Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
7 Cards in this Set
- Front
- Back
|
Describe how the rate of heartbeat is increased as muscle activity increases during exercise
|
Increase in carbon dioxide / hydrogen ions;
detection by / stimulation of chemoreceptors; pressure receptors detect changes in blood pressure; (receptors) in aorta / carotid arteries / medulla; (cardio) acceleratory centre (in medulla) / cardiovascular centre; impulses via sympathetic nerves/system; to SAN; change in rate of impulse production by SAN; |
|
|
Describe the role of the nervous system in modifying the heart rate in response to an increase in blood pressure.
|
Pressure receptors;
in aorta/carotid artery/sinus; send impulses (award once only); to medulla; send impulses (award once only); along parasympathetic / vagus pathway; slows heart rate; |
|
|
When pressure is applied to a Pacinian corpuscle, an impulse is produced in its sensory neurone. Explain how.
|
(Pressure) deforms and opens (sodium) channels
Entry of sodium ions; Causes depolarisation (generator potential) Ions diffuse downstream and when threshold of nearby voltage gated channels is reached they open and sodium diffuses in causing depolarisation |
|
|
Explain how the structure of the retina and its neuronal connections enable a person to have a high degree of visual sensitivity in low light levels.
|
Rod cells (responsible for sensitivity);
Several rods connected to each bipolar cell; Additive effect of small amount of light striking several rod cells; creating a large enough depolarisation to generate an |
|
|
Explain how the structure of the retina and its neuronal connections enable a person to have a high degree of visual acuity.
|
Cone cells (responsible for acuity);
Each cone cell connected to an individual neurone; idea of light striking each individual cone cell to generate a separate action potential / impulse; very small area of retina stimulated, so very accurate vision; Each cone is connected to a specific neurone; light striking cone cells generating separate action potentials; |
|
|
Describe the events that take place in a neurone which produce an action potential
|
Stimulus to threshold / critical firing level;
Sodium channels/gates open; Sodium ions enter; Down electrical/chemical gradient Inside becomes positive / membrane potential reverses; Potassium channels/gates open; Potassium ions leave; Sodium channels/gates close; Sodium-potassium pump restores resting potential; |
|
|
Describe how the body responds to a rise in core body temperature.
|
Temperature receptors stimulated in hypothalamus
Heat loss centre stimulated nerve impulses to sweat glands increase rate of / start sweat production nerve impulses to skin arterioles vasodilation |
