Nervous system, Hormones, Co-ordination, Homeostasis Flashcards
What is as reflex action?
Rapid, automatic responses to stimuli.
How does the body detect changes in the external and internal environment?
The body has receptors.
Where do voluntary actions start?
With impulses from the brain.
Which organ is the centre for co-ordination with the ability to learn and remember?
The brain.
What is the path of a reflex action?
Stimulus to Receptor to Co-ordination system to Effector to Response.
How is long sight caused?
By a short eyeball, or flat cornea, when the light focuses behind the retina.
How is long sight corrected?
By a convex lens.
How is short sight caused?
By a long eyeball, when the light focuses infront of the retina.
How is short sight corrected?
By a concave lens.
What does an endocrinologist do?
They investigate the effect of hormones on body functioning.
What are hormones?
Chemicals released by endocrine glands into the blood which affect a target organ or, in some cases, the whole body.
What is the function of the growth hormone?
To stimulate growth and cell reproduction.
What is the function of thyroxin?
To control metabolic rate.
What is the function of insulin?
Causes the liver to absorb glucose and convert it to glycogen when blood sugar levels are high.
What is the function of glucagon?
Causes the liver to change glycogen to glucose when blood sugar levels are low.
What is the function of adrenaline?
Increases blood sugar, heart rate, breathing rate and blood pressure at times of stress.
What is the function of oestrogen?
Controls female sexual development.
What is the function of testosterone?
Controls development of male sexual characteristics.
How are endocrine glands stimulated?
By chemical changes in the blood, e.g. changes in blood sugar concentration.
What does ADH do?
Increases reabsorption of water by the kidneys when they hypothalamus detests that the blood water content is too low.
What did Banting and Best do?
They extracted insulin. Banting released that digestive juices in the pancreas destroyed the hormone when other scientists tried to extract it from a complete pancreas. So instead they decided to tie off the pancreatic duct in healthy dogs. This means the cells producing digestive juice withered away. The cells which were left, were removed, mashed up and the extract was injected into diabetic dogs. The dogs recovered.
What is homeostasis?
The way the body maintains a constant internal environment.
Where is the body temperature monitored and controlled?
The thermoregulatory centre.
What does sweating do?
Helps to cool the body.
Where is the thermoregulatory centre?
In the hypothalamus.
How is heat lost from the skin?
By evaporation and radiation.
