3. organisms P3

system integration

when components communicate and coordinate

tissue

group of 2 or more different cell types which are working together for a common purpose

EG: type 1 and 2 pneumocytes in alveolar tissue

organ

group of two or more tissue types working together

EG spongy mesophyll tissue and palisade mesophyll tissue

organ system

group of organs which work together to perform a function of life

organism

a living thing made up of multiple integrated and interdependent systems at various levels of organisations.

integration requires…

coordination

1. communication

   a. hormones

   b. nervous

2. transport materials

hormones

chemicals produced by the endocrine glands

• travel through the bloodstream to the whole body

• affects any cell with the proper receptor (target cell)

• affects last a long time

• take longer to take affect

the brain general function

for processing information and providing a response

process of brain receiving information.

1. brain receives information from sensory organs

2. brain stores the information for when it is required again

process of brain processing information.

if the brain determined that a reaction is needed, it may send signals to effector organs

effector organs

muscles and glands

central nervous system

brain and spinal cord

white matter

transmission centre

• either receiving transmissions from sensory receptors or it will be transmitting them to the brain

• contains many nerve fibres

• myelinated

gray matter

more for processing

• some functions need to happen rapidly and there is not enough time for the information to be transported to the brain

• contains cell bodies and synapses of some neurons

• decision making of unconscious processed only.

sensory receptors

gather information and sends it to a sensory neuron

sensory neuron

sends to the brain or spinal cord

types of receptors

• touch

• light

• heat

• stretch

• chemoreceptors

motor cortex

section of the brain which contains the origin of our motor neuron (cell body).

these cell bodies are located in the motor cortex but their axons and terminals stretch to different regions.

nerve

a bundle of nerve fibres surrounded by a sheath

contains both sensory and motor neurons which each can signal one way.

reflex arc

an involuntary and rapid response to certain stimulus

reflex arc example

1. stimulus (dust in eye)

2. receptor (eye)

3. sensory neuron

4. interneuron

5. motor neuron

6. effector neurons

inter neuron

CNS in between the sensory and motor neuron.

cerebellum

coordination centre (timing of muscle contractions)

balance, posture

circadian rhythm

pattern of sleep/wake cycles that organisms are adapted form

melatonin

hormone secreted by the pineal glands that control the circadian rhythm

why is melatonin inhibited by light?

when the light receptor senses light, it sends a message to the CNS inhibiting melatonin production

epinephrine

secreted by the adrenal glands

fight or flight hormones

goal of epinephrine

increase glucose and oxygen supply to skeletal muscles

how does epinephrine achieve this?

• hydrolysis of glycogen to become glucose

• increased diameter of bronchioles

• SA node increases heart rate

• Ventilation rate and tidal volume increases

• vasodilation of liver and muscles

• vasoconstriction of gut and kidney

hypothalamus

attached to the pituitary gland and connects the nervous system to the endocrine.

• it received input from other parts of the brain and sensors for temp, blood glucose.

• input is from nerves output is a hormone

SA node and medulla

the SA node is connected to the medulla oblongata by the vagus and sympathetic nerves

both nerves travel from the brain to the SA node

vagus nerve

causes the SA node to slow down the heart rate

sympathetic nerve

causes an increase in the heart rate

how is the SA node in feedback loops

with the chemoreceptors which:

sense ph (low=high CO2)

increases heartrate for reoxgenation

chemoreceptors

from the medulla to the corotid artery

baroreceptors

sense blood pressure in the aorta

increase heart rate when blood pressure is low.

normal Ph of blood

7.3-7.4

what happens to blood ph when exercises and why

• when exercises there is an increase in respiration

• CO2 is a product of cell respiration so it increases in concetration

• therefore ph decreases

what happens when blood ph drops

causes nerve signals to be passed to our muscles (intercostals) to cause ventilation rate to increase

how is blood ph regulation a negative feedback loop

as soon as blood ph returns to normal, the ventilation becomes normal.

peristalsis

smooth muscle contractions which move food through the digestive tract

voluntary part of the digestive system

• initiation of swallowing

• defection (later)

involuntary part of the digestive system

moving food through teh digestive tract

what controls the voluntary part of the digestive system

the CNS

what controls the involuntary part of the digestive system

the enteric nervous system

tropism

growth response to stimuli

positive tropism

growing towards the stimuli

negative tropism

growing away from stimuli

plant growing and tropism

the part of the plant furthest from the light grows at a faster rate so that it curves

phytohormone

plant hormone which can control growth, development and response to stimuli

phytohormone—growth

• promote or inhibit cell division or elongation

• EG. gibberellin causes stem elongation

phytohormone—development

• promote or inhibit differentiation of plant tissues

• EG. ethylene ripens fruit

phytohormone—response to stimuli

controls tropism

EG auxin controls phototropism

auxin

produced in roots and transported to the shoots

how does auxin work

cells must coordinate to get high concentrations in the area where it needs to be

auxin efflux carriers

transmembrane proteins which pump auxin into cells

• are able to move around the membrane.

coordination for auxin

nearby cells need to coordinate to move the auxin efflux carriers to where ever is necassary.

how does auxin actually promote growth

it promotes protein pump synthesis

pumps protons into the apoplast

this lowers ph and low ph results in acidification which in turn weakens the cell wall and allows elongation.

apoplast

outside cell wall

cytokinen

another phytochrome produced in roots and transported to shoots

auxin and cytokinen

sometimes they work together to achieve grown at the same time

sometimes they work antagonistically

ensure that the root and shoot growth are integrated.

why does fruit ripen

to ensure seed dispersal, so that parents don’t compete with the offspring

effect of ripening fruit

colour change, softening, scent

ethylene

a phytochrome that works in positive feedback lop to ripen fruit

is a gas so it also effects nearby fruit.