UNIT 2 Flashcards

1
Q

Name the structure within the testes which produces the male gamete

A

Seminiferous tubules

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2
Q

Name the structure within the testes which produces testosterone

A

Interstitial cells

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3
Q

Describe the function of the prostate gland and seminal vesicles

A

Secrete fluids that maintain the mobility and viability of the sperm

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4
Q

Name the part of the brain which secretes a releaser hormone

A

Hypothalamus

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5
Q

Describe the role of the releaser hormone

A

Stimulates pituitary gland to produce hormones that trigger puberty

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6
Q

Name the part of the brain which secretes FSH, ICSH and LH

A

Pituitary gland

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7
Q

Describe the effect of FSH and ICSH on the testes

A

FSH acts on semeinferous tuboulues, it promotes sperm production,
and
ICSH acts on interstitial cells, its stimulates testosterone production.

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8
Q

Describe the effects of testosterone

A

Stimulates sperm production
and activates prostate gland and seminal vesicles.

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9
Q

Name the hormones which are inhibited by high levels of testosterone

A

FSH and ICSH.

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10
Q

Explain how levels of testosterone are controlled by negative feedback

A

As testosterone levels increase it inhibits secretion of FSH and ICSH

This causes the levels of FSH and ICSH to decrease reducing the volume of testosterone production.

As testosterone levels decrease, inhibitory effect is switched off and levels of FSH and ICSH increase
This causes an increase in testosterone level

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11
Q

Name the structure where ova mature

A

Follicle

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12
Q

Describe the role of the follicle

A

Protectsthe developing ovum and secretes hormones (oestrogen)

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13
Q

State the site of fertilisation in females

A

Oviduct

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14
Q

Describe the process of fertilisation

A

Fusion of gamete nuclei to form zygote, which divides into embryo.

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15
Q

State the length of the average menstrual cycle

A

28 days, first day of mesutration is regarded as day one.

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16
Q

Name the first phase of the menstrual cycle

A

Follicular Phase

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17
Q

Describe the effect of FSH on the ovary

A

Stimulates follicle development and oestrogen production.

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18
Q

Name the hormone produced by the follicle

A

Oestrogen.

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19
Q

Describe the effects of oestrogen

A

stimulates proliferation of the endometruim , preparing it for implantation.
it also affects the consistency of cervial mucus, becoming thin and watery

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20
Q

Explain why the consistency of cervical mucus changes during the follicular phase

A

to make it easily penetrable by sperm.

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21
Q

Describe what happens to the LH levels following peak levels of oestrogen

A

There is a surge in LH.causing ovulation

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22
Q

Name the event which occurs following a surge in LH

A

Ovulation

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23
Q

Describe the process of ovulation

A

Release of matureovum from a follicle, usually occurs in mid-point of the cycle.

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24
Q

Name the second phase of the menstrual cycle

A

Luteal phase.

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25
Q

Name the structure produced when the follicle degrades (breaks down)

A

The follicle develops into a Corpus luteum.

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26
Q

Name the hormone produced by the corpus luteum

A

Progesterone.

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27
Q

Describe the effects of progesterone

A

Progesterone promotes further development and vascularisation of the endometrium preparing it for implantation if fertilisation occurs.

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28
Q

Describe the negative feedback effect of the ovarian hormones on the pituitary gland

A

The ovarian hormones inhibit the secretion of FSH and LH by the pituitary, which prevents further follicles from developing.

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29
Q

Describe the effect of a lack of LH

A

Leads to corpus luteum degeneration and levels of progesterone to drop.

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30
Q

Describe how menstruation is triggered

A

Drop in progesterone levels leads menstruation.

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31
Q

State what happens to the corpus luteum and progesterone levels if fertilisation occurs

A

If fertilisation does occur, the corpus luteum does not degenerate and progesterone levels remain high

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32
Q

Compare fertility periods in males and females

A

Men have continuous fertility, women have cyclical fertility.

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33
Q

Explain why females have cyclical fertility

A

they are only fertile for few days during each menstrual cycle

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34
Q

Describe the physiological changes which indicate a woman is in her fertile period

A

body temperature rising by around 0.5°C after ovulation, and her cervical mucus becoming thin and watery

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35
Q

Give examples of causes of infertility in both males and females

A

Males: low sperm, abnormal sperm, low motility.

Females: failure to ovulate, blocked oviducts, implantation failure.

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36
Q

Describe the process of artificial insemination

A
  • is the insertion of semen into the female reproductive tract.
  • particularly useful when male has a low sperm count
  • several samples of semen are collected overtime.
  • if a male is sterile, a donor may be used
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37
Q

Describe how to stimulate ovulation

A

can be stimulated by Drugs that prevent oestrogen negative feedback or mimic FSH/LH. causing superovulation resulting in multiple births

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38
Q

Describe the process of IVF

A

-eggs are surgically removed from the ovaries after hormone stimulation.
- eggs are mixed with sperm in a culture dish and zygote is incubated until they make at least 8 cells.
then they are transferred to the uterus for implantation

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39
Q

Suggest when IVF should be used

A

when a couple fail to conceive

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40
Q

Describe the process of ICSI

A
  • If mature sperm are defective or very low in number,
  • the head of the sperm is drawn into a needle
  • and injected directly into the egg to achieve fertilisation
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41
Q

Explain why PGD is available to some couples

A

PGD can be used with IVF to identify single gene disorders and chromosomal abnormalities.

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41
Q

Give examples of physical methods of contraception and describe how they prevent pregnancy

A

Barrier methods like condoms and diaphragms prevent fertilisation,

while IUDs prevent implantation of the blastocyst.

Sterilisation blocks the reproductive ducts to prevent sperm and ova from meeting

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42
Q

Describe how the oral contraceptive pill, progesterone only and morning after pill prevent pregnancy

A

Oral pill(contain oestrogen and progesterone), it mimics negative feedback to prevent ovulation, progesterone -only pill thickens mucus, morning-after prevents ovulation/implantation.

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43
Q

Describe the role of antenatal screening

A

Identifies disorder risk for further testing and diagnosis.

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44
Q

Name the type of screening used for dating and anomaly scans

A

Ultrasound imaging.

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45
Q

Compare dating and anomaly scans

A

Dating scan: determine pregnancy stage and due date.
they take place between 8 and 14 weeks.

Anomaly scan: detect serious physical abnormalities in the fetus
they take place between 18 and 20 weeks

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46
Q

Explain why routine blood and urine tests are carried out throughout the pregnancy

A

To monitor the concentrations of marker chemicals

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47
Q

Explain how false positive results can occur

A

Measuring a chemical at the wrong time

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48
Q

Describe how to carry out CVS

A

Fetal cells can be obtained from a sample of cells taken from the placenta using a needle

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49
Q

Describe how to carry out amniocentesis

A

Fetal cells obtained from a sample of amniotic fluid taken and used to produce a karyotype

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50
Q

Compare the advantages and disadvantages of CVS to amniocentesis

A

CVS can be carried out earlier in pregnancy but has a higher risk of miscarriage compared to amniocentesis.

51
Q

Name the diagram produced which shows the chromosome complement of a person

A

A karyotype.

52
Q

Describe how karyotypes are produced

A

Cells from samples obtained from amniocentesis or CVS can be cultured to obtain sufficient cells to produce a karyotype

53
Q

Explain why males are more likely to inherit a recessive sex-linked disorder

A

Males only have one X chromosome, so one recessive allele is enough.

54
Q

Explain why predicted and observed ratios are often different

A

Fertilization is random

55
Q

Describe how postnatal screening can diagnose PKU

A

Newborns tested for metabolic disorders like PKU.

56
Q

Explain why individuals with PKU are placed on a restricted diet

A

Individuals with high levels of phenylalanine are placed on a restricted diet, which keeps the effect to a minimum

57
Q

Describe the structure of arteries, capillaries and veins

A

Arteries: Outer connective tissue, middle smooth muscle, elastic to accommodate surges.

Veins: Outer connective tissue, thinner muscle, contain valves to prevent backflow.

Capillaries: Thin walls to allow exchange.

58
Q

Explain how the structure of each blood vessel relates to their function

A

Arteries: Thick, elastic walls withstand high pressure. Smooth muscle controls flow.

Veins: Thinner walls, valves suited for lower pressure return to heart.

Capillaries: Thin walls enable gas, nutrient and waste exchange.

59
Q

Compare vasoconstriction and vasodilation

A

Vasoconstriction: Smooth muscle contracts, reducing vessel diameter, decreasing flow.

Vasodilation: Smooth muscle relaxes, increasing vessel diameter, increasing flow.

60
Q

Describe the formation of tissue fluid by pressure filtration

A

Narrowing arteries increase blood pressure, forcing plasma out of capillaries into tissue.

61
Q

Explain why tissue fluid has less plasma proteins than blood plasma

A

Plasma proteins are too large to be filtered through capillary walls.

62
Q

Describe the role of tissue fluid

A

Supplies cells with glucose, oxygen, absorbs waste.

63
Q

Describe the role of lymphatic vessels

A

Absorb excess tissue fluid and return it to circulation as lymph.

64
Q

Identify the chambers, blood vessels and valves within the heart

A

4 Chambers - left/right atria, left/right ventricles.

Blood vessels - pulmonary artery/vein, aorta, vena cava

Valves - AV, SL.

65
Q

Describe the flow of blood through the heart and its associated blood vessels

A

Deoxygenated blood flows to right atrium, through tricuspid valve to right ventricle, then to lungs.

Oxygenated blood returns to left atrium, through mitral valve to left ventricle, then to body via aorta

66
Q

Define cardiac output

A

Volume of blood pumped per minute by each ventricle.

67
Q

Calculate cardiac output from stroke volume and heart rate

A

CO = HR x SV

68
Q

Describe each stage of the cardiac cycle

A

1-Diastole - ventricles relax, AV valves open., SL closed

2- Atrial systole - atria contract.

3-Ventricular systole - ventricles contract, AV valves close, SL valves open.

69
Q

Describe the pressure changes which occur during the cardiac cycle which causes the valves to open and close

A

Ventricular pressure drops below atrial, opening AV.
Ventricular rises above aortic/pulmonary, opening SL.

70
Q

Calculate heart rate in beats per minute from the length of one cardiac cycle

A

HR (bpm) = 60 / Cardiac cycle length (s)

71
Q

State the location of the SAN and describe its role

A

SAN in right atrium wall, sets heart contraction rate.

72
Q

State the location of the AVN and describe its role

A

AVN in heart center, transmits impulses from SAN to ventricles.

73
Q

Describe the flow of impulses across the heart

A

SAN to atria, then AVN to ventricles.

74
Q

Name the test which detects impulses in the heart

A

Electrocardiogram (ECG).

75
Q

Calculate heart rate from an ECG

A

HR (bpm) = 60 / Time between P waves (s)

76
Q

Identify atrial systole, ventricular systole and diastole from an ECG

A

P QRS T:
P wave - atrial, QRS - ventricular, T wave - diastole.

77
Q

Name the part of the brain and the branch of the nervous system which regulates the rate of the SAN

A

Medulla, autonomic nervous system.

78
Q

Name the neurotransmitter which is released by the sympathetic nerves and describe its effect on heart rate

A

Noradrenaline, increases heart rate.

79
Q

Name the neurotransmitter which is released by the parasympathetic nerves and describe its effect on heart rate

A

Acetylcholine, decreases heart rate.

80
Q

Describe the changes to blood pressure during the cardiac cycle

A

Increases during ventricular systole, decreases during diastole.

81
Q

Compare systolic and diastolic pressure

A

Systolic is higher pressure during contraction, diastolic is lower pressure during relaxation.

82
Q

State the typical value of blood pressure for a young adult

A

120/80 mmHg.

83
Q

Describe how a sphygmomanometer is used to measure blood pressure

A

Inflatable cuff stops flow, deflates to detect systolic and diastolic pressures.

84
Q

State the term used to describe high blood pressure

A

Hypertension.

85
Q

Describe the process of atherosclerosis

A

Accumulation of fatty material, including cholesterol, forming plaque under artery’s endothelium.

86
Q

Describe the effects of an atheroma on an artery and blood pressure

A
  • Artery thickens, loses elasticity,
  • lumen narrows, restricting flow and increasing blood pressure.
87
Q

Give examples of CVDs which can develop following atherosclerosis

A
  • Angina
  • heart attack
  • stroke
  • peripheral vascular disease.
88
Q

State the term used to define the formation of a clot

A

Thrombosis

89
Q

Describe the process of thrombosis

A

1- an atheroma ruptures damaging the endothelium.
2- clotting factors are released from the damaged area
3- the clotting factors activates a cascade of reactions
4-resulting in conversion of enzyme prothrombin to its active form thrombin.
5- thrombin cause molecules of plasma protein fibrinogen to form threads of fibrin
6- the fibrin threads form a meshwork

90
Q

State the 3 functions of meshwork

A

1- it clots the blood
2- it seals the blood
3- it provides scaffold for the scar tissue

91
Q

What is an Embolus

A

when a thrombus breaks loose and travels throughout the bloodstream till it blocks the blood vessel

92
Q

Describe the effect of thrombosis in a coronary artery and in the brain

A

Coronary artery- heart attack, brain
Artery in the brain - stroke

93
Q

Explain why cells die following the formation of a thrombus

A

because they are deprived of oxygen leading to sudden death

94
Q

Describe peripheral vascular disease (PVD)

A

Narrowing of arteries, due to atherosclerosis other than heart/brain.
common in legs.

95
Q

Explain why pain is often experienced in the leg in people with PVD

A

Limited oxygen supply

96
Q

Describe deep vein thrombosis

A

Blood clot forming in deep vein, commonly in leg.

97
Q

Explain how a pulmonary embolism can occur

A

DVT can break off and travel to lungs.

98
Q

State the location of cholesterol synthesis in the body

A

25% in liver, rest in all cells.

99
Q

Describe the role of cholesterol in the body

A

Cholesterol is a type of lipid found in the cell membrane.
It is also used to make the sex hormones — testosterone, oestrogen, and progesterone.

100
Q

Explain how cholesterol levels in the blood can increase

A

High saturated fat/cholesterol diet increases blood levels.

101
Q

Describe the role of HDL

A

Transports excess cholesterol to liver for elimination.

102
Q

Describe the role of LDL

A

Transports cholesterol to cells.

103
Q

Explain why LDL can sometimes deposit cholesterol in arteries

A

Negative feedback inhibits LDL receptor synthesis, reduces the amount of cholesterol that is absorbed into the cells

104
Q

Explain why it is best to have a high HDL to LDL ratio

A

Higher HDL:LDL reduces blood cholesterol and atherosclerosis risk.

105
Q

Describe the benefits of physical activity and a low fat diet in the control of cholesterol levels

A

Activity raises HDL, diet reduces total/saturated fat.

106
Q

Explain how statins reduce blood cholesterol levels

A

by inhibiting the synthesis of cholesterol by liver cells

107
Q

Explain blood vessels can be damaged from chronic elevation of blood glucose levels

A

Chronic high glucose causes endothelial cells to take in
more glucose, damaging blood vessels.

108
Q

State the possible outcomes of blood vessels damaged by elevated glucose levels

A

Atherosclerosis, CVD, stroke, PVD, retinal haemorrhage, renal failure, nerve damage

109
Q

Name the receptors which monitor blood glucose levels

A

Pancreatic receptors.

110
Q

Name the hormone whose secretion increases when blood glucose levels decreases and describe its action

A

Insulin.
Insulin activates glucose to glycogen conversion in liver, decreasing blood glucose.

111
Q

Name the hormone whose secretion increases when blood glucose levels increases and describe its action

A

Glucagon.
Glucagon activates glycogen to glucose conversion in liver, increasing blood glucose.

112
Q

Name the organ which stores glucose as glycogen

A

The liver.

113
Q

Name the hormone released from exercise or during a flight or fight response

A

Adrenaline.

114
Q

Explain why individuals with Type 1 diabetes require insulin injections

A

Type 1 diabetics cannot produce insulin, so require injections.

115
Q

Explain why the cells in individuals with Type 2 diabetes are less sensitive to insulin

A

Type 2 has insulin resistance due to decreased liver insulin receptors

116
Q

Name the test used to indicate diabetes

A

Glucose tolerance test

117
Q

Explain why glucose appears in the urine of diabetics

A

Kidneys remove excess blood glucose, which appears in urine

118
Q

Describe how to carry out a glucose tolerance test to diagnose diabetes

A

Measure fasting blood glucose, then after drinking glucose solution.

119
Q

Compare the results of a diabetic to a non-diabetic following a glucose tolerance test

A

Diabetic starts higher, increases more, takes longer to return to start.

120
Q

Describe how obesity is characterised

A

Excess body fat relative to lean tissue.

121
Q

Calculate BMI from an individual’s weight and height

A

BMI = weight (kg) / height^2 (m^2)

122
Q

State the value of BMI deemed to indicate obesity

A

<30

123
Q

Explain why BMI can wrongly classify individuals as obese

A

BMI misclassifies muscular people as obese.

124
Q

Describe how an individual becomes obese

A

Linked to high fat diet and low exercise

125
Q

Explain why obese individuals should have a low-fat diet and avoid free sugars

A
  • Fats have high calories,
  • free sugars require no digestion energy.
126
Q

Explain the importance of exercise to health and wellbeing

A

Increases energy expenditure, reduces CVD risk factors.