Organisation in animals Flashcards
What are tissues
A group of similar cells that work together to carry out a particular function
What is an organ
A group of different tissues that work together to perform a particular function
What is an organ system
A group of organs working together to perform a particular function
What is the function of the circulatory system
To get food and oxygen to every cell in the body.
Name the 4 chambers of the heart
Right atrium, right ventricle, left atrium, left ventricle
Name the main blood vessels leading into and out of the heart
Vena cava, pulmonary artery, pulmonary vain, aorta
Define aorta
An artery which transports blood from the heart to the rest of the body
define vena cava
A vein which transports blood into the heart from the rest of the body.
define pulmonary artery
An artery which transports blood out of the heart to the lungs
define pulmonary vein
A vein which transports blood into the heart from the lungs
What are arteries
Arteries are blood vessels which carry blood away from the heart, towards the organs.
Artery adaptations
- Strong elastic walls
- thick layers of muscle and elastic fibres allow them to stretch
- Thick walls and a narrow lumen
What is the function of capillaries
supply food and oxygen to the cells and take away waste products like carbon dioxide
Capillary adaptations
- Permeable walls so substances being exchanged can diffuse in and out.
- Walls are one cell thick to reduce diffusion distance
- Very narrow to give them a large surface area to volume ratio. Also increases the rate of diffusion.
What is the role of a vein
To carry blood to the heart
Vein Adaptations
- Thinner walls as there is less blood pressure.
- Bigger lumen to help blood flow
Rate of blood flow equation
rate of blood flow = volume of blood/ number of minutes
What is the job of a red blood cell
to transport oxygen around the body
Red blood cell adaptations
- They have a biconcave shape to give them a large surface area to absorb oxygen.
- They contain red pigment called HAEMOGLOBIN, which carries oxygen.
- No nucleus which allows more room for haemoglobin, so they can carry more oxygen.
Role of white blood cells
To defend against microorganisms that cause disease.
How do white blood cells prevent disease
- They engulf foreign microorganisms and digest them.
- They can produce antibodies to fight microorganisms.
- They can produce antitoxins to neutralise any toxins produced by microorganisms.
What are platelets
Small fragments of cells that have no nucleus. They help the blood to clot at a wound.
What are 3 things that plasma carries
- Red and white blood cells and platelets.
-Urea from the liver to kidneys.
- Antibodies and antitoxins produced by the white blood cells.
