9 - Histology of Endocrine Organs Flashcards
Both of these systems influence the physiologic functions of other organs, but differ by the methods used to communicate and accomplish their influence.
Endocrine System
Nervous System
In the _________ system, it involves membrane depolarization and transmission of a signal from synapses. Communication is rapid but effects on target cells/organs are short-lived.
Nervous
In the _________ system, it involves chemicals called hormones that are distributed throughout the body by the cardiovascular system. Communication is much slower but the effects on target cells/organs are of longer duration.
Endocrine
T/F. Neurons do not secrete hormones.
False. Some neurons do secrete hormones.
This type of hormonal release is controlled by monitoring levels of ions and nutrients in blood and body fluids. An example is the release of parathyroid hormone stimulated by low serum calcium levels.
Humoral Stimuli
This type of hormonal release is stimulated by nerve signals. An example is the release of epinephrine from the adrenal gland in response to a signal from sympathetic nerve fibers.
Neuronal Stimuli
This type of hormonal release is caused by a hormone being secreted into the bloodstream by another endocrine organ or cell. An example is the release of thyroid hormone stimulated by the release of the hormone, TSH, from the pituitary.
Hormonal Stimuli
Endocrine glands are made of _________ cells, which lack a free surface (apical lumen). They are arranged as cords/follicles and some as isolated individual cells. They are derived from epithelia.
Epithelioid
***Only gland that has a lumen is thyroid gland
Endocrine glands are well vascularized, and vessels often have _________ endothelium.
Fenestrated
What are the direct targets of Hypothalamic hormones, and what are the hormones?
Anterior Pituitary – releasing and inhibiting factors that influence its secretion
Kidney and Uterus – releasing ADH and oxytocin (stored in posterior pituitary)
Adrenal Medulla – Hypothalamus oversees ANS, helps via Sympathetic innervation
The hypothalamus releases hormones, collectively referred to as ________ hormones, that stimulate or inhibit release of other hormones from the anterior pituitary.
Tropic
The hypothalamus works indirectly by stimulating secretion of hormones by the anterior pituitary gland. Where do the hormones from the anterior pituitary go to?
Thyroid gland Adrenal cortex Mammary gland Gonads (testes or ovaries) Bone and other organs
These cells from the anterior pituitary secrete TSH, which regulates thyroid gland secretion.
Thyrotropic cells
These cells from the anterior pituitary secrete Prolactin, which stimulates milk production.
Mammotropic cells
These cells from the anterior pituitary secrete ACTH and MSH.
Corticotropic cells
These cells from the anterior pituitary secrete GH.
Somatotropic cells
These cells from the anterior pituitary secrete FSH and LH, which act on the gonads.
Gonadotropic cells
In the origin of the pituitary, ectodermal placode leading to _______ _______ is seen by 3 weeks. This loses it connection with the outside and is near final location by 8 weeks. It joins the diverticulum from the developing _________ of the neural tube.
Rathke’s Pouch
Diencephalon
In the development of the pituitary, the __________ forms the posterior pituitary and the infundibular stalk. _______ _______ forms the rest of the pituitary.
Infundibulum
Rathke’s Pouch
In the development of the pituitary, at what weeks do ACTH, GH, TSH and LH, and FSH start being produced?
ACTH – 7 weeks
GH – 8-9 weeks
TSH and LH – 12 weeks
FSH – 13 weeks
The anterior pituitary constitutes ______ percent of the gland. It is comprised of glandular epithelial cells controlled by _________ released from the hypothalamus.
80
Neurohormones
The posterior pituitary is comprised of axons from the __________ and support cells. The axons carry ______ and _______ for storage and release in the posterior pituitary.
Hypothalamus
ADH
Oxytocin
What are the parts of the anterior pituitary (adenohypophysis)?
Pars tuberalis
Pars intermedia
Pars distalis
What are the parts of the posterior pituitary (neurohypophysis)?
Infundibular stalk
Pars nervosa
This is small and in between the anterior and posterior pituitary. It is a remnant of the lumen of Rathke’s pouch.
Cyst Intermedia
This hormone stimulates the adrenal cortex to secrete stress-related hormones and mediate metabolism.
ACTH
This hormone stimulates melanocytes to produce melanin.
MSH
What are the cells of the Pars Distalis (in anterior pituitary)?
Acidphils
Basophils
Chromophobes
Sinusoidal (fenestra) capillaries
What are the types of acidphil cells in the anterior pituitary?
Somatotrophs – secrete GH
Mammotrophs – secrete Prolactin
What are the types of basophil cells in the anterior pituitary?
Corticotrophs – secrete ACTH
Thyrotrophs – secrete TSH
Gonadotrophs – secrete FSH/LH
This portion of the pituitary lies between Pars Distalis and Pars Nervosa. It is rudimentary in adults, and its function is unknown.
Pars Intermedia
Pars Intermedia contains small basophils and colloid-filled follicles lined by _________ epithelium. It frequently contains the _______ ______, which is remnant of lumen of Rathke’s pouch.
Cuboidal
Cyst Intermedia
This portion of the pituitary is continuous with the median eminence of the hypothalamus via the infundibular stalk. It does NOT manufacture hormones, rather it stores and releases them from axon terminals.
Pars Nervosa
The Pars Nervosa consists of hypothalamic unmyelinated axons called _______ _______, which are expanded axonal nerve terminals storing ADH and Oxytocin.
Herring bodies
The Pars Nervosa contain _________, which are glia-like and support the nerve fibers. It also has fenestrated capillaries.
Pituicytes
Hypothalamic hormones are released into special blood vessels, called the _________ ________ _________, controls the release of anterior pituitary hormones.
Hypophyseal Portal System
What does a portal system consist of?
A portal system is two capillary plexuses (beds) connected by veins.