Unit 2 - Let’s Achieve Flashcards
1
Q
Sperm
A
Sperm is the male gamete produced by the seminiferous tubules.
2
Q
Testosterone function
A
Testosterone is a hormone produced by the interstitial cells which promote sperm production and activates the prostate gland and seminal vesicles.
3
Q
What do prostate gland and seminal vesicles do
A
The prostate glands and seminal vesicles secrete fluids that maintain the mobility and viability of the sperm.
4
Q
Ova in ovaries
A
The ovaries contain immature ova in various stages of development.
Each ovum is surrounded by a follicle that protects the developing ovum and secretes hormones.
5
Q
Location and product of fertilisation
A
Mature ova are released into the oviduct where they may be fertilised by sperm to form a zygote.
6
Q
Hormones released by pituitary gland
A
Hormones released by the pituitary gland at puberty are:
Follicle stimulating hormones (FSH)
Luteinising hormone (LH)
Interstitial cell stimulating (ICSH)
7
Q
What triggers puberty
A
A releaser hormone produced in the hypothalamus stimulates the release of hormones by the pituitary gland to trigger the onset of puberty.
8
Q
Hormanal control of soerm production
A
FSH promotes sperm production and ICSH stimulates the production of testosterone. Testosterone promotes sperm production and activates the prostate gland and seminal vesicles.
9
Q
What controls testosterone production
A
Negative feedback controls the production of testosterone.
10
Q
Menstrual cycle
A
The menstrual cycle takes approximately twenty-eight days and the first day of menstruation is regarded as day one.
11
Q
Menstrual cycle stages
A
Follicular phase
Luteul phase
12
Q
Menstrual cycle - role of FSH
A
Follicle stimulating hormones (FSH) stimulates the development of the follicle and production of oestrogen by the follicle in the follicular phase.
13
Q
Effects of oestrogen of uterus
A
Oestrogen stimulates the proliferation of the endometrium (lining of the uterus) preparing it for implantation and affects the consistency of cervical mucus. The mucus becomes thinner and waterier in consistency making it more easily penetrated by sperm.
14
Q
What triggers ovulation
A
Peak levels of oestrogen stimulate the surge in the secretion of LH. The surge in LH triggers ovulation.
15
Q
Ovulation
A
Ovulation is the release of (ovum) from a follicle in the ovary. It usually occurs around the mid-point of the menstrual cycle.
16
Q
Luteul phase
A
The follicle develops into a corpus luteum which secretes progesterone.
17
Q
What does progesterone lead to
A
Progesterone promotes further development and vascularisation of the endometrium preparing it for implantation if fertilisation occurs.
18
Q
What inhibits secretion of FSH and LH and what does this cause
A
Progesterone and oestrogen inhibit further secretion of FSH and LH to prevent further follicles from developing.
19
Q
What leads to menstration
A
The lack of LH leads to degeneration of the corpus luteum with a subsequent drop in progesterone levels leading to menstruation.
20
Q
Impact of fertilisation on progesterone and the corpus luteum
A
Progesterone levels remain high and the corpus luteum does not regenerate if fertilisation occurs.
21
Q
Men fertility
A
Men show continuous fertility, continually producing sperm from the onset of puberty.
22
Q
Women fertility
A
Women show cyclic fertility, only being fertile for a few days during each menstrual cycle.
23
Q
How does a women change after ovulation
A
A woman’s body temperature rises by around 0.5oC after ovulation and her cervical mucus becomes thin and watery. This is how the fertile period of a women can be identified.
24
Q
How do drugs stimulate ovulation
A
Ovulation can be stimulated by drugs that prevent the negative feedback effect of oestrogen on FSH secretion.
25
What do other ovulatory drugs do and what can this cause
Other ovulatory drugs mimic the action of FSH and LH.
These drugs can cause super ovulation.
This can result in multiple births of be used to collect ova for in vitro fertilisation (IVF) programmes.
26
Artificial insemination
Several semen samples are collected over a period of time and injected directly into the uterus/vagina/female reproductive system using a catheter.
This process is used if the male has a low sperm count or if the male is sterile a donor may be used to provide semen.
27
IVF
Eggs are surgically removed from the ovaries after hormone stimulation. Eggs are mixed with sperm in a culture dish and the zygotes (fertilised eggs) are incubated until they have formed at least eight cells and are then transferred to the uterus for implantation.
28
What can IVF be used in conjunction with
IVF can be used in conjunction with pre-implantation genetic diagnosis to identify single gene and chromosome abnormalities.
29
Intra-cytoplasmic sperm injection
| ICSI
A process similar to IVF but if the sperm are defective or very low in number, ICSI can be used. The head of the sperm is drawn into a needle and injected directly into the egg to achieve fertilisation.
30
Physical barriers of contraception
Condom
Female condom
Diaphragm
Cervical cap
31
IUD
An IUD is a small T-shaped plastic and copper device that is inserted into the uterus.
The IUD releases copper and prevents pregnancy for between 5 to 10 years. They are more than 99% effective at preventing pregnancy.
32
Sterilisation
Sterilisation is the surgical method to prevent pregnancy.
33
Female sterilisation
Female sterilisation involves cutting, tying or blocking the oviducts.
34
Male sterilisation
Male sterilisation involves cutting, tying or blocking the sperm ducts.
35
Contraceptive pill
The contraceptive pill is a chemical method of contraception. It contains a combination of synthetic oestrogen and progesterone that mimics negative feedback preventing the release of FSH and LH from the pituitary gland. Therefore, it prevents the development of any follicles.
36
Progesterone only pill
The progesterone only (mini pill) thickens cervical mucus preventing the sperm from entering the uterus.
37
Emergency/ morning after pill
The emergency or morning after pill prevent or delay ovulation. It can be taken up to 72 hours or 120 hours after unprotected sex depending on which type of pill is used.
38
Antenatal and postnatal screening
Antenatal and postnatal screening is when a variety of techniques are used to monitor the health of the mother, developing foetus and baby.
39
What does Antenatal screening identify
Antenatal screening identifies the risk of a disorder so that further tests and a prenatal diagnosis can be offered.
40
Dating scan
Dating scan – takes place between 8 and 14 weeks. It determines the stage of pregnancy and due date.
This is used with tests for marker chemicals which vary normally during pregnancy.
41
Anomaly scan
takes place between 18-20 weeks and may detect serious physical abnormalities in the foetus.
42
Routine blood and urine tests
Routine blood and urine tests are carried out to monitor the concentrations of marker chemicals.
Measuring a chemical at the wrong time could lead to a false positive result.
43
What can an atypical chemical concentration lead to
An atypical chemical concentration can lead to further diagnostic testing to determine if the foetus has a medical condition.
44
Amniocentesis
Amniocentesis is a procedure is usually carried out between the 15th and 20th week of pregnancy which involves the collection of foetal cells contained within amniotic fluid.
A needle is inserted through the abdomen/uterus wall into the amniotic sac and a sample of the amniotic fluid is collected.
45
Amniocentesis advantage and disadvantage
Advantage- it is used to detect genetic or chromosomal abnormalities of the foetus.
Disadvantage - the procedure carries a risk of miscarriage.
46
Chronic villus sampling
Chorionic villus sampling is procedure usually carried out between the 11th and 14th week of pregnancy.
This procedure removes a small sample of cells from the placenta. These can be obtained through the abdomen or through the cervix.
47
Chronic villus sampling advantage
Advantage – it is used to detect genetic or chromosomal abnormalities of the foetus and can be performed earlier than an amniocentesis.
48
Chronic villus sampling disadvantage
the procedure carries a higher risk of miscarriage than an amniocentesis
49
Diagnostic testing
Diagnostic testing - cells from samples are cultured to obtain sufficient cells to produce a karyotype to diagnose a range of conditions.
50
Karyotype
A karyotype shows an individual’s chromosomes arranged as homologous pairs
51
Diagnostic testing - proveeding with tests
In deciding to proceed with these tests, the element of risk will be assessed, as will the decisions the individuals concerned with the likely to make if a test is positive.
52
Autosomal recessive disorders
In autosomal recessive disorders are expressed very rarely and often skip generations and it affects both males and females equally.
Example - cystic fibrosis
53
Autosomal dominant disorders
In autosomal dominant disorders, affected individuals will always have an affected parent, it affects both males and females equally. When the trait does not appear in a branch it won’t appear in future generations.
Examples include: Huntington’s chorea
54
Incomplete dominance disorders
With incomplete dominance disorders carriers of the allele show a mild form or intermediate form of the trait, as neither allele is completely dominant over the other.
Example: Tay Sachs disease.
55
sex-linked recessive single gene disorders
Occurs on the X chromosome. Sex linked recessive disorders always have more males affected than females.
Always skips a generation and may appear in the next generation after it
Example
56
What causes phenylketonuria
Phenylketonuria is caused by a substitution mutation meaning that an enzyme which converts phenylalanine to tyrosine is non-functional.
57
What happens to individuals with high levels of phenylketonuria
Individuals with high levels of phenylalanine are placed on a restricted diet.
58
Postnatal diagnostic test for PKU
The heels of new-born babies are pricked, and samples of blood are pressed onto the test card and analysed for levels of phenylalanine.
59
Blood circulation from the heart
Blood circulates from the heart through arteries to the capillaries then to the veins and back to the heart. There is a decrease in pressure as blood moves away from the heart
60
Arteries
Arteries have an outer layer of connective tissue containing elastic fibres and a middle layer of smooth muscle with more elastic fibres. The elastic walls of the arteries stretch and recoil to accommodate the surge of blood after each contraction of the heart.
61
Smooth muscle control of blood flow
The smooth muscle surrounding arteries can contract causing vasoconstriction and can relax causing vasodilation. This controls blood flowing within the arteries.
62
Capillaries
Capillaries form dense networks around body tissues and have very thin walls to allow efficient exchange of materials.
63
Veins
Veins have an outer layer of connective tissue containing elastic fibres but a much thinner muscular wall than arteries. They contain valves to prevent the backflow of blood.
64
Pressure filtration
Pressure filtration causes blood plasma to pass through the capillary walls into the tissue fluid surrounding the cells.
65
Tissue fluid
Tissue fluid supplies cells with glucose, oxygen and other substances.
Carbon dioxide and other metabolic wastes diffuse out of the cells and into the tissue fluid to be excreted. Much of the tissue fluid returns to the blood.
66
Tissue fluid and blood plasma similarities and differences
Tissue fluid and blood plasma are similar in composition, with the exception of plasma proteins which are too large to be filtered through the capillary walls.
67
Excess tissue fluid
Excess tissue fluid is absorbed by lymphatic vessels and return it as lymph to the circulatory system.
68
Blood flow through the heart
The left and right ventricles pump the same volume of blood through the aorta and pulmonary artery.
69
Cardiac output
Cardiac output is the volume of blood pumped through each ventricle per minute.
Cardiac output is determined by heart rate and stroke volume.
CO = HR x SV
70
Diastole
During diastole, blood returning to the atria flows into the ventricles. In diastole the pressure in the arteries closes the semi-lunar valves.
71
Atrial systole
Atrial systole transfers the remainder of the blood through the atrio-ventricular (AV) valves to the ventricles.
72
Ventricular systole
Ventricular systole closes the AV valves and pumps the blood out through the semi-lunar (SL) valves to the aorta and pulmonary artery.
73
Sino atrial node
The heartbeat originates from the heart itself. The auto-rhythmic cells of the sino-atrial node (SAN) located in the wall of the right atrium, set the rate at which the heart contracts.
74
What controls timing of cardiac muscle contraction
The timing of cardiac muscle contraction is controlled by impulses from the SAN spreading through the atria causing atrial systole.
75
Atrio-ventricular node
Impulses from the SAN travel to the AVN, located in the centre of the heart. Impulses from the AVN travel down fibres in the central wall of the heart and then up through the walls of the ventricles, causing ventricular systole.
76
What detects heart impulses
Impulses in the heart generate currents that can be detected by an electrocardiogram.
77
Medulla controlling heart rate
The brain’s medulla regulates the rate of the sino-atrial node through the antagonistic action of the autonomic nervous system (ANS).
78
Autonomic nervous system- what increases heart rate
A sympathetic nerve releases noradrenaline which increases heart rate.
79
Autonomic nervous system - what decreases heart rate
A parasympathetic nerve releases acetylcholine which decreases heart rate.
80
What is blood pressure
Blood pressure is a measure of the force that your heart uses to pump blood around your body.
81
When does blood peessure change
Blood pressure changes through the aorta during the cardiac cycle. Pressure increases during ventricular systole and decreases during diastole.
82
Atherosclerosis
Atherosclerosis is the accumulation of fatty material forming an atheroma or plaque beneath the endothelium of the artery.
83
The impact of atherosclerosis of health
As the atheroma grows the artery thickens and loses its elasticity. The diameter of the lumen becomes reduced and blood flow becomes restricted resulting in increased blood pressure.
Atherosclerosis is the root cause of various cardiovascular diseases (CVD) such as angina, heart attack, stroke and peripheral disease.
84
Atheroma
Atheroma’s may rupture leading to damage to the endothelium. This damage releases clotting factors that activate a cascade of reactions resulting in the conversion of the enzyme prothrombin to its active form thrombin.
85
Thrombin
Thrombin causes molecules of the plasma protein fibrinogen to form threads of fibrin. The fibrin threads form an insoluble meshwork that clots the blood, seals the wound and provides a scaffold for the formation of scar tissue.
86
Embolus
In some cases, a thrombus may break loose forming an embolus which travels through the bloodstream until it blocks a vessel.
The formation of a clot (thrombus) is referred to as thrombosis.
87
What can a thrombosis lead to in the coronary artery
A thrombosis in the coronary artery may lead to a myocardial infarction (MI), commonly known as a heart attack. A thrombosis in an artery in the brain may lead to a stroke.
Cells are deprived of oxygen leading to death of the tissues.
88
Deep vein thrombosis
A deep vein thrombosis (DVT) is a blood clot that forms in a deep vein, most commonly in the leg. This can break off and result in a pulmonary embolism in the lungs.
89
Peripheral vascular disease
Peripheral vascular disease is narrowing of the arteries due to atherosclerosis other than those of the heart the brain.
The arteries in the legs are most commonly affected. Pain is experienced in the leg muscles due to a limited supply of oxygen.
90
Cholesterol use
Cholesterol is a type of lipid found in the cell membrane. It is also used to make the sex hormones, testosterone, oestrogen and progesterone.
91
What increases blood cholesterol levels
A diet high in saturated fats increases cholesterol levels in the blood.
92
High density lipoproteins
High density lipoproteins (HDL) transport excess cholesterol from the body cells to the liver for elimination. This prevents accumulation of cholesterol in the blood.
93
Low density lipoproteins
Low density lipoproteins (LDL) transport cholesterol to body cells.
94
What do most cells have - LDL
Most cells have LDL receptors that take LDL into the cell where it releases cholesterol.
95
Negative feedback of cholesterol
Once a cell has a sufficient cholesterol a negative feedback system inhibits the synthesis of new LDL receptors and LDL circulates the blood where it may deposit cholesterol in the arteries forming an atheroma.
96
Ratio of HDL to LDL
A higher ratio of HDL to LDL will result in lower blood cholesterol and a reduced chance of atherosclerosis.
97
What do chronic elevated blood fglucose levels leas to
Chronic elevated blood glucose levels lead to the endothelium cells taking in more glucose than normal, damaging the blood vessels.
98
Atherosclerosis may develop and lead to what?
Atherosclerosis may develop leading to cardiovascular disease, stroke or peripheral vascular disease.
99
What can small blood vessels damaged by elevated glucose levels lead to
Small blood vessels damaged by elevated glucose levels may result in haemorrhage of blood vessels in the retina, renal failure or peripheral nerve dysfunction.
100
Response to Increased Blood Glucose Concentration
Pancreatic receptors respond to raised blood glucose levels by increasing secretion of insulin from the pancreas.
Insulin activates the conversion of glucose to glycogen in the liver decreasing blood glucose concentration.
101
Response to Decreased Blood Glucose Concentration
Pancreatic receptors respond to lowered blood glucose levels by increasing secretion of glucagon from the pancreas.
Glucagon activates the conversion of glycogen to glucose in the liver increasing blood glucose concentration.
102
Blood glucose concentrations during exercise
During exercise and the fight or flight response, glucose concentrations in the blood are raised by adrenaline released from the adrenal glands. This stimulates glucagon secretion and inhibits insulin secretion.
103
Type 1 diabetes
A person with type 1 diabetes is unable to produce insulin and can be treated with regular doses of insulin.
104
Type 2 diabetes
Type 2 diabetes, individuals produce insulin, but their cells are less sensitive to it.
This insulin resistance is linked to a decrease in the number of insulin receptors in the liver, leading to a failure to convert glucose into glycogen.
105
Indiactors for diabetes- urine tests
In both types of diabetes, individual blood glucose levels rise rapidly after a meal. The kidneys remove some of this glucose, resulting in glucose appearing in urine.
Testing urine is often used as an indicator of diabetes.
106
What test diagnoses diabetes
The blood glucose tolerance test is used to diagnose diabetes.
107
Obesity
Obesity is characterised by excess body fat in relation to lean body tissue such as muscle.
Obesity is a major risk factor for cardiovascular disease and type 2 diabetes. Obesity may impair health.
108
BMI
Body mass index is commonly used to measure obesity.
BMI = body mass divided by height squared.
