Unit 2: Essay Questions Flashcards

1
Q

Describe the development of ova in the ovary and their possible fates after ovulation (10)?

A

Development of ova in the ovary:

1- The ovary contains many immature ova.

2- Each ovum develops in a follicle.

3- Follicle protects the ova.

4- Follicle secretes hormones/oestrogen.

5- Every 28 days a (mature) follicle moves to the surface of the ovary.

6- An ovum is released.

7- The follicle develops into the corpus luteum.

8- Which releases hormones/progesterone.

After ovulation:

9- Ovum may be fertilised to form a zygote.

10- Fertilised ovum/zygote divides many times to become a blastocyst.

11- Blastocyst implants in the endometrium.

12- Unfertilised ova pass out the body.

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2
Q

Describe hormonal control of the first half of the menstrual cycle (10)?

A

1- Cycle starts with menstruation.

2- Menstruation is a breakdown of the lining of the uterus.

3- The pituitary gland secretes FSH.

4- FSH stimulates the growth of a follicle.

5- The follicle and ovary produces oestrogen.

6- Oestrogen stimulates the repair of the endometrium.

7- Oestrogen stimulates changes in the consistency of cervical mucus.

8- Oestrogen also stimulates the production of LH.

9- LH is produced by the pituitary gland.

10- LH brings about ovulation.

11- Rising levels of oestrogen inhibit FSH production.

12- This is an example of negative feedback.

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3
Q

Discuss the biological basis of contraception (10)?

A

1- Contraception is the prevention of fertilisation/pregnancy/conception.

2- Fertile period lasts for a few days around day 14/mid point of menstrual cycle.

3- Fertile period can be detected by rise in body temperature.

4- Fertile period can be detected by changes in cervical mucus/ ices becoming thinner.

5- Contraceptives can be pills/injections/implants.

6- These contain oestrogen/progesterone.

7- Pills usually taken for 3 weeks/one pill taken each day.

8- Concentration of hormones (in blood) is increased.

9- Causes negative feedback effect/inhibitory effect on pituitary gland.

10- Reduced production of FSH prevents menstruation of ova/eggs.

11- Reduced production of LH prevents ovulation.

12- Mention of Reduced production of FSH and LH without functions.

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4
Q

Give an account of negative feedback control under the headings:

A) Testosterone production. (3)

B) The luteal phase of the menstrual cycle. (7)

A

A)
1- Pituitary gland releases LH/ICSH.

2- LH stimulates the interstitial cells of the testes to release testosterone.

3- Increasing level of testosterone inhibits/reduces the production/release of LH.

4- Pituitary gland releases less LH so testes/interstitial cells release less testosterone.

B)
5- After ovulation, the high level of LH cause the follicle to develop into the corpus luteum.

6- The corpus luteum secretes progesterone and oestrogen.

7- During this phase the secretion of oestrogen and progesterone rise to a maximum and then decline.

8- The high levels of oestrogen inhibit the pituitary gland from secreting FSH.

9- The high levels of progesterone inhibit the pituitary from secreting LH.

10- The resulting low levels of FSH suppress the development of further follicles.

11- The low level of LH causes the corpus luteum to degenerate and progesterone secretion to fall to a minimum.

12- The falling level of progesterone at the end of the cycle triggers the start of menstruation.

13- The low levels of oestrogen at the end of the cycle causes the pituitary to increase secretion of FSH.

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5
Q

Give an account of the causes and treatment of female infertility (10)?

A

1- Failure to ovulate.

2- Cause: hormone imbalance/lack of hormones (FSH and LH).

3- Prolonged use of contraceptive pill.

4- Health reasons: anorexia/obesity/drug misuse/smoking/stress/poor diet.

5- Treatment: fertility drugs/hormone treatment/donor egg/improved lifestyle.

6- Blockage of uterine tube.

7- Cause: infection/STD/cancer.

8- Treatment: surgery/laser treatment/anti-spasmodic drugs.

9- IVF

10- IVF- Fertilisation outside woman’s body/in glass/Petri dish.

11- Failure of implantation

12- Cause: hormone imbalance (not awarded twice).

13- Treatment: fertility drugs (not awarded twice).

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6
Q

Give an account or the tests which can be carried out once a woman has been confirmed as pregnant, under the headings:

A) Screening tests (6).

B) Diagnostic tests (4)

A

A)
1- Screening indicates possibility of a condition.

2- Ultrasound dating scan at 8-14 weeks.

3- Indicates age of fetus/likely due date.

4- Ultrasound anomaly scan at 18-20 weeks.

5- indicates possible unusual development, associated with e.g. down syndrome.

6- Biochemical tests on blood samples.

7- Levels of marker chemicals inappropriate to stage of pregnancy, e.g. alpha-feto protein.

8- Indicates possible presence of Down’s syndrome.

B)
9- Diagnostic tests confirm the presence of condition.

10- Amniocentesis removes cells from the amniotic fluid.

11- Carried out about 18 weeks.

12- Chronic villus sampling (CVS) removes cells from the placenta.

13- Carried out at 10-12 weeks.

14- Karyotyping - examination of fatal chromosomes.

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7
Q

Describe the exchange of substances between plasma and body cells (10)?

A

1- Plasm is the liquid part of the blood.

2- (Any 3) named dissolved substances carried - oxygen, carbon dioxide, glucose, amino acids, urea, vitamins, minerals, etc.

3- Site of exchange is at the capillaries.

4- Capillaries have a large surface area/thin walls/narrow diameter.

5- High pressure (at the arterial end) forces fluid/plasma out of capillaries / pressure filtration.

6- Tissue fluid (that bathes the cells).

7- Plasma proteins/blood cells do not pass through the capillary walls/stay in blood.

8- (dissolved) substances diffuse/move from tissue fluid into body cells.

9-waste products/named example diffuse/move out of the cells.

10- To be excreted/carbon dioxide breathed out.

11- Liquid/water/tissue fluid returns returns into the plasma/blood.

12- (Excess) tissue fluid enters the lymphatic vessels/lymph.

13- This lymph/fluid is carried back to the blood (by lymphatic system).

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8
Q

Discuss the conducting system of the heart and how it is controlled (10)?

A

1- Controlled by autonomic nervous system.

2- Sympathetic speeds up heart and parasympathetic slows down the heart.

3- Medulla is the control centre (in the brain).

4- Adrenaline speeds up the heart rate.

5- Pacemaker/SAN in right atrium.

6- Pacemaker starts contraction/produces impulses.

7- Impulses cause the atria to contract/atrial systole.

8- Reaches/stimulates the AVN.

9- AVN found at the junction

10- Impulse (from AVN) carried by (conducting) nerves/fibres.

11- Fibres/nerves spread out over the ventricles.

12- Causes contraction of the ventricles/ventricular systole.

13- Followed by the relaxation/resting/diastolic phase.

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9
Q

Describe the cardiac cycle under the following headings:

A) Nervous and hormonal control of heart beat (4).

B) The conducting system of the heart (6).

A

A)
1- Controlled by the autonomic nervous system.

2- Sympathetic speeds up.

3- Parasympathetic slows down.

4- Medulla is the centre of control in the brain.

5- Adrenaline speeds up the heart rate.

B)
6- Pacemaker/SAN in right atrium.

7- Initiates contraction on its own/is myogenic.

8- Impulse spreads across atria.

9- Leads to atrial systole.

10- AVN at junction of atria/ventricles.

11- Conducting fibres

12- Branch over ventricles.

13- Synchronised contraction of ventricles/ventricular systole.

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