CO-ORDINATION + RESPONSE IN HUMANS Flashcards
how do organisms respond to change in the environment
- STIMULUS-internal or external change
- RECEPTORS-sense organs
- CO-ORDINATORS-brain
- EFFECTOR-muscle or gland
- RESPONSE-action taken
what does HOMEOSTASIS control
- TEMPERATURE-too hot (enzymes control things like respiration)
- WATER CONTENT- to much (blood is dilute) to little (blood is constentrated
1.STIMULUS-hight temperature
- RECEPTORS-skin
- CO-ORDINATORS-brain
- EFFECTORS-sweat gland
- RESPONSE-sweating
VASODILATION-hot weather
- muscle cells in the arterioles (small ateries) relax
- this causes dilation of blood vessels
* they get wider
* more blood flows through capillaries
* more heat can be lost by radiation
* red skin
VASOCONSTRICTION-cold weather
- muscle cells in the arterioles (small ateries) contract
- this causes constriction of blood vessels
* they get narrower
* less blood flows through capillaries
* less heat can be lost by radiation
* pale skin
sense organs
see touch taste hear smell
Hormonal system
- slow responses
- long-lasting
- GLANDULAR cells that makes hormones
- hormones transported in the blood
Nervous system
- fast response
- short-lasting
- Nerve cells involved
- electrical impules go along nerves
CENTRAL NERVOUS SYSTEM (CNS)
made of brain and spinal cord and is linked to sense organsby nerves.
3 types of NEURONES
SENSORY-take messages from receptors
RELAY-transfere messages from sensory neurons to other nerve cells
MOTOR-take messages from CNS to effectors (e.g muscles or glands)
- neurotransmitter diffuses across the synapase
- nerve impules travels along a neurone
- at the end of the neurone vesictes of neurotransmitter join the cell membrane
- neurotransmitter triggers an impules in the next neurone
2.
3.
1.
4.
role of the neurotransmitters at synapses
it makes sure that nerve impules can only travel in one direction along a nerve pathway
EYE distant objects
- Ciliary muscles relax
- suspensory ligament pulled tight
- lens pulled thin
EYE nearby objects
- ciliary muscles contact
- suspensory ligaments slackened
- lens allowed to bulge
in darkness
- pupil gets bigger (dilates)
- circular muscles in the iris relax
- radial muscles in the iris contract
- iris pulls open the pupil
in bright light
- pupil gets smaller (constricts)
- circular muscles in the iris contract
- radial muscles in the iris relax
- iris makes the pupil smaller
ADRENALINE
ADRENAL GLAND
makes heart beat faster
INSULIN
PANCREAS
causes liver and muscles take glucose and restores blood level to normal
TESTOSTERONE
TESTES
development of male sex organs
OESTROGEN
PROGESTRONE
OVARIES
development of sex organs, lining of uterus to get thick and sponge
maintains lining of uterus