Unit 2 - Physiology and Health Flashcards
What causes puberty?
The release of releaser hormones from the hippocampus causes the pituitary gland to produced hormones follicle stimulating hormone, luteinising hormone/interstitial cell stimulating hormone.
In males, what does follicle stimulating hormone do?
Promotes sperm production in the seminiferous tubes
In males, what does interstitial cell stimulating hormone do?
Promotes testosterone production in the seminiferous tubes
Where is sperm produced?
Seminiferous tubes
What does testosterone do?
Stimulates sperm production by acting on the seminiferous tubules
In females, what does follicle stimulating hormone do?
Stimulates the development of the follicle and the production of oestrogen.
In females, what does luteinising hormone do?
Stimulates ovulation and the development of the corpus luteum.
What is the corpus luteum?
Structure that forms after ovulation. Secretes progesterone. Forms from empty follicle
What is a Graafian follicle?
Fully mature follicle with a ready-to-release ovum
What does progesterone do?
Promotes the vascularisation of the endometrium and inhibits FSH and LH
What does oestrogen do?
Secreted by the growing follicle. Builds the endometrium
Where does fertilisation take place?
Oviduct
What is vascularisatiom?
The growing of blood vessels through the endometrium
Why is only one ova released at a time?
FSH triggers the development of a follicle and that follicle releases oestrogen which inhibits the FSH and prevents another ova being developed.
What occurs during the Follicular Phase?
FSH is released
FSH stimulates the development of a follicle
Follicle secrets oestrogen
Oestrogen inhibits FSH
Oestrogen builds the endometrium preparing it for implantation
Peak level of oestrogen causes the release of luteinising hormone (LH)
LH trigger ovulation
What is phase 1 of the menstrual cycle called?
The Follicular Phase
What occurs during the Luteal Phase?
Ovulation occurs
Empty follicle develops in a corpus luteum
Corpus luteum secretes progesterone
Progesterone further develops the endometrium and vascularises it
If fertilisation occurs, corpus luteum does not regenerate and progesterone levels remain high
If fertilisation does not occur, corpus luteum degenerates, progesterone levels drop, menstruation occurs
What is phase 2 of the menstrual cycle called?
The luteal phase
What happens during ovulation?
Ovum is released from follicle in the ovary
What happens when oestrogen levels peak?
Release of luteinising hormone and ovulation
What happens at day 14 in the menstrual cycle?
LH is released and ovulation begins
What inhibits FSH and LH?
Oestrogen and Progesterone
What is the negative feedback cycle in male hormones?
High levels of testosterone inhibit the production of FSH and ICSH in the pituitary gland
What are contraceptives used for?
Avoid unwanted pregnancies
Give examples of chemical contraceptives…
Morning After Pill - taken after unprotected sex to prevent implantation if fertilisation occurs.
Mini pills - contains synthetic progesterone, causes mucus to thicken reducing sperms ability to reach ovum
What are the side effects of the mini-pill?
Mood swings, must been taken daily, weight gain, breast tenderness. irregular menstrual cycles
Give examples of physical methods of contraceptives…
Condoms Diaphragm Cervical cap IUD Vasectomy Tubal Ligation
What reasons are there for infertility?
- Ovulation Failure
- Low Sperm Count
- Uterine Blockages
- Implantation Failure
What treatment is there for ovulation failure?
Drugs that prevent the negative feedback effect of oestrogen on FSH and ICSH, causing multiple eggs to mature at once, referred to as ‘super-ovulation’
Why is artificial insemination used and how?
- Used when a male has a low sperm count
- Sperm is collected and processed in a lab
- Semen are artificially injected into the uterus to increase chances of fertilisation
Why would sperm be processed in the lab for artificial insemination?
To ensure only viable sperm are used
When would a sperm donor be used?
When the male is sterile
When is intra-cytoplasmic sperm injection used, and how does it work?
- Used when a male has a low sperm count or defective sperm
- The head of a sperm is artificially injected into an ovum to achieve fertilisation
What is Intra-Vitro Fertilisation?
- IVF is when the ovum and sperm are fertilised outside outside the body
When does menstruation take place and what occurs during it?
- Occurs during days 1-7
- Endometrium breaks down
What is Pre-Implantation Genetic Diagnosis?
- Before IVF, 1 or 2 cells are removed and are tested for genetic abnormalities
- Focus on known chromosomal abnormalities and gene defects
What is Ante-Natal Screening?
Tests which are carried out while the baby is developing to monitor the health of the mother and foetus.
Give examples of Ante-natal screening
- Ultrasound imaging
- Blood and Urine Tests
- Diagnostic Testing
What are the two types of ultrasound imaging?
- Dating scan
- Anomaly scan
When is a dating scan carried out and what does it do?
- 8 to 14 weeks
- used to determine the stage of pregnancy and provide a due date
When is an anomaly scan carried out and what does it do?
- 18 to 20 weeks
- Used to determine presence of serious anomalies
Why are blood and urine carried out?
- Risk assessment for genetic disorders in the foetus
- routine check for marker chemicals
What happens if a blood or urine test is carried out at the wrong time?
can show a false positive
What is diagnostic testing used to do?
- 100% accurate
- shows the presence or absence of a specific condition/disorder
- chronic villus sampling
- amniocentesis
What is karyotyping?
A visual display of chromosome complement to check for chromosome disorders
What does an ultrasound show?
Provides an image of the growing foetus
How does an ultrasound work?
Bounces high frequency waves against the internal structures of the abdomen and creating an image on a computer screen
Give examples of diagnostic tests
- Amniocentesis
- Chronic Villus Sampling
Why are diagnostic tests carried out?
So the mother can make an informed choice about keeping or terminating the child
When is amniocentesis carried out and what are the risks?
- Carried out between 16-18 weeks
- Small risk of miscarriage
- Allows karyotyping
When is chronic villus sampling carried out and what are the risks?
- Carried out at around 8 weeks
- more invasive -> greater risk of miscarriage
- allows karyotyping
What advantage does chronic villus sampling have over amniocentesis?
Is carried out at an earlier date so mother can make an informed choice earlier
When is postnatal screening carried out?
After the baby is born
What is phenylketonuria and how is it treated?
- when the body can’t metabolise milk
- treatment is a restricted diet
- tested for by a heel prick
What does autosomal mean?
Chromosomes that aren’t sex chromosomes
What is a carrier?
Someone who has a defective gene but does not display the condition
only occurs when the defective gene is recessive
What does sex-linked mean?
A condition that is passed on through a defective gene on the X chromosome
What is autosomal dominant inheritance?
- The defective gene is a dominant allele
- If you have one faulty allele then you have the condition
- Affect both sexes equally
What is autosomal recessive inheritance
- The defective gene is recessive
- You have to inherit a faulty allele from each parent to inherit the condition
- Can skip generations
- Both sexes are equally affected
- Examples include PKU and Cystic Fibrosis
What is sex-linked inheritance?
- Daughters of affected males will either be carriers or affected by the condition
- Can skip generations
- Affects more males than females
- Can be recessive or dominant
What is blood made out of?
- Red blood cells
- Plasma
- White blood cells
What are the characteristics of an artery?
- Thick outer wall
- Narrow lumen
- Thick layer of elastic fibres and muscles
What are the characteristics of a vein?
- Relatively thin outer wall
- Thin layer of elastic fibres and muscle
- Wide lumen
What are the characteristics of a capillary?
- very small lumen
- wall made of a single layer of cells
How is blood flow controlled?
Contraction and relaxation of the muscle in the wall of the artery
(Vasoconstriction, Vasodilation)
Does blood pressure increase or decrease as it moves away from the heart?
Decrease
How does tissue fluid leave and enter the capillaries?
Osmosis - down a concentration gradient
What is tissue fluid made of?
Basically just blood plasma minus the plasma proteins
What does tissue fluid supply to the cells?
Glucose
Oxygen
Amino Acids
What does tissue fluid remove from the cells?
Carbon dioxide
Waste products
What happens to the tissue fluid that does not return by osmosis to the capillaries?
Is absorbed by the lymphatic vessels, is transported by the lymphatic system back into the circulatory system. Becomes known as lymph
How do you calculate cardiac output?
stroke volume x heart rate
What is stroke volume?
the volume of blood expelled by each ventricle on contraction
What is cardiac output?
the volume of blood that is pumped through each ventricle per minute
Where is the sino-atrial node located?
Left wall of the right atrium
It is the pacemaker of the heart
Where is the atrio-ventricular node located?
in the inner muscle of the right atrium
What are the three stages in the cardiac cycle, in order?
- atrial and ventricular diastole
- atrial systole
- ventricular systole
What happens during atrial and ventricular diastole?
- atria and ventricles are relaxed
- blood flows from the pulmonary vein and the vena cava into the heart
- volume of blood increases in the atria
- increased volume pushes AV valves
- blood flows into ventricles
- SL valves are closed
What happens during atrial systole?
- both atria contract
- blood is forced into ventricles
- SL valves remain closed
What happens during ventricular systole?
- AV valves close
- ventricles contract
- SL valves are pushed open
- blood is pumped out of the heart through the pulmonary artery and aorta
What does an ECG show?
The electrical impulses generated by the beating of a heart
Shown as a wave
Can pick up abnormalities such as heart damage, high blood pressure and arrhythmia
What is the P wave in an ECG?
The electrical impulse of tissue spreading over the atria from the Sino-Atria node and the contraction of the atria - systole
What does the QRS complex show in an ECG?
Shows the firing of the Atrio-Ventricular node causing the tissue of the ventricles to contract (systole)
What does the T wave in an ECG show?
The recovery of the atrio-ventricular node and the ventricles returning to their relaxed state (diastole)
How do you calculate heart rate?
heart rate = time/intervals
where intervals = no. of peaks in blood pressure
How do you calculate pulse rate?
pulse rate = diastolic pressure + systolic pressure
What number is the diastolic pressure and what number is the systolic pressure?
Diastolic pressure = smaller number
Systolic pressure = bigger number
What controls heart rate?
- Sino atrial node (auto rhythmic cells)
- Nervous system
- Hormonal activity
How does the nervous system act to control heart rate?
Antagonistically
What effect do sympathetic nerves have on heart rate?
- Release noradrenaline to trigger release of adrenaline which increases heart rate
What effect do parasympathetic nerves have on heart rate?
Releases acetylcholine which decreases heart rate
What is cardiovascular disease?
General term used to describe disease in the heart or blood vessels
Give examples of risk factors for cardiovascular disease
- high blood pressure
- smoking
- high blood cholesterol
- diabetes
- lack of exercise
- obesity
- history of heart disease
How do you calculate BPI?
BPI = body mass (kg) / height^2 (m^2)
When is a person classed as obese?
When BPI > 30kgm^2
What is atherosclerosis?
When the smooth wall of the blood vessels becomes roughened by the development of an atheroma (plaque)
What is an atheroma made of?
Fatty material, calcium, cholesterol
What can cause blood clots?
The rupture of an atheroma which damages of an endothelium
What does clotting do?
Protect damaged cells
How does the process of clotting work?
- Damaged cells signal the release of clotting factors
- Clotting factors convert inactive enzyme prothrombin into active thrombin
- Thrombin converts soluble protein fibrinogen into insoluble fibrin
- Fibrin acts as a scaffold for platelets to create a clot and seal the wound.
Why is fibrinogen soluble but fibrin is insoluble?
- Soluble so it can travel through blood stream
- Insoluble so it doesn’t break apart
What is a thrombosis?
The formation of a blood clot
What is an embolus?
A thrombus that has broken loose
What issues can a embolus cause?
- severe blood flow restriction
- artery blockages
What is it called when a embolus blocks an coronary artery?
Coronary thrombosis
What causes a stroke?
- A thrombus causes a blockage in the vessels of the brain
- cells deprived of oxygen lead to the death of the tissue in the brain
What is a peripheral artery?
Any artery other than the aorta, coronary and carotid arteries
What happens to peripheral arteries when affected by atherosclerosis?
Central cavity becomes smaller/narrower
Leads to peripheral vascular disease
PVD affects the arteries in the legs. What happens to the blood vessels?
- Severe blood flow restriction
- Pain is felt in leg muscles due to lack of oxygen
What was the formation of a thrombosis in a vein called?
Deep vein thrombosis
- causes severe pain and swelling
What is it called when a embolus travels to the lungs?
Pulmonary Embolism
Why is cholesterol important?
- component of cell membranes
- required in production of steriods
Where do we get our cholesterol from?
- 25% is made the liver
- diet
What do lipoproteins do?
Transport cholesterol around the body
What does Low density proteins do?
Transport cholesterol from liver to body cells and deposit excess cholesterol in blood vessels
What do High Density Proteins do?
Remove cholesterol from blood vessels and transport it to the liver where it will be broken down into useful components
What is the problem with cholesterol?
- High amounts of LDL cause a build up of cholesterol in arteries
- this causes atheromas
What treatment can be given to help high cholesterol?
- dietary changes - less saturated fats
- statins that inhibit synthesis of cholesterol in the liver
What hormone is released when glucose levels are too high?
Insulin
What hormone is released when blood glucose levels are too low?
Glucagon
What is the storage form of glucose?
Glycogen
What is the test for diabetes?
- fast for 8 hours
- individual drinks glucose solution of known volume
- individuals blood glucose levels are measured
- severe diabetics will have a higher line than doesn’t drop
What can chronic elevation of blood glucose levels over a long period of time cause?
- Atherosclerosis development
- Haemorrhaging of small/large blood vessels
- Diabetes
During the formation of a thrombus, fibrin…?
Forms a mesh network to clot the blood
How do you improve reliability of results?
Repeat
