Download endocrine system - Fullfrontalanatomy.com

ENDOCRINE SYSTEM
Review
PETER REONISTO, MD
MOORPARK COLLEGE
Nervous System vs. Endocrine System
3)
Hormones travel more slowly than nerve impulses, the endocrine system
tends to regulate slow processes such as growth and metabolism.
Major Endocrine
Organs
Pineal gland
Thyroid gland
Pituitary gland
Parathyroid gland
Endocrine cells of the
body contained in:
1. “Pure” endocrine organs
Adrenal gland
Major Endocrine
Organs
Endocrine cells of the
body contained in:
Hypothalamus
Thymus
Pancreas
2. “Partly” endocrine organs
Gonads
CLASSES OF HORMONES
AMINO ACID-BASED
 Most hormones
 Proteins
 Modified amino acid
peptides
STEROIDS
 Lipid molecules derived
from cholesterol
 Sex hormones
 Adrenal cortex
hormones
CONTROL OF HORMONE SECRETION
1. Humoral
2. Neural
3. Hormonal
CONTROL OF HORMONE SECRETION
1. Humoral- influenced by
plasma concentration of the
substance.
+
Parathyroid
gland
Low Ca2 blood
concentration
Parathyroid gland
Parathormone secretion
Nephron, intestinal cells
Action
CONTROL OF HORMONE SECRETION
2.
Neural- SNS stimulation
Adrenal
medulla
Preganglionic SNS
fibers
Medulla of adrenal
gland
Adrenaline secretion
Body
Actions: “Fight, flight, or fright” response
CONTROL OF HORMONE SECRETION
3. Hormonal-influenced by the amount
of hormones in the plasma
Releasing
Hypothalamus
hormones
Releasing hormones
Adenohypohysis
Stimulating Hormones
Thyroid
gland
Thyroxine
Body
Increase
Metabolic
rate
Adrenal
cortex
Cortisol
Gonads
(Testis)
Androgens
Cortisol
Androgens
Anti-stress
Sperm
formation
MAJOR ENDOCRINE ORGAN
PITUITARY GLAND
PITUITARY GLAND
• Or, hypohysis
• Secretes at least 9
major hormones
• Location:
> Hypophyseal fossa
Depression in the
Sella turcica of the
Spenoid bone
ANATOMY: PITUITARY GLAND
infundibulum
Anterior Pituitary Gland
Adenohypophysis
1. Pars distalis
2. Pars intermedia
3. Pars tuberalis
Adenohypophysis
1. Pars distalis
 Largest division
 Contains 5 different endocrine cells that
make and secrete 7 different hormones
Pars distalis
1. Somatotrophic cell
(most abundant)
2. Mammotrophic cells
3. Thyrotrophic cells
5 CELL CLASSES:
Growth Hormone (Somatotrophic Hormone / Somatotropin / GH)
Growth of the entire body
Prolactin (PRL)
Breast milk production
Thyroid Stimulating Hormone (TSH)
Thyroid gland stimulation to release thyroid hormone
Adrenocorticotropic Hormone (ACTH)
Adrenal Cortex stimulation to release glucocorticoids
4. Corticotrophic cells
5. Gonadotrophic cells
Melanocyte Stimulating Hormone (MSH)
Stimulates melanocytes to produce melanin pigment
Follicle Stimulating Hormone (FSH)
Gonads: maturation of sex cells; secretes sex hormones
Gonadotropins
Leutenizing Hormone (LH)
Gonads: maturation of sex cells; secretes sex hormones
Pars distalis
Act directly on
non-endocrine
target tissues
M
P
Growth Hormone (Somatotrophic Hormone / Somatotropin / GH)
Growth of the entire body
Prolactin (PRL)
Breast milk production
G
Tropic Hormones Regulate the secretion
of hormones by other
Endocrine glands
F
L
5 CELL CLASSES:
A
T
Thyroid Stimulating Hormone (TSH)
Thyroid gland stimulation to release thyroid hormone
Adrenocorticotropic Hormone (ACTH)
Adrenal Cortex stimulation to release glucocorticoids
Melanocyte Stimulating Hormone (MSH)
Stimulates melanocytes to produce melanin pigment
Follicle Stimulating Hormone (FSH)
Gonads: maturation of sex cells; secretes sex hormones
Leutenizing Hormone (LH)
Gonads: maturation of sex cells; secretes sex hormones
HYPOTHALAMIC CONTROL OF THE
ADENOHYPOPHYSIS
Controlled by RELEASING HORMONES and INHIBITING
HORMONES
Target cell
Target cell
Peripheral
Endocrine
gland
Peripheral
Endocrine
gland
Peripheral
Endocrine
gland
HYPOPHYSEAL PORTAL SYSTEM
Hypothalamic neurons
Releasing hormones are made in
Hypothalamic neurons
Releasing hormones are secreted at
the neuron synapse
Primary capillary complex
To the primary capillary complex
Releasing hormones goes to the
Hypophyseal portal vein
To the secondary capillary complex
Releasing hormones leaves the plexus & Secondary
Capillary
attach to the adenohypophyseal cells complex
Somatotropic
Mammotropic
Thyrotropic
Corticotropic
Gonatotropic
Posterior Pituitary Gland
Neurohypophysis
1. Median eminence
2. Infundibular stalk
3. Pars nervosa
Median
eminence
Infundibular
stalk
Pars
nervosa
NEUROHYPOPHYSIS HORMONE PRODUCTION
Hormone produced at neuron cell
bodies located at the SUPRAOPTIC
and PARAVENTRICULAR nuclei of
the Hypothalamus
Hormones are transported
along the axons
(Hypothalamic-hypophyseal
Tract)
Upon stimulation, stored
hormones are released in the
capillary bed for distribution
throughout the body
Hormones are stored in
dilated axon terminals
called HERRING BODIES
ADH
Oxytocin
NEUROHYPOPHYSIS: Hormones
CELL TYPE
HORMONE
TARGET/EFFECTS
Neurons from
supraoptic nucleus
of hypothalamus
Antidiuretic
hormone
(ADH,
vasopressin)

Neurons from
paraventricular
nucleus of
hypothalamus
Oxytocin

Stimulates kidneys (distal
tubules and collecting
tubules) to reclaim water from
urine.
 Raises blood pressure by
constricting peripheral
arterioles when blood volume
is low.
Initiates labor through
uterine contraction
 Facilitates milk ejection
from breast
MAJOR ENDOCRINE ORGAN
THYROID GLAND
THYROID GLAND
located in the
anterior neck; on the
trachea just
inferior to the larynx
PARATHYROID GLAND
Located at the posterior
surface of the thyroid
gland
PARATHORMONE
FUNCTION:
Increase blood
Calcium level
ADRENAL CORTEX
ADRENAL MEDULLA
ADRENAL GLAND
Balance electrolyte
Concentration (Na+/K+)
--Inc Na+ Reabsorption
--Inc K+ excretion
--Inc water reabsorption
Mineralocorticoid
(Aldosterone)
Glucocorticoid
(Cortisol)
Stress control
Glucocorticoid
(Cortisol)
Produce sex hormone precursor (DHEA)
----Dehydroepiandrosterone---
ADRENAL MEDULLA: Hormones
Simulate a “fight, fright, flight response”
PANCREAS
Other Endocrine Glands
Pineal Gland
• secretes melatonin
• regulates circadian rhythms
Thymus Gland
• secretes thymosins
• promotes development of certain lymphocytes
• important in role of immunity
Reproductive
• ovaries produce estrogens and progesterone
• testes produce testosterone
• placenta produces estrogens, progesterone, and
gonadotropins
END