Endocrine system

1
Endocrine system

• Chapter 45

2
(No Transcript)
3
Endocrine system

• Regulation communication
• Blood system
• Glands (ductless)
• Hormones (chemicals)
• Target tissues

4
(a) Endocrine signaling
Blood vessel
Response
5
Nervous system

• Regulation communication
• Nerves
• Axon
• Neurotransmitters
• Synapse

6
Both systems (overlap)

• Neurohormone
• Released by the nervous system
• Into blood stream (ADH)
• Norepinephrine
• Chemical involved in both
• Nervous system (cleft)
• Endocrine system (adrenal gland)

7
Both systems

• Neural control of endocrine system
• Hypothalamus
• Regulates hormonal secretion of the anterior
  pituitary
• Glands derived from nervous tissue
• Adrenal medulla, posterior pituitary pineal
  gland

8
Local regulators

• Paracrine
• Messages between neighboring cells
• 1. Cytokines
• Regulate immune system
• 2. Growth factors
• Regulate cell growth
• 3. NO
• Vasodilation (local blood vessels)

9
Local regulators

• 4. Prostaglandins
• 20-carbon fatty acid
• Derived from lipids in plasma membrane
• Found in many organs
• Released into interstitial fluid

10
Local regulators

• 4. Prostaglandins
• A. Immune system
• inflammation
• B. Reproductive system
• Labor
• Semen
• C. Digestive system
• Inhibit gastric secretions
• Increase gut motility

11
Local regulators

• D. Respiratory system
• Some cause dilation
• Some cause constriction
• E. Circulatory system
• Platelets
• F. Urinary system
• Renal vasodilation
• Increased excretion

12
Hormone types

• 1. Polypeptide
• Short, lt100 aa, insulin, ADH
• 2. Glycoprotein
• gt100 aa, carbohydrate attached, FSH, LH
• 3. Amines
• Tyrosine tryptophan
• Adrenal medulla (NE, Epinephrine)
• Thyroid (T3 T4
• Pineal (Melatonin)

13
Hormone types

• 4. Steroids
• Lipids from cholesterol
• Testosterone
• Estradiol, progesterone
• Aldosterone, cortisol

14
Mechanism of regulation

• 1. Enter the cell
• Lipophilic
• Lipid soluble
• 2. Do not enter the cell
• Lipophobic
• Water soluble

15
Mechanism of regulation

• 1. Lipophilic (Steroids, thyroxine)
• Not water soluble
• Plasma attached to protein carriers
• Target cell-release carrier
• Cross plasma membrane
• Bind receptor protein (/- nucleus)
• Hormone receptor binds DNA
• Protein synthesis

16
Mechanism of regulation
E\Chapter_45\A_PowerPoint_Lectures\45_Lecture_Pre
sentation\45_05bLipidSolubleHormone_A.html
17
Mechanism of regulation

• 2. Lipophobic or too large
• Bind receptors on target cell membrane
• A. Triggers second-messenger system
• cAMP
• IP3/Ca2
• B. Causes change in an ion channel

18
Mechanism of regulation
E\Chapter_45\A_PowerPoint_Lectures\45_Lecture_Pre
sentation\45_05aWaterSolubleHormone_A.html
19
Mechanism of regulation
20
Mechanism of regulation
21
Mechanism of regulation
22
(No Transcript)
23
Thyroid

• Neck
• 2 lobes/isthmus
• T4 (tetraiodothyronine) thyroxine
• T3 (triiodothyronine)
• Regulates metabolism in the body
• Calcitonin
• Stimulates Ca2 uptake into bones
• Decreases serum Ca2

24
Thyroid
25
Parathyroid glands

• Neck
• 4 small glands on top of thyroid
• PTH (parathyroid hormone)
• Increase in blood calcium levels
• Stimulates osteoclasts
• Break down calcium phosphate crystals
• Stimulates kidneys to reabsorb Ca2
• Activates Vitamin D

26
Parathyroid glands
27
Pancreas

• Abdomen behind stomach
• Islets of Langerhans
• Insulin (? cells)
• Decreases blood glucose levels
• Stores in glycogen (liver/muscle) fat (adipose
  cells)
• Glucagon (? cells)
• Increases glucose blood levels

28
Pancreas
29
(No Transcript)
30
Ovaries

• Abdomen
• Estrogen
• Secondary female characteristics
• Menstruation
• Progesterone
• Prepares/maintains pregnancy

31
Testes

• Inguinal region
• Testosterone
• Maintain male characteristics

32
Ovaries and Testes
33
Steroids
34
Adrenal glands

• Small glands on top of kidneys
• 1. Adrenal cortex
• Outer layer
• 2. Adrenal medulla
• Inner layer

35
Adrenal glands

• Adrenal cortex
• A. Corticosteriods
• Cortisol (glucocorticoid)
• Increases serum levels of glucose
• Gluconeogenesis
• Converts aa to glucose
• Exercise or fasting

36
Adrenal glands

• B. Mineralcorticoids
• Aldosterone
• Stimulates kidneys to reabsorb Na1
• Stimulates kidneys to eliminate K1
• C. Gonadocorticoids
• Androgens
• Sex characteristics

37
Adrenal glands

• Adrenal medulla
• Catacholamines
• Epinephrine/norepinephrine
• Increased heart rate, BP, glucose blood levels,
• Dilation of bronchioles
• Decreased blood flow to skin and gut

38
Adrenal glands
39
Pituitary gland (hypophysis)

• In the brain
• Hangs by a stalk from hypothalamus
• 1.Anterior
• Adenohypophysis
• Developed from epithelial tissue
• 2. Posterior
• Neurohypophysis
• Developed from the neural tissue
• Nerve axons from hypothalamus end here

40
Pituitary gland
41
Anterior pituitary gland

• All hormones stimulate growth in target organs
• Tropins
• A. GH (growth hormone)
• Somatotropin
• Stimulates muscle growth (bone)

42
Anterior pituitary gland

• B. ACTH
• Adrenocorticotropic hormone
• Corticotropin
• Stimulates adrenal cortex (cortisol)
• C. TSH
• Thyroid-stimulating hormone
• Thyrotropin
• Stimulates thryroid to produce thyroxine

43
Anterior pituitary gland

• D. LH
• Luteinizing hormone
• Stimulates ovulation lining of uterus
• Stimulates testes to produce testosterone

44
Anterior pituitary gland

• E. FSH
• Follicle stimulating hormone
• Stimulates the egg development
• Development of sperm
• F. Prolactin
• Stimulates mammary glands to produce milk

45
LH, FSH
46
Anterior pituitary gland

• G. MSH
• Melanocyte-stimulating hormone
• Causes darkening of skin in some fish, amphibians
  reptiles

47
Posterior pituitary gland

• A. ADH
• Antidiuretic hormone (vasopressin)
• Stimulates water retention in the kidneys
• B. Oxytocin
• Milk ejection from mammary glands
• Stimulates uterine contractions in labor

48
Pituitary gland
49
(No Transcript)
50
Pineal gland

• Small mass of tissue located near center of brain
• Synthesizes secretes melatonin (modified aa)
• Regulates functions related to day and night
• Seasons

51
Hypothalamus
Cerebrum
Thalamus
Pineal gland
Hypothalamus
Cerebellum
Pituitary gland
Spinal cord
Hypothalamus
Posterior pituitary
Anterior pituitary
52
Hypothalamus control

• Posterior pituitary (direct)
• Stimulation in hypothalamus
• Causes release of hormone from axon in pp
• ADH released increased blood osmolality
• Oxytocin released due to baby suckling

53
Hypothalamus
Hypothalamus
Neurosecretorycells of thehypothalamus
Axon
Posterior pituitary
Anterior pituitary
HORMONE
Oxytocin
ADH
Kidney tubules
TARGET
Mammary glands,uterine muscles
54
Hypothalamus control

• Controls release of AP hormones
• Neurons in Hypothalamus secrete releasing or
  inhibiting hormones
• Anterior Pituitary (negative feedback)

55
Hypothalamus
56
thyroid
Pathway
Example
Cold
Stimulus

Sensoryneuron
Hypothalamus secretesthyrotropin-releasinghormon
e (TRH )
Neurosecretorycell
Bloodvessel
Anterior pituitary secretes thyroid-stimulating ho
rmone (TSH or thyrotropin )
57
thyroid
Pathway
Example
Cold
Stimulus
Sensoryneuron

Hypothalamus secretesthyrotropin-releasinghormon
e (TRH )
Neurosecretorycell
Bloodvessel

Anterior pituitary secretes thyroid-stimulatingh
ormone (TSHor thyrotropin )
Negative feedback
Thyroid gland secretes thyroid hormone (T3 and
T4 )
Targetcells
Body tissues
Increased cellularmetabolism
Response
58
Anterior pituitary
Tropic effects onlyFSHLHTSHACTH
Neurosecretory cellsof the hypothalamus
Nontropic effects onlyProlactinMSH
Nontropic and tropic effectsGH
Hypothalamicreleasing andinhibitinghormones
Portal vessels
Endocrine cells ofthe anterior pituitary
Posterior pituitary
Pituitary hormones
HORMONE
FSH and LH
TSH
ACTH
Prolactin
MSH
GH
TARGET
Testes orovaries
Thyroid
Adrenalcortex
Mammaryglands
Melanocytes
Liver, bones,other tissues
59
Problems

• Thyroid
• Graves disease
• Over production of thyroxine
• Cretinism
• To little thyroxine in children
• Leads to delayed skeletal and mental growth

60
Hyperthyroidism
61
Negative feedback
62
Problems

• Diabetes mellitus
• Decreased insulin
• Decreased response to insulin
• Increased blood sugar

63
Diabetes
64
Problems

• Growth hormone (anterior pituitary)
• Gigantism too much hormone
• Pituitary dwarfism to little hormone
• Acromegaly to much hormone after growth plates
  are fused

65
(No Transcript)
66
Acromegaly
67
Problems

• Addisons disease
• Insufficiency in ACTH
• Increased pigmentation of skin
• Imbalance of electrolytes