Fundamentals of Anatomy and Physiology

262 Chapter 11

health Alert

Caffeine Alert

Caffeine is found in coffee, tea, Coca-Cola,

Pepsi, and other soda drinks as well as in

small amounts in chocolate. It is one of our

“staple” and legal drugs enjoyed by millions

around the world. Caffeine functions in the

same way as the sympathetic division of the

autonomic nervous system. That is, it stimu-

lates physiological activity, causing increased

heartbeat rates. We view this as giving us a

jump start in the morning or keeping us alert

during busy work hours. Moderate amounts of

caffeine pose no serious threats to our health.

However, excessive con-sumption can lead to

high blood pressure,

anxiety, irregular heartbeat rate, and diffi-culty

falling asleep.

Caffeine levels of tolerance vary from

individual to individual. We should moni-tor

ourselves and determine how much caf-feine

is safe and what amounts can lead to

problematic symptoms. A moderate amount of

caffeine is equivalent to about two cups of

coffee or cola per day. Since studies with

animals have shown a link to birth de-fects

and caffeine consumption, pregnant women

should avoid or moderately reduce their

caffeine consumption throughout pregnancy.

Bipolar nerve fibers

within the olfactory bulb

Olfactory bulb

Olfactory tract^ Cribriform plate^

Columnar

Olfactory area epithelial cells of nasal cavity

Superior nasal

concha

Olfactory

®^

receptor cells

Lear n i ng^

Nasal cavity (^)
Ceng age^
Cilia (^)
(^)
(A)
2016

(B)

©^

Figure 11- 8 (A) The olfactory area in the nose formed by the superior nasal conchae. (B) Columnar
epithelial cells support olfactory- receptor cells with cilia at their ends.

(^) ®
Learning
Cengage
2016 ©
neurons transmit the impulse along their axons whose ends
become enlarged olfactory bulbs. From here, they connect
with association neurons to the area of the brain called the
olfactory cortex found in the temporal and frontal lobes of

The Pharynx.

The receptor cells are neurons that have cilia at the dis-

tal ends of their dendrites (see Figure 11-8B). It is these

cilia that function as chemoreceptors to detect odors. These

molecules first become dissolved in the mucous mem-brane

that lines the olfactory shelf in the nose and then are