Biology End of Term Exam

What is a disease?

a problem with a structure or process in the body which is not a result from injury.

What are infectious diseases?

Diseases caused by pathogens (microorganisms which cause disease) and can be passed person to person.

What are non-infectious diseases?

Diseases caused by genetics or lifestyle and cannot be passed from person to person. 

What are the two modes of transmission for diseases?

Direct and indirect contact

What is direct contact?

transmission through blood or other body fluids i.e. wounds and sexual contact

What is indirect contact?

contaminated surfaces or food, contact with infected animals, breathing in droplets from the air, touching an infected surface

How can you control the spread of pathogens?

clean water supply, hygienic food preparation, good personal hygiene, waste disposal, and sewage treatment

What is the general defence system?

defends the body against anything that enters the body that is not recognised by the white blood cells.

What is the specific defence system?

defends the body against specific infections, involves lymphocytes and antibodies

Function of skin in non-specific immunity:

physical barrier which secretes sebum which has antibacterial properties

Function of mucus in non-specific immunity:

catches dirt particles (nose, mouth, airways, reproductive tracts)

Function of phagocytic white blood cells:

cells engulf bacteria, viruses (any microorganisms) in the bloo

What happens when an infection occurs?

In the general defence system phagocytic white blood
cells engulf pathogens defence proteins such as complement proteins and interferons help to
destroy pathogens Inflammation increases the temperature of the infected area which helps to kill bacteria and viruses and inflammation also increases blood flow to the area which brings more white blood cells.

Function of lymphocytes:

White blood cells that are produced in the bone marrow with a very large round nucleus that secrete antibodies and produce memory cells that recognize infection in future.

What are antibodies?

are specific protein molecules produced by lymphocytes in response to an antigen

What are antigens?

chemicals found on foreign bodies that stimulate body cells to produce antibodies

How do antibodies act against antigens?

Targeting the pathogen for destruction by a phagocyte they cause pathogens to clump together and prevent further infectionand trigger the complement protein to be released which causes the pathogens to burst

What is active immunity?

immunity that relies on the immune system to produce antibodies and memory cells giving long term immunity. A natural example is infection an artificial example is vaccination. It is long term due to memory cells.

What is passive immunity?

immunity that passes the antibodies for a specific antigen but does not provide long term immunity as no memory cells have been made. A natural example is maternal antibodies an artificial example is monoclonal antibodies. It is short term lasting from a few weeks to 6 months.

How many times does the human heart beat per day?

100,000

Most mammals have a circulatory system that…

consists of the blood, blood vessels and the heart (pump) with valves to ensure one-way flow of blood.

Three different ways to record heart activity:

EKG – electrocardiogram
- electrodes are placed on the patient’s chest
- detect the tiny electrical charges from the sinoatrial node (pacemaker cells) Pulse rate – thumb meter is best but you can also measure using the radial or carotid pulse Stethoscope – detects the sounds of the valves opening and closing

Function of hepatic portal vein:

brings absorbed nutrients from capillaries in the small intestine to the liver

Main function of capillaries:

exchange substances between the blood and body cells.

Function of veins:

To carry mainly deoxygenated blood To the heart except for the pulmonary vein which brings oxygenated blood from the lungs to the left side of the heart.

Function of arteries:

To carry mainly oxygenated blood Away from the heart except for the pulmonary artery which carries blood from the right side of the heart to the lungs to collect oxygen.

What is the function of blood

Transport, distribution of heat, transport of oxygen, and the defence against disease

What is blood composed of?

Plasma, red blood cells, white blood cells and platelets

Why are double circulatory systems more efficient?

Blood can move around the body more quickly which allows nutrients and oxygen to reach body cells faster and as a result the organism can have a faster metabolism Blood flow can be directed towards different parts of the body when required

What is the function of plasma?

is to transport blood cells and dissolved materials including glucose, amino acids, minerals, vitamins, salts, carbon dioxide, urea, hormones, heat

How long do RBCs live?

4 months

What is the difference between red and white blood cells?

Red blood cells carry oxygen and lack a nucleus. White blood cells defend against infection and have a nucleus. RBCs are numerous, while WBCs are fewer.

What are the two main types of wbcs?

Lymphocytes and phagocytes

What are platelets?

Tiny cell frragments present in blood, which help with clotting.

Descreibe the clotting process

1. Capillary is damaged

2. This activates platelets

3. They convert a clotting protein from fibrinogen to fibrin

4. Fibrin makes a mesh that traps red blood cells and makes a clot