B5 Flashcards
mwhat do cells need?
oxygen, glucose, amino acids, water, ions
what are waste products?
carbon dioxide and urea
how are alveoli specialised?
- enormous surface area
- moist lining
- thin walls with calls with partially permeable cell membranes
- a good blood supply
what is the job of the lungs?
transfers oxygen to the blood and removes carbon dioxide
what is a partially permeable membrane?
the membrane will only allow a certain type of substances to go through the membrane
what is the gaseous exchange system?
- system made up of the nose, mouth, trachea and lungs
- responsible for oxygenating the blood, and removing carbon dioxide from it
what is the digestive system?
- food is broken down
- dissolved food molecules are transferred into the bloodstream at the small intestine by diffusion and other transport processes
- once the dissolved food molecules are in the bloodstream, they can be transported to all the cells in the body.
- this is particularly important for glucose as it is needed by all cells for the process of respiration
what is the excretory system?
- system made up of the kidneys and bladder
- responsible for removing waste products that have been made by the body
what is the circulatory system?
transports substances, such as oxygen, around the body in the bloodstream. It links together all the other systems in the body
what is diffusion?
the movement of a substance from an area of high concentration to low concentration
how does the body diffuse oxygen?
in the lungs by the alveoli
what does the blood transport?
oxygen, carbon dioxide, glucose, urea
what is osmosis?
the net movement of water molecules from a high concentration to a lower concentration across a partially permeable membrane
what is active transport?
the transport of molecules against their concentration gradient from a region of low concentration to a region of high concentration
why is blood important?
it flows around the body, transporting substances to and from cells
what is in blood?
red blood cells, white blood cells, platelets and plasma
what does plasma do?
transports carbon dioxide, digested food molecules, urea and hormones; distributing heat
what do red blood cells do?
transport oxygen
what do white blood cells do?
Ingest pathogens and producing antibodies
what do platelets do?
Involved in blood clotting
why is the left side of the heart bigger?
it puumps blood to teh body
what is in cardiac heart muscles and why?
mitochondria to provide them with ATP
- this releases the energy needed for the muscle to contract
what are the 4 chambers?
right and left ventricle
right and left atria
what are valves for?
keep blood flowing in one direction and the right direction
how does blood flow into the heart?
vena cave(right)
pulmonary vein(left)
where does the right ventricle pump blood to?
lungs
what do the arteries do
carry blood away from the heart
what do capillaries do
they are involved in the exchange of materials at the tissues
what do veins do
carry blood into the heart
why are arteries thick and elastic?
blood pressure in them is high
so they can stretch and spring back
why are capillary walls one cell thick?
to increase the rate of diffusion by decreasing the distance it occurs by
why are veins thin?
the blood is at a lower pressure
why do veins have a large lumen?
to help blood flow
why do blood cells have a biconcave disc shape?
to give a large surface area to volume ratio
this increases the rate that oxygen diffuses in and out of the cell
what is the advantage of their size?
they can pass through the the capillaries close to the body cells
why do multicellular organisms need exchange surfaces?
they have small surface area to volume ratios which makes diffusion slow
how do multicellular organisms get around the problem?
they have specialised exchange surfaces
what are receptors?
- specialised groups of cells
- sense changes in the environment
- linked to sensory neurons
what are the concentration of receptors based on?
how much information that part of the body gets from the environment
what are the types of receptors?
chemical, pain, pressure, light, stretch, temperature, balance
what are chemical receptors for?
smell and taste
what are neurones?
nerve cells