Hormones Flashcards
Define hormones
Chemical substance produced by a gland which travels in the blood where it alters a specific activity of a target organ
Thyroxine description
Is produced from the thyroid gland and stimulate the metabolic rate
Thyroxine level is low:
Low level of thyroxine stimulate the hypothalamus to release TRH
The TRH causes the pituitary gland to release thyroid stimulating hormones (TSH)
The TSH travels in the blood and acts on the thyroid gland to produce thyroxine
Thyroxine level increases
Thyroxine levels are normal or high
The thyroxine levels inhibit the release of TRH and TSH and the production of TSH
Thyroxine level decrease
Where is adrenaline produced from and where is it affected
Adrenal gland
Target3 organs; liver and heart
Adrenaline role and effect
Readies the body for a flight or fight response
Increased heart rate
Increased blood glucose conc for increasing the respiring muscle cell
Dilate pupils
Where is ADH produced and target
Produced at the posterior and pituitary gland
And affects the kidney
ADH effect
Controls blood water level by triggering uptake of water in kidney
Where is Testosterone produced and effect
Produced ; testis
Target organ; male reproductive organs
Controls puberty in males
Where is oestrogen produc3d and effect
Produced; ovary
Target organ; ovaries, uterus, pituitary gland
OEstrogen effects
-thickens uterine lining
Controls puberty and the menstrual cycle in females
Stimulate production of LH
Suppresss the production of FSH in the pituitary gland
Progesterone produced and target organs impact
Produced by the Ovary
And targets the uterus
Impact
Maintains the uterus lining
Nervous type of signal
Electrical (chemical at synapses)
Nnervous transmission of signal
By nerve cells (neurones)
Nervous effectors
Muscle or glands
Nervous speed of response
Rapid
Nervous duration of response
Short ( until nerve impulse stops)
Hormonal type of signal
Chemical
Hormonal transmission of signal
By the bloodstream
Hormonal effectors
Target cells in particular organs
Hormonal Type of response
Chemical change
Hormonal speed of response
Slower
Hormones duration of response
Long ( until hormones is broken down)
FSH description
Causes one follicle into the ovaries to become mature ( cause eggs maturation in ovary)
Stimulate the ovary to start releasing oestrogen
Released by pituitary gland
LH description
Secreted from pituitary gland, which stimulate ovulation. This is when the ovum is released from the ovaries
Stimulate the ovary to produce progesterone
Stages of menstrual cycle
Lining breaks down sue to the lack of progesterone
Oestrogen level rise which cause lining to build up again
FSh causes maturation of a single follicle into a mature follicle (containing the ovum)
Half way through oestrogen drops and LH causes ovulation. The ovum gets released into the oviduct, leaving behind the remains of the follicle (which develops into corpus luteum)
Corpus luteum secrete progesterone which maintain the thickness of the uterus lining
Eventually corpus luteum degernation and reduce progesterone levels and this lining gets broken down (back to stage 1)
What does oestrogen and progesterone inhibit
The production of LH and FSH
Steps of menstrual cycle
1) pituitary gland produce FSH which stimulate the development of a follicle in the ovary
2) an ovum develop inside the follicle and the follicle produce the hormone oestrogen
3) oestrogen causes growth and repair of the lining of the uterus wall and inhibit of FSH
4) when oestrogen rises to a high enough level it stimulate the release of LH from the pituitary gland which cause ovulation (usually around day 14 of the cycle)
Ovulation releasing of the egg from the ovary to the oviduct
The follicle becomes the corpus luteum and starts producing progesterone
Progesterone maintains the uterus lining (thickness of the uterus wall)
If the egg/ovum is not fertilised, the corpus luteum breaks down and is removed through the vagina - period
If the egg /ovum is fertilised embryo is formed and implanted in the uterus lining then m the corpus outermost continues to produce progesterone, preventing the uterus lining from break down and maintaining the pregnancy
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FSH - oestrogen- LH - progesterone
