Back to 课程
Biology AS CIE
0% Complete
0/0 Steps
-
1-cell-structure10 主题
-
1-2-cells-as-the-basic-units-of-living-organisms AS viruses
-
1-2-cells-as-the-basic-units-of-living-organisms AS prokaryotic-v-eukaryotic-cells
-
1-2-cells-as-the-basic-units-of-living-organisms AS the-vital-role-of-atp
-
1-2-cells-as-the-basic-units-of-living-organisms AS animal-and-plant-cells
-
1-2-cells-as-the-basic-units-of-living-organisms AS eukaryotic-cell-structures-and-functions
-
1-1-the-microscope-in-cell-studies AS calculating-actual-size
-
1-1-the-microscope-in-cell-studies AS resolution-and-magnification
-
1-1-the-microscope-in-cell-studies AS eyepiece-graticules-and-stage-micrometers
-
1-1-the-microscope-in-cell-studies AS magnification-calculations
-
1-1-the-microscope-in-cell-studies AS the-microscope-in-cell-studies
-
1-2-cells-as-the-basic-units-of-living-organisms AS viruses
-
2-biological-molecules19 主题
-
2-4-water AS water-and-the-hydrogen-bond
-
2-4-water AS the-role-of-water-in-living-organisms
-
2-3-proteins AS collagen
-
2-3-proteins AS haemoglobin
-
2-3-proteins AS globular-and-fibrous-proteins
-
2-3-proteins AS protein-shape
-
2-3-proteins AS the-four-levels-of-protein-structure
-
2-3-proteins AS amino-acids-and-the-peptide-bond
-
2-2-carbohydrates-and-lipids AS phospholipids
-
2-2-carbohydrates-and-lipids AS triglycerides
-
2-2-carbohydrates-and-lipids AS cellulose
-
2-2-carbohydrates-and-lipids AS starch-and-glycogen
-
2-2-carbohydrates-and-lipids AS the-glycosidic-bond
-
2-2-carbohydrates-and-lipids AS reducing-and-non-reducing-sugars
-
2-2-carbohydrates-and-lipids AS covalent-bonds-in-polymers
-
2-2-carbohydrates-and-lipids AS biological-molecules-key-terms
-
2-1-testing-for-biological-molecules AS testing-for-non-reducing-sugars
-
2-1-testing-for-biological-molecules AS the-benedicts-test
-
2-1-testing-for-biological-molecules AS biological-molecule-tests
-
2-4-water AS water-and-the-hydrogen-bond
-
3-enzymes13 主题
-
3-2-factors-that-affect-enzyme-action AS enzyme-activity-immobilised-v-free
-
3-2-factors-that-affect-enzyme-action AS enzyme-inhibitors
-
3-2-factors-that-affect-enzyme-action AS vmax-and-the-michaelis-menten-constant
-
3-2-factors-that-affect-enzyme-action AS rate-inhibitor-concentration
-
3-2-factors-that-affect-enzyme-action AS rate-substrate-concentration
-
3-2-factors-that-affect-enzyme-action AS rate-enzyme-concentration
-
3-2-factors-that-affect-enzyme-action AS rate-ph
-
3-2-factors-that-affect-enzyme-action AS rate-temperature
-
3-1-mode-of-action-of-enzymes AS colorimetry
-
3-1-mode-of-action-of-enzymes AS measuring-enzyme-activity
-
3-1-mode-of-action-of-enzymes AS how-enzymes-work
-
3-1-mode-of-action-of-enzymes AS enzyme-action
-
3-1-mode-of-action-of-enzymes AS enzymes
-
3-2-factors-that-affect-enzyme-action AS enzyme-activity-immobilised-v-free
-
4-cell-membranes-and-transport16 主题
-
4-2-movement-into-and-out-of-cells AS comparing-osmosis-in-plants-and-animals
-
4-2-movement-into-and-out-of-cells AS osmosis-in-animals
-
4-2-movement-into-and-out-of-cells AS osmosis-in-plant-cells
-
4-2-movement-into-and-out-of-cells AS estimating-water-potential-in-plants
-
4-2-movement-into-and-out-of-cells AS investigating-surface-area
-
4-2-movement-into-and-out-of-cells AS surface-area-to-volume-ratios
-
4-2-movement-into-and-out-of-cells AS investigating-diffusion
-
4-2-movement-into-and-out-of-cells AS investigating-transport-processes-in-plants
-
4-2-movement-into-and-out-of-cells AS endocytosis-and-exocytosis
-
4-2-movement-into-and-out-of-cells AS active-transport
-
4-2-movement-into-and-out-of-cells AS osmosis
-
4-2-movement-into-and-out-of-cells AS diffusion
-
4-1-fluid-mosaic-membranes AS cell-signalling
-
4-1-fluid-mosaic-membranes AS the-cell-surface-membrane
-
4-1-fluid-mosaic-membranes AS components-of-cell-surface-membranes
-
4-1-fluid-mosaic-membranes AS the-fluid-mosaic-model
-
4-2-movement-into-and-out-of-cells AS comparing-osmosis-in-plants-and-animals
-
5-the-mitotic-cell-cycle8 主题
-
5-2-chromosome-behaviour-in-mitosis AS observing-mitosis
-
5-2-chromosome-behaviour-in-mitosis AS the-stages-of-mitosis
-
5-1-replication-and-division-of-nuclei-and-cells AS how-tumours-form
-
5-1-replication-and-division-of-nuclei-and-cells AS the-role-of-stem-cells
-
5-1-replication-and-division-of-nuclei-and-cells AS the-role-of-telomeres-
-
5-1-replication-and-division-of-nuclei-and-cells AS the-cell-cycle
-
5-1-replication-and-division-of-nuclei-and-cells AS mitosis
-
5-1-replication-and-division-of-nuclei-and-cells AS chromosome-structure
-
5-2-chromosome-behaviour-in-mitosis AS observing-mitosis
-
6-nucleic-acids-and-protein-synthesis9 主题
-
6-2-protein-synthesis AS gene-mutations
-
6-2-protein-synthesis AS transcription
-
6-2-protein-synthesis AS constructing-polypeptides
-
6-2-protein-synthesis AS the-universal-genetic-code
-
6-2-protein-synthesis AS from-gene-to-polypeptide
-
6-1-structure-of-nucleic-acids-and-replication-of-dna AS the-structure-of-rna
-
6-1-structure-of-nucleic-acids-and-replication-of-dna AS semi-conservative-dna-replication
-
6-1-structure-of-nucleic-acids-and-replication-of-dna AS the-structure-of-dna
-
6-1-structure-of-nucleic-acids-and-replication-of-dna AS nucleotides
-
6-2-protein-synthesis AS gene-mutations
-
7-transport-in-plants11 主题
-
7-2-transport-mechanisms AS phloem-mass-flow
-
7-2-transport-mechanisms AS the-sucrose-loading-mechanism
-
7-2-transport-mechanisms AS movement-in-the-phloem
-
7-2-transport-mechanisms AS xerophytic-plant-leaf-adaptations
-
7-2-transport-mechanisms AS water-and-the-transpiration-pull
-
7-2-transport-mechanisms AS transpiration-in-plants
-
7-2-transport-mechanisms AS water-and-mineral-ion-transport-in-plants
-
7-1-structure-of-transport-tissues AS phloem-sieve-tube-elements
-
7-1-structure-of-transport-tissues AS xylem-vessels-elements
-
7-1-structure-of-transport-tissues AS xylem-and-phloem-distribution
-
7-1-structure-of-transport-tissues AS plant-transverse-sections
-
7-2-transport-mechanisms AS phloem-mass-flow
-
8-transport-in-mammals16 主题
-
8-3-the-heart AS heart-action
-
8-3-the-heart AS the-cardiac-cycle
-
8-3-the-heart AS the-walls-of-the-heart
-
8-3-the-heart AS structure-of-the-heart
-
8-2-transport-of-oxygen-and-carbon-dioxide AS the-bohr-shift
-
8-2-transport-of-oxygen-and-carbon-dioxide AS the-oxygen-dissociation-curve
-
8-2-transport-of-oxygen-and-carbon-dioxide AS plasma-and-carbon-dioxide
-
8-2-transport-of-oxygen-and-carbon-dioxide AS the-chloride-shift
-
8-2-transport-of-oxygen-and-carbon-dioxide AS red-blood-cells-haemoglobin-and-oxygen
-
8-1-the-circulatory-system AS blood-tissue-fluid-and-lymph
-
8-1-the-circulatory-system AS the-role-of-water-in-circulation
-
8-1-the-circulatory-system AS cells-of-the-blood
-
8-1-the-circulatory-system AS blood-vessels-structures-and-functions
-
8-1-the-circulatory-system AS observing-and-drawing-blood-vessels
-
8-1-the-circulatory-system AS the-main-blood-vessels
-
8-1-the-circulatory-system AS circulatory-systems
-
8-3-the-heart AS heart-action
-
9-gas-exchange6 主题
-
9-1-the-gas-exchange-system AS gas-exchange-processes
-
9-1-the-gas-exchange-system AS structures-and-functions-of-the-gas-exchange-system
-
9-1-the-gas-exchange-system AS recognising-structures
-
9-1-the-gas-exchange-system AS recognising-tissues
-
9-1-the-gas-exchange-system AS distribution-of-tissues
-
9-1-the-gas-exchange-system AS the-human-gas-exchange-system
-
9-1-the-gas-exchange-system AS gas-exchange-processes
-
10-infectious-diseases6 主题
-
11-immunity10 主题
-
11-2-antibodies-and-vaccination AS vaccination-to-control-disease
-
11-2-antibodies-and-vaccination AS how-vaccines-work
-
11-2-antibodies-and-vaccination AS types-of-immunity
-
11-2-antibodies-and-vaccination AS uses-of-monoclonal-antibodies
-
11-2-antibodies-and-vaccination AS making-monoclonal-antibodies
-
11-2-antibodies-and-vaccination AS antibodies
-
11-1-the-immune-system AS memory-cells-and-immunity
-
11-1-the-immune-system AS primary-immune-response
-
11-1-the-immune-system AS antigens
-
11-1-the-immune-system AS phagocytes
-
11-2-antibodies-and-vaccination AS vaccination-to-control-disease
课 8,
主题 1
In Progress
8-3-the-heart AS heart-action
课 Progress
0% Complete
Exam code:9700
Heart action: initiation & control
-
Control of the basic heartbeat is myogenic, which means the heart will beat without any external stimulus
-
This intrinsic rhythm means the heart beats at around 60 times per minute
-
The sinoatrial node (SAN) is a group of cells in the wall of the right atrium
-
The SAN initiates a wave of depolarisation that causes the atria to contract
-
-
The Annulus fibrosus is a region of non-conducting tissue which prevents the depolarisation spreading straight to the ventricles
-
Instead, the depolarisation is carried to the atrioventricular node (AVN)
-
This is a region of conducting tissue between atria and ventricles
-
-
After a slight delay, the AVN is stimulated and passes the stimulation along the bundle of His
-
This delay means that the ventricles contract after the atria
-
-
The bundle of His is a collection of conducting tissue in the septum (middle) of the heart
-
The bundle of His divides into two conducting fibres, called Purkyne tissue, and carries the wave of excitation along them
-
-
The Purkyne fibres spread around the ventricles and initiate the depolarization of the ventricles from the apex (bottom) of the heart
-
This makes the ventricles contract and blood is forced out of the pulmonary artery and aorta
-
|
Stage in cardiac cycle sequence |
Event |
|---|---|
|
1 |
Sinoatrial node sends out a wave of excitation |
|
2 |
Atria contract |
|
3 |
Atrioventricular node sends out a wave of excitation |
|
4 |
Purkyne tissue conducts the wave of excitation |
|
5 |
Ventricles contract |
Examiner Tips and Tricks
Remember that the heart is myogenic, which means that the heart will generate a heartbeat by itself and without any other stimulation. Instead, the electrical activity of the heart regulates the heart rate. Be aware that you may sometimes see an alternative spelling of “Purkyne” as “Purkinje” they mean the exact same thing!
Responses