Unit 2: Essay Questions Flashcards
Describe the development of ova in the ovary and their possible fates after ovulation (10)?
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.
Describe hormonal control of the first half of the menstrual cycle (10)?
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.
Discuss the biological basis of contraception (10)?
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.
Give an account of negative feedback control under the headings:
A) Testosterone production. (3)
B) The luteal phase of the menstrual cycle. (7)
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.
Give an account of the causes and treatment of female infertility (10)?
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).
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)
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.
Describe the exchange of substances between plasma and body cells (10)?
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).
Discuss the conducting system of the heart and how it is controlled (10)?
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.
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)
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.
