Coordination And Response Flashcards
What is a stimulus
A change in an internal or external environment that brings about a response
What are is the CNS
Central nervous system, brain and spinal cord
What are synapses
The connection between two neurons, neurotransmitters diffuse across the gap between them.
What are reflexes
Automatic response to certain stimuli to avoid injury
Describe the reflex arc
Stimulus is detected by receptors which send impulses along a sensory neurone to the CNS. In the CNS, the sensory neurone passes along the message to a relay neurone, the relay neurone relays the impulse to a motor neurone, across a synapse, the impulse then travels to the effector (gland or muscle), which contracts or releases a hormone in response.
What is the conjunctiva
Lubricates and protects the surface of the eye
What is the sclera
Tough outer layer that protects the eye
What does the cornea do
Refracts light into the eye, it has no blood vessels so oxygen diffuses into it from the outer surface
What does the iris do
Controls the diameter of the pupil, and therefore how much light can enter the eye
What does the lens do
Focuses light onto the retina
What are rods and cones
Light receptors
Rods are more sensitive in dim light but can sense colour
Cones are found all over the retina and in the fovea, they detect colour but are not very receptive in dim light
How does the eye respond to bright light
Circular muscles contract, radial muscles relax , reducing pupil size and therefore reducing the light intensity
How does the light focus on distant objects
Ciliary muscles relax which pulls the suspensory ligaments tight, thinning the lens and decreasing refraction
What are hormones
Long lasting chemicals released into the blood and carried by blood plasma
what is the site, role, and effect of adrenaline
adrenal gland, readies body for fight or flight response, and causes and increased heart rate and blood flow to muscles
what is the site, role , and effect of insulin
pancreas, controls blood sugar level, and stimulates liver to turn glucose into glycogen
what is the role, site, and effect of testosterone
testes, male sex hormone, promotes male secondary sexual characteristics
what is the site, role and effect of progesterone
ovary, supports pregnancy, maintains uterus lining
what is the role of oestrogen
female sex hormone, controls menstrual cycle and promotes secondary sexual characteristics
what is the role of ADH
produced in pituitary gland, it increases permeability of kidney tubules to water
what is the role of FSH
causes egg to mature in ovary and stimulates ovary production
what is the role of LH
stimulates release of egg from ovary
what are the differences between hormones and nerves
nerves are faster, short effect and act on a specific area
what is homeostasis
the maintenance of a constant stable internal environment
