
Glycogen
synthase
glucose
phosphorylase
Glucose 6-PO4
Glycolysis
Insulin R.
Glucose
transporter
pyruvate
89. II. On lipid metabolism: lipogenesis
III. On protein metabolism: (Anabolic)
IV. On Growth
mRNA
1. Rate of DNA
transcription
2. a.a. transport into the
cell
a.a.
a.a
.
90. Actions of Glucagon
Insulin
Glucagon
On CHO
metabolism
glycogenolysis
gluconeogenesis
glycogenolysis
gluconeogenesis
On lipid
metabolism
Lipogenesis
Lipolysis
On protein
metabolism
Anabolic
Catabolic
hyperglycemia
hypoglycemia
Stimulus
92. Glucose Homeostasis
The importance to maintain a normal blood
glucose concentration
Insulin returns blood glucose
Body response to ingestion of a meal (high
140
level back to control level
glucose)
120
100
1h
2h
3h
4h
93. Mechanisms controlling blood
glucose concentration
1. Glucostatic function of the liver
Glycogenesis (after meals)
Glycogenolysis (between meals)
Gluconeogenesis (during fasting)
2. Hormonal Mechanism
Both insulin & glucagon function as important
feedback control systems to maintain a normal
blood glucose level