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B11: Hormonal Coordination - Coggle Diagram
B11: Hormonal Coordination
11.1 Principles of Hormonal Control
Endocrine system - composed of glands that secrete hormones directly into the blood stream
Effects of hormones are often slower but longer lasting
The pituitary gland is the master gland, secreting several hormones, some of these hormones stimulate other glands to produce hormones that have a specific effect
Main glands are: Pituitary, thyroid, arenal, pancreas, ovaries, and testis
11.10 Using Plant Hormones
Auxin can be used as weed killers, rooting powders, and in tissue cultures
Ethene controls fruit ripening
Gibberellins used to increase fruit size, end seed dormancy, promote flowering
11.4 Role of Negative Feedback
Negative Feedback - If a factor in the internal environment increases, changes take place to reduce it and restore the original level
Thyroxine from the thyroid gland stimulates the basal metabolic rate
Adrenaline is produced by the adrenal glands, it increases heart rate and boosts the delivery of oxygen & glucose to the brain and muscles; preparing for fight or flight
Thyroxine is controlled by negative feedback, adrenaline is not
11.2 Control of Blood Glucose Levels
Blood glucose concentration is monitored & controlled by the pancreas
Insulin (secreted from pancreas) - allows glucose to be taken in by cells, and controls the storage of glycogen in the liver and muscles
Glucagon (secreted from pancreas) - allows the glycogen to be converted back into glucose and released into the blood
Glucagon interacts with insulin in a negative feedback cycle to control glucose levels
Type 1 diabetes - pancreas doesn't produce enough insulin
Type 2 diabetes - Body becomes insulin resistant
11.3 Treating Diabetes
Type 1 is caused by pancreatic cells being destroyed by immune system, or it doesn't produce enough
Treated with insulin injections and is diagnosed relatively young
Type 2 is when body becomes insulin resistant due to there being a constant excess
Treated with a carbohydrate-controlled diet and exercise, diagnosed typically in adults 30+
11.6 Hormones & Menstrual Cycle
FSH from the pituitary gland stimulates eggs to mature in the follicles of the ovary and stimulates the ovaries to produce oestrogen
Oestrogen secreted from the ovaries stimulates the growth of the uterus lining, trigger the release of LH, and inhibits FSH
LH stimulates ovulation
Progesterone produced by the empty follicle after ovulation, maintains the uterus lining for around 10 days and inhibits FSH and LH
11.8 Infertility Treatments
FSH and LH used to stimulate ovulation
IVF uses FSH and LH to stimulate maturity of eggs to be collected, fertilized, and replanted in the uterus
IVF is stressful on the body, often unsuccessful and can lead to multiple births or miscarriage
11.5 Human Reproduction
During puberty, reproductive hormones cause secondary sexual characteristics
Oestrogen is produced by the ovaries, eggs begin to mature in the ovary and 1 is released every 28 days (ovulation)
Testosterone is produced in the testes and stimulates sperm production
11.7 Artificial Control of Fertility
Contraceptives may include: oral contraceptives (birth control pills), hormonal injections, implants and patches, barrier methods (condoms & diagrams), intrauterine devices (IUD), spermicidal, abstinence, and surgical sterilisation)
Fertility controlled by hormonal and non-hormonal contraception
11.9 Plant Hormones & Responses
Response to light or gravity are called tropisms
Light - Phototropism
Gravity - Gravitropism
Responses in root and shoot are due to the unequal distribution of auxin
Shoot grows towards light against gravity as auxin moves to the shady side of the shoot and speeds growth causing the shoot to bend towards the light
Roots grow in direction of gravity as no light present, auxin moves to the lower side inhibiting growth causing the root to bend downwards