Title: Chapter 45 ~ Chemical Signals in Animals Endocrine system ~Hormones
1Chapter 45 Chemical Signals in
AnimalsEndocrine system Hormones
growth hormones
2Regulatory systems
- Hormone chemical signal secreted into body
fluids (blood) communicating regulatory messages - Target cells body cells that respond to hormones
- Endocrine system/glands hormone secreting
system/glands (ductless) exocrine glands secrete
chemicals (sweat, mucus, enzymes) through ducts - Neurosecretory cells actual cells that secrete
hormones - Feedback mechanisms negative and positive
3Local regulators cells adjacent to or near
point of secretion
- Growth factors proteins for cell
proliferation - Nitric oxide (NO) neurotransmitter cell
destruction vessel dilation - Prostaglandins modified fatty
acids secreted by placenta and immune system
also found in semen
4Regulation
- Why are hormones needed?
- chemical messages from one body part to another
- communication needed to coordinate whole body
- daily homeostasis regulation of large scale
changes - solute levels in blood
- glucose, Ca, salts, etc.
- metabolism
- growth
- development
- maturation
- reproduction
growth hormones
5Regulation Communication
- Animals rely on 2 systems for regulation
- endocrine system
- system of ductless glands
- secrete chemical signals directly into blood
- chemical travels to target tissue
- target cells have receptor proteins
- slow, long-lasting response
- nervous system
- system of neurons
- transmits electrical signal release
neurotransmitters to target tissue - fast, short-lasting response
6Regulation by chemical messengers
- Neurotransmitters released by neurons
- Hormones release by endocrine glands
endocrine gland
neurotransmitter
axon
hormone carried by blood
receptor proteins
receptor proteins
Lock Keysystem
target cell
7Classes of Hormones
- Protein-based hormones
- polypeptides
- small proteins insulin, ADH
- glycoproteins
- large proteins carbohydrate FSH, LH
- amines
- modified amino acids epinephrine, melatonin
- Lipid-based hormones
- steroids
- modified cholesterol sex hormones, aldosterone
insulin
8Mode of Action Chemical Signaling
- 1- Plasma membrane reception
signal-transduction pathways
(neurotransmitters, growth factors, most
hormones) - 2- Cell nucleus reception
steroid hormones, thyroid
hormones, some local regulators
9Action of lipid (steroid) hormones
steroid hormone
target cell
blood
S
1
S
cross cell membrane
protein carrier
S
2
cytoplasm
binds to receptor protein
becomes transcription factor
5
mRNA read by ribosome
S
3
plasma membrane
4
DNA
mRNA
6
7
nucleus
protein
protein secreted
ex secreted protein growth factor (hair, bone,
muscle, gametes)
10Action of protein hormones
signal-transduction pathway
1
signal
proteinhormone
plasma membrane
P
activates G-protein
binds to receptor protein
activates enzyme
cAMP
acts as 2 messenger
receptor protein
ATP
transduction
GTP
activatescytoplasmicsignal
ATP
activates enzyme
2
secondary messengersystem
activates enzyme
cytoplasm
response
3
produces an action
target cell
11Benefits of a 2 messenger system
1
signal
Activated adenylyl cyclase
receptor protein
Not yet activated
2
amplification
4
amplification
3
cAMP
5
amplification
GTP
G protein
protein kinase
6
amplification
enzyme
Cascade multiplier!
7
amplification
FAST response!
product
12Maintaining homeostasis
hormone 1
lowersbody condition
gland
specific body condition
raisesbody condition
gland
Negative FeedbackModel
hormone 2
13Vertebrate Endocrine System
- Tropic hormones a
hormone that has another endocrine gland as a
target - Hypothalamuspituitary
- Pituitary gland
- Pineal gland
- Thyroid gland
- Parathyroid glands
- Thymus
- Adrenal glands
- Pancreas
- Gonads (ovary, testis)
14Nervous Endocrine systems linked
- Hypothalamus master nerve control center
- nervous system
- receives information from nerves around body
about internal conditions - releasing hormones regulates release of hormones
from pituitary - Pituitary gland master gland
- endocrine system
- secretes broad rangeof tropic hormones
regulating other glands in body
hypothalamus
posterior
pituitary
anterior
15tropic hormones target endocrine glands
hypothalamus
thyroid-stimulating hormone (TSH)
antidiuretic hormone (ADH)
posterior pituitary
Thyroid gland
anterior pituitary
Kidney tubules
adrenocorticotropic hormone (ACTH)
oxytocin
Muscles of uterus
gonadotropic hormones follicle- stimulating horm
one (FSH) luteinizing hormone (LH)
melanocyte-stimulating hormone (MSH)
growth hormone (GH)
prolactin (PRL)
Adrenal cortex
Melanocyte in amphibian
Mammary glands in mammals
Bone and muscle
Ovaries
Testes
16The hypothalamus pituitary, I
- Releasing and inhibiting hormones
- Anterior pituitary
- Growth (GH)bones vgigantism/dwarfism
vacromegaly - Prolactin (PRL)mammary glands milk production
- Follicle-stimulating (FSH)
- Luteinizing (LH)ovaries/testes
- Thyroid-stimulating (TSH) thyroid
- Adrenocorticotropic (ACTH) adrenal cortex
- Melanocyte-stimulating (MSH)
- Endorphinsnatural opiates brain pain
receptors
17The pituitary, II
- The posterior pituitary
- Oxytocin uterine and mammary gland cell
contraction - Antidiuretic (ADH) retention of water
by kidneys
18The pineal, thyroid, parathyroid
- Melatonin pineal gland biological rhythms
- Thyroid hormones Calcitonin lowers
blood calcium Thyroxine metabolic processes - Parathyroid (PTH) raises blood calcium
19Regulation of Blood Calcium
Endocrine System Control
Feedback
calcitonin
blood calcium level(10 mg/100mL)
activated Vitamin D
parathyroid hormone (PTH)
20Regulating metabolism
- Hypothalamus
- TRH TSH-releasing hormone
- Anterior Pituitary
- TSH thyroid stimulating hormone
- Thyroid
- produces thyroxine hormones
- metabolism development
- bone growth
- mental development
- metabolic use of energy
- blood pressure heart rate
- muscle tone
- digestion
- reproduction
tyrosine iodine
thyroxines
21The pancreas
- Islets of Langerhans
- Alpha cells glucagon raises blood
glucose levels - Beta cells insulin lowers blood
glucose levels - Type I diabetes mellitus (insulin-dependent
autoimmune disorder) - Type II diabetes mellitus (non-insulin-dependent
reduced responsiveness in insulin targets)
22Regulation of Blood Sugar
Endocrine System Control
Feedback
islets of Langerhans beta islet cells
insulin
body cells takeup sugar from blood
liver storesglycogen
reducesappetite
blood sugar level (90mg/100ml)
liver releasesglucose
triggershunger
islets of Langerhansalpha islet cells
glucagon
23The adrenal glands
- Adrenal medulla (catecholamines) epinephrine
norepinephrine increase basal metabolic rate
(blood glucose and pressure) - Adrenal cortex (corticosteroids) glucocorticoids
(cortisol) raise blood glucose
mineralocorticoids (aldosterone) reabsorption
of Na and K
24The gonads
- Steroid hormones precursor is cholesterol
- androgens (testosterone) sperm formation male
secondary sex characteristics gonadotropin - estrogens (estradiol)uterine lining growth
female secondary sex characteristics
gonadotropin - progestins (progesterone)uterine lining growth