Unit 5 - Endocrine System Flashcards
State the 3 main types of hormone action
- Antagonistic Interaction
- Synergistic Interaction
- Permissive Interaction
What is antagonistic interaction?
Antagonistic Interaction: when… the effect of one hormone opposes effects of another (ex., insulin and glucagon)
What is synergistic interaction?
Synergistic Interaction: when… the sum total of the action of 2 or more hormones is necessary to produce the required effect on the target (ex., prolactin + oxytocin + estrogen are required for breast-feeding)
What is permissive interaction?
Permissive Interaction: when… one hormone exerts its effect only when the target cell has been “primed” by another hormone (ex., pregnancy is dependent on the uterus being exposed first to estrogen then progesterone)
Describe antagonistic hormone control. Provide an example
Antagonistic Control: hormones controlled by both releasing and inhibitory signals (ex., GH and also prolactin)
- GH: the hypothalamus secretes both GHRH and GHIH- hich travel to the anterior pituitary and regulate the secretion of the growth hormone.
Describe negative feedback hormone control. Provide two examples.
Negative Feedback Control: reverses hormone production; all hormones produced in the anterior pituitary experience negative feedback.
- Thyroxine: the anterior pituitary secretes TSH (thyroid stimulating hormone) –> secretion of thyroxine from the thyroid gland –> thyroxine travels to body cells but also travels back to the anterior pituitary and shuts it down.
- Estrogen: the anterior pituitary secretes FSH (follicle-stimulating hormone) –> secretion of estrogen from the ovary –> estrogen travels to the uterus but also travels back to the anterior pituitary and shuts it down. (Same thing with progesterone and testosterone)
How do hormones signal cells?
Cells have receptors that may detect one hormone but not another
The number of receptors depending on the activity of the cells (ex., muscle > bone)
What are steroid hormones? Provide examples
Steroid hormones: hormones made from cholesterol. They are composed of rings of C, H, and O and are fat soluble only.
Ex., sex hormones, cortisol, oxytocin
How do steroid hormones interact with the cell?
- They diffuse from capillaries into the interstitial fluid (fluid surrounding cells) and then into target cells
- They combine with the receptor molecules located in cytoplasm
- The combination of hormone and receptor moves to the nucleus and attaches to some chromatin (chromosome strands made up of DNA and proteins) that has an opposite shape
- They activate a gene on the chromatin that sends a message to the ribosomes telling it to begin production of a specific protein
What are protein hormones? Provide examples.
Protein hormones (a.k.a. non-steroid hormones): hormones composed of chains of amino acids. They are water soluble only.
Ex., insulin, growth hormone
How do protein hormones interact with the cell?
Provide an example scenario.
- Protein hormones cannot diffuse into the cell, so they combine with receptors on the cell membrane
- When bound to the receptors, they activate the production of enzyme adenylyl cyclase
- This causes the cell to convert ATP into cyclic AMP/cAMP which functions as a secondary messenger, activating enzymes in the cytoplasm to carry out their functions
For example, thyroid-stimulating hormone (TSH) attaches to the receptor sites in the thyroid gland, it produces cyclic AMP in thyroid cells. The cyclic AMP in the thyroid cell activates enzymes which produce thyroxine.
Describe the menstrual cycle
The beginning and end of a previous menstrual cycle is marked by shedding endometrium.
- Day 1: a follicle begins developing and secreting estrogen.
- Day 14: ovulation occurs, the egg is released decreasing estrogen levels, and the follicle becomes a corpus luteum (serves to regulated hormones).
- The luteum secretes estrogen and progesterone, which increases body temperature and prevents uterine contracts.
- Progesterone serves to prepare the endometrium for an egg, but if it is not fertilized, both progesterone and estrogen levels crash and uterine contracts commence; the endometrium is shed.
State the gonadotropic hormones involved in the menstrual cycle
Gonadotropic hormones involved: FSH, which travels to the follicle (fluid-filled sac in the ovary containing an egg), and LH, which travels to the corpus luteum.
State the ovarian hormones involved in the menstrual cycle
Ovarian hormones involved: progesterone, which is secreted from the corpus luteum and estrogen, which is secreted from the follicle.
What do nephrons do?
The functional unit of the kidney, consisting of a glomerulus and its tubule, designed for producing urine
Compare hormones and neutrotransmitters
