Section 7- Animal Coordination, Control And Homoestasis Flashcards
What are hormones
Hormones are chemical messengers released directly into the blood and carried by the blood to other parts of the body, but only affects the target organs
What is the function of hormones
They control things in organs and cells that need constant adjustment
Where are hormones produced in
Hormones are produced and secreted by endocrine glands which makes up your endocrine system.
What makes the endocrine system
- pituitary gland
- ovaries
- testes
- thyroid gland
- adrenal gland
- the pancreas
What is the pituitary gland
Produces many hormones and regulates body conditions. These hormones act on other glands directing them to release other hormones for change
What do ovaries do
They are a female organ which produces oestrogen that is involved in the menstrual cycle
What do testes do
They are a male organ which produces testosterone which controls puberty and perm production
What do thyroid glands do
Produces thyroxine which regulates rate of metabolism, heart rate and temperature
Adrenal gland
Produces adrenaline which is used to prepare the fight or flight response
The pancreas
Produces insulin which is used to regulate blood glucose levels
Difference between hormones and neurones
NEURONES:
- very fast
- act for a short time
- act on a precise area
HORMONES:
- slower action
- act for a long time
- act in a more general way
How does your body prepare you for your fight or flight response
Adrenaline
The brain detects a stressful situation which sends a nervous impulse to the adrenal gland which secretes adrenaline.
1. Adrenaline binds into specific receptors in the heart which makes the heart muscle contract with more force so the heart rate and blood pressure increases
2. This increases blood flow to the muscles meaning cells will receive a lot of oxygen and glucose for respiration
3. Adrenaline also binds to the receptors in the liver to break down glycogen releasing glucose.
4. This increases the blood glucose level so there is more glucose in the blood to be transported into the cells.
What can hormone release be affected by
Negative feedback
When the body detects the hormone levels being too high or too low from the normal level, it triggers a release in order to bring it back to the normal level.
Where is thyroxine released
By the thyroid gland
What does thyroxine do
Regulates the metabolic rate.
What happens if your thyroid gland is under active
You gain weight as less thyroxine is being produced making your metabolic rate drop. This means that less of the glucose you take in is being broken down for respiration so more is stored as fat
What is metabolic rate
The speed at which chemical reactions in the body occur.
What happens if the blood thyroxine level is too low
- The hypothalamus is stimulated which releases TRH.
- TRH stimulates the pituitary gland which releases TSH.
- TSH stimulates the thyroid gland making thyroxine so the blood thyroxine levels rise up to normal
What happens if the blood thyroxine level is too high
- The hypothalamus is inhibited meaning the release of TRH is inhibited
- This reduces the production of TSH as TRH cannot stimulate the pituitary gland
- So TSH cannot produce thyroxine
- Blood thyroxine levels fall
What is the menstrual cycle
Monthly sequence of events where the female body releases an egg and prepares the uterus in case the egg gets fertilised.
Stage 1 of the menstrual cycle
Day 1: when the menstruation starts, the endometrium of the uterus breaks down and released
FSH stimulates the ovaries to mature the egg.
The egg will start maturing in the follicles and oestrogen inhibits FSH
Ovaries start producing oestrogen
Stage 2 of the menstrual cycle
The endometrium is prepared from day 4 to day 14 until if becomes a thick and spongy layer full of blood vessels. This is ready for a fertilised egg to be planted there
Oestrogen it produces and stimulates LH.
LH stimulates ovulation
Stage 3 of the menstrual cycle
An egg is develops and is released from the ovary at about day 14
The egg is inside the phelopean tube.
Stage 4 of the menstrual cycle
The lining (endometrium) is maintained for about 14 days until day 28. If no fertilised egg has landed on the uterus day 28, the spongy lining starts to break down again, repeating the cycle
The corpus luteum maintains the endometrium, without progesterone, the endometrium breaks down and it repeats the cycle
What hormones control the menstrual cycle
- FSH
- oestrogen
- LH
- progesterone
FSH
- released by the pituitary gland
- stimulates ovaries to mature the eggs
- stimulates oestrogen production
Oestrogen
- released by the ovaries
- causes the endometrium to thicken and grow
- inhibits FSH
- too much oestrogen won’t mature any eggs
LH
- released by the pituitary gland
- LH surge stimulates ovulation at day 14-, the follicle ruptures and the egg is released
- stimulates the remains of the follicle to develop into a structure called a corpus luteum which secretes progesterone
Progesterone
- released by the corpus luteum
- maintains the lining of the uterus
- inhibits the release of FSH and LH
- when the level of progesterone falls and there’s a low oestrogen level, the endometrium breaks down
- low progesterone levels allows FSH to increase and the whole cycle starts again.
What happens if a fertilised egg implants the uterus
The level of progesterone stay high to maintain the lining of the uterus during pregnancy
What causes infertility
- same sex couple
- not the right reproductive organs
- women don’t ovulate
- women don’t ovulate regularly
Ways for infertility treatment
- IVF
- Clomifene therapy
Clomifene therapy
A woman takes a drug called Clomifene which causes more FSH and LH to be released by the body. This stimulates egg maturation and ovulation.
It is more easier to get pregnant as you know when the woman is ovulating, therefore the sperm will easily fertilise the egg which improves the change of getting pregnant
IVF
- collecting eggs from the woman’s ovaries and fertilising it with a man’s sperm in a lab
- they are then grown into embryos and then collected and put inside a woman’s uterus to improve the chance of pregnancy
- FSH and LH is given before egg collection to stimulate egg production
- Example of ART
What is ART
Fertility treatment where an egg is handled outside of the body
How are hormones used for contraceptives
- high oestrogen prevents the release of an egg, it inhibits the production of FSH and after a whole egg development and production is stopped
- progesterone can be used to reduce fertility, by stimulating the production of thick cervical mucus which prevents sperm from getting through the cervix and reaching the egg.
- some hormonal contraceptives contain oestrogen and progesterone as high oestrogen prevents the release of the egg and high progesterone inhibits the release of FSH and LH.
Barrier methods of contraceptives
- puts a barrier between the sperm and the egg so they don’t meet.
- Condoms
- Diaphragms (woman condom)
Pros of hormonal and barrier contraceptive methods
- When used correctly, hormonal methods are more effective at preventing pregnancy
- helps more smaller families so less poverty
- controls population growth in countries
- allows families to make decisions
Disadvantages of hormonal and barrier contraceptives
- some religious groups disapprove with contraception
- side effects, mood changes, headaches
- hormonal methods don’t protect against sexually transmitted infections - only physical barriers
What is homeostasis
Maintaining a balance in internal environment
Why is homeostasis important
-conditions in the body need to be kept steady as the cells need the right conditions in order to function properly and the right conditions for enzyme actions
Examples of homeostasis
- blood glucose regulations, need the right amount of glucose in the blood and it doesn’t get too high or too low
-Osmoregulation (regulating water content), need to keep a balance between water you gain and water you take out of your body - thermoregulation ( regulating body temperature), you need to reduce body temperature when you’re hot and increase when the environment is cold.
What is negative feedback
Helps keep conditions in the body steady. When the condition changes away from the normal level, a response is triggered that counteracts a change.
What happens if the blood glucose concentration is too high
Pancreas produces insulin and makes less blood glucose levels by making cells which is taken in Glucose. The liver converts glucose to glycogen which is insoluble making the blood glucose level decrease
What happens if blood glucose level is too low
Pancreas produces glucagon which makes more blood glucose level as amino acids and fats break down and the liver converts glycogen to glucose, increasing the blood glucose level
Type 1 diabetes
What is it: when pancreas produces little to no insulin.
How is it treated: Insulin therapy, injecting insulin into the fatty tissue under the skin (subcutaneous tissue). And also insulin pumps
They should take regular exercise and limit intakes of food with carbohydrates
It is lifelong and it usually diagnosed in children
It is caused by genetic factors or damage to the pancreas
Type 2 diabetes
What is it? When the pancreas doesn’t produce enough insulin or when the person becomes resistant to the insulin
How is it treated? Exercise, change in diet
What is the correlation between type 2 diabetes and obesity
Obese people have a higher risk of developing type 2 diabetes. This is because the body stores excess fat and it is stored in the abdomen which increases the risk of type 2 diabetes
Calculate BMI
BMI= Mass/height^2
Waist to hip ratio
Waist circumference/hip circumference
