Transcript Endocrine glandsx

Endocrine glands
• It controls and regulates many
functions of the human systems
through messengers that act on
target organs.
• The messengers are hormones
secreted by the EG Master EG;
Hypophysis cerebri(pituitary)
Pituitary gland
Its located in the sella turcica of the sphenoid bone
and attached to the under surface of the brain by
the infundibulum. Size of grape
The pituitary gland is divided into
• Anterior lobe adenohypophysis.
• Posterior lobe, neurohypophysis.
The anterior lobe hormones:
Growth hormone
• Increase protein synthesis, and glucose
level in the blood
• it is a hyperglycemic hormone.
Prolactin
• Responsible for breast development
during pregnancy and the generation of
milk after delivery.
Thyroid stimulating hormone (TSH )
• Controls thyroid hormone Thyroxin
secretion.
Adrenocorticotropic hormone ( ACTH )
• Controls adrenal cortex hormones
secretion.
Follicle stimulating hormoneFSH
• Stimulates formation of Graffian
follicle and ovum maturation in
female, while induce
spermatogenesis in the testes in
male.
Luteinizing hormone ( LH )
• Induces ovulation and formation of
the corpus luteum in female, while
stimulates testosterone hormone.
Hormones of the neurohypophysis
Antidiuretic hormone ( ADH )
• Preserve body water by
Reabsorption of water from urine
decreasing the urine output.
Oxytocin
• Stimulates uterine muscle
contraction during delivery
• Promotes milk ejection from the
breast of a lactating woman.
Thyroid gland
• The thyroid gland is located
in the anterior aspect of the
neck
• Consists of right and left
lobes connected by a
narrow isthmus, its
• weight is about 30 gm.
• The gland is attached
posteriorly to the larynx
and trachea.
• The gland is supplied by
branches of the external
carotid, subclavian arteries.
Thyroid hormones:
Tetraiodothyronine ( T4 ) and
triiodothyronine ( T3 )
• Both increase the basal metabolic
rate in the human body
Cacitonin is secreted by the
parafollicular cells C cells .
• It decreases calcium concentration
in blood
Adrenal glands
They are two, fitting like a cap on the upper pole of
each kidney, the outer part of each gland is called
the adrenal cortex , the inner part is called the
adrenal medulla.
Adrenal cortex
This part of the suprarenal gland is formed
of three layers:
• Zona glomerulosa: secretes
mineralocorticoid H (aldosterone )
• Zona fasciculate: secretes
glucocorticoids H ( cortisol )
• Zona reticularis: secretes
gonadocorticoid H (sex hormones}
• Go For Rest
And Come Soon
Adrenal medulla
A special tissue of nervous origin
secretes Catecholamine’s
• Adrenaline 80% ,
• Norepinephrine 20%
They act on many organs of the body,
mainly CVS .
Gonads
These are primary sex organs, in male
two testes and in female two ovaries.
Testes :
• Present in the scrotum, formed of
many seminephrous tubules. that form
the sperms.(exocrine function)
• There are interstitial cells of Leydig
that secrete testosterone
Ovary:
• present in the pelvis, secretes estrogen
( female sex hormone ) and
progesterone (hormone of pregnancy)
secreted from corpus luteum.
• Gastric and intestinal mucosa
By contact with food materials the GI
mucosa secretes different types of
hormones like secretin, Cholecystokinin,
gastrin
Pancreatic islets
Islets of Langerhans represent 2-3% of the
pancreatic tissue, they are the endocrine part of
the pancreas consist of three types of cells:
• Alpha cells secretes Glucagon hormone that
increase serum glucose level.
• Beta cells secretes Insulin hormone that
decrease serum glucose level.
• Gamma or Delta cells secrete Somatostatin
hormone which is a pan inhibitor to many
hormones and functions of the body
Thymus gland
• Large in children,
atrophy after puberty
• Lie in upper thorax,
under sternum
• Produce thymosin
hormone.
• Important rule in
immunity.
Parathyroid gland
• There are usually four glands,
two at each side embedded in
the posterior surface of the
thyroid gland size 5 mm,
yellow in color.
• Parathyroid hormone
Increase the serum calcium
level in blood
• Stimulate osteoclasts to
increase Ca++ level
• Increase Ca++ reabsorption
from kidney
• Stimulate synthesis of active
vit D in kidney Calcitirol
Heart
Has secondary endocrine role as a
specific area of the right atrium
secretes Atrial natriuretic
hormone
( ANH ), which promotes the loss
of sodium in urine.
Pineal gland
– Cone shaped
gland found in
roof of third
ventricle
– Secrete
melatonin
hormone
– Responsible for
– day night cycle
– Coordinates
fertility
hormones