Topic 9 - Hormones and Fertility Flashcards
what are hormones
chemical messengers which travel in the blood to activate cells in target organs
where are hormones produced
endocrine glands which are part of the endocrine system
pituitary gland
produces many hormones that regulate body conditions. sometimes these hormones act on other glands
thyroid gland
produces thyroxine which regulates body temp, metabolism, etc
pancreas
produces insulin which regulates blood glucose level
adrenal glands
produces adrenaline which triggers fight or flight response
ovaries
produces oestrogen which is involved in female menstrual cycle
testes
produces testosterone whcih controls sperm production in males
3 differences between nerves and hormones
- nerves are faster action compared to hormones
- nerves act for a short time, compared to hormones
- nerves act on localised area but hormones act in more general way
role of adrenaline
- released in response to scary or stressful situations
- this gets your body ready for fight ot flight
how does adrenaline acheive this ( P1)
- binds to specific receptors in heart
- causes heart to contract more frequently so heart rate and b.p go up
- increases blood flow to muscles so cells recieve more glucose + o2 for increased respiration
- gives you more energy for muscle contraction allowing you to fight/flight
how does adrenaline acheive this ( P1)
- binds to specific receptors in liver
- causes liver to break down glycogen stores to release more glucose
- increases blood glucose level so more in blood to be transported to cells
- increased glucose used to fuel muscle contraction
negative feedback
- when levels of certain substance go above/below a normal level
- body triggers responses that help bring these levels back to normal
role of thyroxine
- regulates the basal metabolic rate which is the speed at which chemical reactions in body occur at rest
decrease from normal thryoxine level
- low levels of thyroxine stimulates production of TRH in hypothalamus
-this causes release of TSH from the pituitary gland - TSH acts on the thyroid to produce thyroxine
increase from normal thryoxine level
- when thyroxine levels are higher normal thyroxine, release of TRH is and the production of TSH is inhibited
- reduces amnt of thyroxine produced so falls back towards normal
homeostasis
- regulation of the conditions inside the body to maintain a constant internal environment
- in response to changes in both internal and external conditions
why is maintaining homeostasis important
- cells and enzymes need right conditions to function properly, to keep you alive
which two hormones are produced by pancrease to regulate blood glucose level?
- insulin
- glycagon
how to decrease blood glucose level when it becomes rises ( after eating carbs or sugary sweets )
- rise detected by pancreas : produces insulin which is secreted into blood
- insulin causes body cells to take up more glucose in blood
- cells in liver and muscle take glucose and convert into glycogen, reducing glucose level
how to increase blood glucose level when it becomes decrease (
- fall detected by pancreas : produces glygacon which is secreted into blood
- glycagon causes glycogen stored in liver and muscles to be converted back into glucose
- causes blood glucose level to rise
type 1 diabetes cause
- when the pancrease produces little to no insulin which means blood glucose level can rise to fatal level
controlling type 1
- insulin injections into subcutaneous tissue, several times a day during meals
- makes sure glucose has been removed quickly after digestion
- limiting intake of carbs
- taking regular exercise
type 2 diabetes cause
- same as type 1 OR they become resistant to own insluin and cells stop responding to it
controlling type 2
- healthy diet
- getting regular exercise
- losing weight ( being obese is risk factor )
why is thermoregulation important
- body temp needs to be kept at 37
- optimum temp for enzyme activity
- above this temperature and enzymes start to denature
where is the thermoregulatory centre located?
- in the hypothalamus
what different receptors are there
- receptors in thermoregulatory centre sensitive to body blood temp
- receptors that send info about skin temp via nervous impulses
how does hypothalamus co-ordinate responses to temp change
- these receptors detect changes in temp and send nervous impulses to H
- hypothalamus send impulses to effectors which respond
how does body respond to high temp to cool it down
- erector muscles in dermis relax
- sweat is produced by sweat glands in dermis
- vasodilation
erector muscles in dermis relax
- makes hairs on skin lie flat
- less air trapped near surface of skin so no insulating air surrounding skin
- more heat can be transferred to environment more easily
sweat produced by sweat glands
- released into surface through pores of epidermis
- when sweat evaporates it transfers thermal energy to environment
- reducing body temp
vasodilation
- blood vessels dilate (widen)
- more blood flows close to surface of skin which helps transfer energy from skin to environment
how does body respond to cold temp to warm it up
- erector muscles contract
- very little sweat produced
- vasoconstriction
- shivering
shivering
- muscles contract automatically
- increases rate of respiration which transfers more energy to warm the body
stage 1 menstrual cycle ( 1- 4 )
- menstruation ( bleeding ) occurs.
- uterus lining breaks down and released
stage 2 menstrual cycle ( 4 - 14 )
- lining of uterus is repaired
- into thick spongy layer full of blood vessels
stage 3 menstrual cycle ( 14 )
ovulation - egg released from one of ovaries
stage 4 menstrual cycle ( 14 - 28 )
- lining maintained for 14 days until day 28. if no fertilized egg lands on uterus by 28,
- lining breaks down again, cycle restarted
FSH
- produced in pituitary gland
- causes one of follicles in ovary to mature
- stimulates oestrogen production in ovary
Oestrogen
- causes lining of uterus to thicken and grow
- stimulates LH surge
- inhibits production of FSH
LH
- produced by pituitary gland
- causes follicle to rupture and egg to be released
- stimulates remains of follicle to develop into corpus luteum
Progesterone
- produced by corpus luteum
- maintains lining of uterus lining
- inhibits release of FSH and LH
