Download Document

Endocrine System
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Endocrine System
Primary function: produce ____________
► Works together with __________ system to maintain ____________
► Hormones act on specific target cells
to produce specific effects
► No _________
►
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Endocrine System vs. Nervous System
Characteristic
General Function
Reaction to stimuli
Duration of effect
Target tissue
Chemical messenger
Endocrine System
Nervous System
Maintain homeostasis
Maintain homeostasis
slow
rapid
long
short
entire body
muscles and glands
hormone
neurotransmitter
Messenger producing cell
endocrine gland
neurons
Distance to target cells
long (via bloodstream) short (across synaptic space)
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Exocrine/Endocrine Glands
Gland
Pancreas
Ovary
Testes
Kidney
Exocrine
Endocrine
digestive enzymes
insulin, glucagon
egg
estrogen, progesterone
sperm
testosterone
urine
erythropoietin
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
►
►
Chemical messengers produced
by endocrine glands
Secreted into interstitial fluid
and absorbed into blood
vessels
Hormones
 Contact all cells in body
►
Produce effects only on cells
containing specific receptors
 __________ cell
 ‘Lock and key’ arrangement
causes a change in activity of
target cell
► Growth hormone—all cells
► Prolactin—mammary tissue
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Control of
Hormone Secretion
___________ feedback systems (like
a thermostat)
►
If hormone level is low:
 Appropriate endocrine gland is
stimulated to produce more hormone
►
Once adequate hormone concentration is
attained in the bloodstream:
 Stimulation of endocrine gland is
reduced and production of the
hormone is stopped/reduced
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Control of Hormone Secretion
►
Direct stimulation from the nervous system
 Secretion of some hormones is stimulated by ________________ nerve
impulses when an animal feels threatened.
► “Fight
or flight" response
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Hypothalamus
►
Part of _____________ section of brain
►
Controls activities of pituitary gland
 Portal system of blood vessels links
hypothalamus with anterior portion of
pituitary gland
►
Modified neurons in hypothalamus secrete
releasing and inhibiting hormones into
portal blood vessels
 Specific for a particular anterior pituitary
hormone
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Hypophyseal Portal System
GHRH, GHIH (Don’t memorize)
Thyrotropin releasing hormone (TRH)
Gonadaotropin releasing hormone (GnRH)
PRH, PIH
Corticotropin releasing hormone (CRH)
Growth hormone
Thyroid stim hormone (TSH)
Follicle stim hormone (FSH)
Luteinizing hormone (LH)
Prolactin
Adrenocorticotropic hormone (ACTH)
Melanocyte stim hormone (MSH)
Posterior
pituitary
Oxytocin
Antidiuretic hormone (ADH)
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Hypothalamus
►
Modified neurons in hypothalamus also
secrete antidiuretic hormone (ADH)
and oxytocin
►
Transported to posterior pituitary (along
neurons) for storage
►
Released into the bloodstream by nerve
impulses from hypothalamus
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
►
Two separate glands with different
structures, functions, and
embryological origins
 Anterior pituitary _______hypophysis; rostral
portion
Pituitary
Gland
(Hypophysis)
► Stimulated
by hypothalamus (portal
system) and direct (neg) feedback
from target tissues to produce
hormones
 Posterior pituitary _______hypophysis; caudal
portion
► Stores
and releases hormones
produced in hypothalamus
(oxytocin, ADH)
Rostral
Caudal
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Growth Hormone (GH)
►
►
►
a.k.a. somatotropin and somatotropic hormone
Promotes body growth in young animals
Helps regulate metabolism of proteins, carbohydrates, and lipids in
all body cells
The effect of GH on protein metabolism is to encourage
anabolism (synthesis of proteins by body cells)
► The effects of GH on carb and lipid metabolism are linked.
►
 While lipids are broken down via catabolism for energy production, the
use of carbs (especially glucose) as energy sources is discouraged.
 Less glucose is removed from the blood and hyperglycemia occurs
(hyperglycemic effect).
 Important for the body to maintain a balance between GH and insulin to
control blood glucose levels.
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Prolactin
►
Helps trigger and maintain
__________ in females
 Secretion of milk by mammary
glands
►
Prolactin production continues as
long as ________ are stimulated by
nursing or milking
►
When prolactin stimulation stops:
 Milk production stops
 Mammary gland shrinks to
original/nonlactating size
1. Baby sucks/stimulates
2. ↓PIH, ↑PRH
3-4. Stimulates milk glands
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
ThyroidStimulating
Hormone (TSH)
►
a.k.a. Thyrotropin/Thyrotropic
►
Stimulates growth/development
of thyroid gland and causes
thyroid to produce its hormones.
►
Secretion regulated by:
Hormone
Feedback (neg) from thyroid gland
hormone
► Thyroid
hormone levels too lowTSH production increases
► Thyroid hormone levels too highTSH production diminishes
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Adrenocorticotropic Hormone (ACTH)
►
Stimulates growth/development of adrenal
cortex and the release of some of its
hormones
►
Regulated by:
 Release of CRF from hypothalamus to
anterior pituitary through portal system
 Negative feedback from adrenal
hormones and administered cortisones
 During sudden stress, ACTH can quickly
be released after the hypothalamus is
stimulated to send out ACTH- releasing
factor (CRF/CRH) to the anterior
pituitary via the portal system
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
►Females—stimulates
growth/development of ovarian
follicles – where oogenesis occurs
►Also stimulates the cells lining the
follicles to produce/secrete
____________
►Used to superovulate
Males- stimulates
__________________
in the testes
FollicleStimulating
Hormone
(FSH)
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
►
Completes follicle development in
ovary
►
Increasing amounts of estrogens
feedback to the anterior pituitary and
cause reduced production of FSH and
increased production of LH
►
LH levels reach a peak when follicle
is fully mature
Luteinizing
Hormone (LH)
 Usually causes _______________
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
►
After ovulation, LH stimulates cells
in empty follicle to multiply and
develop into ________
__________(CL)
Luteinizing
Hormone (LH)
 CL produces progesterone necessary
for maintenance of
______________
►
In males, LH stimulates interstitial
cells to produce _______________
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Melanocyte-Stimulating Hormone (MSH)
►
Controls color changes in pigment
cells (melanocytes) of reptiles,
fish, and amphibians
►
Administration of artificially large
amounts of MSH to higher
mammals can cause darkening of
skin from melanocyte stimulation
(↑ melanin)
 Effect at normal levels in
mammals unknown
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
►
________(does NOT produce) two
hormones produced in hypothalamus
 ______________ _________(ADH)
and _______________
►
Transported from hypothalmus to post
pituitary along axons and stored in
nerve endings
►
Periodically released into
bloodstream in response to
nerve impulses from
hypothalamus
Posterior
Pituitary
Posterior
pituitary
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Oxytocin
ADH
►
►
►
Helps prevent diuresis
Receptors in hypothalamus detect changes in osmotic pressure
(concentration) of blood (due to dehydration - hemoconcentration)
 Generates nerve impulses from hypothalamus- causes release of ADH
► ADH causes kidneys to reabsorb more water
from urine and return it to bloodstream
► Urine then more concentrated
ADH deficiency causes Diabetes ____________ (PU/PD occurs)
Antidiuretic
Hormone
(ADH)
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Oxytocin
►
Effects on uterus:
 Causes ____________ of myometrium at breeding and at
parturition
 Induces uterine contractions that aid transport of spermatozoa to
oviducts
 Stimulates uterine contractions that aid in delivery of fetus and
placenta
►
Effect on active mammary glands:
 Stimulation of teat/nipple by nursing or milking causes oxytocin
release into bloodstream
 Causes contraction of musclelike myoepithelial cells around mammary
gland alveoli and small ducts
 Forces milk into lower parts of gland, making it accessible for
nursing/milking (______ __________)
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Oxytocinpositive
feedback
Mosby items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.