biology b4

• what organisation level is the heart?

  organ
• what does the heart do?

  Pumps blood around the body
• what muscle is the heart made from?

  cardiac muscle
• which artery is the cardiac muscle supplied with oxygen from?

  the coronary artery
• pulmonary artery...

  Carries deoxygentated blood from the heart to the lungs
• vena cava

  a large vein carrying deoxygenated blood into the heart
• right ventricle

  pumps deoxygenated blood to the lungs where gas exchange happens
• aorta

  carries oxygenated blood around the body
• pulmonary vein

  brings oxygenated blood from the lungs
• left ventricle

  pumps blood around the body
• what is the heart rate controlled by?

  a group of cells in the right atrium that generate electrical impulses acting as a pacemaker.
• what can artificial pacemakers do?

  they can control irregular heartbeats.
• label the heart

  diagram

  
• what is a double circulatory system?

  Blood passes through the heart twice for each complete circuit of the body
• what organisation level is the blood?

  a tissue
• red blood cells

  bind to oxygen and transport it around the body
• white blood cells

  part of the immune system to defend the body against pathogens
• platelets

  form blood clots to create barriers to infections
• plasma

  transports substances and blood cells around the body
• function of arteries

  carries blood away from the heart high pressure
• function of veins

  carries blood to the heart low pressure
• function of capillaries

  carries blood to tissues and cells

  connects arteries and veins
• structure of artery

  thick, muscular and elastic walls

  the walls can stretch and withstand high pressure

  small lumen

  
• structure of veins

  -have valves to stop blood flowing the wrong way

  - thin walls

  - large lumen
• structure of capillaries

  one cell thick - short diffusion distance for substances to move

  between the blood and tissues (e.g., oxygen into cells and carbon dioxide out)

  - very narrow lumen

  
• What is coronary heart disease?

  a build up of fatty materials in the coronary arteries, making them narrow and restricting blood flow.
• what can help coronary heart disease

  stents can be used to keep them open
• what can people with heart failure do before a donor is available?

  have to use artificial hearts before a donor heart becomes available for a heart transplant.
• faulty heart valves can cause..

  breathlessness, a less efficient heart
• what can faulty heart valves be replaced by?

  Biological (animal) or mechanical valves (titanium and polymers)
• order of air travel

  trachea, bronchi, bronchioles, alveoli
• where does oxygen diffuse to after the alveoli?

  into the blood in the network of capillaries over the surface of the alveoli.

  
• define bronchi

  The main passageways directly attached to the lungs
• Define bronchioles

  Small passages in the lungs that connect bronchi to alveoli
• define alveoli

  Microscopic air sacs in lungs that are where diffusion (exchanges of gases) occurs with blood vessels.
• what level of organisation are plants

  organ because they contain many tissues that work together to perform photosynthesis.
• waxy cuticle

  makes the leaf waterproof
• upper epidermis

  • single layer of cells

  • protects against water loss

  • transparent to allow light to pass through
• palisade mesophyll

  • tightly packed cells

  • lots of chloroplasts to absorb light for photosynthesis
• spongy mesophyll

  • spherical cells

  • lots of air spaces to allow gases to diffuse quickly

  • large surface area-to-volume ratio to increase gas exchange