Chapter 24 RegulationSec. 3-5
Question?
• Look around you.• What do you see?• What sounds can you hear?• Do you smell any odors?– Information about your environment is detected
1st by your sense organs.
The 5 Sense organs
1. Eyes2. Ears3. Skin4. Tongue5. Nose
How do sense organs work?
• Each sense organ has special cells called receptor cells that detect information.
• The receptor cells send nerve impulses to sensory neurons, which carry impulses to the brain.
• The brain interprets the impulse (Ex: taste or vision).
Vision• Eyes are very sensitive to light• How light travels through the eye?– Light Cornea Iris/Pupil Lens Retina (rods &
cones) Optic Nerve Brain
• Cornea = curved part of the eye• Iris = smooth muscle behind the cornea (color
part of the eye)• Pupil = controls the amount of light that enters
the eye• Lens = focuses the incoming light
Vision cont.• Retina = thin tissue @ the back of the eye
contains rods and cones• Rod = detect black and white colors• Cones = detect color
Hearing• Ear has 3 main parts:1.Auricle (ear flap) = outer ear2.Eardrum, incus, stapes, malleus = middle ear3.Cochlea, auditory nerve = inner ear
Have you ever felt dizzy after spinning around in a circle?
• Your ear also helps maintain balance.• Dizziness is a sensation produced by 3 looped
tubes (semicircular canals) in your inner ear.• These are fluid filled tubes that have hairlike
receptors.• Every time you move your head, the fluid
inside these tube move.• The hairlike receptors also move based on
orientation.
Touch• Your skin is the largest sense organ in your body.• Skin can detect touch, pressure, pain, heat, and
cold.• Touch receptors are found near the surface of
the skin• Pressure and pain receptors are found deep
within the skin.• Receptors on the skin are not evenly distributed
over your body.
Taste & Smell• The organs of taste and smell are stimulated by
chemicals.• Receptors for taste are located on taste buds
found on your tongue.• Taste buds can only detect 4 tastes: sweet, sour,
salty, and bitter.
Taste & Smell cont.
• The flavor of food is also detected by odor receptor of the nose.
• When your nose is blocked, your odor receptors don’t function as well.
• This is why food often taste bland when you have a cold.
• Odor receptors = olfactory cells respond to gas molecules
Why do people grow rapidly during adolescence? Have you ever heard of
someone having “superhuman” strength during an emergency?
• These responses result from the action of the endocrine system
The Endocrine System• This system is made up
of glands that secrete hormones into the bloodstream.
• Hormones are chemical messages that regulate many of your bodily functions.
Endocrine GlandsEndocrine Gland Hormone FunctionPituitary Growth hormone /
other hormonesControls growth; regulates other glands
Thyroid Thyroxine Regulates growth and metabolism
Parathyroid Parathyroid hormone Regulates calcium useAdrenals Cortisone
Adrenaline
Maintains salt/water balanceRegulates body response to stress
Pancreas Insulin Regulates blood-sugar levels
Ovaries Estrogen Female characteristicsTestes Testosterone Male characteristics
What regulates the endocrine glands?
• Most endocrine glands are regulated by a feedback mechanism.– Ex: Thermostat of an heater or AC unit
Behavior
• 2 main types of behavior:– Innate: unlearned that you are born with• Ex: coughing, swallowing, sneezing, blinking
– Learned behavior• Things that you practice and get better at over time.