Biology

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The biology of the ear

Líffræði eyrans


Hvernig heyrum við?

Eyranu er skipt í þrjá megin hluta sem kallast ytra-, mið- og innra eyra.


Ytra eyrað

Ytra eyrað er bæði sýnilegi hluti eyrans, þ.e.a.s. eyrnablaðkan og hlustarinngangurinn og síðan hlustin sem nær inn að hljóðhimnunni. Ytra eyrað fangar hljóðið líkt og trekt og safnar því saman í hlustina en um hana berst hljóðið áfram að hljóðhimnunni. Hlustin næst eyrnablöðkunni er þakin fínum hárum og eyrnamerg sem verndar hana fyrir óhreinindum, en mergurinn ver einnig eyrað fyrir bakteríum.

Miðeyrað

Miðeyrað er loftfyllt holrúm sem afmarkast annars vegar af hljóðhimnu og hins vegar innra eyranu dýpra inni í höfði. Hljóðhimnan telst vera hluti miðeyrans. Hún er sporöskjulaga og myndar eins konar trekt sem er tæplega 8 mm í þvermál. Í holrúmi miðeyrans eru þrjú minnstu bein líkamans örsmá en með stórt hlutverk, en þau nefnast hamar, steðji og ístað. Beinin þrjú mynda keðju þar sem hamarinn tengist hljóðhimnunni í botni trektarinnar. Beinakeðjan hefur síðan það hlutverk að endurvarpa með vægri mögnun hljóðbylgjum frá hljóðhimnu og til innra eyrans frá hamri yfir í steðja og steðja yfir í ístað. Ístaðið stingur sér inn í glugga/himnu innra eyrans og kemur þar af stað bylgjuhreyfingum. Það er í holrúmi miðeyrans sem eyrnasýkingar verða.

Frá miðeyranu liggur kokhlustin niður í nefkok. Að jafnaði er kokhlustin lokuð en hlutverk hennar er að jafna þrýstinginn í miðeyranu. Það gerist við það að kokhlustin opnast t.d. þegar við geispum, kyngjum eða tyggjum.

Innra eyrað

Innra eyrað er vökvafyllt og samanstendur af boggangakerfi annarsvegar en kuðungslöguðu líffæri hinsvegar, sem nefnist kuðungur. Í kuðungnum eru þúsundir hárfruma sem framkalla boðspennu eftir því sem þær sveigjast í bylgjuhreyfingu vökvans. Boðspennan berst síðan eftir heyrnartauginni til heilans sem upplifir tal og tóna. Sérhver hárfruma framkallar boðspennu fyrir tiltekna tíðni hljóðs.


The biology of the ear

How do we hear?
The ear is divided into three main parts that are called the outer-, middle- and inner ear.

The outer ear
The outer ear is both the visible part of the ear, that is the pinna or the auricle, and the ear canal that connects to the sound membrane. The outer ear captures sound like a funnel and gathers it all together into the ear canal and carries the sound to the membrane. The ear canal that is located near the pinna is covered with fine hairs and earwax that protects her from dirt, but the earwax also protects the ear from bacteria.

The middle ear
The middle ear is an air-filled void that is limited to the sound membrane and the inner ear deeper in the head. The sound membrane is a part of the middle ear. The membrane is oval shaped and forms a kind of a funnel that is roughly 8 mm wide. In the void of the middle ear are three of the smallest bones in the body that are very important. They are called the hammer, the anvil and the stirrup. Those three bones form a sort of chain where the hammer connects to the membrane in the bottom of the funnel. The chain´s role is to reflect minor sound waves from the membrane to the inner ear from the hammer to the anvil and from the anvil to the stirrups. The stirrups places itself into the membrane of the inner ear and starts a sort of wave motions. That is in the void of the middle ear where ear infections happen.

The inner ear
The inner ear is filled with fluids and consists of bow-like tunnelsystem and of a conch-shaped organ. In that organ are thousands of haircells that produce signals when they are moved around in the wavy fluid. Those signals are then transported through the hearingnerve to the brain and senses talking and music. Each indivitual haircell produces a sertain signal for each individual sound frequency.



Why I chose this paragraph

I chose this paragraph to translate because I wanted to learn more about the ear. I used an online dictionary to help me translate sertain words that I didn´t understand.

The biology of the eye

The basic biology of the eye


The outer covering of the eyeball consists of a relatively tough, white layer called the sclera (or white of the eye). Near the front of the eye, in the area protected by the eyelids, the sclera is covered by a thin, transparent membrane (conjunctiva), which runs to the edge of the cornea. The conjunctiva also covers the moist back surface of the eyelids and eyeballs.



How light enters the eye


Light enters the eye through the cornea, the clear, curved layer in front of the iris and pupil. The cornea serves as a protective covering for the front of the eye and also helps focus light on the retina at the back of the eye. After passing through the cornea, light travels through the pupil (the black dot in the middle of the eye). The iris—the circular, colored area of the eye that surrounds the pupil—controls the amount of light that enters the eye. The pupil dilates (enlarges) and constricts (shrinks) like the aperture of a camera lens as the amount of light in the immediate surroundings changes. The iris allows more light into the eye when the environment is dark and allows less light into the eye when the environment is bright. The size of the pupil is controlled by the action of the pupillary sphincter muscle and dilator muscle.



Behind the iris sits the lens. By changing its shape, the lens focuses light onto the retina. Through the action of small muscles (called the ciliary muscles), the lens becomes thicker to focus on nearby objects and thinner to focus on distant objects.



Líffræði augans


Almennn líffræði augans


Ytri breiða augans samanstendur af tiltölulega þykku, hvítu lagi sem kallast augnvökvi(eða hvíta augans). Fyrir framan vökvann, á svæðinu sem er varið með augnlokunum, er hvítan varin með þunnri, glærri himnu(lita) sem rennur til horna glærunnar. Litan hylur einnig rakt yfirborð augnlokanna og augans.


Hvernig ljós berst til augans


Ljós berst til augans í gegn um glæruna, glæra, bogna lagið fyrir framan augnhólfið og augasteininn. Hlutverk glærunnar er að vernda fremsta hluta augans og hjálpar einnig ljósinu að einbeita á sjónuna sem er aftast í auganu. Eftir að hafa farið í gegn um glæruna, ljós berst í gegn um augasteininn(svarti punkturinn sem er í miðju auganu). Litan-hringlótti, litaði hluti augans sem umlykur augasteininn-stjórnar hversu mikið ljós berst í gegn um augað. Augasteinninn víkkar og minnkar eins og linsa á myndavél sem breytist eftir þvi sem ljós í umhverfinu breytist. Litan leyfa meira ljósi að berast til augans þegar umhverfi er dimmt og leyfir minna ljós þegar umhverfi er bjart. Stærð augasteinsins er stjórnað með hreyfingum beltisþræða og brábauga.


Bakvið lituna er linsan. Með því að breyta lögun sinni, einbeitir linsan ljósinu inn til sjónunnar. Með hreyfingum lítilla vöðva(sem kallast beltisþræðir), verður linsan þykkari þegar hún einbeitir sér að hlutum sem eru nálægir og verður þynnri þegar hún einbeitir sér að hlutum sem eru í meiri fjarlægð.



Why I chose this paragraph

I chose to talk about the eye and how light enters it because I wrote about the structure of the ear before and I wanted to know more about the organs in the head. I used an icelandic webpage to help me find the words of the parts in the eye in icelandic.

An interview with a biologist

On Monday, the 27. of April I got the chance to interview my cousin who gratuated from Háskóli Íslands as a biologist majouring in studies of the microorganisms.

My questions for her were:
1. What intrigued you about biology?
2. Why did you decide to persue a career in biology?
3. Is the education hard in collage when you study biology?
4. Did you get a job right away after collage and was it in the field you choose.
5. Why microorganisms?

I summarized the interview into a short paragraph using her answers to my questions:

Lena: I have always been facinated about biology, even when I was in middle school my favourit lesson that I can remember was learning about the bones and veins and the whole human body. Through out my time in FSu I always put most of my effort into biology classes and I was always determined to learn more from theese classes. After Fsu the only smart thing in the situation was to carry on studying biology. The education at HÍ was and still is very difficult and can be very hard if you aren´t interrested in it that much. After collage I did get a job right away with a company that tested the effectsof particular drugs on microorganisms but now I work for another company where I test the effects of many different things on microorganisms. I probably choose microorganisms because it was one of the first things I learnt in biology and it sort of stuck through the years. I have always found it most interresting.

Why I choose to interview this person:

Lena Valdimarsdóttir
I choose to interview Lena because she is my cousin and I know that she is very hard working and interrested in the field. I knew that she would be the perfect person to answer my questions.

The animations of unseeable biology by Drew Berry

I wanted to share with you a video from TED.com about the unseeable biology of the world. I found this video to be very interesting mainly because I had just interviewed my cousin who studies theese kind of things and I wanted to know more about them

Summary:
A mister Drew Berry talks about the animations of the unseeable biology. He first tries to explain what he means by unseealbe and takes examples such as the first telescope that Galileo Galilei used to look at the moon up close and how this revolutionized how we could see and understand the things we cant see with the naked eye. Of course he mentiones Charles Darwin also and his discovery of how life beginned. Then he starts to talk about how he didn´t find some scientist´s animations of the unseeable biology to be understandable by anyone. He then takls about how some scientists have made an accurate drawing of the unseeable biology without it beeing complicated. After seeing this lecture you really understand how important animations of the little things we cant see are and how they have to be accurate, perfect and understandable for anyone.

If you want to see the lecture yourself you can click on this website:

http://www.ted.com/talks/drew_berry_animations_of_unseeable_biology#t-191174

How butterflies self medicate

Today I watched an interresting video on TED.com. It was a lecture about how butterflies self medicate and how we humans can learn from them. What intrigued me about this was the title. It seemed very interresting and I wanted to know more about it.

I drew up a quick summary about the video in case you don´t have time to watch it.
The biologist Jaap de Roode talks about how humans are struggling when they are fighting disises. He then starts talking about how many animals can treat themselfs of disises and how, even insects, are evolving more and more when it comes to self medication. As an example Japp de Roode talks about the Monarch butterfly. The Monarch butterfly can take chemicals from the environment and use them to treat themselfs and get rid of parasites. But the real reson they can self medicate is that mother butterflies lay theyr eggs on healthier plants. This was tested as he put butterflies into a room where there were plants their larva could use to take up chemicals that can benifit them and then there were plants where they would be no help to the larva. So the mother butterflies would lay 68 % of their eggs on medicine plants and only 32 % on the non-medicine plants, therefore creating a better future for their offspring.

If you do, however, have the time to see the video, you can click this link:
http://www.ted.com/talks/jaap_de_roode_how_butterflies_self_medicate#t-291616

How a fly flies

A lecture on TED.com really captured my eye today and I wanted to share it with you. The lecture is called "How a fly flies" and is presented by Michael Dickinson. I decided to share this with you because the flying of incects really is one of the most important things in the biology world, in Michael´s oppinion.

I wrote a summary along watching the video and I´m also going to post that in here.
Michael Dickinson talks about how flying of incects is very comlicated and needs to be studied as much as possible. He talks about the similarities between humans and fruit flies that have been proven to be many. However, he doesn´t want to talk about the similarities in this lecture but, the differences between the two species. First of all he talks about how much faster the fly´s brain is to recieve and react to messages it is getting from the environment than a human brain. He then talks about how the brain of the fly sends out neurotic messages to make the fly flap it´s wings in a sertain direction so that it is most convinient for them to stay in the air. Flies have two types of muscles that also help them stay in the air, that are the power muscles and the controling muscles that are a lot smaller. From that he talks about how many neurons are in a fly´s brain and a human brain and although the human brain has many more neurons he proposes to us that the brain of a fly is no were near less important or less complicated than the brain of a human.

This lecture is really interresting and if you want to see it click this link:
http://www.ted.com/talks/michael_dickinson_how_a_fly_flies#t-623189