Endocrine Flashcards
Functions of Endocrine System
- regulates growth, reproduction, metabolism
How does Endocrine system work
- glands and tissue secrete hormones and travel in blood to target cell
- bind to specific receptors and change cell activity
Where can receptors be found in
cell membrane and intracellular
what hormones types are involved
- Water soluable
- Lipid Soluable
What are considered Water Soluble
peptides, proteins, catercholamines
steps for water soluable hormones
- bind to cell membrane receptors ( does not enter)
- hormone receptor activates membrane proteins ( g proteins)
- G proteins activate 2nd messenger system ( CAMP)
Why use 2nd messenger system in water soluable hormones
- hormones can’t enter cell
- rapid acting ( just need activation)
- many ezymes can be activated = many signals
- limited - messenger can broken down or removed
What is considered a lipid soluble hormones
steriods and thyroid hormones
What is the function of lipid soluble hormones
trigger protein synthesis and allows for long lasting response
Steps for lipid soluble hormones
- enters target cells and bind to intracellular in cytosol or nucleus
- binds to specific region on dna (activiates gene) => starts gene transcription - producing mRNA
- mRNA attaches to ribosomes to produce proteins * translation)
Types of stimuli use on endocrine gland
- Humoral: stimulus is ion/nutrients
- Neural: internal or external changes that trigger a response ( feedback mechanism)
- Hormonal: released of hormones in response to certain signal or condition
What is stress and what does it trigger
extreme external or internal change that triggers set of body changes ( General Adaptation syndrome) directed by the hypothalamus
Phases of stress
- Flight or Flight response
- adaptation to stress ( conserve energy while on alert) = more tired
- Exhaustion: lack of body resources(lipid reserve), loss of K and damage to heart
Function of testorone
- development of organs ( reprod)
- Stimulate bone growth at epiphyseal line
- promotes protein anabolism
- stimulates spermatogenesis
Function of FSH
stimultes 1 to become 2 follicle and stops the rise of progesterone
function of LH
- Stimulate E production
2.Surge of LH = ovulation and formation of corpus luteum
- Follicular stage: E rises => stimulates LH release => stimulating follicle to increase Estrogen secretion => a LH surge
function of Estrogen
- needed for ovulation
- develops 2 sex characteristic
- Stimulates growth and maintains endometrium
- increase in bone growth
Function of Progesterone
- forms corpus luteum
- prepares uterus for preganacy
Ovarian Cycle
Day 1-14: follicular phase
Day 1-5: Menstrual Phase
Day 6-12 phase
Day 14- Ovulation stage
Day 15-28: luteal and secretory phase
What happens during follicular phase
Early: Progesterone is low and LH + FSH is secreted -> follicles secrete E causing blood E to rise
Later: follicle becomes vesicular follicle
Menstruation and proliferative phase also occurs at this time
What happens during menstrual phase
stratum functionalis sheds causing bleeding = menstrual flow of blood, cells and secretion
What happens in the proliferative phase
E => repairs and rapid increase of stratum functionalis ( due to mitosis)
What happens during ovulation
LH surge => triggers LH causing the completion of meiosis 1 and the rupture of vesicular follicle with the released of 2 oocyte
What happens during the luteal phase
High P from corpus luteum that stop the growth of GnRH (Lh + FSH) = no follicles develop
What happens during the secretory phase
P prepares endometrium for implantation ( vascular, thicker and stores glycogen) and stops uterine contractions
What happens if fertilization occurs
- placenta secretes hCG to maintain corpus luteum => P, E for 6 weeks than placenta take over where it secretes P + E
- FSH, LH stopped by high P ( no follicles develop)
If NO fertilization occurs, what happens
- corpus luteum => corpus albicans ( no hCG, low LH)
- decrease in P and E causing production in LH and FSH ( increase)
- no longer maintain endometrium => menstruation
What are the types of contraceptives
- Oral
- Implants
- Morning after pil
How does Oral Contraceptives work
- produces high E + P which stops GnRH secretion causing low FSH and LH = no follicle maturation and no ovulation
How does implants work ( progestin)
- similar to oral = produces high E + P causing low FSH and LH = no ovulation and follicle maturation
How does the morning after pill work
- high E and Progestin or Progestin only
- prevents implantation, ovulation or fertilization
The placenta is formed by
the chroion (fetus) and the endometrium ( maternal)
What are the functions of the placenta
- Exchange site for gases, nutrients, drugs and viruses
- Secretes hormones ( E + P) and hCG
* maintains corpus luteum, detected by pregnancy test and stimulates testosterone secretion by fetal testes
Phase 1 of Stress (pathway)
CNS detect change -> Hypothalamus where it increases alertness -> SNS -> organs and Adrenal medulla where it releases E + NE prolonging fight and flight response
What happens in Phase 1
- increase in blood glucose
- increase in Hr and respiration rate
- decrease blood flow to skin ( keeping it more internally)
- decrease in urine production
What happens in Phase 2
release of hormones
1. GH - stimulates growth, cell production
2. cortisol is released immedietly but does not take affect until hrs and stops insulin released
What are the long term effects for stress
- decrease in weight, bone density
- increase in BP, HR, risk of type 2 diabetes due to increase in blood glucose
What happens in phase 3 of stress
- decrease in body resourches
- loss of K (aldosterone)
- damage to organs
Example of humoral stimulus
- Increase in Blood glucose after eating -> B cells release insulin -> lowering blood glucose
- parathyroid gland detects decrease in Ca -> releases parathyroid hormone -> increases bone resorption -> increase in blood Ca
