The heart

Arteries - Away from the heart

Veins - Into the heart

Capillaries - Gas exchange

The heart is made of muscle

It is called a double pump because it pumps blood too two different places simultaneously, made up of two circuits the pulmonary circuit (lungs) and systemic (the rest of the body)

The cardiovascular system, also known as the circulatory system is made up of the heart, blood vessels, and blood. This allows nutrients and oxygen to be taken to the tissues and help remove waste products such as CO2

Blood flow and if its oxygenated:

Blood is carried through vena cava - Deoxygenated

Blood moves from the right atrium to the right ventricle - Deoxygenated

Blood is pumped through the pulmonary artery to the lungs - Deoxygenated

Blood returns to the heart through the pulmonary vein - Oxygenated

Blood moves from the left atrium to the left ventricle - Oxygenated

Blood is pumped to the rest of the body via the aorta - Oxygenated

Heart dissection

Instructions:

1. Put the heart on the chopping board with newspaper underneath

2. Make sure your heart is facing the right way, the right side will be thinner than the left side

3. Make sure the thinner right side is to your left

4. Cut around the heart locating the different veins and arteries

Blood vessels and the components of blood

The natural resting heart rate is controlled by a group of cells located in the right atrium that act as a pacemaker. Artificial pacemakers are electrical devices used to correct irregulations in the heart rate.

The aorta takes oxygenated blood to the body.

The pulmonary artery takes deoxygenated blood to the lungs

The vena cava returns deoxygenated blood from the body

The pulmonary vein takes oxygenated blood from the lungs

Blood is made up of red blood cells, white blood cells, platelets and plasma

Red blood cells don’t have a nucleus they have a biconcave shape and have haemoglobin

White blood cells prevent infection, ingest pathogens and produce antibodies

Platelets clot blood

Plasma carry’s carbon dioxide, digested food molecules, urea and hormones

Coronary heart disease

Coronary arteries are located around the heart itself and keep the heart muscle supplied with blood and oxygen (allows it to contract)

Coronary heart disease is when the hearts blood supply becomes blocked interrupted by a build up of fatty substance caused by certain kinds of ‘bad’ cholesterol

Risk factors for CHD

Genetics

Amount of exercise

Stress

High lipoprotein

Sedentary lifestyle

Diet - High levels of saturated fat

Thrombosis ( blood clot in vein/artery)

Age

Smoking

High blood pressure

Diabetes

Overweight

Health issues and lifestyle

Health is a state of physical and mental wellbeing.

Disease can be sorted into two categories communicable and non-communicable, they are both major causes of ill health

Communicable - Pathogens such as bacteria, viruses, fungi and protists e.g. HIV, gonorrhoea, flu, food poisoning, athletes foot, malaria, TMV

Non-communicable - Genetics or lifestyle choices e.g. Alzheimer’s, heart disease

Pathogens can be passed in a number of ways:

In the air (coughing and sneezing)

Direct contact (shaking hands, kissing, unprotected sex)

Infected food or water (water in poorer countries may contain sewage or lack hygiene when preparing foods)

Vectors (flies or mosquitoes can carry harmful pathogens to humans)

A risk factor is any aspect of a persons life or substances in their body or environment that have been linked to an increased rate of disease

Cancer

Carcinogen: Chemicals that cause cancer or significantly increase the risk of cancer

Benign tumour: Growth of abnormal cells that are contained in one area, usually within a membrane and do not invade other tissues

Malignant tumour: Often called a cancer and can invade neighbouring tissues and spread to different parts of the body in the blood where they can form secondary tumours

A tumour is a swelling that can occur almost anywhere in the body. It is made up of a mass of abnormal cells that divide continuously. Cancer can be caused by genetic mutation or by carcinogens

Increase risk of cancer:

Genetics

Age

Radiation exposure

Smoking

Not wearing sun cream

Diet

Sedentary lifestyle

Drinking

Body weight

Chemotherapy - Drugs are used to destroy cancer cells, can also harm healthy cells, used to cure, control and ease symptoms

Radiotherapy - High energy radiation is used to shrink tumours and kills cancer cells by damaging their DNA

Monoclonal antibodies

Monoclonal antibodies are identical copies of the same antibody. The antibodies are specific to a certain binding site on a protein antigen so can target specific chemicals or cells in the body

Process:

1. Mouse is injected with a specific pathogen, the mouse’s immune system responds

2. Specific WBC called B lymphocytes produce antibodies

3. Tumour cells are able to divide but can’t make antibodies

4. B cells are combined with tumour cells

5. These cells are now called hybridoma cells and can make specific antibodies. They are screened to make sure they are producing the right antibodies

6. The hybridomas cells clone themselves and produce more antibodies

7. These antibodies are called monoclonal antibodies (because they came from a single cloned cell)

8. Antibodies are collected and used for a range of purposes

Uses of monoclonal antibodies:

Pregnancy test- When pregnant HCG or human chorionic gonadotrophin is produced when taking a pregnancy test small amounts of the HCG pass out through the urine and onto the test, the monoclonal antibodies bind to the HCG and cause a colour change.

This use is a positive because its a quick test and removes the need to visit the doctors for a test

Detect and treat cancer - Monoclonal antibodies can act as markers to help doctors locate cancer, they are coated in a fluorescent dye and can be picked up on scans

The advantages of using monoclonal antibodies to detect cancer cells are that they reduce the need for more harmful treatments such as chemotherapy and radiotherapy in detecting cancer, using blood tests and testing for blood clots reduces need for more invasive procedures

Donated blood - They can test for STD’s or drugs in blood

Ethics of using monoclonal antibodies

The production involves the use of mice and inducing sickness in them

Genetic engineering - to eliminate the use for humanisation of the antibody, transgenic mice can be used by placing a human gene in the mice

Saved many lives but there has been deaths associated with the treatments of diseases linked with side effects

Plant diseases

Plant pests

Nematodes:

Worms and insect larvae that live in the soil and feed in and on the plant roots

Reduce the mineral ions and water that can pass into the root

Plant could have stunted growth or discoloured leaves

Aphids:

Sharp mouth parts that pierce the stem of the plant and penetrate the phloem

Feeds on the sugary sap weakening and damaging the plant

Act as vectors and carry viruses, bacteria and fungi to the plant

Plants can be sprayed with pesticides to kill aphids and natural predators like ladybirds can be used

Mineral deficiencies

Nitrate ions:

Needed for protein production. Proteins are needed for growth and repair, plant growth will be stunted

Magnesium ions:

Make chlorophyll for photosynthesis, plants are unable to photosynthesis fully and leaves will look yellow (chlorosis)

Rose Black Spot

Symptoms:

Large black/ dark purple spots on the surface of the leaves or stems

The foliage gradually turns yellow

Leaves droop prematurely

Plant weakens as there are less leaves to that can photosynthesis

Fewer flowers are produced

Treatment:

Chemical fungicides can be applied to try to prevent spread

Disease resistant rose plants can be used

All infected plants should be burned

Transmission:

The black spot fungus produces spores which are released and are carried on the wind. When it rains the spores of the fungi splash onto the leaves

Rose black spot is extremely common and widespread fungal disease of both cultivated and wild rose varieties. The spores remain dormant over winter on dead leaves so its best to burn infected plants

Tobacco Mosaic Virus - TMV

TMV was the first virus to be discovered (in 1930). It attacks the leaves making them mottled or discoloured. It affects around 150 plant species.

Transmission:

This virus is transmitted through direct contact with a diseased plant however some insects working as vectors can carry it from plant to plant

Effects:

TMV stops chloroplasts forming

Chloroplasts are the site of photosynthesis in plants so if chloroplasts are not being produced then photosynthesis cannot occur and therefore crop yield is reduced

Bacterial disease in plants

There are very few bacterial diseases

Agrobacterium tumefaciens is a bacteria that causes Crown Gall Disease (a mass of unspecialised cells that grow at the joints of roots and shoots)

It infects fruit trees, vegetables and flowering plants by inserting a plasmid into the plants DNA, genetically modifying its cells. It is spread by direct contact the bacteria is normally present in soil and can enter the plant through wounds made by cultivating or weather damage.

The agrobacterium tumefaciens can be used to modify crops , scientists will add a desired gene to the bacterial plasmid and can insert it into the plant, the plant will then exhibit the desired characteristic.