Lecture 25 Flashcards
What is homeostasis and what factors affect it?
Presence ot a stable internal environment. Affected by temperature, ph, etc.
w hat is the difference between set points and refereece ranges?
A set paint is the physiological value around which the reference
. Range fluctuates.
What is the function of the endocrine system?
The release ot hormones into bloodstream
Endocrine secretion process.
Endocrine gland cells secrete hormones wich are carried in the bloodstreamto target cells upon which they act.
What ave target cells?
Cells mainly in other distant tissues and organs and must have appropriate receptors.
Physiological variables maintained homeostatically?
Amount of water, circadian rhythm, sexual maturity and reproduction.
What does the hypothalamus do?
Links the nervous and endocrine systems and controls secretion of many endocrine glands.
The major endocrine glands?
Pituitary, thyroid, adrenal, parathyroid, pancreas
Physiological variables that are maintained homeostatically?
Blood sugar concentration, growth and repair, basal metabolic rate, blood calcium concentration.
What are hormones?
Chemical messengers produced in one location and transported via bloodstream to a second location (target cells) where they cause a response in these.
Relationship between hormones and receptors?
A hormone can only affect cells with specific receptors for that hormone. Each receptor is a protein, it can be in the target cell membrane.Or inside.
peptides and catecholamines
w later soluble hormones made and stored until required then released by exccytosis. Travel dissolved in blood.
steroids and thyroid hormones
Lipid, fat soluble hormones, steroids are. made from cholesterol and required not stored. Thyroid hormones are made in thyroid cells and stored until required. Both travel in blood bound to curvier proteins.
Location of receptors for water soluble hormones.
Target cell plasma membrane.
Location of receptors for fat soluble hormones?
Nucleus or cytoplasm et target cells.
