Transcript Endocrine (regulatory) System

Endocrine (regulatory) System
Chapter 45
Introductory Questions #3
1)
2)
3)
4)
5)
Name the nine major endocrine glands found in the body.
Which one ins called the “master gland”?
Name three major local regulators that act on nearby target
cells. (pgs. 947-948)
Name three key molecules that play a role in the signal
transduction pathway (typical reactions in the endocrine
system).
How is the anterior part of the pituitary gland different from
the posterior part? Name the hormones secreted from each
area. Which region secretes fewer types of hormones?
Using the table on pg. 949, name the hormone(s) that:
-Raises blood-calcium levels
-maintains metabolic processes
Vertebrate Endocrine System
•
•
•
•
•
•
•
•
•
•
Tropic hormones ~
a hormone that has another
endocrine gland as a target
Hypothalamus~pituitary
Pituitary gland
Pineal gland
Thyroid gland
Parathyroid glands
Thymus
Adrenal glands
Pancreas
Gonads (ovary, testis)
Regulatory 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
Local 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
Mode 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
Hypothalamus & Pituitary Gland
•
•
•
•
•
•
•
•
•
•
Releasing and inhibiting hormones
Anterior pituitary:
Growth (GH)~bones
√gigantism/dwarfism
√acromegaly
Prolactin (PRL)~mammary glands;
milk production
Follicle-stimulating (FSH) &
Luteinizing (LH)~ovaries/testes
Thyroid-stimulating (TSH)~ thyroid
Adrenocorticotropic (ACTH)~
adrenal cortex
Melanocyte-stimulating (MSH)
Endorphins~natural ‘opiates’; brain
pain receptors
Hypothalamus & Pituitary Gland
Posterior Region of the Pituitary Gland
• The posterior pituitary:
• Oxytocin~
uterine and mammary gland
cell contraction
• Antidiuretic (ADH)~
retention of water by kidneys
The Pineal, Thyroid, & Parathyroid
• Melatonin~ pineal gland;
biological rhythms
• Thyroid hormones:
Calcitonin~
lowers blood calcium
Thyroxine~
metabolic processes
• Parathyroid
(PTH)~ raises blood
calcium
The 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)
The 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+
The 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
Ch. 45 Endocrine System: Systems in Balance
1.
2.
3.
4.
5.
What organism does Dr. Hunt & Dr. Fry use to discuss and show
how a toxic chemical affects hormone balance?
How is a hormone defined in the video and how do these chemicals
control metabolic activities in animals?
What two structures in the brain does Dr. Catherine Rivier explore
that relates to stress?
How is the endocrine system similar to the nervous system? How
do they interact?
In the final segment name two methods scientists use to study the
endocrine system and the effects of hormones?
Important Text Pages: Pg.
**Write the title for each segment and FIVE statements for each
segment.
The 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
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
Homeostasis & Osmoregulation
Chapter
Let Sleeping Bears Lie
• Bears don’t technically hibernate
– They do enter a dormant state, when their body
temperature drops by several degrees
• Bears are endotherms
– Endothermic animals derive
most of their body heat from
metabolism
– Ectothermic animals warm
themselves mainly by absorbing
heat from their surroundings
• Dormant bears have internal homeostatic
mechanisms that compensate for fluctuations in
the external environment
– Thermoregulation maintains the
body temperature within a
tolerable range
– Osmoregulation controls the
gain and loss of water and
dissolved solutes
– Excretion is the disposal of
metabolic wastes
Heat is gained or lost in four ways
• Body temperature regulation requires
adjustment to heat gained from or lost to an
animal’s environment
Convection
Radiation
Evaporation
Conduction
Figure 25.1
• Hormonal changes may increase heat production
by raising the metabolic rate
– Fur and feathers help the body retain heat
– Shivering, as these honeybees are doing, also
increases metabolic heat production
Figure 25.2A
The liver is vital in homeostasis
• It assists the kidneys by
– making urea from ammonia
– breaking down toxic chemicals
Homeostasis: regulation of internal environment
• Thermoregulation
internal temperature
• Osmoregulation
solute and water balance
• Excretion
nitrogen containing waste
•
•
•
•
•
•
Regulation
of
body
temperature
Thermoregulation
4 physical processes:
Conduction~transfer of heat between
molecules of body and environment
Convection~transfer of heat as
water/air move across body surface
Radiation~transfer of heat produced
by organisms
Evaporation~loss of heat from liquid
to gas
• Sources of body heat:
•
•
Ectothermic: determined by
environment
Endothermic: high metabolic rate
generates high body heat
•
Regulation during environmental
Torpor~ low activity; decrease
in
extremes
metabolic rate
• 1- Hibernation
long term or winter torpor
(winter cold and food scarcity);
bears, squirrels
• 2- Estivation
short term or summer torpor (high
temperatures and water scarcity);
fish, amphibians, reptiles
• Both often triggered by length of
daylight