C 3.1integration of body systems

emergent property- cheetah

flexible spine : spring during running - increase stride length

longer hind limb : enable longer stride

cerebrum

biggest part in the brain , two halves - cerebrum hemispheres

→ advance mental activity

consist of of 5 idiffernet part

• corpus callosum ( band connect two cerebrum hemisphere)

• frontal(learning) , temporal( auditory) , parietal (sensory) and occuptal (visual) lobes

spinal cord responsible for

• unconscious processing

input of CNS

input

• Changes in the external or internal environment → detected by receptors, sensory neuron convey signal → CNS

swallowing of good, Egestion - CNS

role of cerebellum

• receive information from cerebrum, spinal cord, brainstem 

• cerebrum motor cortex receive movement

• movement begins, cerebellum receive feedback impluses from various area of body - sent out impluse to coordinate movement and time 

• walking, hand movement…

hypothamus and pituitary gland 

hypothamuls maintain homeostasis -. lining endocrine system to nervous system

respond to signal by inhibit/stimulate pituitary gland 

nuclei in hypothalamus - control release of hormones in pituitary gland

melatonin

circadian rhythm ( 24hr of physical, behavioural and mental) → set by SCN cells in hypothalamus → controls secretion of serotonin in pineal glands 

• light inhibit secretion, night secretion ^ , decreases by age 

→adjusted by exposure of light 

cell in retina detect light - send neural impluse to SCN - adjust timing of release of metatonin 

epinephrine

• flight or fight response

• Prepare body for vigorous, immediate response with intense muscle contractions.

• secreted by adrenal glands 

peristalsis control

wavelike contractions of smooth muscle → peristalsis

Swallowing and egestion are voluntary actions controlled under the CNS.

Peristalsis is an involuntary action controlled by the (ENS)

• ensure material through gut is coordinated 

• stretch receptors in gut - detect position + direction of movement of bolus 

• various excitatory& inhibitory neurotransmitter - released on longitudinal+circular muscle around bolus - coordinate contraction

trophic

the turning of all or part of an organism in a particular direction in response to an external stimulus.

ex. shoot grows towards light - positive phototrophism

root bend away from light - negative phototropism

Phytochromes

plant hormones that regulate physiological processes in plants.

phytochromes example

 auxin

• growth hormone

• produced in shoot apical meristem

• cell elongation for tropic movements + inhibit growth of lateral buds- vertical elongation

cytokinins

• promote cell division

• abundant in growing tissue 

• produced in root , pass to leaves and fruits 

• promote cell division, differentiation of meristem

auxin

• produced in tip of stem, promote cell elongation

• tropic movement in plants - auxin uneven distribution

• move away from light stimulus

sun on top 

• diffuse evenly - all cell grow at same rate

• shoot grow vertically upwards

sun on side

• auxin molecules move towards shaded side of shoot , away from light

• ^ concentration on auxin - rapid cell elongation + growth on that side

• uneven growth , cause stem bend towards light source

phototrophism

the turning of plant in one direction in response to external stimuli

phototrophism in auxin - auxin gradient

• Auxin is produced at the apex (tips) of the shoot.

• When light in the shoot is detected → trigger movements of auxins by active transport by auxin efflux pumps

• Efflux pump pumps auxin from cytoplasm→ cell wall, diffused to the next cell.

• enters the cell→ auxin is trapped inside the cytoplasm until the efflux pump pumps it out again.

• Auxin efflux pumps→ move in response to differences in light intensity→ creating a concentration gradient of auxin from lower on the lighted side and higher in the shaded side.

phototrophism in auxin - elongation of cell 

• Plant cells contain auxin receptor. Auxin binds→ transcription of the genes for proton pump 

• Expression of these genes → the secretion of hydrogen ions into the cell wall.

• hydrogen bonds between cellulose , weakened, loosens the cell wall.

• expansion of cell due the increase water uptake and higher turgor pressure.

auxin and cytokinin work together

• Auxin is produced in the shoot and cytokinin is produced in the root.

• Both areas are growing regions of the plant.

• Auxin is responsible for cell elongation, cytokinin is responsible for cell division.

• Both phytochromes needs to be transported to the opposing growth regions → regulate the growth of all parts of the plant and integrate both signals.

Cytokinin is transported through xylem up the plant and auxin is transported through phloem down the plant.

• Together, the phytohormones work on meristems to integrate cell growth

• The ratio of the two determines whether it results in:

  • Synergism - work together to stimulate a process 

  • Antagonism - have opposing effects to regulate a process 

fruit ripening - feedback control

• Positive feedback: the amplification of response to a stimulus

• Ethylene (Ethene) is produced in ripping fruits.

• Once the ripening process starts, fruit produces more ethene.

• one fruit started to produce ethen → cause surrounding fruit to ripen and produce even more ethene.

This helps fruits to become more attractive to herbivores→ increasing the seed dispersal rate