27 terms

Anatomy Chp 17: Endocrine System

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Endocrine System
system of ductless glands that release hormones into the circulation
Hormones
messenger molecules that travel in the circulatory vessels and signal physiological changes in target cells
True Endocrine Organs (5)
Pituitary Gland
Pineal Gland
Thyroid Gland
Parathyroid Glands
Adrenal Glands
Other Endocrine Glands (4)
Pancreas
Thymus
Gonads
Hypothalamus
Types of Hormones (2)
Steroids- lipid molecules derived from cholesterol
Amino Acid Based Hormones- peptides, proteins, and modified amino acids
Target Cells
-have specific receptors which bind to specific hormones and then react in a pre-programmed response
Path of Hormones
secreted from particular gland ----(neural/blood pathway)----> target cell ---->physiological response
Types of Hormone Stimuli
Humoral
Hormonal
Neural
Humoral Stimuli
endocrine glands secrete hormone in direct response to change in the blood
Neural Stimuli
nerve fibers stimulate cells within endocrine gland to release hormones
Hormonal Stimuli
hormones from certain endocrine glands secrete hormones that stimulate other endocrine glands so that they released their hormone
Negative Feedback
Hormone secretion is started/stopped based on a set blood concentration level. Once the blood concentration achieves homeostasis hormone secretion stops.
Positive Feedback
As blood concentration of hormone increases, the effector organ secretes more hormone ex:oxytocin
Divisions of the Pituitary Gland
Anterior Lobe (composed of glandular tissue)
pars distalis
pars intermedia
pars tuberalis
Posterior Lobe (composed of neural tissue)
pars nervosa
infundibular
Pituitary Anterior Lobe Hormones
Tropic
-Thyroid Stimulating Hormone
-Adrenocorticotropic Hormone
-Follicle Stimulating Hormone
-Luteinizing Hormone

Other
-Growth Hormone
-Prolactin
-Melanocyte Stimulating Hormone
Growth Hormone (GH)
type of cells: somotropic
target organ: liver, muscle, bone, etc.
response: stimulated protein synthesis, somatic growth
Thyroid Stimulating Hormone (TSH)
type of cells: thyrotroph
target organ: thyroid gland
response: stimulates thyroid to release TH
Adrenocorticotropic Hormone (ACTH)
type of cells: corticotroph
target organ: adrenal cortex
response: release of adrogens
Follicle Stimulating Hormone (FSH)
type of cells: gonadotropic cells
target organ: gonads
response: stimulates estrogen/testosterone production
Prolactin (PRL)
type of cells: prolactin
target organ: breast tissue
response: lactation
Posterior Lobe Hormones
Neural Stimuli
-Antidiuretic Hormone (ADH)
-Oxytocin
Antidiuretic Hormone (ADH)
target: kidneys
response: kidney cells resorb water and return it to blood
Oxytocin
target: uterus, breasts
response: uterine contractions, milk ejection
Thyroid Gland
location: anterior neck
hormones:
thyroid hormone (TH)
calcitonin
Thyroid Hormone (TH)
target: all cells
response: increased basal metabolic rate
Calcitonin
target: kidneys
response: lowers blood calcium level
Parathyroid Gland/Hormone
location: posterior surface of thyroid gland
Parathyroid Hormone (PTH)
produced by chief cells
target: kidneys
effect: increases blood calcium level