The senses

Life Science 2010

鄭鄭鄭 (Ayo) 製作

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Fig. 23.1 These appear to us as yellow flowers. 但若是感應不同，所呈現出的顏色就會有所不同。

The senses

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Thermoreceptors Fig. 23.2 Heat

sensors, such as the rattlesnake. Pit vipers detect their prey through a pair of heat sensing device located in the depressions near the eyes.

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Free nerve endings

Fig. 23.3 Specialized receptors in the skin of humans. Meisner's corpuscles are located close to the surface and register light touch.

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Fig. 23.4 Jumping spiders are extremely sensitive to touch. They have a tremendous number of sensory hairs that cover their bodies.

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Fig. 23.5 human auditory receptors.

內耳

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Fig. 23.5 human auditory receptors. 歐氏管

耳蝸

半規管

搥骨

蹬骨覘骨

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Fig. 23.5 human auditory receptors.

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Fig. 23.6 Many rock musicians and some members of their audience have permanently impaired hearing due to the loss of hair cells brought on by loud music.

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Chemoreceptors

Fig. 23.7 The oversized antennae of the atlas moth. The receptors in the antennae are extremely sensitive to a chemical attractant released by females.

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Essay 23.1 That wonderful you

人體的 armpit 有許多的汗腺， produce the scent that so distinctly you.

Underarm secretions are largely steroids, the chemical group that includes the sex hormones estrogen and testosterone.

Other sweat gland of the body also secrete an oily mixture that mark us individually.

The sense aggregations of sweat glands on the soles of the feet may release half a fluid ounce of sweat per day.

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Fig. 23.8 The olfactory receptors in the human nose.

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Fig. 23.9 Taste buds on the tongue respond most strongly to one of four flavors, bitter, sour, salty, and sweet.

The senses 14Fig. 23.10 品酒

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Essay 23.2 Fooling mother nature's sweet tooth

In West Africa people can eat lemons just as people here eat oranges.

Do they like the sour taste?

How can they stand it?

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Turn sour to sweet miracle It turns out that there is no sour taste. This is because, before they ate the lemo

n, they chewed a few miracle fruits, small red berries, about the size of olives, from the plant Synsephalum dulcificum.

They can eat all sorts of local sour foods because chewing the miracle fruit first make anything sour seem sweet for up to three hours afterward.

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Glycoprotein do The active ingredient is a glycoprotein. The protein can attach to a site close to

where sweet receptors are located. The acidity of the sour food then alters

the glycoprotein so that its sugar components are released.

These then bind to sweet receptor sites, stimulating them, and masking the sour taste.

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Proprioceptors

Proprioceptors sense the position of the body or of various parts of the body.

Vertebrates have very precise equilibrium proprioceptros located in the inner ear.

In most species, there are three fluid-filled loops, or semicircular canals ( 三半規管 ) (Fig. 23.5 和 23.11).

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Fig. 23.11 Semicircular canals. The saccule and utricle are fluid-filled cavities in which grains are embedded in a jellylike matrix.

球囊橢圓囊

耳蝸

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Fig. 23.12 (a) The structure of the human eye

睫狀體

Iris 虹膜 Lens 水晶體Cornea 角膜

視網膜脈絡膜鞏膜

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Fig. 23.12 (b) the rods ( 桿細胞 ) and cones ( 錐細胞 ) of the retina.

Rod cell

Cone cell

Rods, specialized for black and white vision ; cones, specialized for color

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