Download File ap notes chapter 45

Chapter 45: Hormones & the Endocrine
System
Regulatory systems
Nervous system
High
speed messages
Endocrine
Slower;
system
longer lasting
Result of hormone secretion
Connections between Nervous & endocrine
systems
Neurosecretory cells
Nerve
cells that release hormones
Concentrated in hypothalamus
Some
Ex:
hormones act as neurotransmitters
epinephrine

Hormones


Chemical signal secreted into circulatory
system through ductless glands
Action of hormones

Operate at all levels of organization


Produce developmental change


Intracellular, cell to cell, organ to organ, organism
to organism (pheromones)
Ex. puberty
Metamorphosis (insects & amphibians)

Incomplete


Eggnymphadult (grasshoppers)
Complete

Egglarvapupaadult (butterfly)

Regulation of hormones

Negative feedback



Positive feedback



Increase in substance inhibits its own production
Ex. Metabolic control
Increase in substance increases its own production
Ex. Release of milk in nursing mother
Local regulators

Histamines


Interleukins


Chemical from local cell for antigen-antibody response
(allergies)
Cytokine acting as communicator between immune cells
Prostaglandins

Modified fatty acid which stimulates contraction of smooth
muscles, induces fever & blood flow to infection sites

Classes of molecules acting as hormones




Proteins & peptides; H2O soluble
Amines (derived from amino acids); H2O
soluble
Steroids; non- H2O soluble
Events of hormone action

Reception (signal binds to receptor protein in
or on target cell)
Water soluble hormones bind to surface receptor
triggering activation of internal proteins in
transduction pathway
 Steroid hormones enter cell & bind to internal
receptor which enters nucleus to activate genes



Signal transduction
response
Endocrine Gland
Hormone
Effect on target tissue
Anterior pituitary
(adenohypophysis)
FSH
Stimulate growth of
ovarian follicle & sperm
production
LH
Stimulate ovulation;
secretion of sex
hormones by
ovaries/testes
Prolactin
Induces milk secretion
in mammary glands
TSH
Stimulate throxin
production by thyroid
ACTH
Stimulate adrenal cortex
to produce cortisone
GH
Stimulate growth
MSH
Regulation of pigment in
skin cells; inhibits
hunger
Beta endorphin
Dull pain perception
Endocrine Gland
Hormone
Effect on Target tissue
Posterior pituitary
(neurohypophysis)
ADH
Stimulate increased H2O
absorption by kidneys;
constrict blood vessels
Oxytocin
Stimulate uterine
contractions & release
of milk
Thyroxin (T4) &
Triiodothyronine (T3)
Stimulate oxidative
metabolism
Calcitonin
Regulation of calcium &
phosphate blood levels
Parathyroid gland
Parathormone (PTH)
Controls abosorption of
Ca & P from blood;
stimulates release of Ca
from bone
Thymus
Thymosin
Stimulates production of
T lymphocytes
Adrenal cortex
Cortisone*
Regulate H2O
reabsorption, electrolyte
balance, protein &
carbohydrate
metabolism
Thyroid gland
Endocrine gland
Hormone
Effect on target tissue
Adrenal medulla
Epinephrine &
norepinephrine
Raises blood glucose
levels; increases
metabolic activity;
constricts blood vessels
Pancreas (islet of
Langerhans)
Insulin (beta cells)
Stimulates uptake of
glucose by cells
Glucagon (alpha cells)
Converts glycogen into
glucose
Estrogen*
Stimulate female
secondary sex
characteristics; build
uterine lining
Progesterone*
Maintain pregnancy
Testes
Testosterone*
Stimulate male
secondary sex
characteristics
Pineal
Melatonin
Biological rhythms
Ovaries
*denotes steroid hormone
Endocrine Disorders

Thyroid

Cretinism


Goiter



Most common form of hyperthyroidism
Autoimmune
Hashimoto’s disease



Enlarged gland usually related to hypothyroidism
Graves disease


Under secretion of thyroxin in utero
Most common form of hypothyroidism
autoimmune
Pituitary

Dwarfism


Giantism


Under secretion of GH in child
Over secretion of GH in child
Acromegaly

Over secretion of GH in adult

Pancreas

Diabetes mellitus

Type I (insulin dependant)



Type II




Autoimmune
Beta cells destroyed; little to no insulin production
Reduced responsiveness of target cells to insulin
Controlled through diet & exercise
Accounts for >90% of diabetes cases
Adrenal gland

Addison’s disease

Under-secretion of ACTH