Endocrine System Flashcards
Ductless gland whose secretion is released directly into the bloodstream
Endocrine gland
Glands making up the endocrine system
Pituitary, thyroid, parathyroid, adrenal, pineal
Other organs that secrete hormones but are not part of the endocrine system
Hypothalamus Thymus Pancreas Ovaries Testes Kidneys Stomach Liver Small intestine Skin Heart Adipose tissue
Define exocrine gland
Gland whose secretion is drained by ducts onto the body surface OR into a body cavity
DUCTED GLANDS
Examples of exocrine glands
Sebaceous
Sudiferous
Mammary
Define hormone
Substances produced in one part of the body and transported to another where they affect chemical actions or the secretion of other hormones
The body’s method of maintaining its internal environment within certain physiological limits
Homeostasis
Hormones affect only specific cells called
Target cells
Hormones that enter the bloodstream to reach distant target cells are called
Circulating hormones
Circulating hormones may remain in the blood for how long? And when will they stop?
Few minutes to few hours
When the liver inactivates it and kidneys excrete it
Hormones that do not enter the bloodstream to reach target cells are called
Local hormones
Paracrine
Local hormone acting on neighboring cells (histamine)
Autocrine
Local hormone acting on the same cell that secreted it (interleukin-2)
How are local hormones inactivated?
By enzymes in the interstitial fluid which surrounds cells
3 different hormone interactions
Permissive effect (one hormone enhances the effect of another hormone)
Synergistic effect (2 hormones working together are better than 1)
Antagonistic effect (1 hormone has a greater effect than another)
The synthesis and release of most hormones are through a. ___________________________, which is a corrective mechanism that helps maintain homeostasis
Negative feedback system
What stimulates or inhibits hormonal secretions?
Humoral stimuli (changing levels of ions and nutrients in the blood)
Hormonal stimuli (release of other hormones)
Neural stimuli (nervous system)
The “master” endocrine gland
Pituitary gland/hypophysis
Major link bringing together the nervous and endocrine systems
Hypothalamus
What does the hypothalamus synthesize?
Oxytocin and ADH
Together, the hypophysis and hypothalamus regulate what?
Practically all aspects of growth, development, metabolism, and homeostasis
Location of the hypothalamus
Inferior to the two lobes of the thalamus
Location of the hypophysis
Sits in the sella turcica of the sphenoid bone. Located inferiorly to the hypothalamus
What attaches the pituitary gland to the hypothalamus?
Infundibulum
What are the two lobes of the pituitary gland?
Anterior lobe (adenohypophysis)
Posterior lobe (neurohypophysis)
What stimulates the synthesis and release of hormones from the anterior lobe?
Suppresses?
Releasing hormones (RHs)
Inhibiting Hormones (IHs)
There are _ different types of cells in the Anterior lobe that secretes _ major hormones.
5
7
What secretes HGH?
Somatotrophs (of the anterior lobe of hypophysis)
What secretes TSH?
Thyrotrophs, of the anterior lobe of hypophysis
What produces FSH and LH?
Gonadotrophs of the anterior lobe of hypophysis
What produces prolactin?
Lactotrophs of AL of PG
What secretes adrenocoritotropic hormone (ACTH) and melanocytes-stimulating hormone (MDH)?
Corticotrophs of AL of PG
The PL of PG stores and releases what 2 hormones?
Oxytocin and ADH
Synthesized by neurosecretory cells in the hypothalamus
Location of the thyroid gland
Right and left lobes lie on either side of the trachea
Isthmus lies anterior to the trachea
Thyroid gland consists of __________ ____________
The wall of each of these structures consists of what 2 types of cells?
Thyroid follicles
Follicular cells and parafollicular cells
What secretes T3 and T4?
Follicular cells of the thyroid gland
What secretes calcitonin?
Parafollicular cells of the thyroid gland
Most important function of the thyroid hormones/gland
To increase basal metabolic rate (to maintain body temp)
Where are the parathyroid glands?
On the posterior side of the thyroid gland.
Parathyroid glands consists of what 2 cell types?
Principal/chief cells and oxyphil cells (function unknown)
What secretes PTH?
Principal/chief cells of the PTG
Location of the Adrenal/suprarenal glands
Paired, on each kidney
Each adrenal gland has a covering _________ of CT, then the adrenal ________, and an innermost adrenal _________
Capsule
Cortex
Medulla
3 zones of the adrenal cortex
Zona glomerulosa (controls water and electrolyte)
Zona fasciculata (increase fat and protein breakdown)
Zona reticularis (cells produce male sexual hormone)
Adrenal medulla contains what type of cells? What do they secrete?
Chromatin cells
The fight or flight hormones, Epinephrine/Adrenaline and Norepinephrine/Noradrenaline
Location of the pineal gland
Inferior to the posterior portion of the brains corpus callosum
The pineal gland contains secretory cells called ____________ which form the hormone ___________
Pinealocytes
Melatonin
Melatonin is important to JEREMY BECAUSE WHY
Its an antioxidant protecting the CNS and maintains CIRCADIAN RHYTHM
JEREMY
YOU NEED MELATONIN DUDE
Functions of the pancreas (2 portions)
Exocrine portion (produces digestive enzymes)
Endocrine portion (produce hormones to raise and lower blood glucose)
What makes of 99% of the pancreatic cells?
The exocrine portion (digestive enzymes)
Clusters of exocrine cells that produce digestive enzymes in pancreas
Acini
In the acini, there’s 1-2 million tiny clusters of endocrine tissues called:
Islets of langerhans
Each islet of langerhans contains 4 cells types:
A-cells
B-cells
D-cells
F-cells
What produces glucagon?
alpha cells of pancreas
What produces the insulin?
Beta cells of pancreas
Function of glucagon
Raise blood glucose level
Function of insulin
Lowers blood glucose levels
Function of the ovaries
Produce the ovum
Produce sex hormones (estrogen and progesterone)
