B11 - Hormonal Coordination Flashcards
The endocrine system
• glands produce hormones
• hormones are chemicals which travel in the blood (capillaries)
• to reach their target organ which has an effect
- Thyroid (throat)
- Adrenal (below pancreas)
- Testes
- Pituitary (in brain)
- Pancreas
- Ovaries
How does a hormone travel?
• secreting cell
• to blood stream
• deposited to target cell
Adrenaline
• found in the adrenal gland
• prepares body for action
Increasing heart/breathing rate to supply more O2 and glucose to muscles and brain
Prepared body for action in stressful situations
‘Fight or flight’ response
Increases awareness
Pupils dilate
Not controlled by negative feedback
Testosterone
Testes
Male sexual development
Insulin/glucagon
• pancreas
Blood sugar
Oestrogen and progesterone
Ovaries
For menstruel cycle
Thyroxine
Thyroid
Metabolic rate
Controlled by negative feedback
ADH/FSH/LH/TSH
Pituitary
Water level/female sexual development/regulates thyroid
Control of blood sugar - glucagon and insulin (negative feedback)
• when blood sugar goes up, body lowers it (responding with the opposite)
Control of blood sugar process
- High blood sugar after food
Promotes insulin release - Detected by pancreas
- Pancreas secretes insulin which stimulates formation of glycogen
- So liver converts glucose to glycogen
- This reduces blood sugar levels
- Low blood sugar (after exercise)
Promotes glucagon release - Detected by the pancreas
- The pancreas secretes glucagon which stimulates the breakdown of glycogen and the liver converts glycogen to glucose
- This raises blood sugar and increases blood sugar levels
What is glycogen?
• store of glucose - storage molecule made of many glucose molecules
What hormone is released if blood sugar is too high?
• insulin
• causes blood glucose to be stored as glycogen in liver (and muscles)
• decrease blood sugar
What hormone is released if blood sugar is too low?
• glucagon
• causes liver to release glucose from glycogen stores
• increased blood sugar
What is glucagon?
• hormone that raises blood sugar
Thyroxine production
TSH (thyroid stimulating hormone) from the pituitary, which stimulates the thyroid to produce thyroxine (from iodine, hence iodised salt) that stimulates the basal metabolic rate - plays an important role in growth and development
Thyroxine production process
When your thyroxine level increases
Pituitary produces less TSH
Thyroid makes less thyroxine
Normal thyroxine
Thyroxine level decreases
Pituitary produces more TSH
Thyroid makes more thyroxine
Normal thyroxine
Type 1 Diabetes
Caused by genes so it is inherited
No insulin produced
Blood sugar remains very high after a meal (hyperglycaemia)
This can damage blood vessels and organs
No glycogen is stored
No release of glycogen when blood sugar low (hypoglycemia)
Can lead to a coma
Treatment: low carb diet and limited sugars
Insulin injections after meals
Exercise after meals
Carry a source
Type 2 Diabetes
Caused by environmental factors eg obesity
Body doesn’t respond to insulin produced
Don’t need to use insulin injections
Treatment: low carb diet and limited sugars
Exercise after meals
Carry a source of carbs
If this doesn’t work, drugs may be needed
Hormonal control of the menstrual cycle
1) increase in FSH (stimulates follicle)
2) FSH stimulates egg maturation
3) FSH stimulates release of oestrogen by ovaries (positive feedback)
4) oestrogen causes the uterus lining to thicken
5) as oestrogen levels rise, it inhibits FSH production
6) oestrogen also stimulates LH production (luteinising)
7) LH stimulates ovulation
8) A yellow body is left after releasing the egg (corpus luteum)
9) the yellow body in the ovary produces progesterone
10) progesterone inhibits LH and FSH production
11) progesterone maintains thickness of the uterus wall
12) if no fertilisation happens, progesterone levels drop as yellow body breaks down
13) period starts
Hormone/ gland / function / feedback - FSH
FSH
pituitary
Egg maturation
Stimulates oestrogen
Hormone / gland / function / feedback - oestrogen
Oestrogen
Ovary
Thickens uterus lining
Inhibits FSH
Hormone / gland / function / feedback - LH
LH
Pituitary
Stimulates ovulation
Stimulates progesterone
Hormone / gland / function / feedback - progesterone
Progesterone
Yellow body
Maintains uterus lining for around 10 days
Inhibits LH/FSH
Hormonal contraception (the pill)
Oestrogen (inhibits FSH so no eggs develop)
Progesterone (inhibits LH and FSH so no eggs released)
Combined pill (both so more effective)
Can be oral, patch or implant
Why may a couple not use protection?
Past the menopause
Pregnant
Wanting to concieve
Not having sex
Endocrine system compared to the nervous system
Effects of hormones, often slower, but longer lasting
Other contraceptive methods
Oral contraceptives
Hormonal injections, implants and patches
Barrier methods (condoms and diaphragms)
Intrauterine devices
Spermicidal agents
Abstinence
Surgical sterilisation
IVF
In vitro fertilisation uses FSH and LH to stimulate maturation of eggs that are collected, fertilised, allowed to start development and replaced in the uterus
Emotionally and physically stressful, often unsuccessful, can lead to risky multiple births
