According to a report issued in May 1998, elderly people who have consistently high blood levels of cortisol dont score as well on memory tests as their peers with lower levels of the stress hormone. Whats more, high levels of cortisol are also associated with shrinking of the hippocampus, a region of the brain that plays a key role in learning and memory.
The finding suggest that even cortisol levels in the normal, healthy range can actually accelerate brain aging.
The study results now pride substantial evidence that long-term exposure to adrenal stress hormones may promote hippocampal aging in normal elderly humans, write Nada Porter and Philip Landfield of the University of Kentucky in Lexington in their editorial. Cortisol is a hormone released in response to stress by the adrenal glands, which sit on top of the kidneys.
Over a 5 to 6-year period, Dr. Sonia Lupien and his colleagues measured 24-hour cortisol levels in 51 healthy volunteers, most of whom were in their 70s.
Despite wide variation in cortisol levels, the participants could be divided into three subgroups: those whose cortisol progressively increased over time and was currently high; those whose cortisol progressively increased over time and was currently moderate; and subjects whose cortisol decreased, but was currently moderate.
The researchers tested the volunteers memory on six people in the increasing/high category and five people in the decreasing/moderate group. The groups did not differ on tests of immediate memory, but the increasing/high cortisol group had other memory problems compared with those in the decreasing/moderate group.
The researchers also found that the total volume of the hippocampus in those in the increasing/high group was 14% lower than those in the decreasing/moderate group, although there were no differences in other brain regions.
The results suggest that brain again can be accelerated by levels of adrenal hormones that are not generally regarded as pathological and that variation within this normal range is related to variation in the rate of brain aging, write Porter and Landfield. This further suggests that chronic stress may accelerate the worsening of hippocampus.
1. The part of the brain important for a persons learning and memory is
A) the cortisol.
B) the adrenal glands.
C) the stress hormones.
D) the hippocampus.
2. When the levels of cortisol go higher, the hippocampus in the brain may
A) become larger.
B) become smaller.
C) be missing.
D) be totally damaged.
3. According to the article, when people feel too worried or nervous or when they overwork,
A) the adrenal glands will produce a stress hormone.
B) the kidneys will produce adrenal glands.
C) the hippocampus will produce high level of cortisol in the blood.
D) the cortisol will produce something that makes a poorer memory.
4. When the total volume of the hippocampus becomes smaller, other brain regions
A) become smaller too.
B) Become larger.
C) may remain the same in size.
D) may be damaged.
5. Porter and Landfields research shows that
A) the change in the levels if adrenal hormones has nothing to do with the degree of brain aging.
B) the change in the levels of adrenal hormones has a lot to do with the degree of brain aging.
C) the long-term stress will gradually make the hippocampus worse.
D) None of the above is correct.
答案 DBACB
8月全球股市下跌是人为抛售决定所致
看脸的世界:颜值高的人讲笑话“笑”果更好
南京街头现“诚实书店”:无人收款、无人看管
杭州拟取消出租车“经营权使用金”
嘉能可计划削减100亿美元债务
中国内地与香港金融市场互通将放缓
藏在咖啡杯盖中的侦查神器
北京纪委开发“电子眼”监视违规上网
习奥会聚焦“双边投资协定”
2016中考英语名词十一大类不规则变化归纳总结
教师节将至:英语中与教师有关的9句至理名言
英国单身男士心目中的女神:褐发、蓝眼、纹身
上海出台措施保障“迪士尼蓝”
文身师为家暴受害者文身遮疤
宇通或开启客车无人驾驶时代
邓布利多当选最佳模范教师
旧金山小学改建无性别厕所
911事件14周年,93航班纪念园游客中心开放
Facebook将推“dislike”按钮
"How"的5种典型问句,可别再说"How to say"了
最强历史顾问:唐顿粉英国女王爱给剧挑BUG
芬兰一城市为新生发应急礼盒
九成老板用Facebook筛应聘者
有些英语,你不能不懂装懂
2015苹果秋季发布会:都有哪些新品神器
每天吃鲑鱼 像戒烟一样有益
习大大引用“靡不有初,鲜克有终”全文英译
饭前拍照党请注意!德国菜肴摆拍算犯法
中国应如何与市场对话
苹果“产品线”大幅更新
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |