Biology

[equalsmcsquared.livejournal.com]

Help yourselves to the snacks and please sign the roll sheet. As was previously announced, there will be no class on Thursday.

Today, we will be discussing the components of human blood.

Normally, 7-8% of human body weight is from blood. This essential fluid carries out the critical functions of transporting oxygen and nutrients to our cells and getting rid of carbon dioxide and other waste products. In addition, it plays a vital role in our immune system and in maintaining a relatively constant body temperature. Blood is a highly specialized tissue composed of many different kinds of components. Four of the most important ones are red cells, white cells, platelets, and plasma. All humans produce these blood components--there are no populational or regional differences.

Red cells, or erythrocytes are relatively large microscopic cells without nuclei. In this latter trait, they are similar to the primitive prokaryotic cells of bacteria. Red cells normally make up 40-50% of the total blood volume. They transport oxygen from the lungs to all of the living tissues of the body and carry away carbon dioxide. The red cells are produced continuously in our bone marrow from stem cells. Hemoglobin is the gas transporting protein molecule that makes up 95% of a red cell. Each red cell has about 270,000,000 iron-rich hemoglobin molecules. People who are anemic generally have a deficiency in red cells. The red color of blood is primarily due to oxygenated red cells.

Comments

[lovelylana.livejournal.com]

Lana signs in and listens to the lecture. She finds herself thinking about just how much blood Shep lost on Saturday and how dangerous that could have been.

[fates_jaye]

Jaye signs in. She understands all the words- almost- but not so much the context.

[demonbelthazor]

Belthazor signed in. While blood would ordinarly hold his attention, today he seemed kind of out of it.

[apocalypsesoon.livejournal.com]

John signs in, and glances around every once in a while to see who else is here.

[12parseckessel.livejournal.com]

Han signs in. His notes are impeccable, but in his mind's eye, he's back in the park and the tourniquet isn't working, and the sleeve and shirt aren't enough.

[lovelylana.livejournal.com]

"Hey, Han. I saw Shep last night. He's doing pretty well and is supposed to come home today. How are you doing?"

[12parseckessel.livejournal.com]

"Hey Lana. I'm okay." Every line on his face says this is a lie.
"So, I'm not okay. Never made anyone bleed like that before. Just glad Shep wasn't number four on my body-count, you know?"

He looks back at his readout. "I'm just going to have to learn all this over break. Blood's really interesting stuff, but not when you spent a fair chunk of Saturday covered in it."

He shrugs. "Look, I'm done until Business class. You want to go to the Perk or something?"

[lovelylana.livejournal.com]

"You know, I'd like that," Lana says. "We could talk about things, maybe get some of it behind us."

[12parseckessel.livejournal.com]

Han shoulders his bookbag and leads the way (http://www.livejournal.com/community/fandomtownies/383149.html)

[iwasawesome.livejournal.com]

Lilly signs in, and pays attention for once. She grabs a snack, and realizes that she's going to be studying a lot over break.

[courier-gavin.livejournal.com]

Jake signs in. He's a little distracted, but listening.

[alchemic-bean.livejournal.com]

Edward signs in and sits down, wincing slightly at the lecture. That brings back unpleasant memories....

[swerval_zero]

Zero signs in and listens to the lecture. Huh, a lecture on blood. How appropriate.

[maias-notebook.livejournal.com]

Maia signed in, sitting quietly at her desk she writes notes not really paying attention to anyone else in the class

[sogothcally.livejournal.com]

Cally signs in, and listens to the lecture attentively.

[mycanonhatesme]

Chloe signs in, and takes notes on as much as she understands.

[psycho-barbie.livejournal.com]

Callisto signs in, and takes notes throughout the lecture.

[notcalledlizzie.livejournal.com]

Elizabeth signs in and tries not to sneeze too many times throughout the lecture.

Stupid cold