b4 questions Flashcards
Name the four main components of blood.
red blood cells, white blood cells, plasma, platelets
What is the function of platelets?
form blood clots – prevent the loss of blood and stop wounds becoming infected
Why is the human circulatory system a double
circulatory system?
blood passes through the heart twice for every circuit around the body – deoxygenated blood is pumped from the right side of the heart to the lungs, and the oxygenated blood that returns is pumped from the left side of the heart to the body
How does the structure of an artery relate to its
function?
carries blood away from the heart under high pressure – has a small lumen and thick, elasticated walls that can stretch
How does the structure of a vein relate to
its function?
carries blood back to the heart at low pressure –doesn’t need thick, elasticated walls, but has valves to prevent blood flowing the wrong way
How does the structure of a capillary relate to its
function?
carries blood to cells and tissues – has a one-cell-thick wall to provide a short diffusion distance
List the structures air passes through when
breathing in.
mouth/nose ➞ trachea ➞ bronchi ➞ bronchioles ➞ alveoli
What is the function of the red blood cells?
Bind to oxygen and transport it around the body
What is the function of the white blood cells?
Defend the body against pathogens
What is the function of the plasma?
Transports blood cells and substances around the body
Why is a leaf an organ?
there are many tissues inside the leaf that work together to perform photosynthesis
How is the upper epidermis adapted for its
function?
- single layer of transparent cells allow light to pass
through - cells secrete a waxy substance that makes leaves
waterproof
How is the palisade mesophyll adapted for its
function?
tightly packed cells with lots of chloroplasts to absorb as much light as possible for photosynthesis
How is the spongy mesophyll adapted for
its function?
air spaces increase the surface area and allow gases to diffuse quickly
What is the function of the guard cells?
control the opening and closing of the stomata