SB7 Flashcards

Animal coordination, control and homeostasis

1
Q

What are hormones

A

Chemical messengers

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2
Q

How are hormones transported

A

Through the blood

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3
Q

What is meant by the endocrine system

A

The various glands that secrete hormones into the blood

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4
Q

What is the difference between the endocrine and nervous system

A
  • ES uses chemical messengers, NS electrical impulses
  • ES is slower and lasts longer, NS is quick and lasts shorter
  • ES act generally, NS is precise
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5
Q

What are the endocrine glands, hormones and location

A
  • Pituitary - FHS, LH, ADH, TSH, TRH -brain
  • Adrenal - Adrenaline - Above kidneys
  • Thyroid - Thyroxine - Neck
  • Pancreas - Insulin + Glucagon - Abdomen
  • Ovaries - Oestrogen + Progesterone - Pelvis
  • Testes - Testosterone - Pelvis
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6
Q

Define homeostasis

A

The regulation of the internal conditions to maintain optimum conditions

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7
Q

Define target cells/organs

A

Tissues that have receptors for specific hormones - allowing hormones to trigger sudden changes

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8
Q

Why is it important to maintain homeostasis

A

To ensure the survival and function of all cells and the body

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9
Q

What is negative feedback response

A

The body’s attempt to counteract and reverse any external or internal stimuli to maintain homeostasis

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10
Q

Why is adrenaline produced

A
  • The body has an increased demand for oxygen
  • To prepare the body for action/ ‘fight or flight’
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11
Q

State the target organs of adrenaline

A
  • Heart
  • Liver
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12
Q

State the effects of adrenaline

A
  • Increase blood pressure to increase oxygen + energy supply to muscles
  • Increases blood sugar level - break down of glycogen stores
  • Increased breathing rate (bronchioles widen)
  • Increased heart rate
  • Redirects blood flow to digestive system
  • Pupil dilation
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13
Q

Why is thyroxine produced

A
  • To regulate metabolism
  • To control body’s energy production
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14
Q

State the target organs of thyroxine

A
  • All cells
  • Digestive system
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15
Q

What is the negative feedback response loop of thyroxine

A
  • Hypothalamus detects low level of thyroxine and releases TRH
  • TRH stimulates pituitary to release TSH
  • TSH stimulates thyroid to release more thyroxine
  • Thyroxine levels become too high
  • Inhibits release of TRH + TSH
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16
Q

What is it called when you have too little thyroxine

A

Hypothyroidism

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17
Q

What are the effects of hypothyroidism

A
  • Weight gain
  • Increased heart rate
  • Loss of appetite
  • Reduced fertility
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18
Q

What is it called when you have too much thyroxine

A

Hyperthyroidism

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19
Q

What are the effects of hyperthyroidism

A
  • Weight loss
  • Palpitations
  • Irregular menstrual cycle
  • Irritability
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20
Q

State the target organs of insulin

A
  • Most cells (respiration)
  • Muscles
  • Liver
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21
Q

What is the target organ of glucagon

A
  • Liver
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22
Q

What are the effects of insulin

A

Tells tissues to absorb excess glucose (which then produces glycogen)

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23
Q

What are the effects of glucagon

A

Tells tissues to break down glycogen to form glucose

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24
Q

What is glycogen

A

The long term storage form of glucose

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25
Q

How is glucose absorbed into the bloodstream

A

Through the consumption of carbohydrates

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26
Q

What happens when the blood glucose levels are too high

A
  • Pancreas detects this
  • Releases Insulin
  • Insulin binds to liver, muscles and most cells
  • They absorb glucose and store it as glycogen
  • Blood glucose levels fall back to normal
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27
Q

In what ways can blood glucose levels fall

A
  • Vigorous exercise
  • Skipping meals
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28
Q

What happens when the blood glucose levels are too low

A
  • Pancreas detects this
  • Releases glucagon
  • Glycogen breaks down to form glucose
  • Glucose released into bloodstream
  • Blood glucose levels rise back to normal
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29
Q

What is the cause and effect of Type 1 diabetes

A
  • Autoimmune disease
  • Pancreatic cells are killed
  • Little - no insulin produced
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30
Q

What is the cause and effect of Type 2 diabetes

A
  • Lifestyle
  • Body cells become resistant to insulin
  • Not enough insulin is produced
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31
Q

How is Type 1 diabetes controlled

A
  • Injecting insulin into the subcutaneous tissue of the thigh or abdomen
  • Exercising a lot - muscles absorb more glucose
  • Low carb/sugar diet
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32
Q

How is Type 2 diabetes controlled

A
  • Low carb/sugar diet
  • Exercising a lot
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33
Q

What are the four hormones involved in the menstrual cycle

A
  • FSH
  • Oestrogen
  • LH
  • Progresterone
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34
Q

What are the stages of the menstrual cycle

A
  • Stage 1: Day 1-5, menstruation occurs, uterus lining breaks down
  • Stage 2: Day 5-14, uterus lining builds up again
  • Stage 3: Day 14, ovulation occurs
  • Stage 4: Day 15-28: uterus lining is maintained in case of fertilisation
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35
Q

What is the function of FSH and what stage is it released in

A
  • Stimulates maturation of egg and follicle
  • Stage 1
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36
Q

What is the function of oestrogen and what stage is it released in

A
  • Builds up uterus lining
  • Stage 2
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37
Q

What is the function of LH and what stage is it released in

A
  • Ruptures egg follicle and the remains form corpus luteum
  • Stage 3
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38
Q

What is the function of progesterone and what stage is it released in

A
  • Released from corpus luteum
  • Maintains uterus lining
  • Creates thick mucus
  • Stage 4
39
Q

Define puberty

A

When adolescents develop their secondary sex characteristics

40
Q

Give examples of pubic changes

A
  • Men grow facial hair
  • Women develop breasts
41
Q

Define contraception

A

An artificial method used to prevent pregnancy

42
Q

What are the hormonal methods of contraception and how long do they last

A
  • The pill - 1 day
  • Patch - 1 week
  • Injection - 3 months
  • Implant - 3 years
  • IUD - 5-10 years
43
Q

How do hormonal contraceptives work

A
  • They slowly release oestrogen and/or progesterone
  • They inhibit the release of FSH and LH - egg cant mature
44
Q

What are the advantages of hormonal contraceptives

A

+ Reliable
+ (Some) are long lasting
+ Reduced period pain

45
Q

What are the disadvantages of hormonal contraceptives

A
  • Do not protect from STI
  • Cause nausea and headaches
  • Weight gain
  • Acne
  • Change in blood pressure
46
Q

What are the physical methods of contraception and how do they work

A
  • Condom - catch and kill sperm
  • Diaphragm - prevent sperm from entering the cervix
  • Spermicide - kills sperm
  • Copper IUD - kills sperm
47
Q

How do physical contraceptives work

A

Prevent sperm from reaching egg

48
Q

What are the advantages of physical contraceptives

A

+ They can protect from SDI
+ Quick and easy

49
Q

What are the disadvantages of physical contraceptives

A
  • Can break or tear
  • Aren’t 100% reliable
50
Q

Define sterilisation

A

A surgery making a human incapable of producing offspring

51
Q

How does sterilisation work

A
  • Vasectomy - cutting and tying sperm ducts to prevent sperm leaving
  • Tube ligation - fallopian tubes blocked and sealed to prevent egg reaching uterus
52
Q

What is the most reliable form of contraception

A
  • Abstinence
53
Q

What is ART

A
  • Assistive Reproduction Therapy
  • Use of artificial hormones to trick body into producing an embryo
54
Q

What is clomifene therapy

A
  • Women’s pituitary gland may not produce enough FSH
  • A drug that contains FSH and LH is given to her
  • Follicle can now mature and ovulation can occur
55
Q

What is IVF

A

In Vitro Fertilisation

56
Q

When is IVF considered

A

If clomifene therapy is ineffective

57
Q

What are the steps of IVF

A
  • Egg follicle maturation is stimulated via hormones
  • Egg released by many follicles and are taken out of ovary into a lab
  • Man’s sperm is collected
  • Eggs are fertilised (sometimes by injecting sperm into egg ICSI)
  • Multiple embryos are placed back into the uterus
58
Q

Advantages of IVF

A

+ Infertile couples have a chance at having children
+ Unused embryos can be donated

59
Q

Disadvantages of IVF

A
  • Expensive
  • Not always successful
  • Multiple births increase chance of complications e.g. miscarriage
60
Q

Define osmoregulation

A

Maintenance and regulation of water levels in blood

61
Q

What roles do the kidneys have

A
  • Regulate water levels
  • Regulate ion levels
  • Remove waste
62
Q

What happens if an animal cell is placed in a hypotonic solution

A
  • Hypotonic - higher concentration of water outside of cell
  • Water moves into cell
  • Cell becomes turgid
  • Lysis occurs (no cell wall to keep structure)
63
Q

What happens if an animal cell is placed in a hypertonic solution

A
  • Hypertonic - higher concentration of water inside cell
  • Water moves out of cell
  • Cell becomes flaccid
  • Crenation occurs (membranes wrinkles)
64
Q

What organ is responsible for managing water levels

A

Kidney

65
Q

What is a nephron

A

A filtration unit in the kidney

66
Q

How does blood flow to the kidney

A

Through the renal artery

67
Q

How does blood flow out of the kidney

A

Through the renal vein

68
Q

What is urea

A

The products of deamination

69
Q

What is deamination

A

The breakdown of excess amino acids in blood

70
Q

Why is it important to filter out urea

A

It is slightly poisonous

71
Q

Explain the process of filtration (kidneys)

A
  • Liquid part of blood is forced out of glomerulus into the Bowman’s capsule at a high pressure
  • Bigger molecules (protein and blood cells) are too large to be forced through
72
Q

Explain the process of selective reabsorption

A
  • Fluid passes through proximal convulated tubule - loop of Henle - distal convulated tubule - collecting duct
  • As fluid passes necessary substances are reabsorbed
  • All glucose, some water + ions
73
Q

What is urine

A

Anything that flows out of the collecting duct

74
Q

How is urine excreted

A

It passes through the ureters to the bladder to the urethra

75
Q

How does the negative feedback response work in osmoregulation

A
  • Hypothalamus monitors and detects changes in water level
  • If water levels decrease, it sends signal to pituitary to release ADH
  • ADH increases the permeability of the collecting duct = more water reabsorbed
  • Less urine produced
76
Q

What is ADH

A

Anti-diuretic hormone

77
Q

What is the danger of kidney failure

A
  • Unable to regulate water + ion levels
  • Unable to remove waste
78
Q

Explain the process of dialysis

A
  • Patients blood flows through dialysis fluid in a semi permeable membrane
  • DF contains attributes of healthy blood e.g. normal water + ion levels, glucose, amino acids
  • Concentration gradient established between blood and DF
  • Excess water + ions, urea etc. diffuse out through the semi permeable membrane
  • Filtered blood is put back into body
79
Q

Why is the dialysis fluid constantly replaced

A

Concentration gradient will eventually reach equilibrium

80
Q

Advantages of dialysis

A

+ Available to anybody
+ No drugs taken

81
Q

Disadvantages of dialysis

A
  • Time consuming (9-16h a week)
  • Lifelong commitment
  • Expensive
82
Q

Describe features of a kidney transplant

A
  • New kidney is placed lower - close to bladder
  • New kidney is first tested for at least six matched antigens - reduce chance of rejection
83
Q

Advantages of kidney transplant

A

+ Cheaper for NHS overall
+ Patients can lead a normal life

84
Q

Disadvantages of kidney transplant

A
  • Only lasts 8-9 years
  • Need immunosuppressive drugs
  • Surgery is risky
  • Hard to get organs
  • Chance of rejection
85
Q

Define thermoregulation

A

Maintenance of temperature levels

86
Q

Why is thermoregulation important

A

To ensure enzymes do not denature

87
Q

Describe the role of the hypothalamus in thermoregulation

A
  • Has a thermoregulatory centre that receives signals from heat receptors in the epidermis and the dermis
  • Skin detects external temperature
88
Q

Describe what happens if you are too hot

A
  • Sweating
  • Vasodilation
89
Q

Purpose of sweating

A
  • Water excreted evaporates = increase heat loss
90
Q

Process of vasodilation

A
  • Arteriole dilates - smooth muscle in walls dilate
  • Increased blood flow to capillaries (close to skin surface)
  • Increased heat loss out of body
  • Less flow of blood through shunt vessel
91
Q

Describe what happens if you are too cold

A
  • Shivering
  • Goosebumps
  • Vasoconstriction
92
Q

Process of shivering

A
  • Repetitive muscles contractions = increased respiration in muscles = increased energy out
  • Heat produced
93
Q

Process and purpose of goosebumps

A
  • Pili erector muscles contract
  • Hairs trap insulating bubble or air
  • Increase heat
94
Q

Process of vasoconstriction

A
  • Arteriole constricts - smooth muscle wall contracts
  • Less blood flow to capillaries
  • Less heat lost through skin
  • More blood flows through shunt valve = reduce heat loss