endocrine glands
DESCRIPTION
Endocrine Glands. Endocrine Glands. Hypothalamus. This organ is a part of the midbrain, and it is located below the thalamus. It has various functions including: regulating the ANS, influencing emotions, and feelings of hunger, thirst, and body temperature. - PowerPoint PPT PresentationTRANSCRIPT
Endocrine Glands
Endocrine Glands
HypothalamusThis organ is a part of the midbrain, and
it is located below the thalamus.
It has various functions including:regulating the ANS,
influencing emotions, and feelings ofhunger, thirst, and body temperature.
Many hormones related to the hypothalamus are considered “releasing hormones”
These releasing hormones are made in the hypothalamus and are released from the
posterior pituitary.
EX: Antidiuretic hormone (vaspressin) and oxytocin.
Other hypothalamic hormones target the anterior pituitary.
The Pituitary
This organ is located in the brain, suspended from the hypothalamus by a stalk called the infundibulum and located in a recess called
the stella turnica (Turk’s saddle).
It is known as the master gland, and it is also known as the hypophysis.
It has two portions – anterior and posterior.
Anterior Pituitary
This organ is located in the brain and is also known as the adenohypophysis.
It is largely regulated by the “releasing” hormones from the hypothalamus.
Anterior Pituitary
Hormones released by the AP include:
1. TSH (thryoid stimulating hormone/thyrotropin)
2. ACTH (adrenocorticotropic hormone)
3. FSH (follicle stimulating hormone)
Anterior Pituitary
Hormones released by the AP include:
4. LH (lutenizing hormone)
5. GH (growth hormone)
6. Prolactin (releasing hormone)
Anterior Pituitary Disorder Example
Growth hormone normally promotes:mitosis and the growth (elongation) of
long bones
A homeostatic imbalance can have serious, life-changing effects.
The hormonal imbalance has various effects that are dependent on when
the imbalance occurs.
In adulthood, too much (hypersecretion) GH results in
acromegaly.
The mandible, feet, and hands enlarge.
In childhood, hypersecretion results in giantism – a large proportional
individual.
In childhood, an insufficient amount (hyposecretion) results in pituitary
dwarfism.
Posterior PituitaryThis organ is located in the brain and is
also known as the neurohypophysis.
It is a storage and a release site for oxytocin and antidiurectic hormone
from the hypothalamus
Oxytocin and ADH are made in the hypothalamus and released by the
posterior pituitary.
Oxytocin - stimulates smooth muscle contraction of uterus & mammary
glands.
ADH - stimulates water reabsorption in collecting ducts and vasoconstriction
People with diabetes insipidus lack ADH
Posterior Pituitary Disorder Example
Hyposecretion of ADH will resultin diabetes insipidus which is
characterized by excessive thirst andurination.
The PinealThis organ is located in the brain toward
the base of the corpus callosum.
This organ has been described as a “lump of tissue in the brain that is light
sensitive”.
It secretes melatonin to the blood and CSF during the night (dark).
MelatoninInfluences the sleep/wake cycle and helps
set the body’s clock
Also influence reproductive organs – it isthought to inhibit early puberty.
Melatonin is high when we are young and is reduced as we age.
MelatoninBecause it influences the sleep/wake cycle,
melatonin plays a role in jet lag.
Because it is secreted in the dark, melatonin plays a role in seasonal affective disorder
(SAD) that is seen in the winter.
Depression often brings on the desire to sleep – made worse when taking
melatonin.