What are the 5 functions of hormones?
- growth and development
- body defenses
How are hormones released and transported throughout the body?
hormones are released by specialized endocrine cells that are secreted into blood or lymph which then targets sites
Name the 3 chemical classification of hormones
- amino acid - proteins, peptides
- steroids - sex hormones
- prostaglandins - lipid based
Describe why hormones are specific
hormones MUST bind to receptors on target cells of its target sites, affecting only target organs and tissues
How do hormones change cell activity (5)
- creating changes in plasma membrane permeability
- synthesizing proteins
- activating, inactivating enzymes
- stimulating mitosis
- stimulating secreting hormones
describe how steroid hormones activates genes directly
- steroid hormones diffuse through plasma membrane of target cells and enter into the nucleus
- bind to specific receptor proteins in nucleus.
- Creates a hormone receptor complex: that binds to specific site on DNA
- turns genes on which synthesizes proteins
What is the difference between a non-steroid hormone and a steroid hormone
non-steroid hormone requires a second messenger
describe the process of the non-steroid hormone acting on the 2nd messenger
- 1st messenger (hormone) binds to membr. receptor, activating a series of reactions on an enzyme
- enzyme catalyzes reaction to produce 2nd messengers (cyclic amp)
- cAMP triggers cellular changes which produce a specific response in target cells
How is the amount of hormones in the blood controlled?
by negative feedback mechanisms. The higher the concentration of hormones in the blood, the body releases chemicals to stop the secretion of hormones
name the three types of endocrine gland stimuli and describe them
- hormonal: hormones are secreted by the hypothalamus which causes PTH to secrete secondary hormones.
- humoral: any fluctuations of ions and nutrients in the blood or lymp (humoral fluids) induces hormone secretion to maintain homeostasis
- neural: nerve fibers stimulate hormones to be released into target cells
Name one hormonal gland
what type of hormone is released by the pituitary gland and describe its function
two types of tropin hormone gonadotropins (FSH) and luteinizing hormone.
name and describe a humoral gland
- parathyroid hormone and calcitonin maintains the Ca+2 levels in the blood.
- calcitonin: decreases Ca+2 levels in the blood through calcium deposits in the bone
- Parathyroid hormone: increases calcium levels in the blood by stimulating osteoclasts to degrade bone
- Insulin and glucagon: maintains blood glucose levels. both released by pancreas
- insulin: reduces glucose levels by converting glucose into glycogen in the liver.
- glucagon: increases glucose levels by breaking breaking down glycogen into glucose within the liver
name and describe the neural hormone stimulus
- Most under control of sympathetic division of nervous system ("fight/flight"). released by adrenal medulla (adrenaline)
Name the 9 endocrine organs
- pituitary gland
- thyroid gland
- pineal gland
- adrenal gland
- gonads = ovaries and testes
of the 9 endocrine glands, which are untrue (hybrid of endo & exocrine glands)
Describe what happens when there is an increase in Ca+
An increase in calcium levels in blood will stimulate the thyroid gland to produce calcitonin which causes calcium to be deposited in the bone; bringing the calcium levels down.
Describe what happens when there is a decrease in Ca+
A decrease in calcium levels in the blood will stimulate the parathyroid glands (within the thyroid glands) to release PTH which produces osteoclasts to degrade bone. As a result, calcium levels will increase
Describe what happens when there is an increase in glucose in the blood.
an increase in blood glucose levels will cause the pancreas to release insulin which causes glucose to bind to glycogen within the liver. Blood glucose will decrease.
Describe the hormonal control for blood glucose levels when there is an increase in glucose and the hormone involved
when there is a decrease in blood glucose levels, the pancreas will release glucagon in the blood which catabolizes glycogen into glucose increasing blood glucose levels.
what target organ controls glucose levels in the body?
What endocrine organs control Ca+ levels of the body?
thyroid and parathyroid
describe the function of gonadotropins (FSH) and luteinizing hormone
They both stimulate the ovaries and testes to produce estrogens and androgens
name a 2nd messenger hormone