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Edexcel - Biology > Chapter 7 - Animal Coordination > Flashcards

Chapter 7 - Animal Coordination Flashcards

1
Q

Hormones

A
  • Chemical messengers released directly into the bloodstream
  • Carried to other parts of the body and trigger a gradual response in their target response
  • Porduced/secreted by various glands called endocrine glands
  • These make up the endocrine system
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2
Q

The Pituitary Gland

A
  • Produce many hormones that are invloved in regulating body conditions
  • It produces hormones that make other glands produce hormones
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3
Q

Ovaries

A

Produced oestrogen used in the memstrual cycle

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4
Q

Testes

A

Produce testosterone which is involved in puberty and sperm production

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5
Q

Thyroid Gland

A

Produces thyroxine which is involved in regulation of metabolism, temperature and heart rate

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6
Q

Adrenal Glands

A

Produces adrenaline which is used to prepare the body for the fight or flight response

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7
Q

The pancreas

A

Produces insulin which regulates the blood glucose level

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8
Q

Neurones and hormones

A
  • Hormones have slow action, act for a long time and act in a more general way
  • Neurones act fast, act for a short time and act in a precise area
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9
Q

Adrenalin

A
  • Prepares the body for the fight or flight response in which you stand your ground or run away in front of danger
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10
Q

Process of adrenalin

A
  • Binds to specific recrptors in the heart. This causes the heart muscle to contract more frequently with more force so heart rate and blood pressure increase
  • This increases blood flow to the muscles which increases oxygen and glucose
  • Adrenalin binds to the liver causing it to break down its glycogen stores and increase glucose in the blood stream
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11
Q

Hormone release

A
  • Controlled by a negative feedback loop
  • The body detects if the levels of a substance are too high or too low and a response is triggered to bring the levels back to normal
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12
Q

Thyroxine

A
  • Released by hryoid glsnd
  • Regulated metablosim
  • Metabloic rate is the speed at which chemical reactions occur in the body
  • Uses a negative feedback loop
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13
Q

Process of thyroxine

A
  • When the blood thryoxine level is lower than normal, the hypothalamus is stimulated to release thyrotropin releasing hormone (TRH)
  • TRH stimulates the release of Thyroid stimulating hormone (TSH) from the pituitary gland
  • TSH stimulates the release of thyroxine so the blood thyroxine level rises back to normal
  • This is is the opposite if the blood thyroxine level is detected to be too high
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14
Q

Four stages of the menstrual cycle

A
  • Day 1 is when menstruation starts and the uterus lining begins to break down
  • From day 4 to 14, the uterus lining builds back up until it becomes a thick spongy layer of blood vessels ready for a fertilised egg to be implanted there
  • An egg develops in the ovary and is released (ovulation)
  • From day 14 to 28, the lining is maintained so the egg has place to be fertilised. It then begins to break down again
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15
Q

The four hormones that cobtrol the menstrual cycle

A
  • FSH (Follicle stimulating hormone)
  • Oestrogen
  • LH (Lutenising hormone)
  • Progesterone
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16
Q

FSH (Follicle stimulating hormone)

A
  • Released by pituitary gland
  • Causes a follicle (an egg and its surrounding cells) to mature in the ovaries
  • Stimulates oestrogen production
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17
Q

Oestrogen

A
  • Released by the ovaries
  • Causes the lining of the uterus to thicken and grow
  • A high level causes an LH surge
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18
Q

LH (lutenising hormone)

A
  • Released by pituitary gland
  • Stimulates ovulation and causes the follicle to breach and the egg to be released
  • Stimulates the remains of the Follicle to develop into a corpus luteum which secretes progesterone
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19
Q

Progesterone

A
  • Released by the coropus luteum after ovulation
  • Maintains the lining of the uterus
  • Inhibits the releases of FSH and LH
  • When the level of progesterone falls and there is a low oestrogen level, the uterus lining breaks down
  • A low progesterone level causes a surge in FSH which restarts the whole process
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20
Q

Clomifene therapy

A
  • Some women are infertile because they do not ovulate
  • Clomifene is a drug that causes a surge in LH and FSH which stimulates egg maturity and ovulation
  • These increases the chance of pregnancy during this time
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21
Q

IVF

A
  • In vitro fertilisation
  • Involves collecting eggs from the woman’s ovaries and fertilising them using the male’s sperm
  • Thses are grown into embryos
  • These embryos are then transferred to the uterus
  • FSH and LH are also given
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22
Q

Contraceptives

A

Methods of preventing pregnancy either natural or artifical

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23
Q

Hormones as a contraceptive

A
  • Oestrogen can be used to prevent the release of an egg because a high level inhibits the production of FSH which will stop egg development
  • Progesterone can reduce fertility as it can stimulate the production of thick cervical mucus,this will prevent the sperm entering the uterus
  • These can be put into pills such as the mini pill which contains progesterone
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24
Q

Barrier methods

A
  • These methods put a barrier between the sperm and the egg

- Examples are condoms and diaphragms

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25
Q

Pros of hormonal methods

A
  • Have a higher success rate than barrier methods

- Couple dont have to stop to think about contraception each time they have intercourse

26
Q

Cons of hormonal methods

A
  • Have unpleasant side effects such as acne and mood swings

- Do not protect against STIs

27
Q

Homeostasis

A
  • The maintaining of a constant internal environment using a negative feedback loop
28
Q

Why is homeostasis needed?

A
  • the body needs the correct conditions to function properly
  • if the conditions vary too much, enzymes can denature causing bodily functions to decline
  • To maintain this constant, the body needs to acknowledge input and output
29
Q

Examples of homeostasis

A
  • Thermoregulation
  • Osmoregulation
  • Blood Glucose regulation
30
Q

Thermoregulation

A
  • The maintaining of a constant body temperature

- An example is reducing the body temperature in a hot temperature

31
Q

Osmoregulation

A
  • The regulation of water content from food, drink and respiration (gain)
  • The regulation of water lost from urination and sweating
32
Q

Blood glucose regualtion

A
  • The regualtion of the amount of sugar in the blood
33
Q

Facotrs effecting blood glucose levels

A
  • Eating food that has large amounts of carbohydrates puts glucose in the bloodstream in the small intestine
  • The normal metabolism of cells removes glucose from the cells
  • Vigourous excersie removes a large amount of glucose from the bloodstream
34
Q

Glucose stores

A
  • Excess glucose can be stored as glycogon in the liver and muscles
  • When these stores are full, the glucose is stored as lipid (fat)
35
Q

Role of the pancreas

A

Changes in the blood glucose are measured by the pancreas using insulin and glucose

36
Q

Insluin

A
  • Added by the pancreas if the blood glucose level is too high
    Process:
  • Blood glucose level is too high
  • Insulin is secreted
  • The blood has too much glucose and insulin
  • Insulin moves glucose into the liver which turns it into glycogon
  • Blood glucose is reduced
37
Q

Glucagon

A
  • Added if blood glucose level is too low
  • Process:
  • Blood has too little glucose
  • Glucagon is secreted by the pancreas
  • Glucagon causes glucose to be released by the liver
  • This causes the blood glucose to increase
38
Q

Type 1 Diabetes

A
  • Caused when a person’s pancreas produces little or no insulin
  • A persons blood glucose level can raise to deadly levels
  • This can be treated with insulin therapy
  • Insulin is directly injected to the bloodstream
  • This is done at mealtimes to remove the blood glucose quickly before it can be digested
  • The amount of insulin needed is dependent on how active the person is
39
Q

Other factors effecting insulin therapy

A
  • Limiting the intake of foods rich in carbohydrates which will limit the amount of sugar
  • Taking regular excersie helps to remove excess glucose from the bloodstream
40
Q

Type 2 Diabetes

A
  • When a person is resistant to insulin or the pancreas does not produce enough insulin
  • The cells do not respond properly to insulin
  • Blood glucose begins to rise
  • There is a correlation between obesity and Type 2 diabetes
  • Obesity is classified if a person’s BMI is above 30
41
Q

How to work out BMI

A

Weight divided by height squared

42
Q

Stores of fat in relation to diabetes

A
  • If there is too much fat stored in the abdomen, there is an increased threat of diabetes
  • This is due to an increased waist to hip ratio
  • Waist to hip ration = waist circumferene (cm) divided by hip circumference (cm)
  • A ratio above 1 for men and 0.85 for women leads to an increased risk of diabetes
43
Q

How to reduce the risk of type 2 diabetes

A
  • Eat healthy
  • Getting regular excersise
  • Losing weight if needed
  • If needed, take medication or have insulin injection
44
Q

More on Thermoregulation

A
  • Body temperature is controlled by hypothalamus
  • All enzymes have an optimum temperature at which rhe enzymes work best
  • The best temperature is around 37 degrees
  • Below or above this temperature, enzymes to denature and slow down, this is irreversible
  • Homeostasis maintains this
  • Any change causes a counteraction
45
Q

The Hypothalamus

A
  • The thermoregulatory centre is located in the hypothalamus
  • It contains receptors that are sensitive to blood temperature in the brain
  • Also recieves impulses from the skin to provide information about external temperature
  • These are located in the epidermis and in the dermis
  • When the hypothalamus detects a change, it causes a change in the skin
46
Q

Actions in the body when you are too hot

A
  • Erector muscles relax, so hairs lie flat
  • Sweat is produced in the sweat glands in the dermis, this sweat is released onto the skin through pores. When the sweat evaporates, it transfers energy from skin to the environment
  • Blood vessels dilate called vasodilation. It allows more blood to flow near the surface so more energy can be transfered to the surroundings
47
Q

Actions in the body when you are too cold

A
  • Erector muscles contract, hairs stand in end to trap an insulating layer of air near the surface of the skin to keep you warm
  • No sweat
  • Blood vessel constrict (vasoconstriction) meaning less blood flows near the surface so less energy is transferred to the surroundings
  • You shiver as well to increase the rate of respiration which transfers more energy to warm the body
48
Q

Importance of Osmoregulation

A
  • Water content of the blood is important to regulate to make sure the body cells function properly
  • If the concentration of the water in blood is tok high, then water will move into the cells through osmosis
  • If too much water moves into the cells, then they may burst
  • If there is too little water, then water will move out of the cells causing them to shrink
  • Kindeys regulate water levels by controlling how much water is reabsorbed and lost in urine
49
Q

Roles of the kidney

A
  • Remove urea from the bloodstream
  • Adjustment of ion levels in the blood
  • Adjustment of water content in the blood

This is done by filtering of the blood under high pressure and then reabsorbing. The end product is urine

50
Q

Urea

A

Produced in the liver from the breakdown of excess amino acids

51
Q

Nephrons

A
  • Filtration units in the kidney
  • The liquid part of the blood is filtered out of the glomerulus and into the Bowman’s capsule at high pressure. Bigger molecules and blood cells can not be forecd out so they remain
  • As the liquid flows along the nephron, useful substances are reabdorbed
52
Q

Useful substances absorbed by the nephron

A
  • All the glucose is selectivley reabsorbed, it is moved back into the blood against the concentration gradient
  • Sufficent ions are reabsorbed
  • Sufficent water is reabsorbed
53
Q

What is not reabsorbed by the nephron

A
  • Urea
  • Excess water
  • Excess ions

These exit the nephron via the collecting duct, into the ureter, into the bladder and into the urine stream

Urine is released through the urethra

54
Q

How the kidneys regulate water

A
  • The amount of water reabsorbed in the kidney nephrons is controlled by anti-diuretic hormone
  • The brain monitors the water content of the blood and instructs the pituitary gland to release ADH into the blood
  • ADH makes collecting ducts of the nephrons more permeable so that more water is reabsorbed. This stops dehydration
  • This is a negative feedback loop
55
Q

The process of regualting water in the bloodstream

A
  • The hypothalamus detects either water gain or water loss
  • If water is lost, then the pituitary gland releases more ADH, if water is gained, then less ADH is released
  • More ADH makes the kidney reabsorb more water
  • Less ADH makes the kidney reabsorb less water
56
Q

Dialysis

A
  • Patients who have kidney failure can not filter their blood properly
  • A dialysis machine can do this
  • Dialysis has to be done regularly to keep the concentration of the blood at an optimum and remove waste
  • Dialysis fluid has the same concentration of glucose and salts as blood plasma which means taht they are not removed
57
Q

Barrier in a dialysis machine

A
  • The barrier is permeable to things like ions and waste products but no proteins
  • Waste products can then move across the membrane into the dialysis fluid
58
Q

How a dialysis machine works

A
  • A circuit is created that ultimatley starts and ends with the persons kidney
  • Blood enters dialysis fluid through a permeable membrane
  • Waste products leave through the membrane
  • The blood then re-enters the person
59
Q

Kidney Transplants

A
  • The only cure for kidney disease is a transplant
  • Healthy kidneys are transplanted from a person who has recently died and are on the donor register or possess a donor card
  • However a kidney can be rejected by the patients immune system
  • It is being treated as a foerign body and is attacked by antibodies
60
Q

How to prevent kidney rejection

A
  • The donor needs to match the donors tissue type

- The patients immune system needs to be supressed so that their immune system will not attack the kidney

61
Q

Causes of kidney failure

A

Excessive drinking

Edexcel - Biology (9 decks)

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