2.11 Coordination and response Flashcards
Adrenaline
a hormone produced by the adrenal glands in response to fear or stress
it increases heart rate and boosts the delivery of blood to the muscles, flight or fight response
Antidiuretic hormone (ADH)
a hormone produced by the pituitary gland that increases the reabsorption of water in the collecting duct of the kidney
auxins
plant hormones that control cell elongation and plant growth
Central nervous system
the brain and spinal cord which coordinates the response of effectors
Coordination centres
areas of the body like the brain, spinal cord and pancreas that receive and process information from the receptors
Effectors
muscles or glands which bring about responses
Eye
a sense organ containing photoreceptors in the retina sensitive to light intensities (rods) and colour (cones)
Follicle stimulating hormone (FSH)
a hormone produced by the pituitary gland that stimulates the growth of follicles in the ovary and stimulates the release of oestrogen
Geo/Gravitropism
a plants directional growth in response to gravity controlled by auxin
Homeostasis
maintenance of a stable environment in the body
Insulin
a hormone secreted by the pancreas when blood sugar glucose concentration is too high, reducing blood glucose concentrations by increasing the uptake of glucose from the blood into the liver
Luteinising hormone (LH)
a hormone secreted by the pituitary gland that stimulates ovulation and the release of progesterone
Nerves
cells that link the CNS to sense organs sensory neurones connecting receptors to the CNS
relay neurones connecting sensory neurones to motor neurones in the CNS
motor neurones which connect to effectors
Neurotransmitters
chemical that are released at synapses
Oestrogen
a female sex hormone released by the ovaries and stimulates the growth of the uterus lining whilst inhibiting the release of FSH
Phototropism
a plants directional growth in response to light
Progesterone
a hormone produced in the ovaries, specifically by the corpus luteum and the placenta that maintains the uterus lining and inhibits the release of FSH and LH
Receptors
cells that detect a stimulus
Reflex arc
a rapid and automatic response to a stimulus
pathway of neurones:
stimulus–>receptor–>sensory neurone–>relay neurone–>motor neurone–>effector–>response
Stimulus
a change in an organisms internal or external environment that can be detected by receptors
Sweating
a secretion of sweat onto the surface of the skin by sweat glands
the evaporation of the water in sweat removes heat energy from the skin, cooling the body down by removing that heat
Synapses
a junction between two nerve cells where neurotransmitters are released to diffuse across
Target hormone
the organ which a hormone acts upon to produce an effect
Testosterone
the main male reproductive hormone, produced by the testes, stimulating sperm production and secondary sexual characteristics
Vasocontriction
constriction of blood vessels near the surface of the skin
less blood flows to the skin surface
less heat loss
less radiation/convection
Vasodilation
the dilation of blood vessels near the surface of the skin
more blood flows to the skin surface
increasing heat loss
more radiation/convection
Exam question: Describe the structure and functioning of the withdrawal reflex of a finger from a hot object. 4/5 marks
receptors in skin surface detect stimulus
send an impulse
sensory neurone to relay neurone
via diffusion of neurotransmitters
at the synapse
motor neurone to muscle
muscle contracts
What happens in the sweat glands when entering a cold environment?
less sweat released
less sweat evaporates/less heat loss
Exam question structure: Explain how this evolutionary change was brought about by natural selection.
variation in …
caused by mutation
(state a point about the change e.eg. less hair increases heat loss)
survive and reproduce
pass on gene to offspring
