B11 - Hormonal coordination Flashcards
1
Q
What is the endocrine system and differences to the nervous system
A
- A system of glands that secrete hormones (chemicals) into the blood where it is carried around the body.
- Produces a slower, longer lasting effect than the nervous system.
- Transports hormones in the blood not electrical impulses in neurones
2
Q
Key glands in the endocrine system and their roles
A
- Pancreas - blood glucose maintenance
- Testes/Ovaries - control secondary sexual characteristics
- Adrenal glands - produced in times of fear or stress
- Thyroid - basal metabolic rate
- Pituitary
3
Q
Role of the pituitary gland
A
‘Master gland’ that releases a number of different hormones. They act on other glands and stimulate other hormones to be released
4
Q
What happens if blood glucose level is too high e.g. meal with carbs eaten
A
- Conc of blood glucose rises
- Detected by receptors in pancreas and releases insulin
- Insulin stimulates cells to take up glucose
- Also tells liver and muscles to store glucose as glycogen
5
Q
What happens if blood glucose level is too low
A
- Detected by receptors in pancreas
- Release glucagon
- This stimulates the liver cells to convert glycogen back into glucose
6
Q
What happens with Type 1 Diabetes
A
- The pancreas doesn’t produce enough insulin
- Their blood glucose levels rise higher and stay high
Can be inherited
7
Q
Symptoms of type 1 diabetes
A
- Glucose in urine
- Patient feels THIRSTY as lots of urine is produced to get rid of excess glucose
- Patient feels TIRED as enough glucose can’t be taken into cells for use in respiration
- This leads to WEIGHT LOSS
8
Q
What happens with Type 2 Diabetes
A
- Body cells have stopped responding to insulin
- Similar symptoms to type 1 diabetes
Linked to obesity, age, lack of exercise
9
Q
How to treat type 1 diabetes
A
- Insulin injections before meals
- Pancreas transplants
- Stem cells (future)
10
Q
How to treat type 2 diabetes
A
- Losing weight
- Regular exercise
- Carb controlled diet
11
Q
How does a person’s blood glucose concentration stay level
A
- If blood glucose rises, insulin released which reduces blood glucose
- When it falls to a certain level, glucagon is released which increases blood glucose
- Each hormone inhibits its own production and have opposite effects
- This is a negative feedback system
12
Q
What does testosterone control and where is it produced
A
- Stimualtes sperm production
- Produced in the testes
13
Q
Describe the menstrual cycle
A
- Lining of uterus breaks down
- It then builds in preparation for release of egg
- Egg is released
- If sperm is present, egg impants into lining but if not, cycle repeats
14
Q
Function of hormones in the menstrual cycle
A
- FSH - Causes an egg to mature
- LH - Stimulates ovulation
- Oestrogen - builds up endometrium
- Progesterone - maintaining endometrium
15
Q
Describe how the hormones in the menstrual cycle interact
A
- FSH released by pituitary gland
- Travels to ovaries and stimulates the maturation of an egg. Also stimulates release of oestrogen from ovary
- Oestrogen builds up uterus lining and inhibits FSH secretion. Stimulates LH secretion.
- LH released from the pituitary stimualtes ovulation
- Corpus luteum secretes progesterone
- This inhibits the secretion of FSH and LH. It also maintains the uterus lining with oestrogen
16
Q
Hormonal methods of contraception and advantages and disadvantages of them
A
- Daily pill - prevent release of FSH - stops eggs maturing. Very effective but can have side effects such as breat cancer or blood clots. Also can be easily forgotten
- Patch, injection or implant - more convenient that the pill. Contain progesterone.
- No hormal contraception methods protect against STIs
17
Q
Barrier methods of contraception and advantages and disadvantages of them
A
- Condom and diaphragm - prevent sperm from reaching egg
- Advantages - don’t need specialist application, prevent against STIs
- Disadvantages - can break
18
Q
What is an IUD and advantages and disadvantages of it
A
- Coil insterted into uterus by professional
- Advantages - very few side effect
- Disadvantages - dont protect against STIs, can prevent future pregnancies
19
Q
Steps during IVF
A
- Mother is given FSH and LH to mature lots of eggs
- Eggs collected from mother
- Sperm is collected and fertilises eggs in lab
- Once eggs have grown into embryos, they are inserted into mother
20
Q
Problems with IVF
A
- Not very high success rates
- Stressful for both parents
- Physically demanding on mother
- Mutiple births could be dangerous
- Ethical issues surroundings destruction of unused embryos
- Very expensive
21
Q
Role of adrenaline and where is it released from
A
- Adrenal glands on top of kidneys release adrenaline into blood in times of stress or fear - FIGHT OR FLIGHT
- Increases heart rate - more oxygen and glucose to brain
- Dilate pupils
- Glycogen converted to glucose
- Blood diverted from digestive system to vital organs
22
Q
Role of thyroxine and where is it released from
A
- Released by thyroid gland in neck
- Stimulates basal metabolic rate
- Growth + development
23
Q
How are thyroxine levels controlled by negative feedback
A
- Thyroxine levels monitored by brain
- When thyroxine falls, brain detects this and pituitary secretes TSH
- TSH stimulates thyroid to release more thyroxine
- Thyroxine levels increase, detected by brain
- This decreases TSH secretion from the pituitary so less thryroxine is released
- Therefore, TSH eventually inhibits its own production
24
Q
What is gravitropism (geotropism) and phototropism
A
- Gravitropism - the groeth response of plants to gravity
- Phototropism the growth reponse of plants to light
25
What hormone is used in phototropism and how does it work
* One side of the shoot is exposed to more light
* Auxin is produced in the root tips which stimulates cell growth in the shoots
* Light causes auxin to concentrate on the darker side (the side further away from the light) causing an unequal distribution of it
* Auxin causes cells on the side away from the light grow faster than the cells on the lighter side
* This causes the shoot to grow towards the light
26
How does auxin work in gravitropism
* Auxin is produced in the root but gravity causes it to concentrate on the lower side of the root causing unequal distribution of it
* In roots, auxin inhibits growth so the lower side grows solwer than the upper side
* This causes the roots to grow towards the force of gravity
27
Uses of auxin
* Weedkillers
* Rooting powders
* Promoting growth in tissue culture
28
Uses of gibberellins
* Starting seed germination
* End seed dormancy
* Promote flowering
* Increase fruit size
29
What fruit releases ethene and what are its uses
* Bananas
* It is used in the food industry to control the ripening of fruit during storage and transportation
* It also controls cell division
