Chapter 17: The Endocrine System - Powerpoint Outline Flashcards
List the four main mechanisms of communication between cells in the Endocrine System
- Gap junctions
- Neurotransmitters
- Paracrine
- Hormones
allows molecules, nutrients, and electrolytes to move from cell to cell
(one of the four main mechanisms of comm. between cells in the endocrine system)
Gap junctions
released from presynaptic neurons to postsynaptic neuron
one of the four main mechanisms of comm. between cells in the endocrine system
Neurotransmitters
secreted into tissue fluids to affect nearby cells
one of the four main mechanisms of comm. between cells in the endocrine system
Paracrine
chemical messengers that travel in the blood stream to other tissues and organs
(one of the four main mechanisms of comm. between cells in the endocrine system)
Hormones
- chemical messengers
- transported by blood
- stimulate physiological responses in target cells
Hormones
is the collection of glands that produce hormones that regulate metabolism, growth and development, tissue function, sexual function, reproduction, sleep, and mood, among other things (system)
Endocrine System
- ducts to epithelial or membrane surface
- release secretions via duct
- extracellular effects (food digestion)
(endocrine or exocrine?)
Exocrine
- no ducts (ductless)
- contain dense, fenestrated capillary networks for easy uptake of hormones into bloodstream
- intracellular effects such as altering target cell metabolism
endocrine or exocrine?
Endocrine
Examples of secretions from exocrine glands:
bile, sweat glands, etc.
Both systems (nervous and endocrine) are used for internal communication
True or False?
TRUE
Speed and Persistence of Response: reacts quickly (ms timescale), stops quickly
nervous or endocrine?
nervous
Speed and Resistance of Response: reacts slowly (seconds or days), effect may continue for days or longer
nervous or endocrine?
endocrine
Adaptation to Long-term Stimuli response declines (adapts quickly)
nervous or endocrine?
nervous
Adaptation to Long-term Stimuli response persists (adapts slowly)
nervous or endocrine?
endocrine
Area of Effect
targeted and specific (one organ)
nervous or endocrine?
nervous
Area of Effect
general, widespread effects (many organs)
nervous or endocrine?
endocrine
Both systems (nervous and endocrine) can have similar effects on target cells
True or False?
TRUE
Norepinephrine and glucagon both cause glucose hydrolysis in liver
The two systems (nervous and endocrine) can regulate each other
True or False?
TRUE
Neurotransmitters can affect glands; hormones can effect neurons
Neuroendocrine cells share characteristics of both systems (nervous and endocrine)
True or False?
TRUE
Both systems (nervous and endocrine) require receptors
True or False?
TRUE
Nervous - postsynaptic neuron requires receptors
Endocrine - target organs or cells must use receptors for a particular hormone; some target cells possess enzymes that convert a circulating hormone to its more active form
Hypothalamus Anatomy
- forms floor and walls of third ventricle of brain
- regulates primitive functions: water balance, thermoregulation, sex drive, childbirth, etc.
- pituitary gland is suspended from hypothalamus by a stalk called the infundibulum
Location of the Pituitary gland
Sphenoid; Sella Turcica
The Pituitary gland is composed of:
Two structures with independent origins and separate functions:
- Adenohypophysis (anterior pituitary); Endocrine
- Neurohypophysis (posterior pituitary); Nervous
eight hormones produced in hypothalamus:
- six regulate the anterior pituitary
- two are released into capillaries in the posterior pituitary
six anterior pituitary hormones are:
- follicle-stimulating hormone (FSH)
- lutenizing hormone (LH)
- thyroid-stimulating hormone (TSH)
- adrenocorticotropic hormone (ACTH)
- prolactin (PRL)
- growth hormone (GH)
hormone that stimulates secretion of ovarian sex hormones, development of ovarian follicles, and sperm production
follicle-stimulating hormone
hormone that stimulates ovulation, stimulates corpus luteum to secrete progesterone, stimulates testes to secrete testosterone
lutenizing hormone
hormone that stimulates secretion of thyroid hormone
thyroid-stimulating hormone
hormone that stimulates adrenal cortex to secrete glucocorticoids
adrenocorticotropic hormone
after birth, this hormone stimulates mammary glands to synthesize milk
prolactin
hormone that stimulates mitosis and cellular differentiation
growth hormone
two posterior pituitary hormones are:
- antidiuretic hormone (ADH)
* oxytocin (OT)
- hormone that increases water retention, thus reducing urine volume, and preventing dehydration
- also called vasopressin because it can cause vasoconstriction
antidiuretic hormone
- surge of hormone released during sexual arousal and orgasm
- promotes feelings of sexual satisfaction and emotional bonding between partners (“cuddle hormone”)
- stimulates labor contractions during childbirth
- stimulates flow of milk during lactation
- may promote emotional bonding between lactating mother and infant
oxytocin
Hypothalamic and cerebral control examples:
- stress: triggers release of ACTH
- pregnancy: triggers prolactin secretion
- osmoreceptors: triggers release of ADH
- infant suckling: triggers release of oxytocin
- increased target organ hormone levels inhibit release of hypothalamic and/or pituitary hormones
positive or negative feedback?
Negative feedback
control of pituitary secretion
- stretching of uterus increases OT release, causes contractions, causing more stretching of uterus, etc. until delivery
positive or negative feedback?
Positive feedback
control of pituitary secretion
- synthesizes melatonin at night
- after age 7, it undergoes involution (shrinkage)
- may influence timing of puberty
- may play a role in circadian rhythms
Pineal gland
- goes through involution after puberty
- site of maturation of T cells (immune system)
- secretes hormones thymopoietin, thymosin, and thymulin
Thymus
- largest gland that is purely endocrine
- composed of two lobes and an isthmus below the larynx
Thyroid gland
sacs that make up most of thyroid are called:
thyroid follicles
thyroxine
T4
triiodothyronine
T3
in response to TSH, the thyroid gland secretes:
- T4
- T3
parafollicular (C or clear) cells secrete:
- calcitonin when blood calcium is high
- stimulates osteoblast activity and bone formation in children
- children need this more
usually four glands partially embedded in posterior surface of thyroid gland
parathyroid glands
the parathyroid glands secrete:
parathyroid hormone (PTH)
the secretion of parathyroid hormone:
- increase blood Ca2+ levels
- promotes synthesis of calcitriol
- increases absorption of Ca2+
- decreases urinary excretion
- increases bone resorption
- small glands that sit on top of each kidney
- retroperitoneal location
the adrenal glands
