The Incredible Human Body

Intro and nervous system

Get out your notebooks

Levels of Organization

Cells—basic unit of life Tissues

› Connective› Muscle› Nervous› Epithelial

Body Characteristics

Vertebrate Bilateral symmetry

Homeostasis—ability to maintain stable internal conditions

Control—Nervous and Endocrine Systems

Positive feedback: the body produces whatever is needed to keep it in balance (ex-childbirth)

Negative feedback: (most common) body senses an internal change and activates mechanisms that reverse, or negate, that change. (ex: sweating, blood pressure)

Why?? Stress is caused by an internal or

external stimulus that creates an imbalance and affects the body

TH

E N

ER

VO

US S

YSTEM

Control Center

The Nervous System Works with other organ

systems to respond to the environment

Made of specialized cells called neurons

Two parts:› CNS—central nervous system› PNS—peripheral nervous

system

The Neuron

What makes a nerve fire??

Impulse comes from either nerve or environment An impulse always travels in the same direction,

from axon to dendrite.

The Synapse

NER

VE IM

PU

LSE

Central Nervous System

Parts Function

Brain

Cerebrum: conscious action, thinking,

intelligence, learning

Cerebellum: balance & movement

Brain stem: breathing, heart rate, swallowing

Process informationRelay messages

Analyze information100 billion neurons

Weighs 1.4 kgs

...all of your "thinking" is done by electricity

and chemicals

SpinalCord

Nerve Cord:Made up of bundles of nerves

Meninges:Membrane covering that bundles

nerves

Relays message to and from your brain.

Brain Parts

Pons

Medulla Oblongata

Hypothalamus

Pituitary Gland

Pineal Gland

Thalamus

Spinal Cord

Protective Structures Skull Meninges (3)- pia

mater, arachnoid layer, dura mater

Cerebrospinal fluid

http://serendip.brynmawr.edu/bb/kinser/Size1.html

The Peripheral Nervous System

Sensory Neurons- detects impulse and transmits to spinal cord, interneurons

Motor Neuron- sends impulse to body parts, causes movement.

Interneuron- connects sensory neuron and motor neuron

Peripheral Nervous System Everything outside of

the CNS

Somatic Nervous System:› Conscious control,

VOLUNTARY› Reflexes, walking, talking

Autonomic Nervous System:› INVOLUNTARY› Heart rate, breathing

1. Sensory neuron detects painful stimulus

2. Sensory neuron carries impulse to spinal cord.

3. An inter-neuron in spinal cord passes message to motor neuron.

4. A motor neuron carries impulse to muscle cell.

5. Muscle contracts.

The Incredible Human Senses

Hearing

Touch

TasteSmell

Sight

Sensory Receptors

Sensitive to light and colors

Eyes

Sensitive to chemicals in the air and food

Nose and taste buds

Sensitive to touch, pressure, muscle stretching, sound, motions

Skin, skeletal muscles & inner ear

FunctionLocation

sType

Detect variations in temperature

Skin, body core and hypothalamus

Everywhere except the brain

Signal danger, injury or diseaseEx: itching

Iris:Colored part of the eye

Pupil: opening

Cornea: clear cover

Lens: focus objects

Muscle: move eye

Vitreous Humor: jellylike substance

Fovea: sharpest vision

Optic Nerve: impulses go to brain

Blood Vessels

Choroid: middle layer

Sclera: white part of eye

Retina: contains rods and cones

Ligaments: connects lens to muscles

SIGHT

Aqueous humor

Rods-detect light

Cones- detect color

Imagine the Hermann Grid as a map of city streets; most intersections appear to be grey, but when you look closely at any individual intersection, you will see that it is white. The streets, on the other hand, appear white no matter where you look.

Optical Illusions Hermann Grid

Optical Illusions Complemtary colors

Stare at the center of the flag for at least 20 second - even longer to enhance the effect - and then look at the white area such as a

light colored wall, or a white piece of paper.

The Ebbinghaus illusion is an optical illusion of relative size perception. In the best-known version of the illusion, two circles of identical size are placed near to each other and one is surrounded by large circles while the other is surrounded by small circles; the first central circle then appears smaller than the second central circle

One type of motion illusion is a type of optical illusion in which a static image appears to be moving due to the cognitive effects of interacting color contrasts and shape position. To properly view this effect, click the image above to see the full sized version.

Instructions: Close your left eye and fixate your right eye on the cross in the first diagram. If your eye is about 12 inches (30 cm) away from the monitor, you should notice that the round dot disappears. This distance may vary according to the screen resolution you have set.

You may be surprised to see that the dot is replaced, not by a black region, but rather blank white space. The brain simply "fills in" the most probable stimulus (in this case, a uniform white area) where there is none. The following examples demonstrate the "filling-in" phenomenon in greater detail. Apply the same instructions as given above and you should notice the red markings each time are replaced by the most probable pattern that your brain is able to perceive. 

How many F’s are there?In the text opposite there are 10 F's! Most people underestimate the number of F's because they fail to notice them in the word 'of'. Function words like 'of' are unconsciously processed by our brain because they aren't important.

HearingCochlea: filled with hairs that vibrate

Semicircular canals: help with balance, equilibrium

Tympanic membrane: ear drum

StirrupHammer

Oval

windowAnvil

Auditory canal

Cochlear nerve

Estachian tubesRound window

Bone

Noises over 90 db can cause hearing loss over extended periods of time.

iPods with ear buds can produce levels of 110-120 db, like a rock concert.

It is recommended that you listen to volume no higher than 6 for no more that 1 hours a day.

Tinnitus (ringing in the ears)

Smell and Taste

Scent particles are chemicals detected by your nose

Scents are closely related to memories Taste buds are the receptors found in

your mouth

Touch Sense of touch is

not limited to one part of the body

Skin is our largest sense organ

Greatest amount of sense receptors are found in our fingers, toes, and face