Biology 1

Control and coordination

Stimulus     →

Receptor    →

Co-ordinator →

Effector     

Change in environment detected by receptors in sense organs

Groups of cells, sensitive to stimulus

Information from sense organs is sent.

Muscles and glands respond according to information

·       Receptors

o   Eyes - Light

o   Ears - Sound and balance

o   Nose and Tongue - Smell and taste

o   Skin - Touch pressure and temperature

·       Types of nerve cells (Neurones)

o   Sensory - Carry signals to CNS

o   Motor - Carry signals away from CNS, controls response

o   Relay - connect other neutrons together

·       CNS - Brain and Spinal cord

·       Reflex actions - Automatic and rapid response to stimuli, protects from harm

Hormones

·       Chemical messengers which travel in the blood to coordinate many processes

·       Slow message

·       Affect rate of metabolism, growth and sexual development

Menstrual cycle:

Hormone: FSH

Made by: Pituitary gland

What it does: Causes egg to mature, stimulates ovaries to produce oestrogen.

Hormone: Oestrogen

Made by: Ovaries

What it does: Stops FSH so no more eggs, causes lining to thicken to receive egg

Hormone: LH

Made by: Pituitary gland

What it does: Stimulates the mature egg to be released

·       Contraceptive pill - contains oestrogen, so no eggs mature.

·       Fertility drugs - contains FSH, stimulates eggs to be made.

Healthy eating

·       7 food groups

o   Carbohydrates -  energy

o   Fats - warmth

o   Proteins - growth and repair

o   Fibre - digestion

o   Vitamins and Minerals - healthy bones, skins and blood

o   Water - hydration

·       Unbalanced diet = malnourished

o   Become too thin or too fat suffer deficiency diseases

o   Deficiency diseases - lack of specific nutrients

o   Obesity leads to :

-  Arthritis

-  High blood pressure

-  Diabetes

-  Heart disease

·       Metabolic Rate - rate of chemical reactions in body

o   Varies because of : Age, gender, genetic traits etc.

o   Metabolic rate increases whilst exercising

·       Cholesterol

o   Too much = Clogs blood vessels

- Leads to heart disease

- Increase blood pressure

o   Liver controls the amount

- Makes new cholesterol

- Removes it from blood

o   Low-density lipoproteins (LDLs)

- Bad cholesterol

- Causes disease

o   High- density lipoproteins (HDLs)

- Good cholesterol

o   Saturated fats - from animals

- Rises cholesterol in blood

- Increases liver making

o   Polyunsatured and Monounsaturated Fats - from plants

- Decreases cholesterol in blood

- Increase removal from body

- Improves LDL and HDL balance

·       Salt

o   Too much = increase risk of heart disease

o   Cause high blood pressure

o   Processed foods have lots of salt and fat

Drugs, Alcohol and Tobacco

·       Tolerance - body gets used to drug, increase intake

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