Endocrine System (KT) Flashcards
General characteristics of the endocrine system (3)
- Chronic regulation of homeostasis
- Slow and prolonged responses
- Interrelated with the nervous system (hypothalamus and posterior pituitary)
Ductless system characteristics (2)
- Hormones produced by specialized cells
2. Carried in blood stream
Substance synthesized by a specific organ or tissue and secreted
Hormone
Hormone secreted into extracellular spaces
Paracrine Signaling
Blood carries hormones to other sites
Endocrine signaling
Hormones act on target cells that…
Have specific receptors for specific hormones
4 Categories of Hormones
- Steroids
- Peptides
- Amines
- Eicosanoids
Hormone that is…
- Made of cholesterol and is nonpolar
- Lipid soluble and can cross the cell membrane
- Transduction –> Regulation of DNA transcription
Steroids
Examples of steroids (4)
- Estrogens like estradiol
- Androgens like testosterone
- Aldosterone
- Cortisol
Hormone that is
- Derived from amino acids
- Derived from tyrosine or tryptophan
- Polar or non polar
Amine Hormones
Example of an amine hormone that is membrane soluble
Thyroxine
Example of amine hormone that is not membrane soluble
Epinephrine
Most important amine hormones are made by… (2)
- Thyroid
2. Adrenal Medulla
Hormone that is…
- Short chains of amino acids
- Cannot cross cell membrane
- All pituitary hormones
Peptide Hormones
Hormone that is…
- Derived from fatty acids
- Most cross the cell membrane
- Coordinate functions in extracellular fluid
Eicosanoids
Example of an eicosanoid
Prostaglandins
Characteristics of a Negative Feedback Loop (4)
- Gland is sensative to a concentration of a substance
- Concentration exceeds limits–> prevents gland from secreting hormone
- Concentration decreases–> secretion increases
- Results in relatively stable concentration of both substance and hormone
The hypothalamus sends signals to the… (2)
- Body
2. Pituitary Gland
- This is really 2 separate glands, developmental origins are key to function
- Most important endocrine gland for regulation
Pituitary Gland
The 2 lobes of the pituitary gland
- Posterior
2. Anterior
Lobe that…
- Does not make any hormones
- Mostly hypothalamic axons
Posterior Lobe of the Pituitary Gland
Lobe that…
- Has 5 types of endocrine cells
- Controlled by hypothalamic regulatory hormones
Anterior Lobe of the Pituitary Gland
2 types of Regulatory Hormones
- Releasing hormones
2. Inhibiting Hormones
Posterior Pituitary Hormone…
-Oxytocin (4)
- Causes contraction of muscles in the uterine walls
- Causes muscles associated with milk ejection to contract
- Causes contraction of the prostate gland
- Significant in emotional bonding (familial and romantic)
Posterior Pituitary Hormone…
-Anti-diuretic Hormone (ADH) (2)
- Causes kidney to decrease water excretion
2. Increases blood volume–> rise in blood pressure
Anterior Pituitary Hormone…
-Melanocyte Stimulating Hormone (MSH) Characteristic (1)
- Increase melanin secretion
Anterior Pituitary Hormone…
-Follicle Stimulating Hormone (FSH) (3)
- Testes to produce sperm
- Follicular development in ovaries
- Stimulate secretion of estrogen
Anterior Pituitary Hormone…
-Luteinizing Hormone (LH) (2)
- Promotes secretion of sex hormones
2. Release of oocyte
Anterior Pituitary Hormone…
-Growth Hormone (GH) (4)
- Increase in size and rate of reproduction of body cells
- Targets muscles and bones- mobilizes fat and glucose
- Enhances movement of amino acids through membranes
- Secreted throughout life, really increase at puberty
Anterior Pituitary Hormone…
-Thyroid Stimulating Hormone (TSH)
- Controls secretion of thyroid hormone