Homeostasis Flashcards
1
Q
Why is homeostasis important?
A
Because it keeps our internal conditions constant so that so that our enzymes and cells can work well.
2
Q
What are 3 internal conditions we have to keep constant?
A
Glucose concentration, water levels, temperature.
3
Q
What is a stimulus? What detects a stimulus?
A
- a stimulus is a change in the environment.
- receptors detect stimuli
4
Q
Give 4 examples of receptors. What do they do?
A
- Skin, Eyes, Nose, Mouth.
- They detect changes in the environment.
5
Q
What is the job of the coordination centre? What body parts are involved in it?
A
- The brain and the Spinal cord.
- their job is to receive and process the information from receptors.
6
Q
Give 2 examples of effectors. What is an effectors job?
A
- Gland, Muscle.
- their job is to carry out the response.
7
Q
What does a sensory neurone do?
A
A sensory neurone transmits electrical impulses from receptors to the CNS.
8
Q
What does a motor neurone do?
A
Motor neurones transmit electrical impulses from the CNS to the effectors.
9
Q
What does a relay neurone do?
What is a synapse?
A
- relay neurones connect sensory neurones to motor neurones.
- A synapse is a junction between two neurones where electrical signals pass across.
10
Q
Describe what would happen when you were to see and pick up a chocolate brownie.
A
- Brownie = stimulus.
- Eyes + nose = receptors.
- Sensory neurone transmits an electrical impulse to the brain.
- Brain receives + processes information.
- Motor neurone transmits electrical impulse from brain to effectors.
- effector = arm.
- pick up brownie = response.
11
Q
What 2 parts does the nervous system consist of?
A
- The CNS
- Neurones that transmit electrical impulses.
12
Q
What is a reflex?
Explain the reflex arc for when you touch a hot object.
A
A reflex is an automatic response of the nervous system that is rapid and doesn’t involve conscious thought. E.g blinking.
- Hot object ( stimulus)
- receptor (skin) detects it.
- sensory neurone transmits electrical signals to the CNS
- The CNS is the spinal cord.
- motor neurones transmit electrical impulses from the spinal cord to the effectors (hand)
- hand moves away from the hot object (response)
13
Q
Does the brain consciously make decisions for reflexes? Why / why not?
A
No, because it takes longer to process it. Reflexes need to happen quickly to prevent us from danger.
14
Q
Definition of endocrine system.
A
A system that consists of glands and hormones. The glands secrete hormones into the bloodstream and these hormones act on specific target organs.
15
Q
Definition of hormones. What do hormones do?
A
Hormones are chemical messengers that are released by glands into the blood.
- They target specific target organs where they produce an effect.
16
Q
Name 2 differences between the nervous and endocrine system.
A
- The endocrine system has longer lasting effects than the nervous system.
- The endocrine system includes hormones, whereas the nervous system transmits electrical impulses.
17
Q
Name the 5 main glands/ organs in the endocrine system + their jobs.
A
- Pituitary = releases a range of different hormones that can cause other glands to release hormones depending on the conditions.
- Pancreas = Releases glucagon + insulin to control blood glucose concentration.
- Ovaries = Releases oestrogen + progesterone
- Thyroid= Releases thyroxine which is involved in growth and regulating the body’s BMR.
- Adrenal gland = releases adrenaline when you’re scared / stressed.
18
Q
Why is the pituitary gland named the ‘master gland’
A
Because it can release hormones that act on other glands that cause other hormones to be released.
19
Q
Why is it important to maintain your BGC?What is your BGC maintained by?
A
- Because every cell needs glucose to have energy for respiration.
- The pancreas.
20
Q
How does the pancreas control your BGC if it’s risen too high?
A
- pancreas releases insulin.
- insulin travels in the bloodstream around the body.
- insulin targets your cells to pick up glucose from the bloodstream + for your muscle and liver cells to store it as glycogen.
- because glucose is taken out of the blood and stored, glucose concentration returns to normal.
21
Q
What is type 1 diabetes?
A
When your pancreas doesn’t produce enough insulin, so your blood glucose concentration cannot be properly regulated.
22
Q
What happens to a person with T1D if they eat a carb rich meal? Why?
A
- Their blood glucose concentration would rise + stay at a high level.
- their pancreas wouldn’t be able to produce enough insulin to bring down their BGC.
23
Q
How is type 1 diabetes controlled?
A
- They have to inject themselves with insulin.
24
Q
What is type 2 diabetes?
A
- When your cells stop responding to insulin.
25
How is type 2 diabetes controlled?
By monitoring your carbohydrate intake and making sure it stays low.
26
What is a major risk factor for someone with T2D?
- Obesity
27
How does the pancreas regulate your BGC if it goes too low?
- The pea creas releases glucagon into the bloodstream.
- glucagon triggers your liver + muscle cells to convert glycogen back into glucose.
- The glucose is released into the blood.
- This causes the BGC to return to normal
28
Why does your BGC rise and fall throughout the day?
Because it’s controlled with a balance of insulin and glucagon.
29
What hormone do the testies produce? What does this hormone do?
- Testosterone
- It stimulates the testies to produce sperm.
30
How long does the menstrual cycle last?
28 days
31
Where are LH and FSH released from? What are their roles?
- They are both released by the pituitary gland.
- FSH causes an egg to mature in the ovary.
- LH stimulates the release of an egg from the ovary. (ovulation)
32
What is the role of progesterone? Where is it released?
- Maintains the lining of the uterus so it can receive the embryo.
- Inhibits the production of LH and FSH.
- It is secreted from empty egg follicles in the ovaries.
33
What is the role of oestrogen? Where is it produced?
- Stimulates the thickening of the uterus lining in preparation for pregnancy.
- inhibits the production of FSH, stimulates production of LH.
- Produced in the ovaries
34
Explain the process of the menstrual cycle.
1. FSH is released by the pituitary gland and causes an egg to mature.
2. Oestrogen causes lining of uterus to thicken. Then stimulates the production of LH.
3. Pituitary gland releases LH. LH triggers egg to be released.
4. Once the egg is released, progesterone is secreted from empty egg follicles in the ovary.
5. Progesterone inhibits the production of LH and FSH. It also keeps the uterus lining thick in case a fertilised egg implants.
6.If it doesn’t, the uterus lining and the egg are released.
35
What does contraception aim to do?
Prevent fertilisation.
36
Which hormones do contraceptive pills have in them?
Oestrogen and Progesterone
37
Why do contraceptive pills have oestrogen and progesterone in them?
Because both oestrogen and progesterone inhibit FSH production so the egg cannot mature.
38
Name one advantage of oral contraception / contraceptive pill
It is very effective if taken correctly.
39
Name 2 disadvantages of oral contraception.
- Have to take it everyday,
- can have side effects - increased chances of breast cancer and blood clots.
40
Name 2 other types of contraception.
Name an advantage + disadvantage of taking these.
- Implant, Patch.
- Advantage = More convenient than taking a pill everyday. Implant can last for 3 years.
- Disadvantage = can also have side effects.
41
Name a disadvantage both types of contraception gave.
None of them protect against STDs
42
Name a barrier method of contraception. Why do barrier methods of contraception work?
Name 2 advantages + a disadvantage
- Condom. Works because sperm is prevented from fertilising egg.
- Advantage = Protect against STDs,
43
What can be used with condoms which helps?
Spermicide gel - it disables the sperm
44
How does an IUD prevent pregnancy?
Name an Adv + Disadv
- An IUD stops an Embryo from implanting.
- Adv = Highly effective- can prevent pregnancy for up to 10 years. Doesn’t have side effects.
- Disadvantage = Doesn’t protect against STDs
45
How does sterilisation prevent pregnancy?
Name an Advantage and disadvantage.
- Women - prevents egg form meeting uterus
- Men - prevents sperm from leaving penis.
Advantage: Very effective
Disadvantage: Extremely hard to reverse. Have to be sure you don’t want children.
46
How do natural forms of contraception prevent you from getting pregnant?
Name an advantage and a disadvantage.
- If you wait until after ovulation, the egg will not get fertilised because there won’t be any sperm.
- Advantage - No side effects
- disadvantage- hard to tell when a woman is going to ovulate. Doesn’t protect against STDs
47
Where is the adrenal gland located? What does it release?
- Located near the top of the kidneys
- Releases adrenaline during times of fear or stress.
48
Explain how adrenaline prepares the body to fight or run away.
- Adrenaline is released in times of stress or fear.
- Adrenaline increases your heart rate.
- Therefore, more glucose and oxygen are delivered to your brain and muscles.
- This increases respiration and prepares your body to fight or run away.
49
Which hormone does your thyroid gland release?
What are the two main effects of this hormone?
- the thyroid gland releases thyroxine.
- thyroxine stimulates the body’s basal metabolic rate (speeds up the body’s chemical reactions)
- thyroxine also plays an important part in growth and development.
50
What is a negative feedback loop?
When condition change from the set point, and the control system responds and returns conditions to this point.
51
Explain how the negative feedback cycle in thyroxine works.
- Level of thyroxine is monitored by the brain.
- When the thyroxine level falls, your pituitary gland releases TSH.
- TSH triggers the thyroid gland to increase more thyroxine into the blood.
- The increased level of thyroxine is detected in the brain.
- The brain stops the pituitary gland from releasing TSH.
- This causes the thyroxine level to fall.
52
Name one cause of infertility for each men and women.
Men: Reduced sperm count.
Women: Endometriosis
53
1. What hormones do a fertility drug contain?
2. How does this increase a woman’s chances of getting pregnant?
1. LH and FSH.
2. It causes the woman to ovulate more than usual. This increases her chances of getting pregnant through sexual intercourse.
54
Explain the process of IVF.
1. The mother is treated with FSH and LH. This causes eggs to mature.
2. These eggs are then collected from the mother and placed into a laboratory.
3. Sperm from the father is then collected and used to fertilise the eggs in the laboratory.
4. These eggs develop into embryos. They are then inserted back into the mothers uterus and develop into a baby.
55
Name an advantage of IVF.
The parents can have a biological child of their own.
56
Name 3 problems with IVF.
1. IVF is emotionally very stressful for both parents.
2. IVF is physically demanding on the mother, with the treatment of fertility drugs and collection of eggs.
3. IVF can lead to multiple births, which is dangerous for both the mother and the child.
57
Name two reasons why some people might be against IVF.
- Many embryos are destroyed. Some people find this unethical.
- IVF is expensive. Some people think this money could be better spent elsewhere in the health service.
58
Definition of homeostasis
Homeostasis is the regulation of internal conditions inside an organism to create the optimal conditions for biological function.
59
Which gene is only involved in reflexes?
The relay neurone.
