Flashcards in Unit 1, Module 1 Glossary Deck (53):
The process by which cells communicate with each other. This is a process in which one cell will release a chemical that is detected by another cell. The second cell will respond to the signal by the first cell.
Any change in the environment that causes a response
A change in behaviour or physiology as a result of a change in the environment.
The maintenance of the internal environment in a constant state despite external changes.
A process in which any change un a parameter brings about the reversal of that change so the parameter is kept fairly constant.
A process in which any change in a parameter brings about an increase in that change.
A hormone released by posterior pituitary gland to facilitate birth and breast feeding.
An organism that relies on external sources of heat to regulate its body temperature
An organism that can use internal sources of heat, such as heat generated from metabolism in the liver, to maintain its body temperature.
A membrane that has a potential difference across it. This is the resting potential
The loss of polarisation across the membrane. It refers to the period when sodium ions are entering the cell making the inside less negative with respect to the outside.
A small depolarisation caused by sodium ions entering the cell.
A brief reversal of the resting potential across the cell surface membrane of a neurones all action potential have a value of +40mV
The potential difference. Or voltage across the neurone cell membrane while the neurone is at rest.
Channels in plasma membranes that allow the passage of ions, they respond to changes in potential difference across a membrane and as a result open or close.
A potential difference (usually -50mV) across the membranes if the Depolarisation of the membrane does not reach the threshold potential then no action potential is created. If the depolarisation reaches the threshold potential then more sodium ion channels open and an action potential is created.
The condition of a membrane that is mor highly polarised than the usual resting state,my resting potential is lower than usual.
Membrane with a potential difference across it.
The loss of polarisation across a membrane - when a membrane loses its resting potential
The short period of time after firing during which it is more difficult to stimulate a neurone.
The movements of ions along the neurone. The flow of ions is caused un an increase in concentration at one point, which causes diffusion away from the region of high concentration.
Refers to the way. That the action potential appears to jump form one more of Ranvier to the next.
A chemical that diffuses across the cleft of the sun apse to transmit a signal to the postsynaptic neurone.
Those that use acetylcholine as their transmitter substance.
A swelling at the end of the presynaptic neurone.
An enzyme in the synaptic cleft. It breaks down the transmitter substance acetylcholine.
All or nothing
Refers to the fact that a neurone either conducts an. Action potential or does not. All action potential are of the same magnitude +40mV.
A term that refers to the way that several small potential changes can combine to produce one larger change in potential difference across the membrane.
Molecules that are released by endocrine glands directly into the blood. They act as messengers, carrying a signal from the endocrine gland to a specific target organ or tissue.
A gland that secretes hormones directly into the blood. Endocrine glands have no ducts.
A gland that secretes molecules into a duct that carries the molecules to where they are used.
Those that possess a specific receptor in their plasma membrane. The shape of the shape is complementary to the shape of the hormone molecule, many similar cells together form a tissue.
An enzyme associated with the reception for many hormones, including adrenaline. It is found on the inside of the cell surface membrane.
A hormone that acts as a message in the blood.
A chemical inside the cell released in response to a hormone binding to the cell surface membrane, e.g. cAMP.
A small organ in the abdomen that secretes digestive fluids and hormones.
A duct leading from the pancreas to carry digestive juices to the small intestine.
Islets of Langerhans
Small patches of tissue in the pancreas that have an endocrine function.
Cells in the islets of Langerhans hat release glucagon in response to low blood glucose levels.
Cells in the islets of Langerhans that release insulin in response to high blood glucose levels.
The hormone, released from the pancreas, that cause blood glucose levels to go down.
The hormone that cause blood glucose levels to rise.
Liver cells. They are specialised to perform metabolic functions.
A disease in which blood glucose concentrations cannot be controlled effectively.
The state in which the blood glucose concentration is too high.
The state in which blood glucose concentration is too low.
Bacteria whose DNA has been altered. In this case a gene coding for human insulin has been inserted into the DNA of the bacteria.
Unspecialised cells that have the potential to develop into any type of cell.
The result of all the chemical reactions taking place in the cytoplasm
Theses muscle tissues can initiate its own contractions
The region of tissue in the right atrium wall that can generate an impulse and initiates the contraction of the chambers
It is found at the base of the brain. It is the region of the brain that coordinates the unconscious functions of the body such as the breathing rate and heart rate.