topic 7 - animal coordination, control and homeostasis

Question 1

how does thyroxine control metabolic rate as an example of negative feedback?

Answer 1

• low levels of thyroxine stimulates the production of TRH in the hypothalamus
• causes a release of TSH from the pituitary gland
• TSH acts on the thyroid to produce thyroxine
• when they thyroxine levels are normal, thyroxine releases TRH and produces TSH

Question 2

what happens when they body goes into fight or flight?

Answer 2

• increased heart rate
• increased blood pressure
• increased blood flow to the muscles
• raised blood sugar levels by stimulating the liver to change glycogen into glucose

Question 3

what are the general roles of hormones in the body?

Answer 3

• chemical messages sent around the body via blood
• they all travel to a specific target organ
• produced in glands around the body

Question 4

what is the importance of hormones around the body?

Answer 4

they only affect specific cells called target organs

Question 5

what are the names of the endocrine glands?

Answer 5

pituitary glands, thyroid gland, adrenal gland, ovaries/testes

Question 6

what is the function of the endocrine glands?

Answer 6

where hormones are produced and secreted

Question 7

what does the pituitary gland produce and release?

Answer 7

produces: hormones that affect/regulate heart rate
releases: hormones that bring about change

Question 8

what does the thyroxine gland produce and release?

Answer 8

produces: thyroxine (regulates heart rate, temp, metabolic rate)
releases: none

Question 9

what does the pancreas produce and release?

Answer 9

produces: insulin (regulated blood glucose levels)
releases: none

Question 10

what does the adrenal gland produce and release?

Answer 10

produces: adrenaline (prepares for fight or flight)
releases: none

Question 11

what do the ovaries produce and release?

Answer 11

produces: oestrogen
releases: unfertilised eggs

Question 12

what do the testes produce and release?

Answer 12

produces: testosterone (controls puberty and sperm production
releases: sperm

Question 13

how is type 2 diabetes caused?

Answer 13

when a person becomes resistant to insulin, blood glucose levels rise
increased risk of obesity

Question 14

how is type 2 diabetes treated?

Answer 14

eating healthy diet, getting regular exercise and losing weight if needed
also medication or insulin injected

Question 15

how is urea produced?

Answer 15

from the break down of amino acids in the liver

Question 16

how do you calculate BMI?

Answer 16

weight / (height) squared

Question 17

what is your BMI supposed to be to be considered obese?

Answer 17

over 30

Question 18

how is type 1 diabetes caused?

Answer 18

pancreas producing little or no insulin

blood glucose levels rise to a level that can kill them

Question 19

how can type 1 diabetes be treated?

Answer 19

insulin therapy - injecting insulin directly into the bloodstream
doing regular exercise removes excess glucose
limiting intake of food rich in simple carbohydrates

Question 20

how is the hormone insulin used to control blood glucose concentration?

Answer 20

if blood glucose is too high, insulin is added
insulin is secreted by the pancreas
insulin makes the liver turn glucose into glycogen

Question 21

how is blood glucose concentrated by glucagon?

Answer 21

if blood concentration is too low, glucagon is added
the glucagon is secreted by the pancreas
glucagon makes the liver glucagon into glucose

Question 22

how does thermoregulation take place when you’re cold?

Answer 22

1. erector muscles contract, hairs stand on end to trap an insulating layer of air near the skins surface
2. very little/ no sweat is produced
3. blood vessels near the skin vasoconstrict so the blood is further from the surface so less blood is transferred to the surroundings

Question 23

how does themoregulation take place when you shiver?

Answer 23

muscles contract automatically (shiver)

- increases rate of transpiration which transfers more energy to the body

Question 24

how does thermoregulation take place when you’re too hot?

Answer 24

1. erector muscles relax to hairs lie flat
2. lost of sweat is produced in the sweat glands in the dermis
3. when the sweat evaporates, it transfers energy from your skin which cools you down
4. blood vessels vasodilate to allow more blood flow nearer to the surface of the skin so more energy can be transferred to the surroundings

Question 25

what is the role of the hypothalamus?

Answer 25

controls body temperature

keeps the body in a stable state called homeostasis

Question 26

what is the role of the dermis?

Answer 26

to support and protect the skin and deeper layers, assists in thermoregulation, located beneath the epidermis

Question 27

what is the role of the epidermis?

Answer 27

protects the body from hard including UV radiation, pathogens and chemicals
contains cells which contain melanin which pigments the skin - causing skin colour

Question 28

what is IVF an example of in terms of technology?

Answer 28

Assisted Reproductive Technology (ART)

Question 29

what is the use of hormones in IVF?

Answer 29

• involves collecting eggs from a womans ovaries and fertilising them in labs
• once the embryos are tiny balls, 1 or 2 are transferred into the womans uterus to improve changes of pregnancy
• FSH and LH are given before egg collection to stimulate egg production

Question 30

what is the use of hormones in Clomifene therapy?

Answer 30

designed for women that do not ovulate

causes more FSH and LH to be released by the body which stimulate egg maturation and ovulation

Question 31

what is the role of FSH?

Answer 31

released by pituitary
causes a follicle to mature in the ovaries
stimulated oestrogen production

Question 32

what is the role of Oestrogen?

Answer 32

released by ovaries
causes lining of the uterus to break thicken and grow
a high level stimulates a rapid LH increase

Question 33

what are the pros and cons of hormonal and barrier contraceptions?

Answer 33

hormonal methods more effective when used correctly
couple done have to think about contraception each time they have intercourse

hormonal methods can have unpleasant side effects such as headaches, acne and mood swings
hormonal methods dont protect against STIs

Question 34

how does hormonal contraception influence the menstrual cycle and prevent pregnancy?

Answer 34

1. oestrogen can be sued to prevent the release of an egg, only if its taken everyday and levels are permanently high, inhibits production of FSH
2. progesterone can be used by stimulating the production of thick cervical mucus to prevent the sperm reaching the egg
3. the combined pill contains oestrogen and progesterone
4. the mini-pill and contraceptive injection that contains progesterone only

Question 35

what is the role of LH?

Answer 35

1. released by the pituitary gland
2. LH increase stimulates ovulation at day 14 , the follicle ruptures and an egg is released
3. stimulates the remains of the follicle to develop into a structure called corpus luteum, which secretes progesterone

Question 36

what are the 4 stages of the menstrual cycle?

Answer 36

stage 1: day 1
- lining of uterus breaks down and released
stage 2: uterus lining is repaired from days 4-14, until it becomes a thick spongy layer full of blood vessels ready for the fertilised egg to be planted there
stage 3: day 14
- an egg develops and is released from the ovary
stage 4: the lining is then maintained until day 28, if no fertilised egg has landed on the uterus wall, the lining breaks down and the cycle repeats