biology year 9

cells

building blocks of life

unicellular organisms

single celled organisms

multicellular organisms

multiple celled organisms

organelle

subcellular structure thats helps things in a cell happen

tissue

group of cells

organs

a group of tissues, a part of an organ that has a specific function

systems

a group of organs that work together in an organism

nervous system

coordinated and controls functions relating to the internal and external stimuli

impulses

messages carried through the nervous system

3 types of nuerons

sensory, motor, interneuron

sensory

carry impulses from sense organs to spinal chord/brain

motor

carry impulses from brain/spinal chord to muscles and glands

internuerons

connect sensory and motor neurons and carry impulses between them

the brain

soft and heavy organ made up of nuerons

3 main structures of the brain

cerebellum, cerebrum, brain stem

cerebellum

responsible for movement, balance, and coordination

cerebum

largest part of the brain, divided into 2 hemispheres

brain stem

lower part of the brain, becomes a spinal chord at the brain

spinal chord

main communications link between the brain and the rest of the body

reflexes

quick, automated response to a stimulus

endocrine system

made up of glands and responsible for the transportation of hormones

pituitary gland

master gland, located in the brain, sends out growth hormones

thyroid gland

located in the throat, makes thyroxin, helps manage metabolism

thymus gland

located near the chest, produces T cells

adrenal gland

located above the kidney, creates adrenaline (flight or fight)

pancreas

creates insulin to help balance blood sugar

ovaries

female sex hormone, responsible for menstruation

testes

male sex hormone, produce testosterone

homeostasis

regulation and maintainence of internal environment, involuntary, controlled by hypothalamus

homeostasis involves……

blood sugar levels, water levels, temperature levels

feed back loops;

compares current condition to set ranges

positive feedback loops

increase change by working opposite direction to cells

negative feedback loops

stops the change by working in the same way as the change