Chapter 24 Regulation Sec. 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 1 st by your sense organs.

The 5 Sense organs 1.Eyes 2.Ears 3.Skin 4.Tongue 5.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 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 ear 2.Eardrum, incus, stapes, malleus = middle ear 3.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 Glands Endocrine GlandHormoneFunction PituitaryGrowth hormone / other hormones Controls growth; regulates other glands ThyroidThyroxineRegulates growth and metabolism ParathyroidParathyroid hormoneRegulates calcium use AdrenalsCortisone Adrenaline Maintains salt/water balance Regulates body response to stress PancreasInsulinRegulates blood-sugar levels OvariesEstrogenFemale characteristics TestesTestosteroneMale 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.