Topic 1

• Atrial systole

  Blood fills the right atria from the vena cava

  pressure in atrium increases

  Some blood begins to leak into the ventricle: isometric ventricular

  filling

  This causes the atrioventricular values to open

  The atria contract forcing all he blood into the ventricle
• ventricular systole

  Pressure in ventricles increases

  After a slight delay, the ventricles contract

  This causes the atrioventricular valves to close to prevent back flow of blood

  The semilunar valves open

  As the ventricles contract, blood is forced int the aorta and the pulmonary artery
• Structure of artery

  smooth, highly folded endothelium

  thick layers of smooth muscle + elastic tissue

  collagen in tunica externa

  narrow lumen
• Structure of veins

  Thinner layers of smooth muscle and elastic tissue

  large lumen

  valves
• Risk factors of cardiovascular disease

  Smoking

  inactivity

  heredity

  free radicals

  salt

  stress
• What do Antihypertensives do?

  Reduces blood pressure

  some remove extra fluid and salt

  some relax and dilate blood vessels

  drugs can be combined to maximise effectiveness
• What do Statins do?

  Reduce the of level of LDL cholesterol

  increases level of HDL cholesterol
• What do Anticoagulants do?

  reduces risk of formation of new blood clots

  can reduce size and growth of existing blood clots
• What do Platelet inhibitors do?

  Reduces risk of formation of new blood clots

  prevents platelets from becoming sticky / being activated

  if no platelets are activated, no thrombus is formed
• What is Tissue Fluid

  Extracellular fluid that is found around cells. it comes from substances that leak out of blood capillaries.

  It helps bring oxygen and nutrients to cells to remove waste products from them
• High hydrostatic pressure

  Tissue fluid forced out through pores in capillary

  high solute concentration creates water potential gradient between capillary and tissue fluid.

  Some fluid moves in by osmosis
• Formation of a lymph

  Some tissue fluid re-enters the capillaries while some enters the lymph

  large molecules not able to pass through the capillary will enter the lymphatic system

  lymph eventually re-enters the bloodstream through veins close to the heart
• Suggest how the location of the atheroma results in the position and size of the dead heart muscle

  The area of dead heart muscle will be downstream of the atheroma

  Arteries supply oxygenated blood to cells for aerobic respiration to provide ATP

  Atheroma blocks the flow of blood / narrows the lumen of coronary artery

  the region of tissue not supplied with blood will die due to lack of respiration

  If atheroma is located near the end of an artery, the area of dead muscle will be small
• effect of LDL cholesterol

  increases blood cholesterol levels

  triglyceride is saturated; therefore, the lipoprotein is LDL

  LDLs transport cholesterol

  LDLs bind to receptors on the cell surface membrane

  LDL accumulates in the blood if receptors are overloaded

  LDL deposits cholesterol in endothelium of arteries leading to atherosclerosis
• Why is diet a risk factor

  A diet high in saturated fats

  High LDL cholesterol diet

  High salt diet

  obesity linked to an increase in CVD
• Why is lack of exercise a risk factor

  allows fatty deposits to accumulate

  high basal heart rate
• Why is smoking a risk factor

  Nicotine can cause endothelial damage

  increases blood clot formation

  atherosclerosis
• Waist-to-hip ratio

  women should be less than 0.86

  men should be less than 1.0
• BMI

  less than 18.5 = underweight

  18.5 - 24.9 = normal

  greater than 30 = obese
• Evidence linking blood cholesterol to CVD

  medical treatments such as statins which reduce blood cholesterol levels also reduce the risk of CVD

  diets high in saturated fats which tend to raise LDL cholesterol have been linked to CVD events

  a significant reduction in total blood cholesterol levels is linked to a decrease in major coronary events

  arterial plaque regression has been observed alongside blood lipid-lowering therapy
• extra factors that influence levels of LDL cholesterol

  presence of alleles that influence levels of cholesterol
• Risk of statins

  false sense of security = return of unhealthy lifestyle

  need to be taken long-term

  side effects: liver damage, neurological issues, joint pain
• Risk of antihypertensives

  side effects: headaches, heart palpitations, drowsiness
• risks of anticoagulants

  can cause internal bleeding, haemorrhage

  side effects: coughing blood, fainting

  can damage foetus
• risk of platelet inhibitors

  excessive bleeding if injury occurs

  side effects: rashes, liver dysfunction
• what is lymph

  lymph is a clear-to-white fluid made of:

  • lymphocytes (WBC)
  • Fluid from the intestines, which contains proteins and fats
• capillary structure

  small lumen = low velocity of blood flow

  more time for processes of diffusion / gas exchange
• organ

  made of many different tissues

  carrying out several different functions
• tissue

  A tissue is a group of specialised cells that work together to perform a particular function
• cell

  The basic unit of a living organism composed of organelles suspended in a cytoplasm with a cell membrane surrounding it.
• Prophase

  the chromosomes condense

  centrioles move to opposite poles of the cell

  to form spindle fibres

  the nucleolus breaks down

  the nuclear envelope/membrane breaks down
• metaphase

  mitotic spindle attaches to centromeres

  sister chromatids line up at the cell equator
• anaphase

  spindle fibres contract

  sister chromatids are separated at the centromere and pulled to opposite ends of the cell

  (requires ATP)
• telophase

  the spindle breaks down

  nuclear envelope reforms

  chromosomes start to decondense
• G1

  mRNA is sythesised and proteins synthesised

  some organelles are copied
• S1

  DNA is replicated
• centromere

  A centromere is a specialised sequence of DNA that links the sister chromatids and is important throughout mitosis.
• G2

  growth and preparation for mitosis
• difference between tissue and an organ

  tissue is made up one type of cell and organ is made up of different tissues
• environmental factors that can increase risk of cancer

  viral infection = virus may contain oncogene that interferes with cell cycle

  UV light = increased mutation of DNA

  Exposure to carcinogenic chemicals = can damage DNA / cause DNA mutations

  diet low in antioxidants = required to destroy free radicals that can damage DNA