Option D5 Flashcards
What is the endocrine system made out of ?
Comprised of ductless glands that release chemicals into the blood to regulate body functions
Endocrine System
What is a hormone?
A chemical messanger that is transported indiscrimanately to the bloodstream
Endocrine System
What is sepcial about hormones?
They are specific so only target cell or tissue that have appropriate target receptor
Endocrine Glands
What are examples of endocrine glands?
-Pancreas that releases insulin/glucagon to the liver to regulate blood sugar levels
-Adrenal gland release adrenaline and cortisol to many target organs for fight or flight anti-stress
-Thyroid gland releases thyroxin to the liver to regulate metabolic rate
-Pineal gland release melatonin to many organs and acts as digital clock
Endocrine Glands
What are neuroendocrine glands?
They link nervous to endocrine system
Endocrine Glands
What are examples of neuroendocrine glands?
Hypothalamus and pituatury gland
Types of Hormones
What are the 2 different types of hormones?
Steroid and peptide hormones
Steroid Hormones
What are steroid hormones?
They are lipophilic, meaning they can easily diffuse across membrane
Steroid Hormones
How is the receptor hormone complex formed?
The steroid hormones bind to receptors in nucleus or cytoplasm
Steroid Hormone
What happens to the receptor hormone complex?
Move into nucleus and bind to DNA acting as transcription factor for gene expression
**Steroid Hormones **
What are examples of steroid hormones?
Estrogen, progesterone, and testosterone
Peptide Hormones
What are peptide hormones?
They are hydrophylic and lipophobic, meaning they cannot move across plasma membrane
Peptide Hormones
How is the hormone receptor complex formed?
Hormones bind to receptors on surface found on surface of cell, which are coupled to internally anchored proteins
Peptide Hormones
What does the hormone receptor protein do?
They activate second messangers which initiate cell activity
Peptide Hormones
What is the process of cell activity initiation called?
Signal transduction
Peptide Hormones
What is the use of second messangers?
Amplify initial message
**Peptide Hormones **
What are examples of peptide hormones?
Insulin, glucagon, and leptin
Pituitary Gland
What is the hypothalamus?
The section of the brain that links the nervous and endocrine systems in order to maintain homeostasis
Pituitary Gland
What are the functions of the hypothalamus?
-It receives information from nerves throughout the body and other parts of the brain and initiates endocrine responses
-It secretes neurochemicals (called releasing factors) into a portal system which target the anterior lobe of the pituitary gland
-It also secretes hormones directly into the blood via neurosecretory cells that extend into the posterior pituitary lobe
Pituitary Gland
What is the pituitary gland?
Lies adjacent to the hypothalamus and is in direct contact due to a portal blood system
Pituitary Gland
What are the 2 lobes that the pituitary gland consists of?
Anterior and posterior lobe
Pituitary Gland
What is the function of the anterior lobe?
As the hypothalamus produces releasing factors into portal vessels by neurosecretory cells, the releasing factors will cause endocrine cells in the anterior pitiatuiry to release specific hormones into blood stream
Pituitary Gland
What is the function of the posterior lobe?
Releases hormones produced by the hypothalamus itself via neurosecretory cells, these neurosecretory cells extend into the posterior lobe from the hypothalamus and release hormones into the blood
Pituitary Gland
What are the body processes that pituitary hormones control?
-Metabolism
-Adult development
-Reproduction
-Growth
-Equilibrium
Growth Hormone
What is the growth hormone?
Anabolic peptide hormone that stimulates growth
Growth Hormone
What are the functions of the growth hormone?
-It acts directly to reduce the formation of adipose cells
-It acts indirectly via insulin growth factor (IGF) – produced by the liver – to increase muscle mass and bone size
Growth Hormone
Where are growth hormones usually used?
By some athletes as a performance enhancer
Growth Hormone
How can the growth hormone be detected?
Traditional urine testing could not detect doping, which historically made bans difficult to enforce. Recent blood tests can now identify between natural and artificial variants of growth hormone
Lactation
What is lactation?
The production and secretion of milk by maternal mammary glands
Lactation
What is lactation controlled by?
Oxytocin and prolactin
Lactation
What is prolactin?
It is responsible for the development of the mammary glands and the production of milk. It is secreted by the anterior pituitary in response to the release of PRH from hypothalamus. The effects of prolactin are inhibited by progesterone, which prevents milk production from occurring prior to birth
Lactation
What is oxytocin?
It is responsible for the release of milk from the mammary glands. It is produced in the hypothalamus and secreted by neurosecretory cells that extend into the posterior pituitary. Oxytocin release is triggered by stimulation of sensory receptors in the breast tissue by the suckling infant. This creates a positive feedback loop that will result in continuous oxytocin secretion until the infant stops feeding
