2278114
Descripción
Fichas por themoonisdown, actualizado hace más de 1 año
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Creado por themoonisdown
hace casi 10 años
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| Pregunta | Respuesta |
| Describe the role of the central nervous system in humans | -Accepts information -Processes information -Responds to information |
| Describe the functions of the cerebrum | controls all higher activities e.g. memory, emotions, processes information and intelligence |
| Describe the functions of the cerebellum | controls balance and co-ordination of muscles, involved in precise, accurate movement |
| Describe the role of the Medulla | Controls activities that animal isn't conscious of - breathing, digestion, heart rate etc. |
| Describe the role of sensory neurons in the nervous system | transmit messages from sense receptors (e.g. nose, eye) to the brain or spinal cord(CNS) Receptors to relay neurons |
| Describe the role of relay neurons in the nervous system | connects a sensory neuron to a motor neuron - passes impulse from sensory to motor neuron |
| Describe the function of the motor neuron in the nervous system | carry information towards an effector which may be a muscle or a gland |
| Describe what happens when electric impulse signal arrives at a synapse | when an electrical impulse arrives at a synapse neurotransmitter molecules are releases from synaptic vesicles. the neurotransmitters diffuse across the synaptic cleft, triggering receptors on receiving neuron to release an electrical impulse |
| Describe the flow of information along a reflex arc | firstly stimulus is detected by receptors and electrical impulses are passed along the sensory neuron. the signal is then passed from sensory neuron to the relay neuron where it is then passed onto the motor neuron. the signal then reaches the muscle/gland and the muscle/gland responds |
| Explain how the action of hormones is specific. (2 marks) | target tissues have cells with receptor proteins - the hormone only affects receptors on it's target cells -each hormone has a function not carried out by any other |
| describe the role of the pancreas in the control of blood sugar. (2 marks) | -produces insulin which causes excess blood glucose to be stored - produces glucagon, which causes the release of glucose from the store |
| Describe the role of the liver in the control of blood | -stores excess glucose as glycogen -release glucose from glycogen |
| describe the control of blood glucose concentration in humans. (3 marks) | - raised glucose triggers insulin release by pancreas -insulin causes liver to convert to glucose to glycogen and store it when glucose levels fall glucagon released by pancreas -glucagon cause liver to convert glycogen back into glucose and release it back into the bloodstream -(glucagon converts glycogen to glucose) (Any 3 of the above is sufficient) |
| Describe the two types of diabetes. (3 marks) | - type 1 appears in childhood usually - type 1 cause by lack of insulin - type 2 often appears in overweight individuals - type 2 caused by liver receptors not responding to insulin |
| What is the meaning of specialised in relation to cells? | has certain physical and structural characteristic which allow the cell to carry out a specific function - structure is suited to the function |
| what is the general function of stem cells? | to produce more cells for growth and repair - to replace cells that are damaged or lost - divide to produce a supply of cells which can then specialise |
| Describe what happens to a stem cell that results in the production of a red blood cell that results in the production of red blood cells in humans | -cell division -stem cells divides -loses nucleus -produces haemoglobin -develops biconcave shape |
| describe the differences and similarities between adult and embryonic stem cells | similarity - both can divide, both are un-specialised differences - embryonic stem cells can become any cell, adult limited to only a few types of cell |
| describe the ethical issues surrounding research into human embryonic stem cells | -moral principle to improve medicine -moral principle to respect human life - these two principles cannot both be respected in embryonic stem cell research |
| give the meaning of haploid | a cell with one set of chromosomes - always sex cells(gametes) |
| give the meaning of diploid | a cell which contains two sets of chromosomes |
| describe the differences between a sperm cell and an ovum | sperm cells are tiny and have a tail for swimming ova are large and have a food supply to feed early embryo |
| describe how fertilisation is achieved in a flowering plant | -male pollen carried from anther to the stigma by wind or insects -pollen grows pollen tube through style to ovary -pollen nucleus fuses with female ovule nucleus |
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