|
PARTS OF BRAIN
|
SUB DIVISIONS
|
THEIR FUNCTION
|
|
Fore brain
|
(i)cerebrum
(ii) lobes (iii) three areas a) sensory area b) motor area c) association area |
main thinking and largest part of the brain
(a) sensory area: receive impulses from the sense organs via receptors (b) motor area: send impulses to various organs or muscles and control voluntary movements (c)association area: Register impressions and respond by interpreting past experiences (iii)each cerebral hemisphere is divided into a)occipital lobe visual reception b)temporal lobe auditory reception c)parietal lobe: touch, smell, temperature, and conscious association d)frontal lobe: muscular activities |
|
Mid brain
|
connects forebrain and hind brain. controls reflex involving eyes and ears
|
|
|
hind brain
|
(i) cerebellum
(ii) Pons (iii) Medulla oblongata |
(i)cerebellum: controls and coordinates muscular movements, maintaining body posture and equilibrium
(ii) pons: acts as a bridge. relays information between cerebrum and cerebellum (iii) medulla :controls involuntary actions |
|
TROPISM
|
IN RESPONSE TO
|
THE FUNCTION
|
POSITIVE RESPONSE
|
NEGATIVE RESPONSE
|
|
phototropism
|
light
|
Ensures plant gets as much as light as possible. stem tip grows in the direction of light.
|
growth towards light i.e growth of stem
|
growth away from light i.e is roots
|
|
geotropism
|
gravity
|
Response of organism to gravity.
|
growth towards gravitational pull i.e growth of roots
|
growth away from the gravitational pull i.e growth of shoots
|
|
chemotropism
|
chemicals
|
response to chemicals e.g pollen tube grows towards a chemical produced by the ovule during fertilisation
|
pollen tubes growth towards ovule
|
stem shows negative chemotropism
|
|
hydrotropism
|
moisture
|
growth of roots towards damper areas of soil towards water in soil
|
growth towards water i.e roots
|
growth away from moisture i.e stem
|
|
thigmotropism
|
touch
|
response to touch or solid surface
|
response towards touch i.e tendrils and other climbing part's growth
|
response away from touch i.e growth of roots underneath the soil. when rock hit is it grows away from the rock
|
|
PLANT HORMONES
|
FUNCTION
|
SITE
|
IT'S OPPOSITE
|
|
Auxin
|
-promotes cell elongation in shoots
|
produced in shoots
|
cytokinin
|
|
cytokinin
|
-promotes cell division
|
mainly present in seeds and fruits
|
auxin
|
|
gibberellins
|
-help in growth of vegetative (like stem...) growth
|
present in young leaves etc
|
abscisic acid
|
|
abscisic acid
|
-inhibits growth and induces witling of leaves
|
thought out the plant
|
gibberellins
|
|
ethylene
|
-helps in ripening of fruits
|
throughtout the plant
|
|
|
GLAND
|
SECRETION
|
HORMONE FUNCTION
|
|
Pituitary gland
|
growth hormone
|
regulates growth
|
|
Hypothalamus
|
releasing hormone
|
regulates the secretion of hormones by pituitary gland
|
|
Thyroid
|
thyroxine
|
regulates metabolism for body growth {controls metabolic rates of carbohydrates, fats and proteins )
|
|
Adrenal
|
adrenaline
|
increase heart beat rate, blood pressure
|
|
Pancreas
|
(i) insulin
(ii) glucagon |
(i)decrease blood glucose{{n}} (ii) increase blood sugar level
|
|
Ovary
|
(i)estrogen
(ii) progesterone |
development of female sex organs , regulates menstrual cycle etc
|
|
Testis
|
testosterone
|
regulates the male secondary sexual characteristics
|
|
Thymus
|
thymosin
|
produces immunity
|
|
Parathyroid
|
(i)calcitonin
(II) parathormone |
(i)lowers blood calcium level
(ii) increases blood calcium level and decreases blood phosphate level |
|
Pineal
|
melatonin
|
stimulates muscle contraction
|
No comments yet.
Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
